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{{Short description|Genetic disorder}} | |||
{{DiseaseDisorder infobox | | |||
{{Pp-move}} | |||
Name = Down syndrome | | |||
{{Pp-semi-indef|small=yes}} | |||
ICD10 = {{ICD10|Q|90||q|90}} | | |||
{{cs1 config|name-list-style=vanc}} | |||
ICD9 = {{ICD9|758.0}} | | |||
{{Good article}} | |||
ICDO = | | |||
{{Infobox medical condition | |||
Image = Drill.jpg <!--- Do not change this picture without discussing it in the Down syndrome discussion page. Because of continued vandalism, pictures will be immediately reverted. ---> | | |||
|
| name = Down syndrome | ||
| image = Boy with Down Syndrome.JPG <!-- Do not change this picture without discussing it in the Down syndrome discussion page. Because of continued vandalism, pictures will be immediately reverted. --> | |||
OMIM = 190685 | | |||
| alt = Eight year old boy with Down syndrome | |||
OMIM_mult = | | |||
| caption = An eight-year-old boy from ] displaying characteristic facial features of Down syndrome | |||
MedlinePlus = 000997 | | |||
| field = ], ] | |||
eMedicineSubj = ped | | |||
| synonyms = Down's syndrome, Down's, trisomy 21 | |||
eMedicineTopic = 615 | | |||
| symptoms = Delayed ], characteristic physical features, mild to moderate ]<ref name=Wei2010/> | |||
DiseasesDB = 3898 | | |||
| complications = | |||
Cause = Trisomy 21 | | |||
| onset = Mostly at conception, rarely after ]<ref name=NIH2014Cause/> | |||
| duration = Lifelong | |||
| causes = Third copy of ]<ref name=Patt2009/> | |||
| risks = ], prior affected child<ref name=Mor2002/><ref>{{cite web |title=Down syndrome – Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/down-syndrome/symptoms-causes/syc-20355977 |website =Mayo Clinic |access-date=17 March 2019 |language=en}}</ref> | |||
| diagnosis = ], ]<ref name=NIH2014Diag/> | |||
| differential = | |||
| prevention = | |||
| treatment = Physical therapy, Occupational therapy, Speech therapy, Educational support, Supported work environment<ref name=Roi2003/><ref name=NADS/> | |||
| medication = | |||
| prognosis = Life expectancy 50 to 60 years (developed world)<ref name=Malt2013/><ref name=Nelson2011/> | |||
| frequency = 5.4 million (0.1%)<ref name=Wei2010/><ref name=GBD2015Pre/> | |||
| named after = ] | |||
}} | }} | ||
'''Down syndrome''' (also '''Down's syndrome''') or '''trisomy 21''' is a ] resulting from the presence of all or part of an extra ]. Down syndrome is characterized by a combination of major and minor abnormalities of body structure and function. Among features present in nearly all cases are impairment of learning and physical growth, and a recognizable facial appearance usually identified at birth. It is named after ], the British doctor who first described it in ]. | |||
<!-- Definition and symptoms --> | |||
Children with Down syndrome have lower than average cognitive ability, normally ranging from mild to moderate retardation. The common physical features of Down syndrome also appear in people with a standard set of chromosomes. They include ] (a single crease across one or both palms), almond shaped eyes, shorter limbs, speech impairment, and enlarged tongue. In addition, health concerns for children with Down syndrome include a higher risk for congenital heart defects, gastroesophageal reflux disease, recurrent ], ], and ] disfunctions. | |||
'''Down syndrome''' or '''Down's syndrome''',<ref name=Smith-2011/> also known as '''trisomy 21''', is a ] caused by the presence of all or part of a third copy of ].<ref name=Patt2009>{{cite journal | vauthors = Patterson D | title = Molecular genetic analysis of Down syndrome | journal = Human Genetics | volume = 126 | issue = 1 | pages = 195–214 | date = July 2009 | pmid = 19526251 | doi = 10.1007/s00439-009-0696-8 | s2cid = 10403507 |issn = 0340-6717}}</ref> It is usually associated with ] delays, mild to moderate ], and characteristic physical features.<ref name="Wei2010">{{cite journal | vauthors = Weijerman ME, de Winter JP | title = Clinical practice. The care of children with Down syndrome | journal = European Journal of Pediatrics | volume = 169 | issue = 12 | pages = 1445–1452 | date = December 2010 | pmid = 20632187 | pmc = 2962780 | doi = 10.1007/s00431-010-1253-0 }}</ref><ref>{{Cite web |title=What are common symptoms of Down syndrome? |url=https://www.nichd.nih.gov/health/topics/down/conditioninfo/symptoms |access-date=28 March 2023 |website=NIH Eunice Kennedy Shriver National Institute of Child Health and Human Development|date=31 January 2017 }}</ref> | |||
<!-- Cause and diagnosis --> | |||
], screening for common problems, such as ] functioning, medical treatment where indicated, a conducive family environment, vocational training, ''etc''., can improve the overall development of children with Down syndrome. Experience with children with Down syndrome shows that while some genetic limitations cannot be overcome, education and proper care can produce progress whatever the starting point. | |||
The parents of the affected individual are usually ] normal.<ref name=Steph2010>{{cite book| vauthors = Hammer GD |chapter=Pathophysiology of Selected Genetic Diseases | veditors = McPhee SJ |title=Pathophysiology of disease: an introduction to clinical medicine|year=2010|publisher=McGraw-Hill Medical|location=New York|isbn=978-0-07-162167-0|pages=Chapter 2|edition=6th}}</ref> The incidence of the syndrome increases with the age of the mother, from less than 0.1% for 20-year-old mothers to 3% for those of age 45.<ref name=Mor2002/> It is believed to occur by chance, with no known behavioral activity or environmental factor that changes the probability.<ref name="NIH2014Cause">{{cite web |date=2014-01-17 |title=What causes Down syndrome? |url=https://www.nichd.nih.gov/health/topics/down/conditioninfo/Pages/causes.aspx |url-status=live |archive-url=https://web.archive.org/web/20160105082310/https://www.nichd.nih.gov/health/topics/down/conditioninfo/pages/causes.aspx |archive-date=5 January 2016 |access-date=6 January 2016 |work=National Institute of Child Health and Human Development |publisher=U.S. National Institutes of Health}}</ref> Usually, babies get 23 chromosomes from each parent for a total of 46, whereas in Down syndrome, a third 21st chromosome is attached.<ref name=":2">{{Cite web |title=The Genetics of Down's Syndrome |url=http://www.intellectualdisability.info/conditions-associated-with-intellectual-disability/articles/the-genetics-of-downs-syndrome |access-date=2023-04-01 |website=www.intellectualdisability.info |language=en}}</ref> The extra chromosome is provided at conception as the egg and sperm combine.<ref>{{Cite web | work = National Association for Down Syndrome | title = Facts About Down Syndrome |url=https://www.nads.org/resources/facts-about-down-syndrome/ |access-date=2023-04-01 |language=en-US}}</ref> In 1–2% of cases, the additional chromosome is added in the embryo stage and only impacts some of the cells in the body; this is known as ].<ref>{{Cite web |title=LSUHSC School of Medicine |url=https://www.medschool.lsuhsc.edu/genetics/down_syndrome.aspx |access-date=2023-04-01 |website=www.medschool.lsuhsc.edu}}</ref><ref name=":2" /> ] is another rare type.<ref name="CDC" /><ref name=":4">{{Cite web |title=About Down Syndrome {{!}} National Down Syndrome Society (NDSS) |url=https://ndss.org/about |access-date=2023-03-28 |website=ndss.org |language=en}}</ref> Down syndrome can be identified during pregnancy by ], followed by diagnostic testing, or after birth by direct observation and ].<ref name=NIH2014Diag>{{cite web|title=How do health care providers diagnose Down syndrome?|url=https://www.nichd.nih.gov/health/topics/down/conditioninfo/Pages/diagnosed.aspx|website=Eunice Kennedy Shriver National Institute of Child Health and Human Development|access-date=4 March 2016|date=2014-01-17|url-status=live|archive-url=https://web.archive.org/web/20160307142500/https://www.nichd.nih.gov/health/topics/down/conditioninfo/Pages/diagnosed.aspx|archive-date=7 March 2016}}</ref> Since the introduction of screening, Down syndrome ] are often ] (rates varying from 50 to 85% depending on maternal age, gestational age, and maternal race/ethnicity).<ref>{{cite journal | vauthors = Seror V, L'Haridon O, Bussières L, Malan V, Fries N, Vekemans M, Salomon LJ, Ville Y | display-authors = 6 | title = Women's Attitudes Toward Invasive and Noninvasive Testing When Facing a High Risk of Fetal Down Syndrome | journal = JAMA Network Open | volume = 2 | issue = 3 | pages = e191062 | date = March 2019 | pmid = 30924894 | pmc = 6450316 | doi = 10.1001/jamanetworkopen.2019.1062 }}</ref><ref name=Nat2012>{{cite journal | vauthors = Natoli JL, Ackerman DL, McDermott S, Edwards JG | title = Prenatal diagnosis of Down syndrome: a systematic review of termination rates (1995-2011) | journal = Prenatal Diagnosis | volume = 32 | issue = 2 | pages = 142–153 | date = February 2012 | pmid = 22418958 | doi = 10.1002/pd.2910 | doi-access = free }}</ref><ref name=Mans1999>{{cite journal | vauthors = Mansfield C, Hopfer S, Marteau TM | title = Termination rates after prenatal diagnosis of Down syndrome, spina bifida, anencephaly, and Turner and Klinefelter syndromes: a systematic literature review. European Concerted Action: DADA (Decision-making After the Diagnosis of a fetal Abnormality) | journal = Prenatal Diagnosis | volume = 19 | issue = 9 | pages = 808–812 | date = September 1999 | pmid = 10521836 | doi = 10.1002/(sici)1097-0223(199909)19:9<808::aid-pd637>3.0.co;2-b | publisher = Wiley | s2cid = 29637272 | url = https://escholarship.org/uc/item/1rj1h8q6 }}</ref> | |||
<!-- Management and prognosis --> | |||
==Characteristics== | |||
As of 2024, there is no known cure for Down syndrome.<ref>{{cite web|title=Down Syndrome: Other FAQs|url=https://www.nichd.nih.gov/health/topics/down/conditioninfo/Pages/faqs.aspx|access-date=6 January 2016|date=2014-01-17|url-status=live|archive-url=https://web.archive.org/web/20160106221704/https://www.nichd.nih.gov/health/topics/down/conditioninfo/Pages/faqs.aspx|archive-date=6 January 2016}}</ref> Education and proper care have been shown to provide better ].<ref name=Roi2003>{{cite journal | vauthors = Roizen NJ, Patterson D | title = Down's syndrome | journal = Lancet | volume = 361 | issue = 9365 | pages = 1281–1289 | date = April 2003 | pmid = 12699967 | doi = 10.1016/S0140-6736(03)12987-X | type = Review | s2cid = 33257578 }}</ref> Some children with Down syndrome are educated in typical school classes, while others require more ].<ref name=NADS/> Some individuals with Down syndrome graduate from ], and a few attend ].<ref name=Stein2011>{{cite book| vauthors = Steinbock B | chapter = The Risk of Transmitting Disease or Disability |title=Life before birth the moral and legal status of embryos and fetuses |year=2011|publisher=Oxford University Press|location=Oxford|isbn=978-0-19-971207-6|page=222| chapter-url = https://books.google.com/books?id=1ehYs43QBYAC&pg=PA222 |edition=2nd|url-status=live|archive-url=https://web.archive.org/web/20170123082359/https://books.google.com/books?id=1ehYs43QBYAC&pg=PA222|archive-date=2017-01-23}}</ref> In adulthood, about 20% in the United States do some paid work,<ref name=US2013>{{cite news| vauthors = Szabo L |title=Life with Down syndrome is full of possibilities |url=https://www.usatoday.com/story/news/nation/2013/05/01/life-down-syndrome-improving/2054953/|access-date=7 February 2014|newspaper=USA Today|date=May 9, 2013|url-status=live|archive-url=https://web.archive.org/web/20140108012711/http://www.usatoday.com/story/news/nation/2013/05/01/life-down-syndrome-improving/2054953/|archive-date=8 January 2014}}</ref> with many requiring a sheltered work environment.<ref name=NADS>{{cite web |title=Facts About Down Syndrome |publisher=National Association for Down Syndrome |url=http://www.nads.org/pages_new/facts.html |access-date=20 March 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120403162637/http://www.nads.org/pages_new/facts.html |archive-date=3 April 2012 }}</ref> Caretaker support in financial and legal matters is often needed.<ref name=Nelson2011/> Life expectancy is around 50 to 60 years in the ], with proper health care.<ref name=Malt2013/><ref name=Nelson2011>{{cite book| vauthors = Kliegma RM |title=Nelson textbook of pediatrics|year=2011|publisher=Saunders|location=Philadelphia|isbn=978-1-4377-0755-7|pages=Chapter 76.2|edition=19th|chapter=Down Syndrome and Other Abnormalities of Chromosome Number}}</ref> Regular ] for health issues common in Down syndrome is recommended throughout the person's life.<ref name="Malt2013">{{cite journal | vauthors = Malt EA, Dahl RC, Haugsand TM, Ulvestad IH, Emilsen NM, Hansen B, Cardenas YE, Skøld RO, Thorsen AT, Davidsen EM | display-authors = 6 | title = Health and disease in adults with Down syndrome | journal = Tidsskrift for den Norske Laegeforening | volume = 133 | issue = 3 | pages = 290–294 | date = February 2013 | pmid = 23381164 | doi = 10.4045/tidsskr.12.0390 | doi-access = free }}</ref> | |||
Individuals with Down syndrome may have some or all of the following physical characteristics:<ref>{{cite web| url=http://healthlibrary.epnet.com/GetContent.aspx?token=94e729bf-2a24-406f-8083-f1484720ce65&chunkiid=11897| title=Down syndrome| author=Debra Wood| date=2005| accessdate=2006-06-30}}</ref> oblique eye fissures with small skin folds on the inner corner of the eyes, ], flat nasal bridge, ], large and protruding tongue, short neck, white spots on the ], excessive flexibility in joints, ], excessive space between large and second toe, and fifth finger with one ] furrow instead of two. In additional to observable physical characteristics, individuals with Down syndrome may have some medical concerns, ]. | |||
<!--Epidemiology and history --> | |||
Most children with Down syndrome have ] in the mild (IQ 50–70) to moderate range (IQ 35–50),<ref>{{cite web|url=http://www.keepkidshealthy.com/welcome/conditions/downsyndrome.html| title=Keep Kids Healthy article on Down syndrome| accessed=2006-04-10}}</ref> with scores for children with Mosaic Down syndrome some 10–30 points higher.<ref>{{cite web| author=Strom, C|url=http://www.mosaicdownsyndrome.com/faqs.htm| title=FAQ from Mosaic Down Syndrome Society| accessdate=2006-06-03}}</ref> Emotional and social abilities follow a more normal path, moderated by whatever ] the child may have. | |||
Down syndrome is the most common ],<ref name="Martínez-Espinosa">{{cite journal | vauthors = Martínez-Espinosa RM, Molina Vila MD, Reig García-Galbis M | title = Evidences from Clinical Trials in Down Syndrome: Diet, Exercise and Body Composition | journal = International Journal of Environmental Research and Public Health | volume = 17 | issue = 12 | page = 4294 | date = June 2020 | pmid = 32560141 | pmc = 7344556 | doi = 10.3390/ijerph17124294 | doi-access = free }}</ref> occurring in about 1 in 1,000 babies born worldwide,<ref name=Wei2010/> and one in 700 in the US.<ref name="CDC"/> In 2015, there were 5.4 million people with Down syndrome globally, of whom 27,000 died, down from 43,000 deaths in 1990.<ref name=GBD2015Pre>{{cite journal | vauthors = ((GBD 2015 Disease and Injury Incidence and Prevalence Collaborators)) | title = Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015 | journal = Lancet | volume = 388 | issue = 10053 | pages = 1545–1602 | date = October 2016 | pmid = 27733282 | pmc = 5055577 | doi = 10.1016/S0140-6736(16)31678-6 }}</ref><ref name=GBD2015De>{{cite journal | vauthors = ((GBD 2015 Mortality and Causes of Death Collaborators)) | title = Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980-2015: a systematic analysis for the Global Burden of Disease Study 2015 | journal = Lancet | volume = 388 | issue = 10053 | pages = 1459–1544 | date = October 2016 | pmid = 27733281 | pmc = 5388903 | doi = 10.1016/s0140-6736(16)31012-1 }}</ref><ref name="GDB2013">{{cite journal | vauthors = ((GBD 2013 Mortality and Causes of Death Collaborators)) | title = Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013 | journal = Lancet | volume = 385 | issue = 9963 | pages = 117–171 | date = January 2015 | pmid = 25530442 | pmc = 4340604 | doi = 10.1016/S0140-6736(14)61682-2 }}</ref> The syndrome is named after British physician ], who fully described it in 1866.<ref name=Hick2012>{{cite journal | vauthors = Hickey F, Hickey E, Summar KL | title = Medical update for children with Down syndrome for the pediatrician and family practitioner | journal = Advances in Pediatrics | volume = 59 | issue = 1 | pages = 137–157 | year = 2012 | pmid = 22789577 | doi = 10.1016/j.yapd.2012.04.006 | publisher = Elsevier BV }}</ref> Some aspects were described earlier by French psychiatrist ] in 1838 and French physician ] in 1844.<ref name=Evans2009p12>{{cite book| vauthors = Evans-Martin FF |title=Down syndrome|year=2009|publisher=Chelsea House|location=New York|isbn=978-1-4381-1950-2|page=|url=https://archive.org/details/downsyndrome0000evan|url-access=registration}}</ref> The genetic cause was discovered in 1959.<ref name=Hick2012/> | |||
{{TOC limit|3}} | |||
== |
==Signs and symptoms== | ||
] | |||
English physician ] first characterized Down syndrome as a distinct form of mental retardation in 1862, and in a more widely published report in 1866 entitled "Observations on an ethnic classification of idiots".<ref>{{cite journal| author=Down, J.L.H.| year=1866| title=Observations on an ethnic classification of idiots| journal=Clinical Lecture Reports, London Hospital| volume=3| pages=259-262| url=http://www.neonatology.org/classics/down.html| accessdate=2006-07-14}} For a history of the disorder, see {{cite web| last=Conor| first=Ward |url =http://www.intellectualdisability.info/values/history_DS.htm| title =John Langdon Down and Down's syndrome (1828 - 1896)| accessdate =2006-06-02}}</ref> Due to his perception that children with Down syndrome shared physical facial similarities (]s) with those of ], Down used the terms ''mongolism'' and ''mongolian idiocy''.<ref>{{cite journal | Author =Conor, W.O.| year =1999| title =John Langdon Down: The Man and the Message| journal =Down Syndrome Research and Practice| volume =6| issue =1| pages =19-24| url =http://www.down-syndrome.info/library/periodicals/dsrp/06/1/019/DSRP-06-1-019-EN-GB.htm| accessdate =2006-06-02}}</ref> ] was a medical term used at that time to refer to a severe degree of intellectual impairment. | |||
Those with Down syndrome nearly always have physical and intellectual disabilities.<ref>{{cite book | veditors = Faragher R, Clarke B | chapter = Introduction | title=Educating Learners with Down Syndrome: Research, theory, and practice with children and adolescents | publisher=Taylor & Francis | year=2013 | isbn=978-1-134-67335-3 | chapter-url=https://books.google.com/books?id=0Y20AQAAQBAJ&pg=PA5 | page=5 | url-status=live | archive-url=https://web.archive.org/web/20170123082416/https://books.google.com/books?id=0Y20AQAAQBAJ&lpg=PR11&pg=PA5 | archive-date=2017-01-23}}</ref> As adults, their mental abilities are typically similar to those of an 8- or 9-year-old.<ref name=Malt2013/> At the same time, their emotional and social awareness is very high.<ref>{{cite journal | vauthors = Hippolyte L, Iglesias K, Van der Linden M, Barisnikov K | title = Social reasoning skills in adults with Down syndrome: the role of language, executive functions and socio-emotional behaviour | journal = Journal of Intellectual Disability Research | volume = 54 | issue = 8 | pages = 714–726 | date = August 2010 | pmid = 20590998 | doi = 10.1111/j.1365-2788.2010.01299.x }}</ref> They can have ]<ref name=Steph2010/> and generally reach ] at a later age.<ref name=Nelson2011/> They have an increased risk of a number of health concerns, such as ], ], ], and ]s.<ref name=Hick2012/> | |||
{| class="wikitable" | |||
By the 20<sup>th</sup> century, "mongolian idiocy" had become the most recognizable form of mental retardation. Most people with it were ]. Few of the associated medical problems were treated, and most died in infancy or early adult life. With the rise of the ] movement, a number of states (33 of the 48 United States) and countries began programs of involuntary sterilization of individuals with Down syndrome and comparable degrees of disability. The ultimate expression of this type of public policy was the ] ] program ] begun in 1940. Court challenges and public revulsion at the nature of these programs led to discontinuation or repeal of such programs during the decades after World War II. Even voluntary institutionalization of children with Down syndrome has become rare in Western countries. | |||
|- | |||
!Characteristics | |||
!Percentage | |||
!Characteristics | |||
!Percentage | |||
|- | |||
|Mental impairment | |||
| 99%<ref>{{cite book | vauthors = Johnston JM, Smyth MD, McKinstry RC | chapter = Basics of Neuroimaging in Pediatric Epilepsy | veditors = Pellock JM, Bourgeois BF, Dodson WE, Nordli Jr DR, Sankar R |title=Pediatric epilepsy diagnosis and therapy|year=2008|publisher=Demos Medical Pub.|location=New York|isbn=978-1-934559-86-4|page=Chapter 67| chapter-url=https://books.google.com/books?id=47fckyBY2XwC&pg=PA216-IA51|edition=3rd|url-status=live|archive-url=https://web.archive.org/web/20170123082424/https://books.google.com/books?id=47fckyBY2XwC&pg=PA216-IA51|archive-date=2017-01-23}}</ref> | |||
|Abnormal teeth | |||
| 60%<ref name=Eps2007>{{cite book| vauthors = Epstein CJ |title=The consequences of chromosome imbalance: principles, mechanisms, and models |year=2007 |publisher=Cambridge University Press |location=Cambridge |isbn=978-0-521-03809-6 |pages=255–256 |url=https://books.google.com/books?id=6SzKSM1t9MYC&pg=PA255 |url-status=live|archive-url=https://web.archive.org/web/20170123082736/https://books.google.com/books?id=6SzKSM1t9MYC&pg=PA255|archive-date=2017-01-23}}</ref> | |||
|- | |||
|Stunted growth | |||
| 90%<ref>{{cite book | vauthors = Marion RW, Samanich JN | chapter = Genetics |title=Pediatrics for medical students|year=2012|publisher=Wolters Kluwer Health/Lippincott Williams & Wilkins|location=Philadelphia|isbn=978-0-7817-7030-9|page=259| chapter-url = https://books.google.com/books?id=z0ohenkQrY0C&pg=PA259 | veditors = Bernstein D, Shelov SP |edition=3rd|url-status=live|archive-url=https://web.archive.org/web/20170123082701/https://books.google.com/books?id=z0ohenkQrY0C&pg=PA259|archive-date=2017-01-23}}</ref> | |||
|] | |||
| 60%<ref name=Steph2010/> | |||
|- | |||
|] | |||
| 90%<ref>{{cite book| vauthors = Bertoti DB, Smith DE | chapter = Mental Retardation: Focus on Down Syndrome | veditors = Tecklin JS |title=Pediatric physical therapy|year=2008|publisher=Lippincott Williams & Wilkins|location=Philadelphia|isbn=978-0-7817-5399-9|page=380| chapter-url = https://books.google.com/books?id=YX8pztQHX0MC&pg=PA380|edition=4th|url-status=live|archive-url=https://web.archive.org/web/20170123082243/https://books.google.com/books?id=YX8pztQHX0MC&pg=PA380|archive-date=2017-01-23}}</ref> | |||
|Shortened hands | |||
| 60%<ref name=Eps2007/> | |||
|- | |||
| Increased skin on back of neck | |||
| 80%<ref name=Hick2012/> | |||
|Short neck | |||
| 60%<ref name=Eps2007/> | |||
|- | |||
|] | |||
| 80%<ref name=Dom2007>{{cite book| veditors = Domino FJ |title=The 5-minute clinical consult 2007|year=2007|publisher=Lippincott Williams & Wilkins|location=Philadelphia|isbn=978-0-7817-6334-9|page=392|url=https://books.google.com/books?id=WSUMZ5ECEbMC&pg=PA392|edition=2007|url-status=live|archive-url=https://web.archive.org/web/20170123082614/https://books.google.com/books?id=WSUMZ5ECEbMC&pg=PA392|archive-date=2017-01-23}}</ref> | |||
|] | |||
| 60%<ref name=Hick2012/> | |||
|- | |||
|Narrow ] | |||
| 76%<ref name=Eps2007/> | |||
|] | |||
| 57%<ref name=Steph2010/> | |||
|- | |||
|] | |||
| 75%<ref name=Steph2010/> | |||
|] in the ] | |||
| 56%<ref name=Steph2010/> | |||
|- | |||
|Flexible ligaments | |||
| 75%<ref name=Steph2010/> | |||
|] | |||
| 53%<ref name=Steph2010/> | |||
|- | |||
|]<ref name=Perk2009>{{cite journal | vauthors = Perkins JA | title = Overview of macroglossia and its treatment | journal = Current Opinion in Otolaryngology & Head and Neck Surgery | volume = 17 | issue = 6 | pages = 460–465 | date = December 2009 | pmid = 19713845 | doi = 10.1097/moo.0b013e3283317f89 | s2cid = 45941755 }}</ref> | |||
| 75%<ref name=Dom2007/> | |||
|Protruding tongue | |||
| 47%<ref name=Eps2007/> | |||
|- | |||
|Abnormal ] | |||
| 70%<ref name=Hick2012/> | |||
|] | |||
| 40%<ref name=Eps2007/> | |||
|- | |||
|Flattened nose | |||
| 68%<ref name=Steph2010/> | |||
|] | |||
| ≈35%<ref name=Wei2010/> | |||
|- | |||
|Separation of first and second toes | |||
| 68%<ref name=Eps2007/> | |||
|] | |||
| 20%<ref>{{cite book| vauthors = Wilson GN, Cooley WC |title=Preventive management of children with congenital anomalies and syndromes.|year=2006|publisher=Cambridge University Press|location=Cambridge|isbn=978-0-521-61734-5|page=190|url=https://books.google.com/books?id=k0AHKmax9gwC&pg=PA190|edition=2nd | url-status=live|archive-url=https://web.archive.org/web/20170123082838/https://books.google.com/books?id=k0AHKmax9gwC&pg=PA190|archive-date=2017-01-23}}</ref> | |||
|} | |||
===Physical=== | |||
Until the middle of the 20th century, the cause of Down syndrome remained unknown, although the presence in all races, the association with older maternal age, and the rarity of recurrence had been noticed. Standard medical texts assumed it was due to a combination of inheritable factors which had not been identified. There was some expert opinion that it might result from trauma occurring during pregnancy.<ref>{{cite book| author=Warkany, J.| title=Congenital Malformations| location=Chicago| publisher=Year Book Medical Publishers, Inc.| date=1971| pages=313-314| id=ISBN 0-8151-9098-0}}</ref> | |||
] | |||
People with Down syndrome may have these physical characteristics: a ], ]s, ], a flat ], and a protruding tongue. A protruding tongue is caused by low tone and weak facial muscles, and often corrected with myofunctional exercises.<ref>{{Cite book | vauthors = Kumin L |title=Resource Guide to Oral Motor Skill Difficulties in Children with Down Syndrome |publisher=Loyola College of Maryland |location= | url = https://www.ndsccenter.org/wp-content/uploads/OralMotor.pdf }}</ref> Some characteristic airway features can lead to ] in around half of those with Down syndrome.<ref name=Hick2012/> Other common features include: excessive joint flexibility, extra space between ] and second toe, a ], and short fingers.<ref name=Eps2007/><ref name=Dom2007/> | |||
Instability of the ] occurs in about 1–2%.<ref>{{cite journal | vauthors = Bull MJ, Trotter T, Santoro SL, Christensen C, Grout RW, Burke LW, Berry SA, Geleske TA, Holm I, Hopkin RJ, Introne WJ, Lyons MJ, Monteil DC, Scheuerle A, Stoler JM, Vergano SA, Chen E, Hamid R, Downs SM, Grout RW, Cunniff C, Parisi MA, Ralston SJ, Scott JA, Shapira SK, Spire P | display-authors = 6 | collaboration = Council on Genetics | title = Health Supervision for Children and Adolescents With Down Syndrome | journal = Pediatrics | volume = 149 | issue = 5 | date = May 2022 | doi = 10.1542/peds.2022-057010 | pmid = 35490285 | s2cid = 248252638 | url = https://publications.aap.org/pediatrics/article/149/5/e2022057010/186778/Health-Supervision-for-Children-and-Adolescents?autologincheck=redirected }}</ref> Atlantoaxial instability may cause ] due to cervical spinal cord compression later in life, this often manifests as new onset weakness, ], bowel or bladder incontinence, and gait dysfunction.<ref name="Bull 2020">{{cite journal | vauthors = Bull MJ | title = Down Syndrome | journal = The New England Journal of Medicine | volume = 382 | issue = 24 | pages = 2344–2352 | date = June 2020 | pmid = 32521135 | doi = 10.1056/NEJMra1706537 | s2cid = 219586275 }}</ref> Serial imaging cannot reliably predict future cervical cord compression, but changes can be seen on neurological exam. The condition is surgically corrected with spine surgery.<ref name="Bull 2020" /> | |||
With the discovery of ] techniques in the 1950s it became possible to identify the obvious abnormalities of chromosomal number or shape. In 1959, ] discovered that Down's syndrome resulted from an extra chromosome.<ref>{{cite web|url=http://www.fondationlejeune.org/eng/Content/Fondation/professeurlj.asp |title=Jérôme Lejeune Foundation|accessdate=2006-06-02}}</ref> The extra chromosome was subsequently labeled as the 21st, and the condition as ] ]. The labeling of chromosome 21 represented an unintentional deviation from the genetic convention by which the 22 pairs of ]s comprising the human karyotype were numbered from largest to smallest (excluding the ]s). Lejeune identified the extra chromosome in mongolism as the second smallest, hence 21. Although it was later determined that chromosome 22 is actually slightly larger than 21, it was deemed too confusing to change either the numbering of the two chromosomes or name of the trisomy. | |||
Growth in height is slower, resulting in adults who tend to have ]—the average height for men is {{convert|154|cm|ftin|abbr=off}}, and for women is {{convert|142|cm|ftin|abbr=off}}.<ref>{{cite book|title=Williams Textbook of Endocrinology Expert Consult|year=2011|publisher=Elsevier Health Sciences|location=London|isbn=978-1-4377-3600-7|url=https://books.google.com/books?id=nbg1QOAObicC&pg=PT4756|edition=12th|url-status=live|archive-url=https://web.archive.org/web/20170123082306/https://books.google.com/books?id=nbg1QOAObicC&pg=PT4756|archive-date=2017-01-23}}</ref> Individuals with Down syndrome are at increased risk for ] as they age due to hypothyroidism, other medical issues and lifestyle.<ref name=Hick2012/><ref>{{cite journal | vauthors = Pierce M, Ramsey K, Pinter J | title = Trends in Obesity and Overweight in Oregon Children With Down Syndrome | journal = Global Pediatric Health | volume = 6 | pages = 2333794X19835640 | date = 2 April 2019 | pmid = 31044152 | pmc = 6446252 | doi = 10.1177/2333794X19835640 }}</ref> ]s have been developed specifically for children with Down syndrome.<ref name=Hick2012/> | |||
In 1961, a group of nineteen geneticists wrote to the editor of '']'' suggesting that ''mongolian idiocy'' had "misleading connotations," had become "an embarrassing term" and should be changed.<ref>{{cite journal| author=Allen, Gordon, C.E. Benda, J.A. Böök, C.O. Carter, C.E. Ford, E.H.Y. Chu, E. Hanhart, George Jervis, W. Langdon-Down, J. Lejeune, H. Nishimura, J. Oster, L.S. Penrose, P.E. Polani, Edith L. Potter, Curt Stern, R. Turpin, J. Warkany, and Herman Yannet| year=1961| title=Mongolism (Correspondence)| journal=The Lancet| pages=775| volume=1| issue=7180}}</ref> The Lancet supported ''Down's Syndrome''. The ] (WHO) officially dropped references to ''mongolism'' in 1965 after a request by the Mongolian delegate.<ref>{{cite journal|last=Howard-Jones |first=Norman| date=1979 |title=On the diagnostic term "Down's disease"| journal=Medical History |volume=23 |issue=1 |pages=102-104 |id=PMID 153994}}</ref> | |||
===Neurological=== | |||
In 1975, the United States ] convened a conference to standardize the nomenclature of malformations. They recommended eliminating the possessive form: "The possessive use of an eponym should be discontinued, since the author neither had nor owned the disorder."<ref>A planning meeting was held on 20 March 1974, resulting in a letter to ''The Lancet''.{{cite journal| year=1974| title=Classification and nomenclature of malformation (Discussion)| journal=The Lancet| pages=798| volume=303| issue=7861}} The conference was held 10-11 February 1975, and reported to The Lancet shortly afterward, {{cite journal| year=1975| title=Classification and nomenclature of morphological defects (Discussion)| journal=The Lancet| pages=513| volume=305| issue=7905}}</ref> While both the possessive and non-possessive forms are used in the general population, Down syndrome is the accepted term among professionals in the USA, Canada and other countries, while Down's syndrome continues to be used in the United Kingdom and other areas.<ref name=name>{{cite web|last=Leshin |first=Len| date=2003 |url=http://www.ds-health.com/name.htm |title=What's in a name|accessdate=2006-05-12}}</ref> | |||
] | |||
This syndrome causes about a third of cases of intellectual disability.<ref name=Steph2010/> Many developmental milestones are delayed with the ability to crawl typically occurring around 8–22 months rather than 6–12 months, and the ability to walk independently typically occurring around 1–4 years rather than 9–18 months.<ref>{{Cite web |title=Early Development for Children with Down Syndrome |url=https://www.cambscommunityservices.nhs.uk/Bedfordshire/services/occupational-therapy/ot-leaflets/down-syndrome |access-date=28 March 2023 |website=INHS Cambridgeshire Community Services NHS Trust}}</ref> Walking is acquired in 50% of children after 24 months.<ref>{{cite journal | vauthors = Winders P, Wolter-Warmerdam K, Hickey F | title = A schedule of gross motor development for children with Down syndrome | journal = Journal of Intellectual Disability Research | volume = 63 | issue = 4 | pages = 346–356 | date = April 2019 | pmid = 30575169 | doi = 10.1111/jir.12580 | s2cid = 58592265 }}</ref> | |||
Most individuals with Down syndrome have mild (IQ: 50–69) or moderate (IQ: 35–50) ] with some cases having severe (IQ: 20–35) difficulties.<ref name=Wei2010/><ref name=Reil2012>{{cite journal | vauthors = Reilly C | title = Behavioural phenotypes and special educational needs: is aetiology important in the classroom? | journal = Journal of Intellectual Disability Research | volume = 56 | issue = 10 | pages = 929–946 | date = October 2012 | pmid = 22471356 | doi = 10.1111/j.1365-2788.2012.01542.x | doi-access = free }}</ref> Those with mosaic Down syndrome typically have IQ scores 10–30 points higher than that.<ref>{{cite book|title=Children with disabilities|year=2005|publisher=Paul H. Brookes|location=Baltimore |isbn=978-1-55766-581-2|page=308|url=https://books.google.com/books?id=P65sAAAAMAAJ&q=IQ+%22mosaic+down+syndrome%22|edition=5th| veditors = Batshaw M |url-status=live|archive-url=https://web.archive.org/web/20170123082658/https://books.google.com/books?id=P65sAAAAMAAJ&q=IQ+%22mosaic+down+syndrome%22|archive-date=2017-01-23}}</ref> As they age, the gap tends to widen between people with Down syndrome and their same-age peers.<ref name=Reil2012/><ref>{{cite journal | vauthors = Patterson T, Rapsey CM, Glue P | title = Systematic review of cognitive development across childhood in Down syndrome: implications for treatment interventions | journal = Journal of Intellectual Disability Research | volume = 57 | issue = 4 | pages = 306–318 | date = April 2013 | pmid = 23506141 | doi = 10.1111/j.1365-2788.2012.01536.x }}</ref> | |||
== Genetics == | |||
{{main|Genetic origins of Down syndrome}} | |||
] for trisomy Down syndrome. Notice the three copies of chromosome 21.]] | |||
Down syndrome is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on the ], either in whole (] ]) or part (such as due to ]). The effects of the extra copy varies greatly from individual to individual, depending on the extent of the extra copy, genetic background, environmental factors, and random chance. Down syndrome can occur in all human populations, and analogous effects have been found in other species, such as chimpanzees and mice. Recently, researchers have been able to create ] mice with most of human chromosome 21 (in addition to their normal chromosomes).<ref>{{cite web| url=http://news.bbc.co.uk/1/hi/health/4268226.stm| title=Down's syndrome recreated in mice| author=BBC News| accessdate=2006-06-14| date=] ]}}</ref> | |||
Commonly, individuals with Down syndrome have better language understanding than ability to speak.<ref name=Hick2012/><ref name=Reil2012/> ] typically emerges around 15 months on average.<ref>{{cite journal | vauthors = Windsperger K, Hoehl S | title = Development of Down Syndrome Research Over the Last Decades-What Healthcare and Education Professionals Need to Know | journal = Frontiers in Psychiatry | volume = 12 | pages = 749046 | date = 2021 | pmid = 34970162 | pmc = 8712441 | doi = 10.3389/fpsyt.2021.749046 | doi-access = free }}</ref> 10–45% of those with Down syndrome have either a ] or ], making it difficult to understand them.<ref>{{cite journal | vauthors = Kent RD, Vorperian HK | title = Speech impairment in Down syndrome: a review | journal = Journal of Speech, Language, and Hearing Research | volume = 56 | issue = 1 | pages = 178–210 | date = February 2013 | pmid = 23275397 | pmc = 3584188 | doi = 10.1044/1092-4388(2012/12-0148) }}</ref> After reaching 30 years of age, some may lose their ability to speak.<ref name=Malt2013/> | |||
The extra chromosomal material can come about in several distinct ways. | |||
===Trisomy 21=== | |||
Trisomy 21 (47,XX,+21) is caused by a ] ] event. With nondisjunction, a gamete is produced with an extra copy of chromosome 21 (the gamete has 24 chromosomes). When combined with a normal gamete from the other parent, the child now has 47 chromosomes, with three copies of chromosome 21. Trisomy 21 is the cause of approximately 95% of observed Down syndromes, with 88% coming from nondisjunction in the maternal gamete and 8% coming from nondisjunction in the paternal gamete.<ref name=occurrence>{{cite web|url=http://www.nichd.nih.gov/publications/pubs/downsyndrome/down.htm#TheOccurrence|title=Down syndrome occurrence rates (NIH)|accessdate=2006-06-02}}</ref> ] nondisjunctions after conception would lead to mosaicism, and is discussed later. | |||
===Robertsonian translocation=== | |||
The extra chromosome 21 material that causes Down syndrome may be due to a ]. The long arm of ] is attached to another chromosome, often ] (45,XX,t(14;21q)) or itself (called an ], 45,XX,t(21q;21q)). Normal ] leading to gametes have a significant chance of creating a gamete with an extra chromosome 21. Translocation Down syndrome is often referred to as ''familial Down syndrome''. It is the cause of 2-3% of the observed Down syndromes. It does not show the maternal age effect, and is just as likely to have come from fathers as mothers. | |||
They typically do fairly well with social skills.<ref name=Hick2012/> Behavior problems are not generally as great an issue as in other syndromes associated with intellectual disability.<ref name=Reil2012/> In children with Down syndrome, ] occurs in nearly 30% with ] occurring in 5–10%.<ref name=Nelson2011/> People with Down syndrome experience a wide range of emotions.<ref>{{cite book| vauthors = McGuire D, Chicoine B |title=Mental Wellness in Adults with Down Syndrome|year=2006|publisher=Woodbine House, Inc.|location=Bethesday, MD|isbn=978-1-890627-65-2|page=49}}</ref> While people with Down syndrome are generally happy,<ref>{{cite book| vauthors = Margulies P |title=Down syndrome|year=2007|publisher=Rosen Pub. Group|location=New York|isbn=978-1-4042-0695-3|page=|url=https://archive.org/details/downsyndrome0000marg|url-access=registration|edition=1st}}</ref> symptoms of ] and ] may develop in early adulthood.<ref name=Malt2013/> | |||
===Mosaicism=== | |||
When some of the cells in the body are normal and some cells have trisomy 21, it is called ] Down Syndrome (46,XX/47,XX,+21).<ref></ref> This can occur in one of two ways: A ] event during an early cell division in a normal embryo leads to a fraction of the cells with trisomy 21; or a Down syndrome embryo undergoes ] and some of the cells in the embryo revert back to the normal chromosomal arrangement. There is considerable variability in the fraction of trisomy 21, both as a whole and tissue-by-tissue. This is the cause of 1–2% of the observed Down syndromes.<ref name=occurrence>{{cite web|url=http://www.nichd.nih.gov/publications/pubs/downsyndrome/down.htm#TheOccurrence|title=Down syndrome occurrence rates (NIH)|accessdate=2006-06-02}}</ref> There is evidence that mosaic Down syndrome, may produce less developmental delay, on average, than full trisomy 21.<ref>{{cite web| author= Leshin, L.| year=2000| url=http://www.ds-health.com/mosaic.htm| title=Mosaic Down Syndrome|accessdate=2006-06-02}}</ref> It is likely that all people have an extremely small fraction of their cells that are trisomy 21, with no discernable effects. | |||
Children and adults with Down syndrome are at increased risk of ], which occur in 5–10% of children and up to 50% of adults.<ref name=Malt2013/> This includes an increased risk of a specific type of seizure called ].<ref name=Hick2012/> Many (15%) who live 40 years or longer develop ].<ref>{{cite book|title=The 5-minute pediatric consult|year=2012|publisher=Wolters Kluwer Health/Lippincott Williams & Wilkins|location=Philadelphia|isbn=978-1-4511-1656-4|page=289|url=https://books.google.com/books?id=v7pbSFfMHCoC&pg=PA289|edition=6th | veditors = Schwartz MW |url-status=live|archive-url= https://web.archive.org/web/20170123083059/https://books.google.com/books?id=v7pbSFfMHCoC&pg=PA289|archive-date=2017-01-23}}</ref> In those who reach 60 years of age, 50–70% have the disease.<ref name="Malt2013"/> | |||
===Duplication of a portion of chromosome 21=== | |||
Rarely, a region of chromosome 21 will undergo a duplication event. This will lead to extra copies of some, but not all, of the genes on chromosome 21 (46,XX,dup(21q)). If the duplicated region has genes that are responsible for Down syndrome physical and mental characteristics, such individuals will show those characteristics. This cause is very rare and no rate estimates are possible. | |||
] is a sudden ] with ] symptoms such as ], possibly caused by an autoimmune disease.<ref>{{Cite journal |last1=Santoro |first1=Jonathan D. |last2=Filipink |first2=Robyn A. |last3=Baumer |first3=Nicole T. |last4=Bulova |first4=Peter D. |last5=Handen |first5=Benjamin L. |date=2023-03-01 |title=Down syndrome regression disorder: updates and therapeutic advances |url=https://pubmed.ncbi.nlm.nih.gov/36705008 |journal=Current Opinion in Psychiatry |volume=36 |issue=2 |pages=96–103 |doi=10.1097/YCO.0000000000000845 |issn=1473-6578 |pmid=36705008}}</ref> It primarily appears in teenagers and younger adults.<ref>{{Cite book |last1=Skoto |first1=Brian G. |chapter-url=https://books.google.com/books?id=KYUCEQAAQBAJ&dq=%22Down+syndrome+regression+disorder%22&pg=PT1514 |title=The 5-Minute Clinical Consult 2025 |last2=Roberts |first2=Michele |date=2024-02-28 |publisher=Lippincott Williams & Wilkins |isbn=978-1-9752-3473-7 |editor-last=Domino |editor-first=Frank J. |language=en |chapter=Down Syndrome}}</ref> | |||
==Incidence== | |||
] | |||
The incidence of Down syndrome is estimated at 1 per 800 to 1 per 1000 births.<ref name=NIHestimates>Based on estimates by National Institute of Child Health & Human Development {{cite web| title = Down syndrome rates| url=http://www.nichd.nih.gov/publications/pubs/downsyndrome/down.htm| accessdate =2006-06-21}} | |||
</ref> A recent study from the Center for Disease Control gives the rate as 1 per 733 live births.<ref>{{cite journal| author=Center for Disease Control| title=Improved National Prevalence Estimates for 18 Selected Major Birth Defects, United States, 1999-2001| journal=Morbidity and Mortality Weekly Report| volume=54| issue=51 & 52| date=] ]| url=http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5451a2.htm| pages=1301-1305}}</ref> Approximately 95% of these are ] ], making it the most common human ]. Down syndrome occurs in all ethnic groups and among all economic classes. | |||
===Senses=== | |||
] influences the risk of conceiving a baby with Down syndrome. At maternal age 20 to 24, the risk is 1/1490, while at age 40 the risk is 1/106, and at age 49 the risk is 1/11.<ref>{{cite journal| author = Hook, E.B.| year = 1981| title = Rates of chromosomal abnormalities at different maternal ages| journal = Obstet Gynecol| volume = 58| pages = 282}}</ref> Although the risk increases with maternal age, most children with Down syndrome (80%) are born to women under the age of 35,<ref>Estimate from {{cite web| title=National Down Syndrome Center|url=http://www.ndsccenter.org/resources/package3.php| accessdate=2006-04-21}}</ref> reflecting the overall fertility of that age group. Other than maternal age, there are no other known risk factors. However, in up to 12% of trisomy 21 cases, the extra chromosome comes from the paternal gamete.<ref>{{cite journal| author=Margareta Mikkelsen, Hanne Poulsen, Kim G. Nielsen| title=Incidence, survival, and mortality in Down syndrome in Denmark| year=2006| journal=American Journal of Medical Genetics| volume=37| issue=S2| pages=75-78| url=http://www.lib.ncsu.edu:2183/cgi-bin/abstract/110515875/ABSTRACT?CRETRY=1&SRETRY=0| accessdate=2006-07-03}}</ref> There does not appear to be a paternal age effect. | |||
], visible in the irises of a baby with Down syndrome]] | |||
Hearing and vision disorders occur in more than half of people with Down syndrome.<ref name=Hick2012/> | |||
<!-- Vision --> | |||
==== Ocular findings ==== | |||
Many standard prenatal screens can discover Down syndrome. ] along with ], such as ], ] (CVS), or percutaneous umbilical blood sampling (PUBS) are usually offered to families who may have an increased chance of having a child with Down syndrome, or where normal prenatal exams indicate possible problems. Genetic screens are often performed on pregnant women older than 30 or 35. | |||
] (small white or grayish/brown spots on the periphery of the ]), upward slanting ]s (the opening between the upper and lower lids) and ] (folds of skin between the upper eyelid and the nose) are clinical signs at birth suggesting the diagnosis of Down syndrome<ref name="Wei20102">{{cite journal |vauthors=Weijerman ME, de Winter JP |date=December 2010 |title=Clinical practice. The care of children with Down syndrome |journal=European Journal of Pediatrics |volume=169 |issue=12 |pages=1445–1452 |doi=10.1007/s00431-010-1253-0 |pmc=2962780 |pmid=20632187}}</ref><ref name=":02">{{Cite web |title=Trisomy 21/Down Syndrome - EyeWiki |url=https://eyewiki.org/Trisomy_21/Down_Syndrome#Diagnosis |access-date=2024-05-07 |website=eyewiki.org |language=en}}</ref> especially in the ].<ref name=":02"/> None of these requires treatment.{{Citation needed|date=May 2024}} | |||
Visually significant congenital ]s (clouding of the ] of the eye) occur more frequently with Down syndrome.<ref name=":02"/> ] with Down syndrome should be screened for cataract because early recognition and referral reduce the risk of vision loss from ].<ref name=":13">{{Cite journal |last1=Bull |first1=Marilyn J. |last2=Trotter |first2=Tracy |last3=Santoro |first3=Stephanie L. |last4=Christensen |first4=Celanie |last5=Grout |first5=Randall W. |last6=THE COUNCIL ON GENETICS |date=2022-05-01 |title=Health Supervision for Children and Adolescents With Down Syndrome |url=https://publications.aap.org/pediatrics/article/149/5/e2022057010/186778/Health-Supervision-for-Children-and-Adolescents |journal=Pediatrics |language=en |volume=149 |issue=5 |doi=10.1542/peds.2022-057010 |pmid=35490285 |issn=0031-4005}}</ref> Dot-like opacities in the cortex of the ] (cerulean cataract) are present in up to 50% of people with Down syndrome, but may be followed without treatment if they are not visually significant.<ref name=":02"/> | |||
== Prenatal screening == | |||
Pregnant women can be screened for various complications in their pregnancy, or due to risk factors such as maternal age. There are several common non-invasive screens that can indicate a Down syndrome fetus, and are normally performed in the late first trimester or early second trimester. Due to the nature of screens, each has a significant chance to indicate a Down syndrome fetus when, in fact, the fetus is normal. Such results are called ]s. Screen positives must be verified before a Down syndrome diagnosis. Common screening procedures for Down syndrome are given in Table 1. | |||
{| class="wikitable" | |||
|+ Table 1: Common First and Second Trimester Down Syndrome Screens | |||
|- | |||
!Screen | |||
!When Performed (Weeks ]) | |||
!Detection Rate | |||
!] Rate | |||
!Description | |||
|- | |||
|Triple Screen | |||
|align="center"|15–20 | |||
|align="center"|75% | |||
|align="center"|8.5% | |||
|This test measures the maternal serum ] (a fetal liver protein), ] (a pregnancy hormone), and ] (hCG, a pregnancy hormone).<ref name=quadrate>For a current estimate of rates, see {{cite journal| author=Benn, PA, J Ying, T Beazoglou, JFX Egan| journal=Prenatal Diagnosis| volume=21| issue=1| pages=46-51| title=Estimates for the sensitivity and false-positive rates for second trimester serum screening for Down syndrome and trisomy 18 with adjustments for cross-identification and double-positive results}}</ref> | |||
|- | |||
|Quad Screen | |||
|align="center"|15–20 | |||
|align="center"|79% | |||
|align="center"|7.5% | |||
|This test measures the maternal serum ] (a fetal liver protein), ] (a pregnancy hormone), ] (hCG, a pregnancy hormone), and high ]-Alpha (INHA).<ref name=quadrate>For a current estimate of rates, see {{cite journal| author=Benn, PA, J Ying, T Beazoglou, JFX Egan| journal=Prenatal Diagnosis| volume=21| issue=1| pages=46-51| title=Estimates for the sensitivity and false-positive rates for second trimester serum screening for Down syndrome and trisomy 18 with adjustments for cross-identification and double-positive results}}</ref> | |||
|- | |||
|AFP/Free Beta Screen | |||
|align="center"|13–22 | |||
|align="center"|80% | |||
|align="center"|2.8% | |||
|This test measures the ], produced by the fetus, and free beta hCG, produced by the ]. | |||
|- | |||
|Nuchal Translucency/freeBeta/PAPPA Screen | |||
|align="center"|10–13.5 | |||
|align="center"|91%<ref name=nasalbone>Some practices report adding Nasal Bone measurements and increasing the detection rate to 95% with a 2% False Positive Rate.</ref> | |||
|align="center"|5%<ref name=nasalbone>Some practices report adding Nasal Bone measurements and increasing the detection rate to 95% with a 2% False Positive Rate.</ref> | |||
|Uses ] to measure ] in addition to the freeBeta ] and PAPPA (pregnancy-associate plasma protein A, {{OMIM|176385}}). NIH has confirmed that this first trimester test is more accurate than second trimester screening methods.<ref>NIH FASTER study (NEJM 2005 ('''353'''):2001). See also J.L. Simplson's editorial (NEJM 2005 ('''353'''):19).</ref> | |||
|} | |||
] | |||
], ] and ] occur more frequently in children with Down syndrome.<ref name=":02"/> Screening for these diagnoses should begin within six months of birth.<ref name=":02"/><ref name=":13" /> Strabismus is more often acquired than ].<ref name=":02"/> Early diagnosis and treatment of strabismus reduces the risk of vision loss from amblyopia.<ref name=":63">{{Cite web |title=Strabismus and Amblyopia {{!}} Boston Children's Hospital |url=https://www.childrenshospital.org/conditions/strabismus-and-amblyopia#:~:text=Early%20diagnosis%20is%20essential%20in,the%20eyes%20are%20not%20aligned. |access-date=2024-05-08 |website=www.childrenshospital.org}}</ref> In Down syndrome, the presence of epicanthal folds may give the false impression of ], referred to as ]. Nasolacrimal duct obstruction, which causes tearing (]), is more frequently bilateral and multifactorial than in children without Down syndrome.<ref name=":02"/> | |||
Even with the best non-invasive screens, the detection rate is 90%–95% and the rate of false positive of 2%–5%. ]s can be caused by undetected multiple fetuses (very rare with the ultrasound tests), incorrect date of pregnancy, or normal variation in the proteins. | |||
] is more common with Down syndrome, though the rate may not differ until after twelve months of age compared to children without Down syndrome.<ref name=":02"/> Early screening is recommended to identify and treat significant refractive error with glasses or contact lenses. Poor ] (ability to focus on close objects) is associated with Down syndrome, which may mean bifocals are indicated.<ref name=":02"/> | |||
Confirmation of screen positive is normally accomplished with ]. This is an invasive procedure and involves taking ] from the mother and identifying fetal cells. The lab work can take a couple of weeks and will detect over 99.8% of all numerical chromosomal problems with a very low false positive rate. The vast majority of early screen positives are false. Since the risk of ] is approximately 1/200 to 1/300, amniocentesis confirmation presents a risk of spontaneously aborting a healthy fetus (from a false positive). | |||
In ], the ] progressively thins and bulges into a cone shape,<ref name=":23">{{Cite web |title=Keratoconus - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/keratoconus/symptoms-causes/syc-20351352 |access-date=2024-05-08 |website=Mayo Clinic |language=en}}</ref> causing visual blurring or distortion. Keratoconus first presents in the teen years and progresses into the thirties.<ref name=":23" /><ref name=":33">{{Cite web |date=2021-08-08 |title=Keratoconus |url=https://www.hopkinsmedicine.org/health/conditions-and-diseases/keratoconus |access-date=2024-05-08 |website=www.hopkinsmedicine.org |language=en}}</ref> Down syndrome is a strong risk factor for developing keratoconus, and onset may be occur at a younger age than in those without Down syndrome.<ref name=":02"/> Eye rubbing is also a risk factor for developing keratoconus.<ref name=":33" /> It is speculated that chronic eye irritation from ] may increase eye rubbing in Down syndrome,<ref name=":02"/> contributing to the increased prevalence of keratoconus. | |||
A ] review of elective abortion rates found that 91–93% of pregnancies with a diagnosis of Down syndrome were terminated.<ref>{{cite journal| author=Caroline Mansfield, Suellen Hopfer, Theresa M. Marteau| title=Termination rates after prenatal diagnosis of Down syndrome, spina bifida, anencephaly, and Turner and Klinefelter syndromes: a systematic literature review| year=1999| journal=Prenatal Diagnosis| volume=19| issue=9| pages=808-812| url=http://www3.interscience.wiley.com/cgi-bin/abstract/65500197/ABSTRACT}}</ref> Physicians and ethicists are concerned about the ethical ramifications,<ref>{{cite journal| author=Glover, NM and Glover, SJ| title=Ethical and legal issues regarding selective abortion of fetuses with Down syndrome| journal=Ment. Retard.| year=1996| volume=34| issue=4| pages207-214}}</ref> with some commentators calling it "eugenics by abortion".<ref>{{cite journal| author=George Will| title=Eugenics By Abortion:Is perfection an entitlement?| date=] ]| journal=Washington Post| pages=A37| url=http://www.washingtonpost.com/wp-dyn/articles/A51671-2005Apr13.html| accessdate=2006-07-03}}</ref> Many members of the disability rights movement "believe that public support for prenatal diagnosis and abortion based on disability contravenes the movement's basic philosophy and goals."<ref>{{cite journal| author=Erik Parens and Adrienne Asch| title=Disability rights critique of prenatal genetic testing: Reflections and recommendations| year=2003| journal=Mental Retardation and Developmental Disabilities Research Reviews| volume=9| issue=1| page=40-47| url=http://www3.interscience.wiley.com/cgi-bin/abstract/102531130/ABSTRACT| accessdate=2006-07-03}}</ref> | |||
An association between ] and Down syndrome is often cited.<ref name="Wei20102"/> Glaucoma in children with Down syndrome is uncommon, with a prevalence of less than 1%.<ref name="Wei20102"/><ref name=":02"/> It is currently unclear if the prevalence of glaucoma in those with Down syndrome differs from that in the absence of Down syndrome.<ref name=":02"/> | |||
==Cognitive development== | |||
Cognitive development in children with Down syndrome is quite variable. Many can be successful in school, while others struggle. Because of this variability in expression of Down syndrome, it is important to evaluate children individually. The cognitive problems that are found among children with Down syndrome are also found among children without Down syndrome. This means that parents can take advantage of general programs that are offered through the schools or other means. Children with Down syndrome have a wide range of abilities. It is not possible at birth to predict their capabilities. The identification of the best methods of teaching each particular child ideally begins soon after birth, through early intervention programs.<ref>{{cite web|url=http://www.ndss.org/content.cfm?fuseaction=NwsEvt.Article&article=1558|title=New Parent Guide|publisher=National Down Syndrome Society|accessdate=2006-05-12}} Also {{cite web|url=http://www.downsed.org/research/projects/early-intervention |title=Research projects - Early intervention and education|accessdate=2006-06-02}}</ref> | |||
Estimates of ] of ocular findings in Down Syndrome vary widely depending on the study.<ref name=":02"/> Some prevalence estimates follow. Vision problems have been observed in 38–80% of cases.<ref name="Wei20102"/> ] are present in 38–85% of individuals.<ref name="Wei20102" /> Between 20 and 50% have ].<ref name="Wei20102" /> ]s occur in 15%,<ref name="Nelson20112">{{cite book |title=Nelson textbook of pediatrics |vauthors=Kliegma RM |publisher=Saunders |year=2011 |isbn=978-1-4377-0755-7 |edition=19th |location=Philadelphia |pages=Chapter 76.2 |chapter=Down Syndrome and Other Abnormalities of Chromosome Number}}</ref> and may be present at birth.<ref name="Wei20102" /> ] may occur in as many as 21–30%.<ref name=":02" /> | |||
Language skills show a difference between understanding speech and expressing speech. It is common for children with Down syndrome to need speech therapy to help with expressive language.<ref>{{cite journal| author =Bird, G. and S. Thomas| year =2002| title = Providing effective speech and language therapy for children with Down syndrome in mainstream settings: A case example | journal =Down Syndrome News and Update| volume =2| issue =1| pages =30-31}} Also, {{cite book| last =Kumin| first=Libby| editor=Hassold, T.J.and D. Patterson| title =Down Syndrome: A Promising Future, Together| year =1998| publisher =Wiley-Liss| location =New York| chapter = Comprehensive speech and language treatment for infants, toddlers, and children with Down syndrome}}</ref> ]s are delayed<ref>{{cite web| title=Development of Fine Motor Skills in Down Syndrome| url=http://www.about-down-syndrome.com/fine-motor-skills-in-down-syndrome.html| accessdate=2006-07-03}}</ref> and often lag behind ]s and can interfere with cognitive development. Occupational therapy can address these issues.<ref>{{cite web |author = M. Bruni|url=http://www.ds-health.com/occther.htm| title=Occupational Therapy and the Child with Down Syndrome|accessdate=2006-06-02}}</ref> | |||
==== <!-- Hearing -->Hearing loss ==== | |||
Mainstreaming of children with Down syndrome is controversial. Mainstreaming is when students of differing abilities are placed in classes with their chronological peers. Children with Down syndrome do not age emotionally/socially and intellectually at the same rates as children without Down syndrome, so eventually the intellectual and emotional gap between children with and without Down syndrome widens. Complex thinking as required in sciences but also in history, the arts, and other subjects is often beyond their abilities, or achieved much later than in most children. Therefore, if they are to benefit from mainstreaming without feeling inferior most of the time, special adjustments must be made to the curriculum.<ref>{{cite web|author=S.E.Armstrong|url=http://www.altonweb.com/cs/downsyndrome/index.htm?page=ndssincl.html|title=Inclusion: Educating Students with Down Syndrome with Their Non-Disabled Peers|accessdate=2006-05-12}} Also, see {{cite web|url=http://www.altonweb.com/cs/downsyndrome/index.htm?page=bosworth.html| title=Benefits to Students with Down Syndrome in the Inclusion Classroom: K-3| author=Debra L. Bosworth| accessdate=2006-06-12}} Finally, see a survey by NDSS on inclusion, {{cite web|url=http://www.altonweb.com/cs/downsyndrome/index.htm?page=wolpert.html| title=The Educational Challenges Inclusion Study| author=Gloria Wolpert| year=1996| publisher=National Down Syndrome Society| accessdate=2006-06-28}}</ref> | |||
Hearing problems are found in 50–90% of children with Down syndrome.<ref name=Rod2012/> This is often the result of ] which occurs in 50–70%<ref name=Nelson2011/> and chronic ] which occur in 40–60%.<ref>{{cite book| vauthors = Evans-Martin FF |title=Down syndrome|year=2009|publisher=Chelsea House|location=New York|isbn=978-1-4381-1950-2|page=|url=https://archive.org/details/downsyndrome0000evan|url-access=registration}}</ref> Ear infections often begin in the first year of life and are partly due to poor ] function.<ref name=Tint2010/><ref name=Sam2011>{{cite book|title=Handbook of neurodevelopmental and genetic disorders in children|year=2011|publisher=Guilford Press|location=New York|isbn=978-1-60623-990-2|page=365|url=https://books.google.com/books?id=Mm81tZFxf9UC&pg=PA365|edition=2nd| veditors = Goldstein S |url-status=live|archive-url=https://web.archive.org/web/20170123082556/https://books.google.com/books?id=Mm81tZFxf9UC&pg=PA365|archive-date=2017-01-23}}</ref> Excessive ] can also cause hearing loss due to obstruction of the outer ].<ref name=Malt2013/> Even a mild degree of hearing loss can have negative consequences for speech, language understanding, and academics.<ref name=Wei2010/><ref name=Sam2011/> It is important to rule out hearing loss as a factor in social and cognitive deterioration.<ref>{{cite book| vauthors = Prasher VP |title=Neuropsychological assessments of dementia in Down syndrome and intellectual disabilities |year=2009 |publisher=Springer |location=London |isbn=978-1-84800-249-4 |page=56 |url= https://books.google.com/books?id=RBQKsxodntgC&pg=PA56 |url-status=live |archive-url= https://web.archive.org/web/20170123082925/https://books.google.com/books?id=RBQKsxodntgC&pg=PA56|archive-date=2017-01-23}}</ref> Age-related hearing loss of the ] occurs at a much earlier age and affects 10–70% of people with Down syndrome.<ref name=Malt2013/> | |||
===Heart=== | |||
A danger in not mainstreaming is underestimating their abilities. This was more common in institutions, where children with Down syndrome often failed to reach their potential despite being capable of much more, but this issue is very real and present in the modern school system as well. | |||
The rate of ] in newborns with Down syndrome is around 40%.<ref name=Eps2007/> Of those with heart disease, about 80% have an ] or ] with the former being more common.<ref name=Malt2013/> Congenital heart disease can also put individuals at a higher risk of ], where arteries in the lungs narrow and cause inadequate blood oxygenation.<ref name=":3">{{cite journal | vauthors = Bush D, Galambos C, Dunbar Ivy D | title = Pulmonary hypertension in children with Down syndrome | journal = Pediatric Pulmonology | volume = 56 | issue = 3 | pages = 621–629 | date = March 2021 | pmid = 32049444 | doi = 10.1002/ppul.24687 | s2cid = 211087826 }}</ref> Some of the genetic contributions to pulmonary hypertension in individuals with Down Syndrome are abnormal lung development, ], and proinflammatory genes.<ref name=":3" /> ] problems become common as people age, even in those without heart problems at birth.<ref name=Malt2013/> Other problems that may occur include ] and ].<ref name=Tint2010>{{cite book | vauthors = Tintinalli JE |title=Emergency Medicine: A Comprehensive Study Guide (Emergency Medicine (Tintinalli)) |publisher=McGraw-Hill Companies |location=New York |year=2010 |pages=Chapter 138|chapter=The Child with Special Health Care Needs|isbn=978-0-07-148480-0}}</ref> People with Down syndrome have a lower risk of ].<ref name=Malt2013/> | |||
Some European countries such as Germany and Denmark advise a two-teacher system, whereby the second teacher takes over a group of disabled children within the class. A popular alternative is cooperation between special education schools and mainstream schools. In cooperation, the core subjects are taught in separate classes, which neither slows down the non-disabled students nor neglects the disabled ones. Social activities, outings, and many sports and arts activities are performed together, as are all breaks and meals.<ref>There are many such programs. One is described by Action Alliance for Children, {{web cite|author=K. Flores| url=http://www.4children.org/news/103spec.htm|title=Special needs, "mainstream" classroom|accessdate=2006-05-13}} Also, see {{web cite|author=Flores, K.|url=http://www.4children.org/pdf/103spec.pdf|title=Special needs, "mainstream" classroom|accessdate=2006-05-13}}</ref> | |||
=== |
===Cancer=== | ||
Although the overall risk of ] in Down syndrome is not changed,<ref name=UrbanoP129>{{cite book| vauthors = Urbano R |title=Health Issues Among Persons With Down Syndrome|url=https://books.google.com/books?id=QbHL8qrgfCoC&pg=PA129|date=9 September 2010|publisher=Academic Press|isbn=978-0-12-374477-7|page=129|url-status=live|archive-url=https://web.archive.org/web/20150512114141/http://books.google.com/books?id=QbHL8qrgfCoC&pg=PA129|archive-date=12 May 2015}}</ref> the risk of ] and certain blood cancers, including ] (ALL) and ] (AMKL) is increased while the risk of other non-blood cancers is decreased.<ref name=Malt2013/> People with Down syndrome are believed to have an increased risk of developing cancers derived from ]s whether these cancers are blood- or non-blood-related.<ref name=Nix2018/> In 2008, the World Health Organization (WHO) introduced a distinct classification for myeloid proliferation in individuals with Down syndrome.<ref>{{cite journal | vauthors = Vardiman JW, Thiele J, Arber DA, Brunning RD, Borowitz MJ, Porwit A, Harris NL, Le Beau MM, Hellström-Lindberg E, Tefferi A, Bloomfield CD | display-authors = 6 | title = The 2008 revision of the World Health Organization (WHO) classification of myeloid neoplasms and acute leukemia: rationale and important changes | journal = Blood | volume = 114 | issue = 5 | pages = 937–951 | date = July 2009 | pmid = 19357394 | doi = 10.1182/blood-2009-03-209262 }}</ref> | |||
] is a non-profit organization which treats children who have, as the IAHP terms it, "some form of brain injury," including children with Down syndrome. The approach of "Psychomotor Patterning" is not proven,<ref>For criticism of the method, see {{web cite| author=Novella, S|url=http://www.quackwatch.org/01QuackeryRelatedTopics/patterning.html| title=Psychomotor Patterning|accessdate=2006-06-02}}</ref> and is considered ]. | |||
== |
==== Blood cancers ==== | ||
] is 10 to 15 times more common in children with Down syndrome.<ref name=Hick2012/> In particular, ] is 20 times more common and the megakaryoblastic form of ] (]), is 500 times more common.<ref name="pmid22867885"/> Acute megakaryoblastic leukemia (AMKL) is a leukemia of ]s, the precursors cells to ]s which form blood ]s.<ref name="pmid22867885">{{cite journal | vauthors = Seewald L, Taub JW, Maloney KW, McCabe ER | title = Acute leukemias in children with Down syndrome | journal = Molecular Genetics and Metabolism | volume = 107 | issue = 1–2 | pages = 25–30 | date = September 2012 | pmid = 22867885 | doi = 10.1016/j.ymgme.2012.07.011 }}</ref> Acute lymphoblastic leukemia in Down syndrome accounts for 1–3% of all childhood cases of ALL. It occurs most often in those older than nine years or having a ] greater than 50,000 per ] and is rare in those younger than one year old. ALL in Down syndrome tends to have poorer outcomes than other cases of ALL in people without Down syndrome.<ref name="pmid22867885"/><ref name="pmid27285583">{{cite journal | vauthors = Lee P, Bhansali R, Izraeli S, Hijiya N, Crispino JD | title = The biology, pathogenesis and clinical aspects of acute lymphoblastic leukemia in children with Down syndrome | journal = Leukemia | volume = 30 | issue = 9 | pages = 1816–1823 | date = September 2016 | pmid = 27285583 | pmc = 5434972 | doi = 10.1038/leu.2016.164 }}</ref> In short, the likelihood of developing acute myeloid leukemia (AML) and ] (ALL) is higher in children with Down syndrome compared to those without Down syndrome.<ref>{{cite journal | vauthors = Li J, Kalev-Zylinska ML | title = Advances in molecular characterization of myeloid proliferations associated with Down syndrome | journal = Frontiers in Genetics | volume = 13 | pages = 891214 | date = 2022 | pmid = 36035173 | pmc = 9399805 | doi = 10.3389/fgene.2022.891214 | doi-access = free }}</ref> | |||
Individuals with Down syndrome are at risk for various medical conditions. There is no way to predict what conditions they will have, if any. In addition, all these medical conditions can be exhibited by individuals without Down syndrome. It is important to keep these medical risks in mind while undergoing wellness checkups.<ref>See {{cite journal|author=Cohen, W.I.|year =1999| title =Health Care Guidelines for Individuals with Down Syndrome: 1999 Revision|journal =Down Syndrome Quarterly| volume =4| issue =3| url=http://www.denison.edu/collaborations/dsq/health99.html| accessdate =2006-06-02}} Some record sheets that can be used are given in {{cite web|author=Cohen, W.I.|url=http://www.ds-health.com/recordsheet1.htm|title=Recordsheet for Children Birth to Age 12|accessdate=2006-06-02}} and {{cite web|author=Cohen, W.I.|url=http://www.ds-health.com/recordsheet2.htm|title=Recordsheet for Children Age 13 to Adulthood|accessdate=2006-06-02}} In the UK, the Down's Syndrome Medical Information Group has {{cite web| url=http://www.dsmig.org.uk/publications/growthchart.html| title=growth charts available| accessdate=2006-06-13}}</ref> The American Academy of Pediatrics has issued a policy statement on the health supervision for children with Down syndrome.<ref>{{cite journal| author=American Academy of Pediatrics| year=2001| title=Supervision for children with Down syndrome| journal=Pediatrics| volume=107| issue=2| pages=442-449| url=http://aappolicy.aappublications.org/cgi/content/full/pediatrics;107/2/442| accessdate=2006-06-03}}</ref> | |||
] typically precedes Down syndrome and is accompanied by a condition known as ] (TAM), which generally disrupts the differentiation of megakaryocytes and erythrocytes.<ref name="The paradox of Myeloid Leukemia ass">{{cite journal | vauthors = Gupte A, Al-Antary ET, Edwards H, Ravindranath Y, Ge Y, Taub JW | title = The paradox of Myeloid Leukemia associated with Down syndrome | journal = Biochemical Pharmacology | volume = 201 | pages = 115046 | date = July 2022 | pmid = 35483417 | doi = 10.1016/j.bcp.2022.115046 | s2cid = 248431139 }}</ref> In Down syndrome, AMKL is typically preceded by ] (TMD), a disorder of ] in which non-cancerous megakaryoblasts with a mutation in the '']'' gene rapidly divide during the later period of pregnancy.<ref name="pmid22867885"/><ref name="pmid25956670">{{cite journal | vauthors = Tamblyn JA, Norton A, Spurgeon L, Donovan V, Bedford Russell A, Bonnici J, Perkins K, Vyas P, Roberts I, Kilby MD | display-authors = 6 | title = Prenatal therapy in transient abnormal myelopoiesis: a systematic review | journal = Archives of Disease in Childhood. Fetal and Neonatal Edition | volume = 101 | issue = 1 | pages = F67–F71 | date = January 2016 | pmid = 25956670 | doi = 10.1136/archdischild-2014-308004 | s2cid = 5958598 | url = https://ora.ox.ac.uk/objects/uuid:73db9b1c-e082-43bc-91a5-db03b26d18d3 }}</ref> GATA1 mutations combined with trisomy 21 contribute to a predisposition to TAM.<ref name="pmid27510823"/> In trisomy 21, the process of leukemogenesis starts in early fetal life, with genetic factors, including GATA1 mutations, contributing to the development of TAM on the preleukemic pathway.<ref name="The paradox of Myeloid Leukemia ass"/> The condition affects 3–10% of babies with Down.<ref name="pmid22867885"/> While it often spontaneously resolves within three months of birth, it can cause serious blood, liver, or other complications.<ref name=Gam2012>{{cite journal | vauthors = Gamis AS, Smith FO | title = Transient myeloproliferative disorder in children with Down syndrome: clarity to this enigmatic disorder | journal = British Journal of Haematology | volume = 159 | issue = 3 | pages = 277–287 | date = November 2012 | pmid = 22966823 | doi = 10.1111/bjh.12041 | s2cid = 37593917 | doi-access = free }}</ref> In about 10% of cases, TMD progresses to AMKL during the three months to five years following its resolution.<ref name="pmid22867885"/><ref name=Gam2012/><ref name="pmid27510823">{{cite journal | vauthors = Bhatnagar N, Nizery L, Tunstall O, Vyas P, Roberts I | title = Transient Abnormal Myelopoiesis and AML in Down Syndrome: an Update | journal = Current Hematologic Malignancy Reports | volume = 11 | issue = 5 | pages = 333–341 | date = October 2016 | pmid = 27510823 | pmc = 5031718 | doi = 10.1007/s11899-016-0338-x }}</ref> | |||
A partial list of risks is given below. Risks run from 80% for hearing deficits to 44% for congenital heart defects<ref>{{cite journal|author=Sallie B. Freeman, Lisa F. Taft, Kenneth J. Dooley, Katherine Allran, Stephanie L. Sherman, Terry J. Hassold, Muin J. Khoury, Denise M. Saker| title=Population-based study of congenital heart defects in Down syndrome| year=1998| journal=American Journal of Medical Genetics| volume=80| issue=3| pages=213-217}}</ref> to 20% for hypothyroidism to rare but significantly increased risks for Leukemia.<ref name=NIHestimates>Based on estimates by National Institute of Child Health & Human Development {{cite web| url=http://www.nichd.nih.gov/publications/pubs/downsyndrome/down.htm| title=Facts About Down Syndrome| accessdate=2006-05-21}}.</ref><ref>For references on health effects, see {{cite web|url=http://www.ds-health.com/ |title=Down syndrome health| accessdate=2006-06-02}} Also, {{cite web|url=http://www.altonweb.com/cs/downsyndrome/index.htm?page=bosworth.html| title=Benefits to Students with Down Syndrome in the Inclusion Classroom: K-3| author=Debra L. Bosworth| accessdate=2006-06-12}}</ref> | |||
* ] | |||
* Increased susceptibility to infection | |||
* Muscular/Skeletal abnormalities, including generally poor muscle tone (]). | |||
* Respiratory problems | |||
* ] | |||
* ] | |||
* Obstructed digestive tracts | |||
* ] dysfunctions (]) | |||
* ], although their survival and relapse rate is much better than average | |||
* ] (nearly absolute in males, fertility in females is possible) | |||
* Hearing deficits | |||
* Enlargement of tongue in relationship to size of mouth | |||
* Eye problems (]s, ], near and far sightedness) | |||
* ] | |||
==== Non-blood cancers ==== | |||
There is some evidence that individuals with Down syndrome have a much lower rate of lung cancer than others, as is expected for cancers caused by ]s (two-hit model). | |||
People with Down syndrome have a lower risk of all major solid cancers, including those of lung, breast, and cervix, with the lowest relative rates occurring in those aged 50 years or older.<ref name=Nix2018/> This low risk is thought to be due to an increase in the expression of ]s present on chromosome 21.<ref>{{cite book|title=Cancer genome and tumor microenvironment |year=2010 |publisher=Springer|location=New York|isbn=978-1-4419-0711-0|page=203|url=https://books.google.com/books?id=x3Lb9Mxl4qcC&pg=PA203|edition=Online-Ausg.| veditors = Thomas-Tikhonenko A |url-status=live|archive-url=https://web.archive.org/web/20150704142502/https://books.google.com/books?id=x3Lb9Mxl4qcC&pg=PA203|archive-date=2015-07-04}}</ref><ref name=Nix2018>{{cite journal | vauthors = Nixon DW | title = Down Syndrome, Obesity, Alzheimer's Disease, and Cancer: A Brief Review and Hypothesis | journal = Brain Sciences | volume = 8 | issue = 4 | page = 53 | date = March 2018 | pmid = 29587359 | pmc = 5924389 | doi = 10.3390/brainsci8040053 | doi-access = free }}</ref> One exception is testicular ] which occurs at a higher rate in Down syndrome.<ref name=Nix2018/> | |||
===Endocrine=== | |||
As with all risks, this does not mean that everyone with Down syndrome will get these diseases, nor that an individual will get any of them. The concentration on wellness in individuals with Down syndrome and increased medical technology has vastly improved the length and quality of life. Current estimates give life expectancy in the United States as 55 years, compared to 77 years for the population in general.<ref>{{cite web| url=http://www.ndss.org/content.cfm?fuseaction=InfoRes.HlthArticle&article=19| title=Associated Medical Conditions| accessdate=2006-06-02}}</ref> This life expectancy is a tremendous increase in recent years. | |||
Problems of the ] occur in 20–50% of individuals with Down syndrome.<ref name=Malt2013/><ref name=Hick2012/> ] is the most common form, occurring in almost half of all individuals.<ref name=Malt2013/> Thyroid problems can be due to a poorly or nonfunctioning thyroid at birth (known as ]) which occurs in 1%<ref name=Nelson2011/> or can develop later due to an attack on the thyroid by the ] resulting in ] or ].<ref>{{cite journal | vauthors = Graber E, Chacko E, Regelmann MO, Costin G, Rapaport R | title = Down syndrome and thyroid function | journal = Endocrinology and Metabolism Clinics of North America | volume = 41 | issue = 4 | pages = 735–745 | date = December 2012 | pmid = 23099267 | doi = 10.1016/j.ecl.2012.08.008 }}</ref> ] is also more common.<ref name=Malt2013/> | |||
=== |
===Gastrointestinal=== | ||
] occurs in nearly half of people with Down syndrome and may result in changes in behavior.<ref name=Hick2012/> One potential cause is ], occurring in 2–15%, which is due to a lack of ] controlling the ].<ref>{{cite journal | vauthors = Moore SW | title = Down syndrome and the enteric nervous system | journal = Pediatric Surgery International | volume = 24 | issue = 8 | pages = 873–883 | date = August 2008 | pmid = 18633623 | doi = 10.1007/s00383-008-2188-7 | s2cid = 11890549 }}</ref> Other congenital problems can include ], ] and ].<ref name=Tint2010/> ] affects about 7–20%.<ref name="Malt2013" /><ref name="Hick2012" /> | |||
] has sometimes been advocated and performed on children with Down Syndrome, based on the idea that surgery can create a more normal facial appearance, which will decrease social stigma, and thus lead to a better quality of life. The has issued a "Position Statement on Cosmetic Surgery for Children with Down Syndrome" <ref>{{cite web|author=National Down Syndrome Society| title=Position Statement on Cosmetic Surgery for Children with Down Syndrome| url=http://www.ndss.org/content.cfm?fuseaction=InfoRes.HlthArticle&article=34|accessdate=2006-06-02}}</ref> which states that "The goal of inclusion and acceptance is mutual respect based on who we are as individuals, not how we look." Plastic surgery on children with Down Syndrome is uncommon.<ref>{{cite book|author=Parens, E. (editor)|year=2006| title=Surgically Shaping Children : Technology, Ethics, and the Pursuit of Normality| publisher=Johns Hopkins University Press| location=Baltimore| id=ISBN 0801883059}}</ref> | |||
===Teeth=== | |||
== Genetic research == | |||
People with Down syndrome tend to be more susceptible to ] as well as early, severe ] disease, ], and early ], especially in the lower front teeth.<ref name="Churchill">{{cite book| vauthors = Cawson RA, Odell EW |title=Cawson's essentials of oral pathology and oral medicine|date=2012|publisher=Churchill Livingstone|location=Edinburgh|isbn=978-0443-10125-0|pages=419–421|edition=8th}}</ref><ref name="Carranza">{{cite book | veditors = Newman MG, Takei HH, Klokkevold PR, Carranza FA |title=Carranza's clinical periodontology|date=2006|publisher=W.B. Saunders Co.|location=Philadelphia|isbn=978-1-4160-2400-2|pages=299, 397, 409, 623|edition=10th}}</ref> While ] and poor ] are contributing factors, the severity of these periodontal diseases cannot be explained solely by external factors.<ref name="Carranza"/> Research suggests that the severity is likely a result of a weakened immune system.<ref name="Carranza"/><ref name="Mosby">{{cite book | vauthors = Avery DR, Dean JA, McDonald RE |title=Dentistry for the child and adolescent |date=2004 |publisher=Mosby |isbn=978-0-323-02450-1 |edition=8th |location=St. Louis, Mo |pages=164–168, 190–194, 474}}</ref> The weakened immune system also contributes to increased incidence of ] in the mouth (from '']'').<ref name="Mosby"/> | |||
Down syndrome disorders are based on having too many copies of the ]s located on chromosome 21. In general, this leads to an overexpression of the genes.<ref>{{cite journal| author=R Mao, CL Zielke, HR Zielke, J Pevsner| title=Global up-regulation of chromosome 21 gene expression in the developing Down syndrome brain| journal=]| year=2003| volume=81| issue=5| pages=457-467| url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WG1-487KHTJ-1&_coverDate=05%2F31%2F2003&_alid=422057371&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6809&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=9ec6c22133f1645bad48a10a8fb14485}}</ref> <ref>{{cite journal| author=Rong Mao, X Wang, EL Spitznagel, LP Frelin, JC Ting, H Ding, J Kim, I Ruczinski, TJ Downey, J Pevsner| title=Primary and secondary transcriptional effects in the developing human Down syndrome brain and heart| journal=Genome Biology| year=2005| volume=6| issue=13| pages=R107| url=http://www.pubmedcentral.gov/articlerender.fcgi?tool=pmcentrez&rendertype=abstract&artid=1414106}}</ref> Understanding the genes involved may help to target medical treatment to individuals with Down syndrome. It is estimated that chromosome 21 contains 200 to 250 genes.<ref name=Leshin>See {{cite web| author=Leshin, L.| year=2003| url=http://www.ds-health.com/trisomy.htm| title=Trisomy 21: The Story of Down Syndrome| accessdate=2006-05-21}}</ref> Recent research has identified a region of the chromosome that contains the main genes responsible for the pathogenesis of Down syndrome,<ref>{{cite journal| author=Zohra Rahmani, Jean-Louis Blouin, Nicole Créau-Goldberg, Paul C. Watkins, Jean-François Mattei, Marc Poissonnier, Marguerite Prieur, Zoubida Chettouh, Annie Nicole, Alain Aurias, Pierre-Marie Sinet, Jean-Maurice Delabar| title=Down syndrome critical region around D21S55 on proximal 21q22.3| journal=]| year=2005| volume=37| issue=S2| pages=98-103| url=http://www3.interscience.wiley.com/cgi-bin/abstract/110515872/ABSTRACT?CRETRY=1&SRETRY=0}}</ref> located proximal to 21q22.3. The search for major genes involved in Down syndrome characteristics is normally in the region 21q21–21q22.3. | |||
People with Down syndrome also tend to have a more ] ] resulting in a greater resistance to ], despite decreased quantities of saliva,<ref name="ReferenceA">{{cite book| vauthors = Sapp JP, Eversole LR, Wysocki GP |title=Contemporary oral and maxillofacial pathology|date=2002|publisher=Mosby|location=St. Louis|isbn=978-0-323-01723-7|pages=39–40|edition=2nd}}</ref> less effective oral hygiene habits, and higher plaque indexes.<ref name="Churchill"/><ref name="Mosby"/><ref name="ReferenceA"/><ref name="Saunders">{{cite book| vauthors = Regezi JA, Sciubba JJ, Jordan RC |title=Oral Pathology: Clinical Pathologic Correlations|date=2008|publisher=Saunders Elsevier|location=St Louis, Missouri|isbn=978-1-4557-0262-6 |pages=353–354|edition=5th}}</ref> | |||
Some suspected genes involved in features of Down syndrome are given in the Table 2: | |||
Higher rates of tooth wear and ] are also common.<ref name="Mosby"/> Other common oral manifestations of Down syndrome include enlarged hypotonic tongue, crusted and hypotonic lips, ], narrow ] with crowded teeth, class III ] with an underdeveloped maxilla and posterior ], delayed exfoliation of ] and delayed eruption of adult teeth, shorter roots on teeth, and often missing and malformed (usually smaller) teeth.<ref name="Churchill" /><ref name="Mosby"/><ref name="ReferenceA"/><ref name="Saunders"/> Less common manifestations include ] and ] (20% prevalence).<ref name="Saunders"/> | |||
], an elongation of the pulp chamber, has a high prevalence in people with DS.<ref>{{cite journal | vauthors = Bell J, Civil CR, Townsend GC, Brown RH | title = The prevalence of taurodontism in Down's syndrome | journal = Journal of Mental Deficiency Research | volume = 33 | issue = 6 | pages = 467–476 | date = December 1989 | pmid = 2533267 | doi = 10.1111/j.1365-2788.1989.tb01502.x }}</ref><ref>{{cite journal | vauthors = Rajić Z, Mestrović SR | title = Taurodontism in Down's syndrome | journal = Collegium Antropologicum | volume = 22 | issue = Suppl | pages = 63–67 | date = December 1998 | pmid = 9951142 | url = https://pubmed.ncbi.nlm.nih.gov/9951142/ }}</ref> | |||
===Fertility=== | |||
Males with Down syndrome usually do not father children, while females have lower rates of ] relative to those who are unaffected.<ref name=Prad2006/> Fertility is estimated to be present in 30–50% of females.<ref name=Nel2010/> ] usually occurs at an earlier age.<ref name=Malt2013/> The poor fertility in males is thought to be due to problems with ]; however, it may also be related to not being sexually active.<ref name=Prad2006/> As of 2006, three instances of males with Down syndrome fathering children and 26 cases of females having children have been reported.<ref name=Prad2006>{{cite journal | vauthors = Pradhan M, Dalal A, Khan F, Agrawal S | title = Fertility in men with Down syndrome: a case report | journal = Fertility and Sterility | volume = 86 | issue = 6 | pages = 1765.e1–1765.e3 | date = December 2006 | pmid = 17094988 | doi = 10.1016/j.fertnstert.2006.03.071 | s2cid = 32384231 | doi-access = free }}</ref> Without ], around half of the children of someone with Down syndrome will also have the syndrome.<ref name=Prad2006/><ref name=Rubin2013/> | |||
==Cause== | |||
{{Main|Genetics of Down syndrome}}The cause of the extra full or partial chromosome is still unknown.<ref name=":0" /> Most of the time, Down syndrome is caused by a random mistake in cell division during early development of the fetus, but not inherited,<ref name=":1">{{Cite news |title=Down syndrome - Symptoms and causes |language=en |website=Mayo Clinic |url=https://www.mayoclinic.org/diseases-conditions/down-syndrome/symptoms-causes/syc-20355977 |access-date=2022-03-24}}</ref> and there is no scientific research which shows that environmental factors or the parents' activities contribute to Down syndrome. The only factor that has been linked to the increased chance of having a baby with Down syndrome is advanced parental age. This is mostly associated with ] but about 10 per cent of cases are associated with advanced ].<ref name="Ramasamy">{{cite journal | vauthors = Ramasamy R, Chiba K, Butler P, Lamb DJ | title = Male biological clock: a critical analysis of advanced paternal age | journal = Fertility and Sterility | volume = 103 | issue = 6 | pages = 1402–1406 | date = June 2015 | pmid = 25881878 | pmc = 4955707 | doi = 10.1016/j.fertnstert.2015.03.011 }}</ref> ] for Down syndrome (trisomy 21) showing the three copies of ]]] | |||
Down syndrome is caused by having three copies of the ]s on ], rather than the usual two.<ref name=Patt2009/><ref name="Lana2011">{{cite journal | vauthors = Lana-Elola E, Watson-Scales SD, Fisher EM, Tybulewicz VL | title = Down syndrome: searching for the genetic culprits | journal = Disease Models & Mechanisms | volume = 4 | issue = 5 | pages = 586–595 | date = September 2011 | pmid = 21878459 | pmc = 3180222 | doi = 10.1242/dmm.008078 }}</ref> The parents of the affected individual are typically genetically normal.<ref name=Steph2010/> Those who have one child with Down syndrome have about a 1% possibility of having a second child with the syndrome, if both parents are found to have normal ]s.<ref name=Nel2010/> | |||
The extra chromosome content can arise through several different ways. The most common cause (about 92–95% of cases) is a complete extra copy of chromosome 21, resulting in ] 21.<ref name=Rubin2013/><ref name=CDC2013>{{cite web |url=https://www.cdc.gov/ncbddd/birthdefects/DownSyndrome.html |title=Birth Defects, Down Syndrome |website=National Center on Birth Defects and Developmental Disabilities |publisher=] |place=US |date=2013-11-06 |url-status=live |archive-url=https://web.archive.org/web/20170728031507/https://www.cdc.gov/ncbddd/birthdefects/DownSyndrome.html |archive-date=2017-07-28 }}</ref> In 1–2.5% of cases, some of the cells in the body are normal and others have trisomy 21, known as ] Down syndrome.<ref name=Nel2010/><ref>{{cite book|title=Treatment & prognosis in pediatrics.|year=2013|publisher=Jaypee Brothers Medical P|isbn=978-93-5090-428-2|page=391|url=https://books.google.com/books?id=LlR5jdVkm8kC&pg=PA391| vauthors = Mandal K |url-status=live|archive-url=https://web.archive.org/web/20170123082941/https://books.google.com/books?id=LlR5jdVkm8kC&pg=PA391|archive-date=2017-01-23}}</ref> The other common mechanisms that can give rise to Down syndrome include: a ], ], or ]. These contain additional material from chromosome 21 and occur in about 2.5% of cases.<ref name=Hick2012/><ref name=Nel2010/> An isochromosome results when the two ] of a chromosome separate together rather than the long and ] separating together during ].<ref name=Rubin2013>{{cite book|title=Essentials of Rubin's Pathology|year=2013|publisher=Lippincott Williams & Wilkins|isbn=978-1-4511-8132-6|pages=129–131|url=https://books.google.com/books?id=JD7YLArg5ncC&pg=PA130| vauthors = Reisner H |url-status=live|archive-url=https://web.archive.org/web/20170123082320/https://books.google.com/books?id=JD7YLArg5ncC&pg=PA130|archive-date=2017-01-23}}</ref> | |||
===Trisomy 21=== | |||
Down syndrome (also known by the ] 47,XX,+21 for females and 47,XY,+21 for males)<ref name=Flet2007>{{cite book| vauthors = Fletcher-Janzen E, Reynolds CR |title=Encyclopedia of special education: a reference for the education of children, adolescents, and adults with disabilities and other exceptional individuals|year=2007|publisher=John Wiley & Sons|location=New York|isbn=978-0-470-17419-7|page=458|url=https://books.google.com/books?id=7n-tu1Q7jBsC&pg=PA458|edition=3rd|url-status=live|archive-url=https://web.archive.org/web/20170123083050/https://books.google.com/books?id=7n-tu1Q7jBsC&pg=PA458|archive-date=2017-01-23}}</ref> is mostly caused by a failure of the 21st chromosome to separate during egg or sperm development, known as ].<ref name=Rubin2013/> As a result, a sperm or egg cell is produced with an extra copy of chromosome 21; this cell thus has 24 chromosomes. When combined with a normal cell from the other parent, the baby has 47 chromosomes, with three copies of chromosome 21.<ref name=Patt2009/><ref name=Rubin2013/> About 88% of cases of trisomy 21 result from nonseparation of the chromosomes in the mother, 8% from nonseparation in the father, and 3% after the egg and sperm have merged.<ref name=Zhang>{{cite book| vauthors = Zhang DY, Cheng L |title=Molecular genetic pathology|year=2008|publisher=Humana|location=Totowa, N.J.|isbn=978-1-59745-405-6|page=45|url=https://books.google.com/books?id=F_7QXO0ZBigC&pg=PA45|url-status=live|archive-url=https://web.archive.org/web/20170123083008/https://books.google.com/books?id=F_7QXO0ZBigC&pg=PA45|archive-date=2017-01-23}}</ref> | |||
=== Mosaic Down syndrome === | |||
] Down syndrome is diagnosed when there is a mixture of two types of cells: some cells have three copies of chromosome 21 but some cells have the typical two copies of chromosome 21.<ref name="CDC"/> This type is the least common form of Down syndrome and accounts for only about 1% of all cases.<ref name=":0">{{Cite web |title=What is Down Syndrome? {{!}} National Down Syndrome Society |url=https://www.ndss.org/about-down-syndrome/down-syndrome/ |access-date=2022-03-24 |website=NDSS |language=en-US}}</ref> Children with mosaic Down syndrome may have the same features as other children with Down syndrome. However, they may have fewer characteristics of the condition due to the presence of some (or many) cells with a typical number of chromosomes.<ref name="CDC">{{Cite web |date=2021-04-06 |title=Facts about Down Syndrome {{!}} CDC |url=https://www.cdc.gov/ncbddd/birthdefects/downsyndrome.html |access-date=2023-03-31 |website=Centers for Disease Control and Prevention |language=en-us}}</ref> | |||
===Translocation Down syndrome=== | |||
The extra chromosome 21 material may also occur due to a ] in 2–4% of cases.<ref name=Nel2010/><ref name=AK2013/> In this translocation Down syndrome, the long arm of chromosome 21 is attached to another chromosome, often ].<ref name=Mich2013/> In a male affected with Down syndrome, it results in a karyotype of 46XY,t(14q21q).<ref name=Mich2013>{{cite book|title=Human Heredity: Principles and Issues|year=2013|publisher=Cengage Learning|isbn=978-1-285-52847-2|page=138|url=https://books.google.com/books?id=KSwLAAAAQBAJ&pg=PA138| vauthors = Cummings M | edition = 10th |url-status=live|archive-url=https://web.archive.org/web/20170123082431/https://books.google.com/books?id=KSwLAAAAQBAJ&pg=PA138|archive-date=2017-01-23}}</ref><ref>{{cite book|title=Yen and Jaffe's reproductive endocrinology: physiology, pathophysiology, and clinical management|year=2009|publisher=Saunders/Elsevier|location=Philadelphia, PA|isbn=978-1-4160-4907-4|page=791|url=https://books.google.com/books?id=NudwnhxY8kYC&pg=PA791| vauthors = Strauss JF, Barbieri RL |edition=6th|url-status=live|archive-url=https://web.archive.org/web/20170123082911/https://books.google.com/books?id=NudwnhxY8kYC&pg=PA791|archive-date=2017-01-23}}</ref> This may be a new mutation or previously present in one of the parents.<ref name=Menk2006/> The parent with such a translocation is usually normal physically and mentally;<ref name=Mich2013/> however, during production of egg or sperm cells, a higher chance of creating reproductive cells with extra chromosome 21 material exists.<ref name=AK2013>{{cite book|title=Family Medicine Principles and Practice|year=2013|publisher=Springer New York|location=New York, NY|isbn=978-0-387-21744-4|page=142|url=https://books.google.com/books?id=icdGAAAAQBAJ&pg=PA142| vauthors = David AK |edition=Sixth|url-status=live|archive-url=https://web.archive.org/web/20170123082720/https://books.google.com/books?id=icdGAAAAQBAJ&pg=PA142|archive-date=2017-01-23}}</ref> This results in a 15% chance of having a child with Down syndrome when the mother is affected and a less than 5% probability if the father is affected.<ref name=Menk2006/> The probability of this type of Down syndrome is not related to the mother's age.<ref name=Mich2013/> Some children without Down syndrome may inherit the translocation and have a higher probability of having children of their own with Down syndrome.<ref name=Mich2013/> In this case it is sometimes known as ''familial'' Down syndrome.<ref>{{cite book| veditors = Gardner RJ, Sutherland GR, Shaffer LG |title=Chromosome abnormalities and genetic counseling|year=2012|publisher=Oxford University Press|location=Oxford|isbn=978-0-19-974915-7|page=292|url=https://books.google.com/books?id=mqNpAgAAQBAJ&pg=PA292|edition=4th|url-status=live|archive-url=https://web.archive.org/web/20170123082500/https://books.google.com/books?id=mqNpAgAAQBAJ&pg=PA292|archive-date=2017-01-23}}</ref> | |||
==Mechanism== | |||
The extra genetic material present in Down syndrome results in overexpression of a portion of the 310 genes located on chromosome 21.<ref name=Lana2011/> This overexpression has been estimated at 50%, due to the third copy of the chromosome present.<ref name=Nel2010/> Some research has suggested the Down syndrome critical region is located at bands 21q22.1–q22.3,<ref>{{cite web |url=http://emedicine.medscape.com/article/943216-overview |title=Genetics of Down syndrome |access-date=2011-05-29 |url-status=live |archive-url=https://web.archive.org/web/20110527214124/http://emedicine.medscape.com/article/943216-overview |archive-date=2011-05-27 }}</ref> with this area including genes for the ], ], and likely the ] proto ].<ref>{{cite book|title=Current diagnosis & treatment psychiatry|year=2008|publisher=McGraw-Hill Medical|location=New York|isbn=978-0-07-142292-5|pages=Chapter 3|edition=2nd| veditors = Ebert MH |chapter=Psychiatric Genetics}}</ref> Other research, however, has not confirmed these findings.<ref name=Lana2011/> ]s are also proposed to be involved.<ref>{{cite journal | vauthors = Patterson D, Cabelof DC | title = Down syndrome as a model of DNA polymerase beta haploinsufficiency and accelerated aging | journal = Mechanisms of Ageing and Development | volume = 133 | issue = 4 | pages = 133–137 | date = April 2012 | pmid = 22019846 | doi = 10.1016/j.mad.2011.10.001 | s2cid = 3663890 }}</ref> | |||
The dementia that occurs in Down syndrome is due to an excess of ] ] produced in the brain and is similar to ], which also involves amyloid beta build-up.<ref name=Wek2013/> Amyloid beta is processed from amyloid precursor protein, the gene for which is located on chromosome 21.<ref name=Wek2013>{{cite journal | vauthors = Weksler ME, Szabo P, Relkin NR, Reidenberg MM, Weksler BB, Coppus AM | title = Alzheimer's disease and Down's syndrome: treating two paths to dementia | journal = Autoimmunity Reviews | volume = 12 | issue = 6 | pages = 670–673 | date = April 2013 | pmid = 23201920 | doi = 10.1016/j.autrev.2012.10.013 }}</ref> ] and ]s are present in nearly all by 35 years of age, though dementia may not be present.<ref name=Steph2010/> It is hypothesized that those with Down syndrome lack a normal number of ] and produce less ] which is said to present an increased risk of infection.<ref name=Hick2012/> | |||
===Epigenetics=== | |||
Down syndrome is associated with an increased risk of some chronic diseases that are typically associated with older age such as Alzheimer's disease. It is believed that accelerated aging occurs and increases the biological age of tissues, but molecular evidence for this hypothesis is sparse. According to a biomarker of tissue age known as ], it is hypothesized that trisomy 21 increases the age of blood and brain tissue (on average by 6.6 years).<ref name="Horvath2015DownSyndrome">{{cite journal | vauthors = Horvath S, Garagnani P, Bacalini MG, Pirazzini C, Salvioli S, Gentilini D, Di Blasio AM, Giuliani C, Tung S, Vinters HV, Franceschi C | display-authors = 6 | title = Accelerated epigenetic aging in Down syndrome | journal = Aging Cell | volume = 14 | issue = 3 | pages = 491–495 | date = June 2015 | pmid = 25678027 | pmc = 4406678 | doi = 10.1111/acel.12325 }}</ref> | |||
==Diagnosis== | |||
===Screening before birth=== | |||
Guidelines recommend screening for Down syndrome to be offered to all pregnant women, regardless of age.<ref name=ACOG2007/><ref>{{cite web|title=CG62: Antenatal care |url=http://publications.nice.org.uk/antenatal-care-cg62 |publisher=London: National Institute for Health and Clinical Excellence |access-date=16 February 2013 |author=National Institute for Health and Clinical Excellence |year=2008 |url-status=dead |archive-url=https://web.archive.org/web/20130126165543/http://publications.nice.org.uk/antenatal-care-cg62 |archive-date=26 January 2013 }}</ref> A number of tests are used, with varying levels of accuracy. They are typically used in combination to increase the detection rate.<ref name=Hick2012/> None can be definitive; thus, if screening predicts a high possibility of Down syndrome, either ] or ] is required to confirm the diagnosis.<ref name=ACOG2007/> | |||
==== Ultrasound ==== | |||
] can be used to screen for Down syndrome. Findings that indicate increased chances when seen at 14 to 24 weeks of ] include a small or no nasal bone, ], ], and an abnormal right ], among others.<ref name=Aga2013>{{cite journal | vauthors = Agathokleous M, Chaveeva P, Poon LC, Kosinski P, Nicolaides KH | title = Meta-analysis of second-trimester markers for trisomy 21 | journal = Ultrasound in Obstetrics & Gynecology | volume = 41 | issue = 3 | pages = 247–261 | date = March 2013 | pmid = 23208748 | doi = 10.1002/uog.12364 | doi-access = free }}</ref> The presence or absence of many markers is more accurate.<ref name=Aga2013/> Increased fetal ] (NT) indicates an increased possibility of Down syndrome picking up 75–80% of cases and being falsely positive in 6%.<ref>{{cite journal | vauthors = Malone FD, D'Alton ME | title = First-trimester sonographic screening for Down syndrome | journal = Obstetrics and Gynecology | volume = 102 | issue = 5 Pt 1 | pages = 1066–1079 | date = November 2003 | pmid = 14672489 | doi = 10.1016/j.obstetgynecol.2003.08.004 | s2cid = 24592539 }}</ref> | |||
<gallery mode="packed" heights="200px"> | |||
T21.JPG|Ultrasound of fetus with Down syndrome showing a ] | |||
Nuchal edema in Down Syndrome Dr. W. Moroder.jpg|Enlarged NT and absent nasal bone in a fetus at 11 weeks with Down syndrome | |||
</gallery> | |||
====Blood tests==== | |||
Several blood markers can be measured to predict the chances of Down syndrome during the first or second trimester.<ref name=Can2012/><ref name=Deek2012/> Testing in both trimesters is sometimes recommended and test results are often combined with ultrasound results.<ref name=Can2012/> In the second trimester, often two or three tests are used in combination with two or three of: ], unconjugated estriol, total hCG, and free βhCG detecting about 60–70% of cases.<ref name=Deek2012>{{cite journal | vauthors = Alldred SK, Deeks JJ, Guo B, Neilson JP, Alfirevic Z | title = Second trimester serum tests for Down's Syndrome screening | journal = The Cochrane Database of Systematic Reviews | volume = 2012 | issue = 6 | pages = CD009925 | date = June 2012 | pmid = 22696388 | pmc = 7086392 | doi = 10.1002/14651858.CD009925 | url = http://eprints.nottingham.ac.uk/31499/1/Second%20trimester%20serum%20tests%20for%20Down%27s%20Syndrome%20screening.pdf | access-date = January 7, 2019 | url-status = dead | archive-url = https://web.archive.org/web/20191209234759/http://eprints.nottingham.ac.uk/31499/1/Second%20trimester%20serum%20tests%20for%20Down%27s%20Syndrome%20screening.pdf | archive-date = December 9, 2019 }}</ref> | |||
Testing of the mother's blood for fetal DNA is being studied and appears promising in the first trimester.<ref name="Mersy 318–29"/><ref>{{cite journal | vauthors = Verweij EJ, van den Oever JM, de Boer MA, Boon EM, Oepkes D | title = Diagnostic accuracy of noninvasive detection of fetal trisomy 21 in maternal blood: a systematic review | journal = Fetal Diagnosis and Therapy | volume = 31 | issue = 2 | pages = 81–86 | year = 2012 | pmid = 22094923 | doi = 10.1159/000333060 | doi-access = free }}</ref> The International Society for Prenatal Diagnosis considers it a reasonable screening option for those women whose pregnancies are at a high likelihood of trisomy 21.<ref name=Benn2011/> Accuracy has been reported at 98.6% in the first trimester of pregnancy.<ref name=Hick2012/> Confirmatory testing by invasive techniques (amniocentesis, CVS) is still required to confirm the screening result.<ref name=Benn2011>{{cite journal | vauthors = Benn P, Borrell A, Cuckle H, Dugoff L, Gross S, Johnson JA, Maymon R, Odibo A, Schielen P, Spencer K, Wright D, Yaron Y | display-authors = 6 | title = Prenatal Detection of Down Syndrome using Massively Parallel Sequencing (MPS): a rapid response statement from a committee on behalf of the Board of the International Society for Prenatal Diagnosis, 24 October 2011 | journal = Prenatal Diagnosis | volume = 32 | issue = 1 | pages = 1–2 | date = January 2012 | pmid = 22275335 | doi = 10.1002/pd.2919 | url = http://www.ispdhome.org/public/news/2011/ISPD_RapidResponse_MPS_24Oct11.pdf | url-status = dead | s2cid = 42116198 | archive-url = https://web.archive.org/web/20120319105150/http://www.ispdhome.org/public/news/2011/ISPD_RapidResponse_MPS_24Oct11.pdf | archive-date = 2012-03-19 }}</ref> | |||
====Combinations==== | |||
{| class="wikitable" | {| class="wikitable" | ||
|+ First- and second-trimester screening<ref name=ACOG2007>{{cite journal | title = ACOG Practice Bulletin No. 77: screening for fetal chromosomal abnormalities | journal = Obstetrics and Gynecology | volume = 109 | issue = 1 | pages = 217–227 | date = January 2007 | pmid = 17197615 | doi = 10.1097/00006250-200701000-00054 | author1 = ACOG Committee on Practice Bulletins }}</ref> | |||
|+ Table 2: Some genes located on the long arm of chromosome 21<ref name=Leshin>See {{cite web| author=Leshin, L.| year=2003| url=http://www.ds-health.com/trisomy.htm| title=Trisomy 21: The Story of Down Syndrome| accessdate=2006-05-21}}</ref> | |||
|- | |- | ||
!Screen | |||
!Gene | |||
!] when performed | |||
!] Reference | |||
!Detection rate | |||
!Location | |||
!False positive | |||
!Purported Function | |||
!Description | |||
|- | |- | ||
|Combined test | |||
!] | |||
| 10–13.5 wks | |||
|align="center"| | |||
| 82–87% | |||
|align="center"| | |||
| 5% | |||
|] A4 precursor protein. Suspected to have a major role in cognitive difficulties. One of the first genes studied with ] ] with Down syndrome.<ref>{{cite web|title=Down syndrome traced to one gene| publisher=The Scientist| author=Chandra Shekhar| url=http://www.the-scientist.com/news/display/23869/| date= ] ]|accessdate=2006-07-11}}</ref> | |||
|Uses ] to measure ] in addition to blood tests for free or total beta-hCG and ] | |||
|- | |- | ||
|] | |||
!] | |||
|15–20 wks | |||
|align="center"| | |||
|81% | |||
|align="center"| | |||
| 5% | |||
|]. Possible role in ]. Anti-oxidant as well as possible affects on the immuno-system. | |||
|Measures the maternal serum alpha-fetoprotein, unconjugated estriol, hCG, and ]-A | |||
|- | |- | ||
|Integrated test | |||
!DYRK | |||
|15–20 wks | |||
|align="center"| | |||
|94–96% | |||
|align="center"| | |||
|5% | |||
|Dual-specificity ]. May have an effect on mental development through abnormal neurogenesis. <ref>{{cite journal| author=Song, W.-J., Sternberg, L. R., Kasten-Sportes, C., Van Keuren, M. L., Chung, S.-H., Slack, A. C., Miller, D. E., Glover, T. W., Chiang, P.-W., Lou, L.; Kurnit, D. M.| title=Isolation of human and murine homologues of the Drosophila minibrain gene: human homologue maps to 21q22.2 in the Down syndrome 'critical region| journal=Genomics| volume=38| pages=331-339| year=1996}}</ref> | |||
|Is a combination of the quad screen, PAPP-A, and NT | |||
|- | |- | ||
|] | |||
!IFNAR | |||
|From 10 wks<ref name=oxhp>{{cite web|title=Noninvasive prenatal diagnosis of fetal aneuploidy using cell-free fetal nucleic acids in maternal blood|url=https://www.oxhp.com/secure/policy/noninvasive_prenatal_diagnosis_fetal_aneuploidy.pdf|publisher=United Healthcare Oxford|access-date=25 March 2014|url-status=live|archive-url=https://web.archive.org/web/20140307093626/https://www.oxhp.com/secure/policy/noninvasive_prenatal_diagnosis_fetal_aneuploidy.pdf|archive-date=7 March 2014}}</ref> | |||
|align="center"| | |||
|96–100%<ref name="Mersy 318–29">{{cite journal | vauthors = Mersy E, Smits LJ, van Winden LA, de Die-Smulders CE, Paulussen AD, Macville MV, Coumans AB, Frints SG | display-authors = 6 | title = Noninvasive detection of fetal trisomy 21: systematic review and report of quality and outcomes of diagnostic accuracy studies performed between 1997 and 2012 | journal = Human Reproduction Update | volume = 19 | issue = 4 | pages = 318–329 | date = Jul–Aug 2013 | pmid = 23396607 | doi = 10.1093/humupd/dmt001 | doi-access = free }}</ref> | |||
|align="center"| | |||
|0.3%<ref>{{cite journal | vauthors = Bianchi DW, Parker RL, Wentworth J, Madankumar R, Saffer C, Das AF, Craig JA, Chudova DI, Devers PL, Jones KW, Oliver K, Rava RP, Sehnert AJ | display-authors = 6 | title = DNA sequencing versus standard prenatal aneuploidy screening | journal = The New England Journal of Medicine | volume = 370 | issue = 9 | pages = 799–808 | date = February 2014 | pmid = 24571752 | doi = 10.1056/nejmoa1311037 | doi-access = free }}</ref> | |||
|Interferon, Alpha, Beta, and Omega, Receptor. Responsible for the expression of ], which affects the immuno-system. | |||
|A blood sample is taken from the mother by ] and is sent for DNA analysis. | |||
|} | |||
====Efficacy==== | |||
For combinations of ultrasonography and non-genetic blood tests, screening in both the first and second trimesters is better than just screening in the first trimester.<ref name=ACOG2007/> The different screening techniques in use are able to pick up 90–95% of cases, with a false-positive rate of 2–5%.<ref name=Can2012>{{cite journal | vauthors = Canick J | title = Prenatal screening for trisomy 21: recent advances and guidelines | journal = Clinical Chemistry and Laboratory Medicine | volume = 50 | issue = 6 | pages = 1003–1008 | date = June 2012 | pmid = 21790505 | doi = 10.1515/cclm.2011.671 | s2cid = 37417471 }}</ref> If Down syndrome occurs in one in 500 pregnancies with a 90% detection rate and the test used has a 5% false-positive rate, this means, of 20 women who test positive on screening, only one will not have a fetus with Down syndrome confirmed.<ref name=Can2012/> If the screening test has a 2% false-positive rate, this means, of 50 women who test positive on screening, one will not have a fetus with Down syndrome.<ref name=Can2012/> | |||
====Invasive genetic testing==== | |||
Amniocentesis and chorionic villus sampling are more reliable tests, but they increase the risk of ] by between 0.5–1%.<ref name=Tab2010>{{cite journal | vauthors = Tabor A, Alfirevic Z | title = Update on procedure-related risks for prenatal diagnosis techniques | journal = Fetal Diagnosis and Therapy | volume = 27 | issue = 1 | pages = 1–7 | year = 2010 | pmid = 20051662 | doi = 10.1159/000271995 | doi-access = free | oclc = 23338607 }}</ref> The risk of limb problems may be increased in the offspring if chorionic villus sampling is performed before 10 weeks.<ref name=Tab2010/> | |||
] | |||
The risk from the procedure is greater the earlier it is performed, thus amniocentesis is not recommended before 15 weeks gestational age and chorionic villus sampling before 10 weeks gestational age.<ref name=Tab2010/> | |||
===Abortion rates=== | |||
About 92% of pregnancies in Europe with a diagnosis of Down syndrome are terminated.<ref name=Mans1999/> As a result, there is almost no one with Down syndrome in ] and ], where screening is commonplace.<ref name=Slate2018>{{Cite web|url=https://slate.com/human-interest/2018/05/how-down-syndrome-is-redefining-the-abortion-debate.html|title=How Down Syndrome Is Redefining the Abortion Debate| vauthors = Graham R |date=2018-05-31|website=Slate Magazine|language=en|access-date=2019-01-09}}</ref> In the United States, the termination rate after diagnosis is around 75%,<ref name=Slate2018/> but varies from 61 to 93%, depending on the population surveyed.<ref name=Nat2012/> Rates are lower among women who are younger and have decreased over time.<ref name=Nat2012/> When asked if they would have a termination if their fetus tested positive, 23–33% said yes, when high-risk pregnant women were asked, 46–86% said yes, and when women who screened positive are asked, 89–97% say yes.<ref>{{cite journal | vauthors = Choi H, Van Riper M, Thoyre S | title = Decision making following a prenatal diagnosis of Down syndrome: an integrative review | journal = Journal of Midwifery & Women's Health | volume = 57 | issue = 2 | pages = 156–164 | date = Mar–Apr 2012 | pmid = 22432488 | doi = 10.1111/j.1542-2011.2011.00109.x | doi-access = free }}</ref> | |||
===After birth=== | |||
A diagnosis can often be suspected based on the child's physical appearance at birth.<ref name=Nelson2011/> An analysis of the child's chromosomes is needed to confirm the diagnosis, and to determine if a ] is present, as this may help determine the chances of the child's parents having further children with Down syndrome.<ref name=Nelson2011/> | |||
==Management== | |||
Efforts such as ], therapies, screening for common medical issues, a good family environment, and work-related training can improve the development of children with Down syndrome and provide good quality of life. Common therapies utilized include physical therapy, occupational therapy and speech therapy.<ref>{{Cite web |title=What are common treatments for Down syndrome? |url=https://www.nichd.nih.gov/health/topics/down/conditioninfo/treatments |access-date=28 March 2023 |website=NIH Eunice Kennedy Shriver National Institute of Child Health and Human Development|date=31 January 2017 }}</ref> Education and proper care can provide a positive ].<ref name=Roi2003/> Typical childhood ]s are recommended.<ref name=Hick2012/> | |||
===Health screening=== | |||
{| class="wikitable" style="float:right; margin-left:10px" | |||
|+ Recommended screening | |||
|- | |- | ||
! Testing !! Children<ref name=Bull2011>{{cite journal | vauthors = Bull MJ | title = Health supervision for children with Down syndrome | journal = Pediatrics | volume = 128 | issue = 2 | pages = 393–406 | date = August 2011 | pmid = 21788214 | doi = 10.1542/peds.2011-1605 | doi-access = free }}</ref>!! Adults<ref name=Malt2013/> | |||
!DSCR1 | |||
|align="center"| | |||
|align="center"| | |||
|Down Syndrome Critical Region Gene 1. Possibly part of a ] pathway involving both heart and brain.<ref>{{cite journal| author=Fuentes JJ, Pritchard MA, Planas AM, Bosch A, Ferrer I, Estivill X| title=A new human gene from the Down syndrome critical region encodes a proline-rich protein highly expressed in fetal brain and heart| journal=Hum Mol Genet| year=1995| volume=4| issue=10| pages=1935-1944}}</ref> | |||
|- | |- | ||
| Hearing || 6 months, 12 months, then yearly || 3–5 years | |||
!COL6A1 | |||
|align="center"| | |||
|align="center"| | |||
|], type I, alpha 1 gene. May have an effect on heart disease. | |||
|- | |- | ||
| ] and ] || 6 months, then yearly|| | |||
!ETS2 | |||
|align="center"| | |||
|align="center"| | |||
|Avian Erythroblastosis Virus E26 Oncogene Homolog 2. Researchers have "demonstrated that overexpression of ETS2 results in ]. Transgenic mice overexpressing ETS2 developed a smaller thymus and lymphocyte abnormalities, similar to features observed in Down syndrome."<ref>{{cite web| author=OMIM, NIH| url=http://www3.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=164740| title=V-ETS Avian Erythroblastosis virus E26 Oncogene Homolog 2| accessdate=2006-06-29}}</ref> | |||
|- | |- | ||
| Eyes || 6 months, then yearly||3–5 years | |||
!CRYA1 | |||
|- | |||
|align="center"| | |||
| Teeth || 2 years, then every 6 months|| | |||
|align="center"| | |||
|- | |||
|Crystallin, Alpha-A. Involved in the synthesis of ], a major component of the lens in eyes. May be cause of cataracts. | |||
| Celiac disease || Between 2 and 3 years of age,<br> or earlier if symptoms occur|| | |||
|- | |||
| ] || 3 to 4 years, or earlier if symptoms<br> of ] occur|| | |||
|- | |||
| Neck X-rays || Between 3 and 5 years of age|| | |||
|} | |} | ||
A number of health organizations have issued recommendations for ] those with Down syndrome for particular diseases.<ref name=Bull2011/> This is recommended to be done systematically.<ref name=Hick2012/> | |||
To date, "no gene has yet been fully linked to any feature associated with Down syndrome."<ref name=Leshin>See {{cite web| author=Leshin, L.| year=2003| url=http://www.ds-health.com/trisomy.htm| title=Trisomy 21: The Story of Down Syndrome| accessdate=2006-05-21}}</ref> | |||
At birth, all children should get an ] and ].<ref name=Hick2012/> Surgical repair of heart problems may be required as early as three months of age.<ref name=Hick2012/> ] problems may occur in young adults, and further ultrasound evaluation may be needed in adolescents and in early adulthood.<ref name=Hick2012/> Due to the elevated risk of testicular cancer, some recommend checking the person's testicles yearly.<ref name=Malt2013/> | |||
== Sociological and cultural aspects == | |||
] for people with Down syndrome point to various factors, such as special education and parental support groups, that make life easier for parents. There are also great strides being made in education, housing, and social settings to create "Down-friendly" environments. In most developed countries, since the early 20th century many people with Down syndrome were housed in institutions or colonies and excluded from society. However, in the 21st century there is a change among parents, educators and other professionals generally advocating a policy of "inclusion"<ref>See the pamphlet: {{cite book| title=Inclusion: Educating Students with Down Syndrome with Their Non-Disabled Peers| publisher=National Down Syndrome Society| url=http://www.ndss.org/content.cfm?fuseaction=InfoRes.SchEduarticle&article=571| accessdate=2006-05-21}}</ref>, bringing people with any form of mental or physical disability into general society as much as possible. In many countries, people with Down syndrome are educated in the normal school system and there are increasingly higher quality opportunities to mix "special" education with regular education settings. | |||
===Cognitive development=== | |||
<!-- Hearing and Speech --> | |||
Some people with Down syndrome experience hearing loss. In this instance, ] or other amplification devices can be useful for language learning.<ref name="Hick2012" /> ] may be useful and is recommended to be started around nine months of age.<ref name="Hick2012" /> As those with Down syndrome typically have good hand-eye coordination, learning ] is a helpful communication tool.<ref name="Reil2012" /> ] methods, such as pointing, body language, objects, or pictures, are often used to help with communication.<ref name="Price2007">{{cite journal | vauthors = Roberts JE, Price J, Malkin C | title = Language and communication development in Down syndrome | journal = Mental Retardation and Developmental Disabilities Research Reviews | volume = 13 | issue = 1 | pages = 26–35 | year = 2007 | pmid = 17326116 | doi = 10.1002/mrdd.20136 }}</ref> Behavioral issues and mental illness are typically managed with counseling or medications.<ref name="Nelson2011" /><!-- School --> | |||
Education programs before reaching school age may be useful.<ref name=Wei2010/> School-age children with Down syndrome may benefit from ] (whereby students of differing abilities are placed in classes with their peers of the same age), provided some adjustments are made to the curriculum.<ref>{{cite web|title=Inclusion: Educating Students with Down Syndrome with Their Non-Disabled Peers|url=http://www.kcdsg.org/files/content/Educating%20Students%20with%20Down%20Syndrome%20With%20Their%20Typical%20Peers.pdf|publisher=National Down Syndrome Society|access-date=5 February 2014|url-status=live|archive-url=https://web.archive.org/web/20141127111652/http://www.kcdsg.org/files/content/Educating%20Students%20with%20Down%20Syndrome%20With%20Their%20Typical%20Peers.pdf|archive-date=27 November 2014}}</ref> In the United States, the ] of 1975 requires public schools generally to allow attendance by students with Down syndrome.<ref>{{cite book| vauthors = New RS, Cochran M |title=Early childhood education an international encyclopedia|year=2007|publisher=Praeger Publishers|location=Westport, Conn.|isbn=978-0-313-01448-2 |page=305 |url=https://books.google.com/books?id=JulOlhMP3JAC&pg=PA305 |url-status=live|archive-url= https://web.archive.org/web/20170123083030/https://books.google.com/books?id=JulOlhMP3JAC&pg=PA305 |archive-date=2017-01-23}}</ref> | |||
<!-- Early Intervention Therapies --> | |||
=== World Down Syndrome Day === | |||
Individuals with Down syndrome may learn better visually. Drawing may help with language, speech, and reading skills. Children with Down syndrome still often have difficulty with sentence structure and grammar, as well as developing the ability to speak clearly.<ref>{{Cite news|url=https://www.dseinternational.org/en-us/about-down-syndrome/development/|title=Development and learning for people with Down syndrome|language=en-US|access-date=2016-11-18|url-status=live|archive-url=https://web.archive.org/web/20161119055326/https://www.dseinternational.org/en-us/about-down-syndrome/development/|archive-date=2016-11-19}}</ref> Several types of early intervention can help with cognitive development. Efforts to develop motor skills include physical therapy, speech and language therapy, and occupational therapy. Physical therapy focuses specifically on motor development and teaching children to interact with their environment. Speech and language therapy can help prepare for later language. Lastly, occupational therapy can help with skills needed for later independence.<ref>{{Cite web|url=http://www.ndss.org/resources/therapies-development/early-intervention/|title=Early Intervention – National Down Syndrome Society|website=www.ndss.org|access-date=2016-11-18|url-status=live|archive-url=https://web.archive.org/web/20161119060027/http://www.ndss.org/resources/therapies-development/early-intervention/|archive-date=2016-11-19}}</ref> | |||
The first World Down Syndrome Day was held on ] ]. The day and month were chosen to correspond with ] and ] respectively. It was proclaimed by Down Syndrome International.<ref>{{cite web| url=http://www.worlddownsyndromeday.org|title=World Down Syndrome Day| accessdate=2006-06-02}}</ref> | |||
===Other=== | |||
== Notable individuals == | |||
]s are often needed<ref name=Hick2012/> and often more than one set during the person's childhood.<ref name=Rod2012>{{cite journal | vauthors = Rodman R, Pine HS | title = The otolaryngologist's approach to the patient with Down syndrome | journal = Otolaryngologic Clinics of North America | volume = 45 | issue = 3 | pages = 599–629, vii–viii | date = June 2012 | pmid = 22588039 | doi = 10.1016/j.otc.2012.03.010 }}</ref> ] is also often done to help with sleep apnea and ].<ref name=Hick2012/> Surgery does not correct every instance of sleep apnea and a ] (CPAP) machine may be useful in those cases.<ref name=Rod2012/> | |||
]'']] | |||
Notable people with Down syndrome include: | |||
* ], actor ('']'') and autobiographer | |||
* ] (1928-1948), daughter of ] | |||
* ], actor ('']'' aka The Eighth Day, ''Toto le héros'' aka Toto the Hero) | |||
* ], actor ('']'') First actor with Down syndrome in the lead part of a motion picture. | |||
* ], ] ] attendant | |||
* ], artist | |||
* ], singer with Argentinian avant-rock band ] | |||
Efforts to prevent ] (RSV) infection with ] should be considered, especially in those with heart problems.<ref name=Wei2010/> In those who develop dementia there is no evidence for ],<ref>{{cite journal | vauthors = Mohan M, Bennett C, Carpenter PK | title = Memantine for dementia in people with Down syndrome | journal = The Cochrane Database of Systematic Reviews | volume = 2009 | issue = 1 | pages = CD007657 | date = January 2009 | pmid = 19160343 | pmc = 7197456 | doi = 10.1002/14651858.CD007657 }}</ref> ],<ref>{{cite journal | vauthors = Mohan M, Carpenter PK, Bennett C | title = Donepezil for dementia in people with Down syndrome | journal = The Cochrane Database of Systematic Reviews | volume = 2009 | issue = 1 | pages = CD007178 | date = January 2009 | pmid = 19160328 | pmc = 7208846 | doi = 10.1002/14651858.CD007178.pub2 }}</ref> ],<ref>{{cite journal | vauthors = Mohan M, Bennett C, Carpenter PK | title = Rivastigmine for dementia in people with Down syndrome | journal = The Cochrane Database of Systematic Reviews | volume = 2009 | issue = 1 | pages = CD007658 | date = January 2009 | pmid = 19160344 | pmc = 7197503 | doi = 10.1002/14651858.CD007658 }}</ref> or ].<ref>{{cite journal | vauthors = Mohan M, Bennett C, Carpenter PK | title = Galantamine for dementia in people with Down syndrome | journal = The Cochrane Database of Systematic Reviews | volume = 2009 | issue = 1 | pages = CD007656 | date = January 2009 | pmid = 19160342 | pmc = 7197502 | doi = 10.1002/14651858.CD007656 }}</ref> | |||
The Down Syndrome Association of Los Angeles has a more complete list of . | |||
==Prognosis== | |||
== Portrayal in fiction == | |||
] | |||
* ]: '']'' | |||
Between 5–15% of children with Down syndrome in Sweden attend regular school.<ref name=EU2006/> Some graduate from high school; however, most do not.<ref name=Stein2011/> Of those with intellectual disability in the United States who attended high school about 40% graduated.<ref>{{cite web|title=Number of 14- through 21-year-old students served under Individuals with Disabilities Education Act, Part B, who exited school, by exit reason, age, and type of disability: 2007–08 and 2008–09|url=https://nces.ed.gov/programs/digest/d11/tables/dt11_118.asp|work=National Center for Education Statistics|access-date=7 February 2014|url-status=live|archive-url=https://web.archive.org/web/20140222132619/https://nces.ed.gov/programs/digest/d11/tables/dt11_118.asp|archive-date=22 February 2014}}</ref> Many learn to read and write and some are able to do paid work.<ref name=Stein2011/> In adulthood about 20% in the United States do paid work in some capacity.<ref name=US2013/><ref>{{cite web|title=Down's Syndrome: Employment Barriers|url=http://www.rehacare.com/cipp/md_rehacare/custom/pub/content,oid,15324/lang,2/ticket,g_u_e_s_t/mcat_id,7738/local_lang,2|work=Rehab Care International|access-date=7 February 2014|url-status=dead|archive-url=https://web.archive.org/web/20140222065400/http://www.rehacare.com/cipp/md_rehacare/custom/pub/content,oid,15324/lang,2/ticket,g_u_e_s_t/mcat_id,7738/local_lang,2|archive-date=22 February 2014}}</ref> In Sweden, however, less than 1% have regular jobs.<ref name="EU2006">{{cite web|url=http://www.down-syndrome.eu/files/profiles/edsa_sweden.pdf |title=European Down Syndrome Association news |year=2006 |archive-url=https://web.archive.org/web/20140222204153/http://www.down-syndrome.eu/files/profiles/edsa_sweden.pdf |archive-date=22 February 2014 |url-status=dead |work=European Down Syndrome Association |access-date=7 February 2014 }}</ref> Many are able to live semi-independently,<ref name=Steph2010/> but they often require help with financial, medical, and legal matters.<ref name=Nelson2011/> Those with mosaic Down syndrome usually have better outcomes.<ref name=Nel2010>{{cite book| vauthors = Nelson MR |title=Pediatrics|year=2011|publisher=Demos Medical|location=New York|isbn=978-1-61705-004-6|page=88|url=https://books.google.com/books?id=8wE1dAYxGhoC&pg=PA88|url-status=live|archive-url=https://web.archive.org/web/20170123082430/https://books.google.com/books?id=8wE1dAYxGhoC&pg=PA88|archive-date=2017-01-23}}</ref> | |||
* ]: ''The Clowns of God'' | |||
* ]: '']'' | |||
Individuals with Down syndrome have a higher risk of early death than the general population.<ref name=Hick2012/> This is most often from heart problems or infections.<ref name=Wei2010/><ref name=Malt2013/> Following improved medical care, particularly for heart and ]s, the life expectancy has increased.<ref name=Wei2010/> This increase has been from 12 years in 1912,<ref name="Urbano2010108">{{cite book | vauthors = Urbano R |title=Health Issues Among Persons With Down Syndrome|url=https://books.google.com/books?id=QbHL8qrgfCoC&pg=PA108|date=9 September 2010|publisher=Academic Press|isbn=978-0-12-374477-7|page=108|url-status=live|archive-url=https://web.archive.org/web/20150512112441/http://books.google.com/books?id=QbHL8qrgfCoC&pg=PA108|archive-date=12 May 2015}}</ref> to 25 years in the 1980s,<ref name=Wei2010/> to 50 to 60 years in the developed world in the 2000s.<ref name=Malt2013/><ref name=Nelson2011/> Data collected between the 1985–2003 showed between 4–12% infants with Down syndrome die in the first year of life.<ref name=Gam2012/> The probability of long-term survival is partly determined by the presence of heart problems. From research at the turn of the century, it tracked those with congenital heart problems, showing 60% survived to at least 10 years and 50% survived to at least 30 years of age. The research failed to track further aging beyond 30 years.<ref name="Steph2010" /> In those without heart problems, 85% studied survived to at least 10 years and 80% survived to at least 30 years of age.<ref name=Steph2010/> It is estimated that 10% lived to 70 years of age in the early 2000s.<ref name=Rubin2013/> Much of this data is outdated and life expectancy has drastically improved with more equitable healthcare and continuous advancement of surgical practice.<ref>{{Cite web |title=Survival Rates Improving for Patients with Down Syndrome and Congenital Heart Defects |url=http://www.cardiosmart.org/news/2016/7/survival-rates-improving-for-patients-with-down-syndrome-and-congenital-heart-defects |access-date=2023-03-31 |website=CardioSmart |language=en}}</ref> The ] provides information regarding raising a child with Down syndrome.<ref>{{cite web|title=Where Should I Go From Here?|url=http://www.ndss.org/Resources/New-Expectant-Parents/Where-Should-I-Go-From-Here/|access-date=19 December 2015|url-status=live|archive-url=https://web.archive.org/web/20151222115201/http://www.ndss.org/Resources/New-Expectant-Parents/Where-Should-I-Go-From-Here/|archive-date=22 December 2015 | work = National Down Syndrome Society }}</ref> | |||
* ]: '']'' | |||
* ] and its American counterpart, '']'' | |||
==Epidemiology== | |||
* Elizabeth Laird: ''Red Sky in the Morning'' | |||
]<ref name=Mor2002>{{cite journal | vauthors = Morris JK, Mutton DE, Alberman E | title = Revised estimates of the maternal age specific live birth prevalence of Down's syndrome | journal = Journal of Medical Screening | volume = 9 | issue = 1 | pages = 2–6 | year = 2002 | pmid = 11943789 | doi = 10.1136/jms.9.1.2 | doi-access = free }}</ref>]] | |||
* ]: '']'' | |||
Down syndrome is the most common chromosomal abnormality in humans.<ref name="Malt2013" /> Globally, {{as of|2010|lc=y}}, Down syndrome occurs in about 1 per 1,000 births<ref name=Wei2010/> and results in about 17,000 deaths.<ref name=Loz2012>{{cite journal | vauthors = Lozano R, Naghavi M, Foreman K, Lim S, Shibuya K, Aboyans V, Abraham J, Adair T, Aggarwal R, Ahn SY, Alvarado M, Anderson HR, Anderson LM, Andrews KG, Atkinson C, Baddour LM, Barker-Collo S, Bartels DH, Bell ML, Benjamin EJ, Bennett D, Bhalla K, Bikbov B, Bin Abdulhak A, Birbeck G, Blyth F, Bolliger I, Boufous S, Bucello C, Burch M, Burney P, Carapetis J, Chen H, Chou D, Chugh SS, Coffeng LE, Colan SD, Colquhoun S, Colson KE, Condon J, Connor MD, Cooper LT, Corriere M, Cortinovis M, de Vaccaro KC, Couser W, Cowie BC, Criqui MH, Cross M, Dabhadkar KC, Dahodwala N, De Leo D, Degenhardt L, Delossantos A, Denenberg J, Des Jarlais DC, Dharmaratne SD, Dorsey ER, Driscoll T, Duber H, Ebel B, Erwin PJ, Espindola P, Ezzati M, Feigin V, Flaxman AD, Forouzanfar MH, Fowkes FG, Franklin R, Fransen M, Freeman MK, Gabriel SE, Gakidou E, Gaspari F, Gillum RF, Gonzalez-Medina D, Halasa YA, Haring D, Harrison JE, Havmoeller R, Hay RJ, Hoen B, Hotez PJ, Hoy D, Jacobsen KH, James SL, Jasrasaria R, Jayaraman S, Johns N, Karthikeyan G, Kassebaum N, Keren A, Khoo JP, Knowlton LM, Kobusingye O, Koranteng A, Krishnamurthi R, Lipnick M, Lipshultz SE, Ohno SL, Mabweijano J, MacIntyre MF, Mallinger L, March L, Marks GB, Marks R, Matsumori A, Matzopoulos R, Mayosi BM, McAnulty JH, McDermott MM, McGrath J, Mensah GA, Merriman TR, Michaud C, Miller M, Miller TR, Mock C, Mocumbi AO, Mokdad AA, Moran A, Mulholland K, Nair MN, Naldi L, Narayan KM, Nasseri K, Norman P, O'Donnell M, Omer SB, Ortblad K, Osborne R, Ozgediz D, Pahari B, Pandian JD, Rivero AP, Padilla RP, Perez-Ruiz F, Perico N, Phillips D, Pierce K, Pope CA, Porrini E, Pourmalek F, Raju M, Ranganathan D, Rehm JT, Rein DB, Remuzzi G, Rivara FP, Roberts T, De León FR, Rosenfeld LC, Rushton L, Sacco RL, Salomon JA, Sampson U, Sanman E, Schwebel DC, Segui-Gomez M, Shepard DS, Singh D, Singleton J, Sliwa K, Smith E, Steer A, Taylor JA, Thomas B, Tleyjeh IM, Towbin JA, Truelsen T, Undurraga EA, Venketasubramanian N, Vijayakumar L, Vos T, Wagner GR, Wang M, Wang W, Watt K, Weinstock MA, Weintraub R, Wilkinson JD, Woolf AD, Wulf S, Yeh PH, Yip P, Zabetian A, Zheng ZJ, Lopez AD, Murray CJ, AlMazroa MA, Memish ZA | display-authors = 6 | title = Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010 | journal = Lancet | volume = 380 | issue = 9859 | pages = 2095–2128 | date = December 2012 | pmid = 23245604 | pmc = 10790329 | doi = 10.1016/S0140-6736(12)61728-0 | hdl-access = free | s2cid = 1541253 | hdl = 10536/DRO/DU:30050819 }}</ref> More children are born with Down syndrome in countries where abortion is not allowed and in countries where pregnancy more commonly occurs at a later age.<ref name=Wei2010/> About 1.4 per 1,000 live births in the United States<ref name=Parker2010>{{cite journal | vauthors = Parker SE, Mai CT, Canfield MA, Rickard R, Wang Y, Meyer RE, Anderson P, Mason CA, Collins JS, Kirby RS, Correa A | display-authors = 6 | title = Updated National Birth Prevalence estimates for selected birth defects in the United States, 2004-2006 | journal = Birth Defects Research. Part A, Clinical and Molecular Teratology | volume = 88 | issue = 12 | pages = 1008–1016 | date = December 2010 | pmid = 20878909 | doi = 10.1002/bdra.20735 }}</ref> and 1.1 per 1,000 live births in Norway are affected.<ref name=Malt2013/> In the 1950s, in the United States, it occurred in 2 per 1,000 live births with the decrease since then due to prenatal screening and abortions.<ref name=Menk2006>{{cite book| vauthors = Menkes JH, Sarnat HB |title=Child neurology|year=2005|publisher=Lippincott Williams & Wilkins|location=Philadelphia, PA|isbn=978-0-7817-5104-9|page=228|url=https://books.google.com/books?id=gnjMX_jtvYoC&pg=PA228|edition=7th|url-status=live|archive-url=https://web.archive.org/web/20170123082801/https://books.google.com/books?id=gnjMX_jtvYoC&pg=PA228|archive-date=2017-01-23}}</ref> The number of pregnancies with Down syndrome is more than two times greater with many spontaneously aborting.<ref name=Nelson2011/> It is the cause of 8% of all ].<ref name=Wei2010/> | |||
* ]: '']'' | |||
* ]: '']'' | |||
] affects the chances of having a pregnancy with Down syndrome.<ref name=Mor2002/> At age 20, the chance is 1 in 1,441; at age 30, it is 1 in 959; at age 40, it is 1 in 84; and at age 50 it is 1 in 44.<ref name=Mor2002/> Although the probability increases with maternal age, 70% of children with Down syndrome are born to women 35 years of age and younger, because younger people have more children.<ref name=Mor2002/> The ] is also a risk factor in women older than 35, but not in women younger than 35, and may partly explain the increase in risk as women age.<ref name=Doug2013>{{cite book | vauthors = Fisch H | chapter = The male biological clock |title=Paternal influences on human reproductive success|year=2013|publisher=Cambridge University Press|isbn=978-1-107-02448-9|page=65| chapter-url = https://books.google.com/books?id=O4Px3Q7f34QC&pg=PA65| veditors = Carrell DT |url-status=live|archive-url=https://web.archive.org/web/20170123082733/https://books.google.com/books?id=O4Px3Q7f34QC&pg=PA65|archive-date=2017-01-23}}</ref> | |||
* ]: Benjamin Compson in '']'' | |||
==History== | |||
], ''The Adoration of the Christ Child'', depicts a person with Down syndrome as one of the angels.<ref>{{cite journal | vauthors = Levitas AS, Reid CS | title = An angel with Down syndrome in a sixteenth century Flemish Nativity painting | journal = American Journal of Medical Genetics. Part A | volume = 116A | issue = 4 | pages = 399–405 | date = February 2003 | pmid = 12522800 | doi = 10.1002/ajmg.a.10043 | quote = We have identified a 16th-century Flemish Nativity painting in which one angelic figure appears distinctly different from other individuals in the painting with an appearance of Down syndrome. | s2cid = 8821338 }}</ref>]] | |||
] — first described Down syndrome]] | |||
English physician ] first described Down syndrome in 1862, recognizing it as a distinct type of mental disability, and again in a more widely published report in 1866.<ref name=Hick2012/><ref>{{cite journal|year= 1866|title= Observations on an ethnic classification of idiots|url= http://www.neonatology.org/classics/down.html|journal= Clinical Lecture Reports, London Hospital|volume= 3|pages= 259–62| vauthors = Down JL |access-date= 2006-07-14|url-status= live|archive-url= https://web.archive.org/web/20060615010343/http://www.neonatology.org/classics/down.html|archive-date= 2006-06-15}}</ref><ref>{{cite book|title=John Langdon Down, 1828–1896|publisher=Royal Society of Medicine Press|year=1998|isbn=978-1-85315-374-7| vauthors = Conor WO }}</ref> ] described it as separate from ] in 1844.<ref name=Evans2009p12/><ref name="Neri2009">{{cite journal | vauthors = Neri G, Opitz JM | title = Down syndrome: comments and reflections on the 50th anniversary of Lejeune's discovery | journal = American Journal of Medical Genetics. Part A | volume = 149A | issue = 12 | pages = 2647–2654 | date = December 2009 | pmid = 19921741 | doi = 10.1002/ajmg.a.33138 | s2cid = 12945876 }}</ref> By the 20th century, Down syndrome had become the most recognizable form of mental disability. | |||
Due to his perception that children with Down syndrome shared facial similarities with those of ], John Langdon Down used the term "]".<ref>{{cite book | vauthors = Reisner H | date = 2013 | title = Essentials of Rubin's Pathology | publisher = Lippincott Williams & Wilkins | pages = 129–131 | isbn = 978-1-4511-8132-6}}</ref> He felt that the existence of Down syndrome confirmed that all peoples were genetically related.<ref>{{cite book | vauthors = Gould S | date = 2010 | title = The Panda's Thumb: More Reflections in Natural History | publisher = W. W. Norton & Company | pages = 166 | isbn = 978-0-393-34083-9 }}</ref> In the 1950s with discovery of the underlying cause as being related to chromosomes, concerns about the race-based nature of the name increased.<ref>{{cite book | vauthors = Keevak M | date = 2011 | title = Becoming Yellow: A Short History of Racial Thinking | publisher = Princeton University Press | page = 120 | isbn = | |||
978-1-4008-3860-8 }}</ref> | |||
In 1961, a group of nineteen scientists suggested that "mongolism" had "misleading connotations" and had become "an embarrassing term".<ref name="Rod2011" /> The ] (WHO) dropped the term in 1965 after a request by the delegation from the ].<ref name="pmid153994">{{cite journal | vauthors = Howard-Jones N | title = On the diagnostic term "Down's disease" | journal = Medical History | volume = 23 | issue = 1 | pages = 102–4 | date = January 1979 | pmid = 153994 | pmc = 1082401 | doi = 10.1017/s0025727300051048 }}</ref> While this terminology continued to be used until the late twentieth century,<ref name=":6">{{Cite book | vauthors = Driscoll MW |title=The Whites are Enemies of Heaven: Climate Caucasianism and Asian Ecological Protection |date=2020 |publisher=] |isbn=978-1-4780-1121-7 |location=Durham}}</ref>{{Rp|page=21}} it is now considered unacceptable and is no longer in common use. | |||
In antiquity, many infants with disabilities were either killed or abandoned.<ref name=Evans2009p12/> | |||
In June 2020, the earliest incidence of Down syndrome was found in genomic evidence from an infant that was buried before 3200 BC at ] in ].<ref>{{cite web |url=https://www.rte.ie/news/2020/0617/1148049-genomes-study/|title=Genetics study shines light on early periods of Ireland's human history|author=<!--Not stated--> |date= 17 June 2020|website= www.rte.ie|publisher=Raidió Teilifís Éireann |access-date= 17 June 2020}}</ref> | |||
Researchers believe that a number of historical pieces of art portray Down syndrome, including pottery from the ] Tumaco-La Tolita culture in present-day ] and ],<ref name="BernalBriceno">{{cite journal | vauthors = Bernal JE, Briceno I | title = Genetic and other diseases in the pottery of Tumaco-La Tolita culture in Colombia-Ecuador | journal = Clinical Genetics | volume = 70 | issue = 3 | pages = 188–191 | date = September 2006 | pmid = 16922718 | doi = 10.1111/j.1399-0004.2006.00670.x | s2cid = 27716271 }}</ref> and the 16th-century painting ''The Adoration of the Christ Child''.<ref>{{cite book | vauthors = Evans-Martin FF | title = Down Syndrome | url = https://books.google.com/books?id=BJf2JgWbYoYC | series = Genes & Disease | location = New York | publisher = Infobase Publishing | date = 2009 | page = 13 | isbn = 9781438119502 | access-date = 20 March 2020 | quote = There is also very little representation of Down syndrome in art over the centuries. Only a few paintings, such as the sixteenth century Flemish painting ''The Adoration of the Christ Child'', have been identified in which characters appear to have facial features and other characteristics typical of Down syndrome.}}</ref><ref name=Evans2009p1314>{{cite book| vauthors = Evans-Martin FF |title=Down Syndrome|year=2009|publisher=Chelsea House|location=New York|isbn=978-1-4381-1950-2|pages=–14|url=https://archive.org/details/downsyndrome0000evan|url-access=registration}}</ref> | |||
In the 20th century, many individuals with Down syndrome were institutionalized, few of the associated medical problems were treated, and most people died in infancy or early adulthood. With the rise of the ], 33 of the then 48 ]s and several countries began programs of forced sterilization of individuals with Down syndrome and comparable degrees of disability. ] in ] saw the systematic murder of people with Down syndrome made public policy.<ref name="Wright2011">{{cite book| vauthors = Wright D |title= Downs: The history of a disability |url= https://books.google.com/books?id=0FMKNv_ALRYC&pg=PA200|access-date= 25 August 2012|date=25 August 2011|publisher= Oxford University Press|isbn= 978-0-19-956793-5|pages= 104–108|url-status= live|archive-url= https://web.archive.org/web/20130528115732/http://books.google.com/books?id=0FMKNv_ALRYC&pg=PA200|archive-date= 28 May 2013}}</ref> | |||
With the discovery of ] techniques in the 1950s it became possible to identify abnormalities of chromosomal number or shape.<ref name=Neri2009/> In 1959 ] reported the discovery that Down syndrome resulted from an extra chromosome.<ref name=Hick2012/> However, Lejeune's claim to the discovery has been disputed,<ref>{{cite book| vauthors = Wright D |title= Downs: The history of a disability|url= https://books.google.com/books?id=0FMKNv_ALRYC&pg=PA200|access-date= 25 August 2012|date= 25 August 2011|publisher= Oxford University Press|isbn=978-0-19-956793-5|page=145|url-status=live|archive-url=https://web.archive.org/web/20130528115732/http://books.google.com/books?id=0FMKNv_ALRYC&pg=PA200|archive-date= 28 May 2013}}</ref> and in 2014 the Scientific Council of the French Federation of Human Genetics unanimously awarded its Grand Prize to his colleague ] for her role in this discovery.<ref>{{cite news|title= Trisomie: une pionnière intimidée|url=http://www.lemonde.fr/sciences/article/2014/02/03/trisomie-une-pionniere-intimidee_4359331_1650684.html|access-date=25 March 2014|newspaper= Le Monde|date= Feb 3, 2014 |language=fr}}</ref> The discovery took place in the laboratory of ] at the Hôpital Trousseau in Paris, France.<ref>{{Cite journal| vauthors = Gautier M, Harper PS |year= 2009|title= Fiftieth anniversary of trisomy 21: returning to a discovery|url= http://www.hopkinsmedicine.org/women_science_medicine/_pdfs/Trisomy%2021%20article.pdf|journal= Human Genetics|volume= 126|issue= 2|pages= 317–324|doi= 10.1007/s00439-009-0690-1|s2cid= 30299551|url-status= live|archive-url= https://web.archive.org/web/20170202012842/http://www.hopkinsmedicine.org/women_science_medicine/_pdfs/Trisomy%2021%20article.pdf|archive-date= 2017-02-02}}</ref> Jérôme Lejeune and Marthe Gautier were both his students.<ref>{{cite journal | vauthors = Pain E | title = History of science. After more than 50 years, a dispute over Down syndrome discovery | journal = Science | volume = 343 | issue = 6172 | pages = 720–721 | date = February 2014 | pmid = 24531949 | doi = 10.1126/science.343.6172.720 | doi-access = free | bibcode = 2014Sci...343..720P }}</ref> | |||
As a result of this discovery, the condition became known as trisomy 21.<ref>{{cite book| vauthors = Wright D |title= Downs: The history of a disability |url= https://books.google.com/books?id=0FMKNv_ALRYC&pg=PA200|access-date= 25 August 2012|date= 25 August 2011|publisher= Oxford University Press|isbn= 978-0-19-956793-5|pages= 9–10|url-status= live|archive-url= https://web.archive.org/web/20130528115732/http://books.google.com/books?id=0FMKNv_ALRYC&pg=PA200|archive-date= 28 May 2013}}</ref> Even before the discovery of its cause, the presence of the syndrome in all races, its association with older maternal age, and its rarity of recurrence had been noticed. Medical texts had assumed it was caused by a combination of inheritable factors that had not been identified. Other theories had focused on injuries sustained during birth.<ref>{{cite book | vauthors = Warkany J |title= Congenital Malformations |location= Chicago |publisher= Year Book Medical Publishers, Inc |year= 1971 |pages= 313–14|isbn= 978-0-8151-9098-1}}</ref> | |||
{{clear}} | |||
==Society and culture== | |||
{{See also|List of people with Down syndrome}} | |||
===Name=== | |||
Down syndrome is named after ]. He was the first person to provide an accurate description of the syndrome. His research that was published in 1866 earned him the recognition as the Father of the syndrome.<ref>{{Cite web |title=About Down Syndrome |url=https://ndss.org/about |access-date=28 March 2023 |website=National Down Syndrome Society}}</ref> While others had previously recognized components of the condition, John Langdon Down described the syndrome as a distinct, unique medical condition.<ref name=":4" /> | |||
In 1975, the United States ] (NIH) convened a conference to standardize the naming and recommended replacing the possessive form, "Down's syndrome", with "Down syndrome".<ref>{{cite journal | vauthors = | title = Classification and nomenclature of morphological defects | journal = Lancet | volume = 1 | issue = 7905 | pages = 513 | date = March 1975 | pmid = 46972 | doi = 10.1016/S0140-6736(75)92847-0 | s2cid = 37636187 }}</ref> However, both the possessive and nonpossessive forms remain in use by the general population.<ref name=Smith-2011>{{cite book| vauthors = Smith K |title=The politics of Down syndrome|year=2011|publisher=Zero|location=|isbn=978-1-84694-613-4|page=3|url=https://books.google.com/books?id=wSWzQyUZJxUC&pg=PA3|url-status=live|archive-url=https://web.archive.org/web/20170123082433/https://books.google.com/books?id=wSWzQyUZJxUC&pg=PA3|archive-date=2017-01-23}}</ref> The term "trisomy 21" is also commonly used.<ref name="Rod2011">{{cite journal | vauthors = Rodríguez-Hernández ML, Montoya E | title = Fifty years of evolution of the term Down's syndrome | journal = Lancet | volume = 378 | issue = 9789 | pages = 402 | date = July 2011 | pmid = 21803206 | doi = 10.1016/s0140-6736(11)61212-9 | s2cid = 8541289 }}</ref><ref>{{cite book| vauthors = Westman JS |title=Medical genetics for the modern clinician.|year=2005|publisher=Lippincott Williams & Wilkins|location=Philadelphia, PA|isbn=978-0-7817-5760-7|page=|url=https://archive.org/details/medicalgeneticsf0000west|url-access=registration}}</ref> | |||
===Ethics=== | |||
] | |||
Obstetricians routinely offer antenatal screenings for various conditions, including Down syndrome.<ref name=Cher2010>{{cite journal | vauthors = Chervenak FA, McCullough LB | title = Ethical considerations in first-trimester Down syndrome risk assessment | journal = Current Opinion in Obstetrics & Gynecology | volume = 22 | issue = 2 | pages = 135–138 | date = April 2010 | pmid = 20125014 | doi = 10.1097/gco.0b013e3283374a9f | s2cid = 2017130 }}</ref><ref>{{Cite journal |last1=Ravitsky |first1=Vardit |last2=Roy |first2=Marie-Christine |last3=Haidar |first3=Hazar |last4=Henneman |first4=Lidewij |last5=Marshall |first5=John |last6=Newson |first6=Ainsley J. |last7=Ngan |first7=Olivia M.Y. |last8=Nov-Klaiman |first8=Tamar |date=2021-08-31 |title=The Emergence and Global Spread of Noninvasive Prenatal Testing |journal=Annual Review of Genomics and Human Genetics |language=en |volume=22 |issue=1 |pages=309–338 |doi=10.1146/annurev-genom-083118-015053 |issn=1527-8204|doi-access=free |pmid=33848430 }}</ref> When results from testing become available, it is considered an ethical requirement to share the results with the patient.<ref name=Cher2010/><ref>{{cite journal | vauthors = Sharma G, McCullough LB, Chervenak FA | title = Ethical considerations of early (first vs. second trimester) risk assessment disclosure for trisomy 21 and patient choice in screening versus diagnostic testing | journal = American Journal of Medical Genetics. Part C, Seminars in Medical Genetics | volume = 145C | issue = 1 | pages = 99–104 | date = February 2007 | pmid = 17299736 | doi = 10.1002/ajmg.c.30118 | doi-access = free }}</ref> | |||
Some bioethicists deem it reasonable for parents to select a child who would have the highest well-being.<ref>{{cite journal | vauthors = Savulescu J, Kahane G | title = The moral obligation to create children with the best chance of the best life | journal = Bioethics | volume = 23 | issue = 5 | pages = 274–290 | date = June 2009 | pmid = 19076124 | doi = 10.1111/j.1467-8519.2008.00687.x | s2cid = 13897639 }}</ref> One criticism of this reasoning is that it often values those with disabilities less.<ref>{{cite journal | vauthors = Bennett R | title = The fallacy of the Principle of Procreative Beneficence | journal = Bioethics | volume = 23 | issue = 5 | pages = 265–273 | date = June 2009 | pmid = 18477055 | doi = 10.1111/j.1467-8519.2008.00655.x | s2cid = 7373407 | url = https://pure.manchester.ac.uk/ws/files/20431080/POST-PEER-REVIEW-NON-PUBLISHERS.DOC }}</ref> Some parents argue that Down syndrome should not be prevented or cured and that eliminating Down syndrome amounts to genocide.<ref>{{Cite web|title = Halifax mom questions Down syndrome suppression|url = http://www.cbc.ca/news/canada/nova-scotia/halifax-mom-questions-down-syndrome-suppression-1.1323401|access-date = 2015-09-26|url-status=live|archive-url = https://web.archive.org/web/20151105024307/http://www.cbc.ca/news/canada/nova-scotia/halifax-mom-questions-down-syndrome-suppression-1.1323401|archive-date = 2015-11-05}}</ref><ref>{{Cite web|title = Should Down Syndrome Be Cured?|url = http://parenting.blogs.nytimes.com/2010/01/11/should-down-syndrome-be-cured/|access-date = 2015-09-26| vauthors = Belkin L |url-status=live|archive-url = https://web.archive.org/web/20150425093102/http://parenting.blogs.nytimes.com/2010/01/11/should-down-syndrome-be-cured/|archive-date = 2015-04-25|date = 2010-01-11}}</ref> The ] does not have a position on screening,<ref name=Paren2003/> although some members consider testing and abortion discriminatory.<ref name=Paren2003>{{cite journal | vauthors = Parens E, Asch A | title = Disability rights critique of prenatal genetic testing: reflections and recommendations | journal = Mental Retardation and Developmental Disabilities Research Reviews | volume = 9 | issue = 1 | pages = 40–47 | year = 2003 | pmid = 12587137 | doi = 10.1002/mrdd.10056 }}</ref> Some in the United States who are ] support abortion if the fetus is disabled, while others do not.<ref name=Green1997>{{cite journal | vauthors = Green RM | title = Parental autonomy and the obligation not to harm one's child genetically | journal = The Journal of Law, Medicine & Ethics | volume = 25 | issue = 1 | pages = 5–15, 2 | date = Spring 1997 | pmid = 11066476 | doi = 10.1111/j.1748-720x.1997.tb01389.x | s2cid = 38939256 | url = https://zenodo.org/record/1230726 }}</ref> Of a group of 40 mothers in the United States who have had one child with Down syndrome, half agreed to screening in the next pregnancy.<ref name=Green1997/> | |||
Within the US, some ] denominations see abortion as acceptable when a fetus has Down syndrome while ] and ] do not.<ref name=Rel2013>{{cite book|title=Encyclopedia of religious controversies in the United States.|year=2013|publisher=ABC-CLIO|location=Santa Barbara, Calif.|isbn=978-1-59884-867-0|page=278|url=https://books.google.com/books?id=vnWE00YVeJQC&pg=PA278|author-link1=Bill J. Leonard|author-link2=Jill Y. Crainshaw| vauthors = Leonard BJ, Crainshaw JY |edition=2nd|url-status=live|archive-url=https://web.archive.org/web/20170123082425/https://books.google.com/books?id=vnWE00YVeJQC&pg=PA278|archive-date=2017-01-23}}</ref> Some of those against screening refer to it as a form of ].<ref name=Rel2013/> Parents may be stigmatized whichever decision they make.<ref>{{cite book|title=Woman-centered care in pregnancy and childbirth|year=2010|publisher=Radcliffe Pub.|location=Oxford|isbn=978-1-84619-161-9|page=140|url=https://books.google.com/books?id=OFvr9oIt1tsC&pg=PA140| vauthors = Shields SG, Candib LM |url-status=live|archive-url=https://web.archive.org/web/20170123082811/https://books.google.com/books?id=OFvr9oIt1tsC&pg=PA140|archive-date=2017-01-23}}</ref> | |||
===Advocacy groups=== | |||
Advocacy groups for individuals with Down syndrome began to be formed after the ].<ref name="Adv2011">{{cite book | chapter = Into the Mainstream |title=Downs: The history of a disability|year=2011|publisher=Oxford University Press|isbn=978-0-19-161978-6|page=147| chapter-url = https://books.google.com/books?id=lm0BrR0POj8C&pg=PA147| vauthors = Wright D |url-status=live|archive-url=https://web.archive.org/web/20170123083050/https://books.google.com/books?id=lm0BrR0POj8C&pg=PA147|archive-date=2017-01-23}}</ref> These were organizations advocating for the inclusion of people with Down syndrome into the general school system and for a greater understanding of the condition among the general population,<ref name="Adv2011" /> as well as groups providing support for families with children living with Down syndrome.<ref name="Adv2011" /> Before this individuals with Down syndrome were often placed in ]. Organizations included the ] founded in the UK in 1946 by ],<ref name="Adv2011" /><ref>{{cite web|title=Timeline|url=http://www.mencap.org.uk/about-us/our-history/timeline|work=MENCAP|access-date=2 February 2014|url-status=dead|archive-url=https://web.archive.org/web/20110617061939/http://www.mencap.org.uk/about-us/our-history/timeline|archive-date=17 June 2011}}</ref> Kobato Kai founded in Japan in 1964,<ref name="Adv2011" /> the National Down Syndrome Congress founded in the United States in 1973 by ] and others,<ref name="Adv2011" /><ref>{{cite web|title=National Down Syndrome Organizations in the U.S.|url=http://www.globaldownsyndrome.org/about-down-syndrome/resources/national-down-syndrome-organizations-2/|work=Global Down Syndrome Foundation|access-date=2 February 2014|url-status=live|archive-url=https://web.archive.org/web/20140118014934/http://www.globaldownsyndrome.org/about-down-syndrome/resources/national-down-syndrome-organizations-2/|archive-date=18 January 2014|date=2012-02-21}}</ref> and the ] founded in 1979 in the United States.<ref name="Adv2011" /> The first Roman Catholic order of nuns for women with Down Syndrome, ], was founded in 1985 in France.<ref name="vatican">{{cite news | title = Religious Sisters with Down syndrome: the joy of shared contemplative life | vauthors = Vet C | date = July 24, 2019 | access-date = July 31, 2019 | publisher = Vatican News | url = https://www.vaticannews.va/en/world/news/2019-07/stories-religious-sisters-with-down-syndrome.html }}</ref> | |||
The first ] was held on 21 March 2006.<ref name=WDSD2014>{{cite web|title=World Down Syndrome Day|url=http://www.ds-int.org/world-down-syndrome-day|work=Down Syndrome International| access-date=2 February 2014|url-status=live|archive-url=https://web.archive.org/web/20140314001941/http://www.ds-int.org/world-down-syndrome-day|archive-date=14 March 2014}}</ref> The day and month were chosen to correspond with 21 and trisomy, respectively.<ref>{{cite book| vauthors = Pratt G, Rosner V |title=The global and the intimate feminism in our time|year=2012|publisher=Columbia University Press|location=New York|isbn=978-0-231-52084-3|page=113|url=https://books.google.com/books?id=bWGPe649QjIC&pg=PA113 |url-status=live|archive-url= https://web.archive.org/web/20170123082556/https://books.google.com/books?id=bWGPe649QjIC&pg=PA113 |archive-date=2017-01-23}}</ref> It was recognized by the ] in 2011.<ref name=WDSD2014/> | |||
Special21.org, founded in 2015, advocates the need for a specific classification category to enable Down syndrome swimmers the opportunity to qualify and compete at the ].<ref>{{Cite web|url=https://www.portugalresident.com/special21-celebrates-world-down-syndrome-day-in-albufeira/|title=Special21 celebrates World Down Syndrome Day in Albufeira|publisher=Portugal Resident|date=March 25, 2022|access-date=March 13, 2024}}</ref> The project began when International Down syndrome swimmer Filipe Santos broke the world record in the 50m butterfly event, but was unable to compete at the Paralympic Games.<ref>{{Cite web|url=https://www.portugalresident.com/algarve-swimmer-with-down-syndrome-breaks-world-record/|title=Algarve swimmer with Down syndrome breaks world record|publisher=Portugal Resident|date=February 27, 2019|access-date=March 13, 2024}}</ref><ref>{{Cite web|url=https://special21.org/sobre-nos/ | |||
|title=Special21 About Us|publisher=Special21.org|access-date=March 13, 2024}}</ref> | |||
===Paralympic Swimming=== | |||
] ] codes are based upon single impairment only, whereas Down syndrome individuals have both physical and intellectual impairments. | |||
Although Down syndrome swimmers are able to compete in the ] ] intellectual impairment category (provided they score low in IQ tests), they are often outmatched by the superior physicality of their opponents.<ref>{{Cite web|url=https://www.insidethegames.biz/articles/1117707/ipc-athletes-downs-syndrome-paralympics|title=IPC urged to allow greater numbers of athletes with Down's syndrome to compete at Paralympics|publisher=Insidethegames.biz|author=Liam Morgan|date=January 12, 2022|access-date=March 2, 2024}}</ref><ref>{{Cite web|url=https://www.mirror.co.uk/sport/other-sports/paralympics-calls-down-syndrome-category-28545992|title=Paralympics faces calls for Down's syndrome category to ensure level playing field|publisher=Mirror|author=Liam Llewellyn|date=November 21, 2022|access-date=February 10, 2024}}</ref> | |||
At present there is no designated Paralympic category for swimmers with Down syndrome, meaning they have to compete as intellectually disadvantaged athletes. This disregards their physical disabilities.<ref>{{Cite web|url=https://mashable.com/article/down-syndrome-athletes-paralympics|title=Athletes with Down syndrome fight for inclusion at the Paralympics|publisher=Mashable.com|author=Ariel Bogle|date=August 29, 2016|access-date=March 2, 2024}}</ref><ref>{{Cite web|url=https://www.skysports.com/more-sports/olympics/news/29177/12563240/paralympic-dream-for-british-down-syndrome-swimmers-at-first-national-championships|title=Paralympic dream for British Down syndrome swimmers at first national championships|publisher=Sky Sports|author=Rebecca Williams|date=March 11, 2022|access-date=March 2, 2024}}</ref> | |||
A number of advocacy groups globally have been lobbying for the inclusion of a distinct classification category for Down syndrome swimmers within the IPC Classification Codes framework.<ref>{{Cite web|url=https://www.portugalresident.com/special21-celebrates-world-down-syndrome-day-in-albufeira/|title=Special21 celebrates World Down Syndrome Day in Albufeira|publisher=Portugal Resident|date=March 25, 2022|access-date=March 2, 2024}}</ref> | |||
Despite ongoing advocacy, the issue remains unresolved, and swimmers with Down syndrome continue to face challenges in accessing appropriate classification pathways.<ref>{{Cite web|url=https://www.dsiso.org/paralympics-participation-swimmers-with-down-syndrome/|title=Paralympics Participation swimmers with Down syndrome|publisher=Down Syndrome International Swimming Organisation|author=Emily Laurence|access-date=March 2, 2024}}</ref><ref>{{Cite web|url=https://www.mirror.co.uk/sport/other-sports/paralympics-calls-down-syndrome-category-28545992|title=Paralympics faces calls for Down's syndrome category to ensure level playing field|publisher=Mirror|author=Liam Llewellyn|date=November 21, 2022|access-date=March 2, 2024}}</ref> | |||
==Research== | |||
{{See also|Down syndrome research|Mouse models of Down syndrome}} | |||
Efforts are underway to determine how the extra chromosome 21 material causes Down syndrome, as currently this is unknown,<ref name=Brigg2013/> and to develop treatments to improve intelligence in those with the syndrome.<ref>{{cite journal | vauthors = Goodman MJ, Brixner DI | title = New therapies for treating Down syndrome require quality of life measurement | journal = American Journal of Medical Genetics. Part A | volume = 161A | issue = 4 | pages = 639–641 | date = April 2013 | pmid = 23495233 | doi = 10.1002/ajmg.a.35705 | s2cid = 43840950 | doi-access = free }}</ref> Two efforts being studied are the use ]<ref name="Brigg2013">{{cite journal | vauthors = Briggs JA, Mason EA, Ovchinnikov DA, Wells CA, Wolvetang EJ | title = Concise review: new paradigms for Down syndrome research using induced pluripotent stem cells: tackling complex human genetic disease | journal = Stem Cells Translational Medicine | volume = 2 | issue = 3 | pages = 175–184 | date = March 2013 | pmid = 23413375 | pmc = 3659762 | doi = 10.5966/sctm.2012-0117 }}</ref> and ].<ref>{{cite journal | vauthors = Mole B |title=Researchers turn off Down's syndrome genes |url=https://www.nature.com/news/researchers-turn-off-down-s-syndrome-genes-1.13406 |journal=Nature News |access-date=25 December 2018 |language=en |doi=10.1038/nature.2013.13406|year=2013 |s2cid=87422171 |doi-access=free }}</ref><ref>{{cite book | vauthors = Fillat C, Altafaj X |title=Down Syndrome: From Understanding the Neurobiology to Therapy |chapter=Gene therapy for Down syndrome |series=Progress in Brain Research |date=2012 |volume=197 |pages=237–47 |doi=10.1016/B978-0-444-54299-1.00012-1 |pmid=22541296|isbn=9780444542991 }}</ref> Other methods being studied include the use of ]s, ], ]s, and ].<ref>{{cite journal | vauthors = Costa AC, Scott-McKean JJ | title = Prospects for improving brain function in individuals with Down syndrome | journal = CNS Drugs | volume = 27 | issue = 9 | pages = 679–702 | date = September 2013 | pmid = 23821040 | doi = 10.1007/s40263-013-0089-3 | s2cid = 24030020 }}</ref> Research is often carried out on an ], the ].<ref>{{cite journal | vauthors = Costa AC | title = On the promise of pharmacotherapies targeted at cognitive and neurodegenerative components of Down syndrome | journal = Developmental Neuroscience | volume = 33 | issue = 5 | pages = 414–427 | year = 2011 | pmid = 21893967 | pmc = 3254040 | doi = 10.1159/000330861 }}</ref> | |||
==Other hominids== | |||
Down syndrome may also occur in ] other than humans. In ] chromosome 22 corresponds to the human chromosome 21{{efn|Using the traditional numbering; the current numbering scheme retains human chromosome numbers, using 2A and 2B instead of 2 and 3 to refer to the two chromosomes that fused into ] in humans.<ref>{{cite journal | vauthors = Sansom C | title = The evolution of human chromosome 2. | journal = The Biochemist | date = October 2015 | volume = 37 | issue = 5 | pages = 40–41 | doi = 10.1042/BIO03705040 | url = https://portlandpress.com/biochemist/article-pdf/37/5/40/3805/bio037050040.pdf }}</ref>}} and thus trisomy 22 causes Down syndrome in apes. The condition was observed in a ] in 1969 and a ] in 1979, but neither lived very long. The common chimpanzee Kanako (born around 1993, in Japan) has become the longest-lived known example of this condition. Kanako has some of the same symptoms that are common in human Down syndrome. It is unknown how common this condition is in chimps, but it is plausible it could be roughly as common as Down syndrome is in humans.<ref>{{cite journal | vauthors = Hirata S, Hirai H, Nogami E, Morimura N, Udono T | title = Chimpanzee Down syndrome: a case study of trisomy 22 in a captive chimpanzee | journal = Primates; Journal of Primatology | volume = 58 | issue = 2 | pages = 267–273 | date = April 2017 | pmid = 28220267 | doi = 10.1007/s10329-017-0597-8 | publisher = Springer | hdl-access = free | lccn = sf80001417 | hdl = 2433/228259 | s2cid = 5536021 | oclc = 51531954 | eissn = 1610-7365 }}</ref><ref>{{cite web | vauthors = Hays B |title=Second case of 'Down syndrome' in chimpanzees identified in Japan |url=https://www.upi.com/Second-case-of-Down-syndrome-in-chimpanzees-identified-in-Japan/3991487709938/ |website=UPI |access-date=11 May 2019}}</ref> | |||
Fossilized remains of a ] aged approximately 6 at death were described in 2024. The child, nicknamed Tina, suffered from a malformation of the inner ear that only occurs in people with Down syndrome, and would have caused hearing loss and disabling ]. The fact that a Neanderthal with such a condition survived to such an age was taken as evidence of compassion and extra-maternal care among Neanderthals.<ref>{{Cite journal|last1=Conde-Valverde |first1=M. |last2=Quirós-Sánchez |first2=A. |last3=Diez-Valero |first3=J. |last4=Mata-Castro |first4=N. |last5=García-Fernández |first5=A. |last6=Quam |first6=R. |last7=Carretero |first7=J. M. |last8=García-González |first8=R. |last9=Rodríguez |first9=L. |last10=Sánchez-Andrés |first10=Á. |last11=Arsuaga |first11=J. L. |last12=Martínez |first12=I. |last13=Villaverde |first13=V. |title=The child who lived: Down syndrome among Neanderthals? |year=2024 |journal=Science Advances |volume=10 |issue=26 |pages=eadn9310 |doi=10.1126/sciadv.adn9310 |pmid=38924400 |doi-access=free |pmc=11204207 |bibcode=2024SciA...10N9310C }}</ref><ref name=neanderthal>{{cite web|url=https://phys.org/news/2024-06-case-syndrome-neanderthals-documented.html|title=First case of Down syndrome in Neanderthals documented in new study}}</ref> | |||
==In popular culture== | |||
], an actor with Down syndrome, born in 1965]] | |||
===Individuals=== | |||
*] is an American actress and model. She is best known for her roles in the ] horror anthology television series '']''.<ref>{{Cite news | vauthors = Lawton A |date=2011-11-21 |title=Interview with Jamie Brewer |url=https://mediamikes.com/2011/11/interview-with-jamie-brewer/ |access-date=2023-04-01 |website=MediaMikes |language=en-US}}</ref> In its first season, '']'', she portrayed ]; in the third season, '']'', she portrayed ], an enigmatic and ] ]; in the fourth season '']'', she portrayed Chester Creb's vision of his doll, Marjorie; in the seventh season '']'', she portrayed Hedda, a member of the 'SCUM' crew, led by feminist ]; and she also returned to her role as Nan in the eighth season, '']''. In February 2015, Brewer became the first woman with Down syndrome to walk the red carpet at ], for designer Carrie Hammer.<ref>{{Cite web | vauthors = Probus S, McNeal J |title=Meet The First Woman With Down Syndrome To Walk At Fashion Week |url=https://www.buzzfeednews.com/article/stephaniemcneal/meet-the-first-woman-with-down-syndrome-to-walk-at-fashion-w |access-date=2023-04-01 |website=BuzzFeed News |date=12 February 2015 |language=en}}</ref> | |||
*] is a ] model with Down syndrome, working with top designers and renowned media outlets such Vogue Mexico, People, Hola!, among others.<ref>{{Cite web |date=2020-02-19 |title=Puerto Rican model with Down Syndrome, Sofía Jirau is conquering the fashion world |url=https://www.hola.com/us/fashion/20211021325691/puerto-rican-model-down-syndrome-sofia-jirau/ |access-date=2023-04-01 |website=HOLA |language=en-US}}</ref><ref>{{Cite web | vauthors = Mier T | date = 17 February 2020 |title=NYFW: Model with Down Syndrome Says 'There Are No Limits' |url=https://people.com/human-interest/latina-model-with-down-syndrome-stuns-at-nyfw/ |access-date=2023-04-01 |website=Peoplemag |language=en}}</ref><ref>{{Cite web |date=2020-02-13 |title=Sofía Jirau, la modelo latina con síndrome de down que decantó en el Fashion Week de Nueva York |url=https://www.vogue.mx/moda/articulo/sofia-jirau-la-modelo-puertorriquena-con-sindrome-de-down-en-el-fashion-week-de-nueva-york |access-date=2023-04-01 |website=Vogue |language=es-MX}}</ref> In February 2020, Jirau made her debut at ].<ref>{{Cite web |last=V |first=Juliette |title=Latina Model With Down Syndrome Walks at New York Fashion Week |url=https://themighty.com/topic/down-syndrome/sofia-jirau-down-syndrome-model-new-york-fashion-week/ |access-date=2023-04-01 |website=The Mighty |language=en}}</ref> Then in February 2022, she became the first-ever model with Down Syndrome to be hired by the American retail company ].<ref>{{Cite web | vauthors = Holender S |date=2022-02-17 |title=Meet Sofia Jirau, Victoria's Secret's 1st Model With Down Syndrome |url=https://www.usmagazine.com/stylish/news/sofia-jirau-is-victorias-secrets-1st-model-with-down-syndrome/ |access-date=2023-04-01 |website=Us Weekly |language=en-US}}</ref> She walked the ] runway in 2022.<ref name="About me">{{Cite web |title=About me |url=https://www.sofiajirau.com/en/quien-soy |access-date=2023-04-01 |website=Sofia Jirau Model |language=en}}</ref> Jirau launched a campaign in 2021 called Sin Límites or No Limits "which seeks to make visible the challenges facing the Down syndrome community, demonstrate our ability to achieve our goals, and raise awareness about the condition throughout the world."<ref name="About me" /> | |||
*] is the first person with Down syndrome to finish an ].<ref>{{Cite news |title=Nikic becomes first person with Down's syndrome to finish Ironman |language=en-GB |work=BBC Sport |url=https://www.bbc.com/sport/triathlon/54869998 |access-date=2023-04-01}}</ref> He was awarded the ] at the ].<ref>{{Cite web |date=2021-07-10 |title=2021 ESPYS award winners |url=https://www.espn.com/espys/story/_/page/voting-winners/2021-espys-award-winners |access-date=2023-04-01 |website=ESPN.com |language=en}}</ref> Nikic continues to run races around the world, using his platform to promote his 1% Better message and bring awareness to the endless possibilities for people with Down syndrome.<ref>{{Cite web |title=About – Chris Nikic |url=https://chrisnikic.com/about/ |access-date=2023-04-01 |language=en-US | work = chrisnikic.com }}</ref> | |||
*] is an American model and the first person with Down Syndrome to represent an American skin-care brand.<ref>{{Cite web | vauthors = Abelman D | date = 21 March 2021 |title=Grace Strobel Knows How Good Her Skin Looks |url=https://www.allure.com/story/grace-strobel-obagi-skin-care-routine-interview |access-date=2023-04-01 |website=Allure |language=en-US}}</ref> She first joined Obagi in 2020, and continues to be an Ambassador for the brand as of 2022.<ref>{{Cite press release |last=Obagi |title=Obagi Announces Partnership with Down Syndrome Advocate, Grace Strobel, as new SKINCLUSION Ambassador and Face of New Obagi Clinical Cleanser |url=https://www.prnewswire.com/news-releases/obagi-announces-partnership-with-down-syndrome-advocate-grace-strobel-as-new-skinclusion-ambassador-and-face-of-new-obagi-clinical-cleanser-301143570.html |access-date=2023-04-01 |website=www.prnewswire.com |language=en}}</ref><ref>{{Cite press release |last=Obagi |title=Obagi Clinical® Continues Collaboration with Down Syndrome Advocate Grace Strobel |url=https://www.prnewswire.com/news-releases/obagi-clinical-continues-collaboration-with-down-syndrome-advocate-grace-strobel-301532656.html |access-date=2023-04-01 |website=www.prnewswire.com |language=en}}</ref> She walked the runway representing ] for Runway of Dreams ] 2020 and ].<ref name="At just 25 years old, Chesterfield native Grace Strobel continues to shatter stereotypes, shift societal expectations and make history.">{{Cite web | vauthors = LeBlanc DA |title=The Grace Effect: Local model is on a mission to change the world in style |url=https://www.westnewsmagazine.com/lifestyles/the-grace-effect-local-model-is-on-a-mission-to-change-the-world-in-style/article_af990822-99d2-11ec-a659-6fef10246f05.html |access-date=2023-04-01 |website=WestNewsMagazine.com |date=March 2022 |language=en}}</ref> Strobel has been featured in '']'', on ], '']'', by ]'s ], Lady Gaga's Kindness Channel, and many more.<ref name="At just 25 years old, Chesterfield native Grace Strobel continues to shatter stereotypes, shift societal expectations and make history." /><ref name="The Grace Effect" /> She is also a public speaker and gives a presentation called #TheGraceEffect about what it is like to live with Down syndrome.<ref>{{Cite web |title=Down syndrome advocate Grace Strobel on pushing boundaries: 'Let no one tell you what you can and cannot achieve' |url=https://www.yahoo.com/lifestyle/down-syndrome-advocate-grace-strobel-on-pushing-boundaries-201717691.html |access-date=2023-04-01 |website=Yahoo Life |date=21 March 2022 |language=en-US}}</ref><ref name="The Grace Effect">{{Cite web | vauthors = Strobel G |date=2020-01-24 |title=#TheGraceEffect – Creating Ripples With Kindness And Respect |url=https://www.channelkindness.org/the-grace-effect/ |access-date=2023-04-01 |website=Channel Kindness |language=en-US}}</ref> | |||
===Television and film=== | |||
*'']'' is an American drama television series that aired on ] from September 12, 1989, to May 23, 1993.<ref>{{Citation |title=Life Goes On (TV Series 1989–1993) - IMDb |url=https://www.imdb.com/title/tt0096635/ |access-date=2023-04-01 |language=en-US}}</ref> The show centers on the Thatcher family living in ]: Drew, his wife Libby, and their children Paige, Rebecca and Charles. Charles, called Corky on the show and portrayed by ], was the first major character on a television series with Down syndrome.<ref>{{Cite web |title=Life Goes On Actor Chris Burke on Being the First Primetime Television Star with Down Syndrome |url=https://www.oprah.com/own-where-are-they-now/chris-burke-the-first-primetime-star-with-down-syndrome-video | archive-url = https://web.archive.org/web/20150814072752/https://www.oprah.com/own-where-are-they-now/chris-burke-the-first-primetime-star-with-down-syndrome-video | archive-date = 14 August 2015 |access-date=2023-04-01 |website=Oprah.com}}</ref> Burke's revolutionary role conveyed a realistic portrayal of people with Down syndrome and changed the way audiences viewed people with disabilities.<ref>{{Cite web |last1=Randle N |date=1990-12-20 |title='Our Ticket to Acceptance' : Actor With Down's Syndrome on 'Life Goes On' Has Become Role Model for Many |url=https://www.latimes.com/archives/la-xpm-1990-12-20-ca-9447-story.html |access-date=2023-04-01 |website=Los Angeles Times |language=en-US}}</ref> | |||
*], an Australian film by ] and starring ], is a comedy-drama depicting the efforts by a newly appointed physical education teacher to introduce soccer to a specialized school for youths with Down syndrome. | |||
*] (2023) is a film starring four main actors with Down syndrome: ], Kevin Iannucci, Matthew Von Der Ahe and James Day Keith.<ref>{{Citation |title=Champions (2023) - IMDb |url=https://www.imdb.com/title/tt15339570/ |access-date=2023-04-01 |language=en-US}}</ref> It is an American ] ] film directed by ] in his ], from a screenplay written by Mark Rizzo. The film stars ] as a temperamental ] coach who after an arrest must coach a team of players with intellectual disabilities as community service; ], ], and ] also star. | |||
*] is an ] ] series produced by ] featuring seven adults with Down syndrome with work hard to achieve goals and overcome obstacles.<ref>{{Cite web |title=Born This Way |url=https://www.emmys.com/shows/born-way |access-date=2023-04-01 |website=Television Academy |language=en}}</ref> The show received a Television Academy Honor in 2016.<ref>{{Cite web | vauthors = Heasley S |date=2015-11-16 |title=New TV Series Features Young Adults With Down Syndrome |url=https://www.disabilityscoop.com/2015/11/16/new-tv-series-down-syndrome/20963/ |access-date=2023-04-01 |website=Disability Scoop |language=en}}</ref> | |||
*'']'' is a 2019 American ] film written and directed by Tyler Nilson and Michael Schwartz, in their directorial film debut, and starring ], ], ] and ].<ref>{{Citation |title=The Peanut Butter Falcon (2019) - IMDb |url=https://www.imdb.com/title/tt4364194/ |access-date=2023-04-01 |language=en-US}}</ref> The plot follows a young man with Down syndrome who escapes from an ], in order to follow his dream of being a wrestler, and befriends a wayward fisherman on the run. As the two men form a rapid bond, a ]er attempts to track them.<ref>{{Cite web |title=The Peanut Butter Falcon |url=https://www.lionsgate.com/movies/the-peanut-butter-falcon |access-date=1 April 2023 |website=Lionsgate}}</ref> | |||
===Music=== | |||
*The ] song "]" is about someone with Down syndrome. | |||
*The ] song "]" is about a fetus with Down syndrome. | |||
===Toys=== | |||
*In 2023, ] released a ] doll with characteristics of a person having Down syndrome as a way to promote diversity.<ref>{{cite news | url=https://www.theguardian.com/society/2023/apr/25/barbie-doll-with-downs-syndrome-launched-by-mattel | title=Barbie doll with Down's syndrome launched by Mattel | newspaper=The Guardian | date=25 April 2023 | last1=Marsh | first1=Sarah }}</ref> | |||
== See also == | |||
* ] | |||
* ] | |||
== Notes == | |||
{{notelist}} | |||
== References == | == References == | ||
{{Reflist}} | |||
<!--See http://en.wikipedia.org/Wikipedia:Footnotes for an explanation of how to generate footnotes using the <ref(erences/)> tags--> | |||
<div class="references-small"><references/></div> | |||
== |
== Further reading == | ||
{{Refbegin}} | |||
* {{cite book | |||
* {{Cite news |vauthors=Fox N |date=2021-11-26 |title='World-leading' Down's syndrome bill clears first hurdle in Parliament |url=https://www.bbc.com/news/uk-politics-59432487 |url-status=live |archive-url=https://web.archive.org/web/20211127155428/https://www.bbc.com/news/uk-politics-59432487 |archive-date= 2021-11-27 |language=en-GB |publisher=] |access-date=2021-11-27}} | |||
| last =Beck | |||
* {{Cite journal |vauthors=Thompson SB |date=1999 |title=Examining dementia in Down's syndrome (DS): decline in social abilities in DS compared with other learning disabilities |journal=Clinical Gerontologist |volume=20 |issue=3 |pages=23–44 |publisher=Taylor & Francis (Routledge) |doi=10.1300/j018v20n03_04 |issn=1545-2301 |oclc=1106716083 }} | |||
| first =M.N. | |||
* {{Cite journal |vauthors=Thompson SB |date=2000a<!-- The "a" and "b" are for convenience—I do not actually know the order of publication. --> |title=The Central Executive System in people with Down's syndrome and dementia |journal=Clinical Gerontologist |volume=21 |issue=3 |pages=3–32 |publisher=Taylor & Francis (Routledge) |doi=10.1300/j018v21n03_02 |issn=1545-2301 |oclc=1106716083 |s2cid=218575706 }} | |||
| year =1999 | |||
* {{Cite journal |vauthors=Thompson SB |date=2000b<!-- The "a" and "b" are for convenience—I do not actually know the order of publication. --> |title=Investigation into Down's syndrome and dementia |journal=Journal of the Association of Practitioners in Learning Disability |volume=17 |issue=3 |pages=10–14 }} | |||
| title =Expecting Adam | |||
{{Refend}} | |||
| publisher =Berkley Books | |||
| location =New York | |||
}} | |||
* {{cite book | |||
| last =Buckley | |||
| first =S. | |||
| year =2000 | |||
| title =Living with Down Syndrome | |||
| publisher =The Down Syndrome Educational Trust | |||
| location =Portsmouth, UK | |||
| url =http://www.down-syndrome.info/library/dsii/01/01/ | |||
}} | |||
* {{cite book | |||
| last =Down Syndrome Research Foundation | |||
| year =2005 | |||
| title =Bright Beginnings: A Guide for New Parents | |||
| publisher =Down Syndrome Research Foundation | |||
| location =Buckinghamshire, UK | |||
| url =http://www.dsrf.co.uk/Reading_material/Bright_beginnings.htm | |||
}} | |||
* {{cite book | |||
| last =Hassold | |||
| first =T.J. | |||
| coauthors =D. Patterson | |||
| editor =editors, | |||
| year =1999 | |||
| title =Down Syndrome: A Promising Future, Together | |||
| publisher =Wiley Liss | |||
| location =New York | |||
}} | |||
* {{cite book | |||
| last =Kingsley | |||
| first =J. | |||
| coauthors =M. Levitz | |||
| year =1994 | |||
| title =Count us in — Growing up with Down Syndrome | |||
| publisher =Harcourt Brace | |||
| location =San Diago | |||
}} | |||
* {{cite book | |||
| last =Pueschel | |||
| first =S.M. | |||
| coauthors =M. Sustrova | |||
| editor =editors, | |||
| year =1997 | |||
| title =Adolescents with Down Syndrome: Toward a More Fulfilling Life | |||
| publisher =Paul H. Brookes | |||
| location =Baltimore, MD USA | |||
}} | |||
* {{cite book | |||
| last =Selikowitz | |||
| first =M. | |||
| edition =2<sup>nd</sup> edition | |||
| year =1997 | |||
| title =Down Syndrome: The Facts | |||
| publisher =Oxford University Press | |||
| location =Oxford | |||
}} | |||
* {{cite book | |||
| last =Van Dyke | |||
| first =D.C. | |||
| coauthors =P.J. Mattheis; S. Schoon Eberly; and J. Williams | |||
| year =1995 | |||
| title =Medical and Surgical Care for Children with Down Syndrome | |||
| publisher =Woodbine House | |||
| location =Bethesda, MD USA | |||
}} | |||
* {{cite book | |||
| last =Zuckoff | |||
| first =M. | |||
| year =2002 | |||
| title =Choosing Naia: A Family's Journey | |||
| publisher =Beacon Press | |||
| location =New York | |||
}} | |||
== External links == | == External links == | ||
{{Commons category|Down syndrome}} | |||
{{Wikiquote}} | |||
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* | * by the UK ] | ||
===Societies and Associations=== | |||
* | |||
'''By Country''' | |||
* | |||
* | |||
* | |||
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* | |||
* | |||
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{{Medical condition classification and resources | |||
===Conferences=== | |||
| ICD11 = {{ICD11|LD40.0}} | |||
* | |||
| ICD10 = {{ICD10|Q90}} | |||
* | |||
| ICD9 = {{ICD9|758.0}} | |||
| ICDO = | |||
| OMIM = 190685 | |||
| OMIM_mult = | |||
| MedlinePlus = 000997 | |||
| eMedicineSubj = ped | |||
| eMedicineTopic = 615 | |||
| DiseasesDB = 3898 | |||
| MeshID = D004314 | |||
}} | |||
{{Autism spectrum}} | |||
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{{Chromosomal abnormalities |state=collapsed}} | |||
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Latest revision as of 19:54, 20 December 2024
Genetic disorderMedical condition
Down syndrome | |
---|---|
Other names | Down's syndrome, Down's, trisomy 21 |
An eight-year-old boy from British Columbia displaying characteristic facial features of Down syndrome | |
Specialty | Medical genetics, pediatrics |
Symptoms | Delayed development, characteristic physical features, mild to moderate intellectual disability |
Usual onset | Mostly at conception, rarely after fertilization |
Duration | Lifelong |
Causes | Third copy of chromosome 21 |
Risk factors | Older age of mother, prior affected child |
Diagnostic method | Prenatal screening, genetic testing |
Treatment | Physical therapy, Occupational therapy, Speech therapy, Educational support, Supported work environment |
Prognosis | Life expectancy 50 to 60 years (developed world) |
Frequency | 5.4 million (0.1%) |
Named after | John Langdon Down |
Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with developmental delays, mild to moderate intellectual disability, and characteristic physical features.
The parents of the affected individual are usually genetically normal. The incidence of the syndrome increases with the age of the mother, from less than 0.1% for 20-year-old mothers to 3% for those of age 45. It is believed to occur by chance, with no known behavioral activity or environmental factor that changes the probability. Usually, babies get 23 chromosomes from each parent for a total of 46, whereas in Down syndrome, a third 21st chromosome is attached. The extra chromosome is provided at conception as the egg and sperm combine. In 1–2% of cases, the additional chromosome is added in the embryo stage and only impacts some of the cells in the body; this is known as Mosaic Down syndrome. Translocation Down syndrome is another rare type. Down syndrome can be identified during pregnancy by prenatal screening, followed by diagnostic testing, or after birth by direct observation and genetic testing. Since the introduction of screening, Down syndrome pregnancies are often aborted (rates varying from 50 to 85% depending on maternal age, gestational age, and maternal race/ethnicity).
As of 2024, there is no known cure for Down syndrome. Education and proper care have been shown to provide better quality of life. Some children with Down syndrome are educated in typical school classes, while others require more specialized education. Some individuals with Down syndrome graduate from high school, and a few attend post-secondary education. In adulthood, about 20% in the United States do some paid work, with many requiring a sheltered work environment. Caretaker support in financial and legal matters is often needed. Life expectancy is around 50 to 60 years in the developed world, with proper health care. Regular screening for health issues common in Down syndrome is recommended throughout the person's life.
Down syndrome is the most common chromosomal abnormality, occurring in about 1 in 1,000 babies born worldwide, and one in 700 in the US. In 2015, there were 5.4 million people with Down syndrome globally, of whom 27,000 died, down from 43,000 deaths in 1990. The syndrome is named after British physician John Langdon Down, who fully described it in 1866. Some aspects were described earlier by French psychiatrist Jean-Étienne Dominique Esquirol in 1838 and French physician Édouard Séguin in 1844. The genetic cause was discovered in 1959.
Signs and symptoms
Those with Down syndrome nearly always have physical and intellectual disabilities. As adults, their mental abilities are typically similar to those of an 8- or 9-year-old. At the same time, their emotional and social awareness is very high. They can have poor immune function and generally reach developmental milestones at a later age. They have an increased risk of a number of health concerns, such as congenital heart defect, epilepsy, leukemia, and thyroid diseases.
Characteristics | Percentage | Characteristics | Percentage |
---|---|---|---|
Mental impairment | 99% | Abnormal teeth | 60% |
Stunted growth | 90% | Slanted eyes | 60% |
Umbilical hernia | 90% | Shortened hands | 60% |
Increased skin on back of neck | 80% | Short neck | 60% |
Low muscle tone | 80% | Obstructive sleep apnea | 60% |
Narrow roof of mouth | 76% | Bent fifth finger tip | 57% |
Flat head | 75% | Brushfield spots in the iris | 56% |
Flexible ligaments | 75% | Single transverse palmar crease | 53% |
Proportionally large tongue | 75% | Protruding tongue | 47% |
Abnormal outer ears | 70% | Congenital heart disease | 40% |
Flattened nose | 68% | Strabismus | ≈35% |
Separation of first and second toes | 68% | Undescended testicles | 20% |
Physical
People with Down syndrome may have these physical characteristics: a small chin, epicanthic folds, low muscle tone, a flat nasal bridge, and a protruding tongue. A protruding tongue is caused by low tone and weak facial muscles, and often corrected with myofunctional exercises. Some characteristic airway features can lead to obstructive sleep apnea in around half of those with Down syndrome. Other common features include: excessive joint flexibility, extra space between big toe and second toe, a single crease of the palm, and short fingers.
Instability of the atlantoaxial joint occurs in about 1–2%. Atlantoaxial instability may cause myelopathy due to cervical spinal cord compression later in life, this often manifests as new onset weakness, problems with coordination, bowel or bladder incontinence, and gait dysfunction. Serial imaging cannot reliably predict future cervical cord compression, but changes can be seen on neurological exam. The condition is surgically corrected with spine surgery.
Growth in height is slower, resulting in adults who tend to have short stature—the average height for men is 154 centimetres (5 feet 1 inch), and for women is 142 centimetres (4 feet 8 inches). Individuals with Down syndrome are at increased risk for obesity as they age due to hypothyroidism, other medical issues and lifestyle. Growth charts have been developed specifically for children with Down syndrome.
Neurological
This syndrome causes about a third of cases of intellectual disability. Many developmental milestones are delayed with the ability to crawl typically occurring around 8–22 months rather than 6–12 months, and the ability to walk independently typically occurring around 1–4 years rather than 9–18 months. Walking is acquired in 50% of children after 24 months.
Most individuals with Down syndrome have mild (IQ: 50–69) or moderate (IQ: 35–50) intellectual disability with some cases having severe (IQ: 20–35) difficulties. Those with mosaic Down syndrome typically have IQ scores 10–30 points higher than that. As they age, the gap tends to widen between people with Down syndrome and their same-age peers.
Commonly, individuals with Down syndrome have better language understanding than ability to speak. Babbling typically emerges around 15 months on average. 10–45% of those with Down syndrome have either a stutter or rapid and irregular speech, making it difficult to understand them. After reaching 30 years of age, some may lose their ability to speak.
They typically do fairly well with social skills. Behavior problems are not generally as great an issue as in other syndromes associated with intellectual disability. In children with Down syndrome, mental illness occurs in nearly 30% with autism occurring in 5–10%. People with Down syndrome experience a wide range of emotions. While people with Down syndrome are generally happy, symptoms of depression and anxiety may develop in early adulthood.
Children and adults with Down syndrome are at increased risk of epileptic seizures, which occur in 5–10% of children and up to 50% of adults. This includes an increased risk of a specific type of seizure called infantile spasms. Many (15%) who live 40 years or longer develop Alzheimer's disease. In those who reach 60 years of age, 50–70% have the disease.
Down syndrome regression disorder is a sudden regression with neuropsychiatric symptoms such as catatonia, possibly caused by an autoimmune disease. It primarily appears in teenagers and younger adults.
Senses
Hearing and vision disorders occur in more than half of people with Down syndrome.
Ocular findings
Brushfield spots (small white or grayish/brown spots on the periphery of the iris), upward slanting palpebral fissures (the opening between the upper and lower lids) and epicanthal folds (folds of skin between the upper eyelid and the nose) are clinical signs at birth suggesting the diagnosis of Down syndrome especially in the Western World. None of these requires treatment.
Visually significant congenital cataracts (clouding of the lens of the eye) occur more frequently with Down syndrome. Neonates with Down syndrome should be screened for cataract because early recognition and referral reduce the risk of vision loss from amblyopia. Dot-like opacities in the cortex of the lens (cerulean cataract) are present in up to 50% of people with Down syndrome, but may be followed without treatment if they are not visually significant.
Strabismus, nystagmus and nasolacrimal duct obstruction occur more frequently in children with Down syndrome. Screening for these diagnoses should begin within six months of birth. Strabismus is more often acquired than congenital. Early diagnosis and treatment of strabismus reduces the risk of vision loss from amblyopia. In Down syndrome, the presence of epicanthal folds may give the false impression of strabismus, referred to as pseudostrabismus. Nasolacrimal duct obstruction, which causes tearing (epiphora), is more frequently bilateral and multifactorial than in children without Down syndrome.
Refractive error is more common with Down syndrome, though the rate may not differ until after twelve months of age compared to children without Down syndrome. Early screening is recommended to identify and treat significant refractive error with glasses or contact lenses. Poor accommodation (ability to focus on close objects) is associated with Down syndrome, which may mean bifocals are indicated.
In keratoconus, the cornea progressively thins and bulges into a cone shape, causing visual blurring or distortion. Keratoconus first presents in the teen years and progresses into the thirties. Down syndrome is a strong risk factor for developing keratoconus, and onset may be occur at a younger age than in those without Down syndrome. Eye rubbing is also a risk factor for developing keratoconus. It is speculated that chronic eye irritation from blepharitis may increase eye rubbing in Down syndrome, contributing to the increased prevalence of keratoconus.
An association between glaucoma and Down syndrome is often cited. Glaucoma in children with Down syndrome is uncommon, with a prevalence of less than 1%. It is currently unclear if the prevalence of glaucoma in those with Down syndrome differs from that in the absence of Down syndrome.
Estimates of prevalence of ocular findings in Down Syndrome vary widely depending on the study. Some prevalence estimates follow. Vision problems have been observed in 38–80% of cases. Brushfield spots are present in 38–85% of individuals. Between 20 and 50% have strabismus. Cataracts occur in 15%, and may be present at birth. Keratoconus may occur in as many as 21–30%.
Hearing loss
Hearing problems are found in 50–90% of children with Down syndrome. This is often the result of otitis media with effusion which occurs in 50–70% and chronic ear infections which occur in 40–60%. Ear infections often begin in the first year of life and are partly due to poor eustachian tube function. Excessive ear wax can also cause hearing loss due to obstruction of the outer ear canal. Even a mild degree of hearing loss can have negative consequences for speech, language understanding, and academics. It is important to rule out hearing loss as a factor in social and cognitive deterioration. Age-related hearing loss of the sensorineural type occurs at a much earlier age and affects 10–70% of people with Down syndrome.
Heart
The rate of congenital heart disease in newborns with Down syndrome is around 40%. Of those with heart disease, about 80% have an atrial septal defect or ventricular septal defect with the former being more common. Congenital heart disease can also put individuals at a higher risk of pulmonary hypertension, where arteries in the lungs narrow and cause inadequate blood oxygenation. Some of the genetic contributions to pulmonary hypertension in individuals with Down Syndrome are abnormal lung development, endothelial dysfunction, and proinflammatory genes. Mitral valve problems become common as people age, even in those without heart problems at birth. Other problems that may occur include tetralogy of Fallot and patent ductus arteriosus. People with Down syndrome have a lower risk of hardening of the arteries.
Cancer
Although the overall risk of cancer in Down syndrome is not changed, the risk of testicular cancer and certain blood cancers, including acute lymphoblastic leukemia (ALL) and acute megakaryoblastic leukemia (AMKL) is increased while the risk of other non-blood cancers is decreased. People with Down syndrome are believed to have an increased risk of developing cancers derived from germ cells whether these cancers are blood- or non-blood-related. In 2008, the World Health Organization (WHO) introduced a distinct classification for myeloid proliferation in individuals with Down syndrome.
Blood cancers
Leukemia is 10 to 15 times more common in children with Down syndrome. In particular, acute lymphoblastic leukemia is 20 times more common and the megakaryoblastic form of acute myeloid leukemia (acute megakaryoblastic leukemia), is 500 times more common. Acute megakaryoblastic leukemia (AMKL) is a leukemia of megakaryoblasts, the precursors cells to megakaryocytes which form blood platelets. Acute lymphoblastic leukemia in Down syndrome accounts for 1–3% of all childhood cases of ALL. It occurs most often in those older than nine years or having a white blood cell count greater than 50,000 per microliter and is rare in those younger than one year old. ALL in Down syndrome tends to have poorer outcomes than other cases of ALL in people without Down syndrome. In short, the likelihood of developing acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) is higher in children with Down syndrome compared to those without Down syndrome.
Myeloid leukemia typically precedes Down syndrome and is accompanied by a condition known as transient abnormal myelopoiesis (TAM), which generally disrupts the differentiation of megakaryocytes and erythrocytes. In Down syndrome, AMKL is typically preceded by transient myeloproliferative disease (TMD), a disorder of blood cell production in which non-cancerous megakaryoblasts with a mutation in the GATA1 gene rapidly divide during the later period of pregnancy. GATA1 mutations combined with trisomy 21 contribute to a predisposition to TAM. In trisomy 21, the process of leukemogenesis starts in early fetal life, with genetic factors, including GATA1 mutations, contributing to the development of TAM on the preleukemic pathway. The condition affects 3–10% of babies with Down. While it often spontaneously resolves within three months of birth, it can cause serious blood, liver, or other complications. In about 10% of cases, TMD progresses to AMKL during the three months to five years following its resolution.
Non-blood cancers
People with Down syndrome have a lower risk of all major solid cancers, including those of lung, breast, and cervix, with the lowest relative rates occurring in those aged 50 years or older. This low risk is thought to be due to an increase in the expression of tumor suppressor genes present on chromosome 21. One exception is testicular germ cell cancer which occurs at a higher rate in Down syndrome.
Endocrine
Problems of the thyroid gland occur in 20–50% of individuals with Down syndrome. Low thyroid is the most common form, occurring in almost half of all individuals. Thyroid problems can be due to a poorly or nonfunctioning thyroid at birth (known as congenital hypothyroidism) which occurs in 1% or can develop later due to an attack on the thyroid by the immune system resulting in Graves' disease or autoimmune hypothyroidism. Type 1 diabetes mellitus is also more common.
Gastrointestinal
Constipation occurs in nearly half of people with Down syndrome and may result in changes in behavior. One potential cause is Hirschsprung's disease, occurring in 2–15%, which is due to a lack of nerve cells controlling the colon. Other congenital problems can include duodenal atresia, imperforate anus and gastroesophageal reflux disease. Celiac disease affects about 7–20%.
Teeth
People with Down syndrome tend to be more susceptible to gingivitis as well as early, severe periodontal disease, necrotising ulcerative gingivitis, and early tooth loss, especially in the lower front teeth. While plaque and poor oral hygiene are contributing factors, the severity of these periodontal diseases cannot be explained solely by external factors. Research suggests that the severity is likely a result of a weakened immune system. The weakened immune system also contributes to increased incidence of yeast infections in the mouth (from Candida albicans).
People with Down syndrome also tend to have a more alkaline saliva resulting in a greater resistance to tooth decay, despite decreased quantities of saliva, less effective oral hygiene habits, and higher plaque indexes.
Higher rates of tooth wear and bruxism are also common. Other common oral manifestations of Down syndrome include enlarged hypotonic tongue, crusted and hypotonic lips, mouth breathing, narrow palate with crowded teeth, class III malocclusion with an underdeveloped maxilla and posterior crossbite, delayed exfoliation of baby teeth and delayed eruption of adult teeth, shorter roots on teeth, and often missing and malformed (usually smaller) teeth. Less common manifestations include cleft lip and palate and enamel hypocalcification (20% prevalence).
Taurodontism, an elongation of the pulp chamber, has a high prevalence in people with DS.
Fertility
Males with Down syndrome usually do not father children, while females have lower rates of fertility relative to those who are unaffected. Fertility is estimated to be present in 30–50% of females. Menopause usually occurs at an earlier age. The poor fertility in males is thought to be due to problems with sperm development; however, it may also be related to not being sexually active. As of 2006, three instances of males with Down syndrome fathering children and 26 cases of females having children have been reported. Without assisted reproductive technologies, around half of the children of someone with Down syndrome will also have the syndrome.
Cause
Main article: Genetics of Down syndromeThe cause of the extra full or partial chromosome is still unknown. Most of the time, Down syndrome is caused by a random mistake in cell division during early development of the fetus, but not inherited, and there is no scientific research which shows that environmental factors or the parents' activities contribute to Down syndrome. The only factor that has been linked to the increased chance of having a baby with Down syndrome is advanced parental age. This is mostly associated with advanced maternal age but about 10 per cent of cases are associated with advanced paternal age.
Down syndrome is caused by having three copies of the genes on chromosome 21, rather than the usual two. The parents of the affected individual are typically genetically normal. Those who have one child with Down syndrome have about a 1% possibility of having a second child with the syndrome, if both parents are found to have normal karyotypes.
The extra chromosome content can arise through several different ways. The most common cause (about 92–95% of cases) is a complete extra copy of chromosome 21, resulting in trisomy 21. In 1–2.5% of cases, some of the cells in the body are normal and others have trisomy 21, known as mosaic Down syndrome. The other common mechanisms that can give rise to Down syndrome include: a Robertsonian translocation, isochromosome, or ring chromosome. These contain additional material from chromosome 21 and occur in about 2.5% of cases. An isochromosome results when the two long arms of a chromosome separate together rather than the long and short arm separating together during egg or sperm development.
Trisomy 21
Down syndrome (also known by the karyotype 47,XX,+21 for females and 47,XY,+21 for males) is mostly caused by a failure of the 21st chromosome to separate during egg or sperm development, known as nondisjunction. As a result, a sperm or egg cell is produced with an extra copy of chromosome 21; this cell thus has 24 chromosomes. When combined with a normal cell from the other parent, the baby has 47 chromosomes, with three copies of chromosome 21. About 88% of cases of trisomy 21 result from nonseparation of the chromosomes in the mother, 8% from nonseparation in the father, and 3% after the egg and sperm have merged.
Mosaic Down syndrome
Mosaic Down syndrome is diagnosed when there is a mixture of two types of cells: some cells have three copies of chromosome 21 but some cells have the typical two copies of chromosome 21. This type is the least common form of Down syndrome and accounts for only about 1% of all cases. Children with mosaic Down syndrome may have the same features as other children with Down syndrome. However, they may have fewer characteristics of the condition due to the presence of some (or many) cells with a typical number of chromosomes.
Translocation Down syndrome
The extra chromosome 21 material may also occur due to a Robertsonian translocation in 2–4% of cases. In this translocation Down syndrome, the long arm of chromosome 21 is attached to another chromosome, often chromosome 14. In a male affected with Down syndrome, it results in a karyotype of 46XY,t(14q21q). This may be a new mutation or previously present in one of the parents. The parent with such a translocation is usually normal physically and mentally; however, during production of egg or sperm cells, a higher chance of creating reproductive cells with extra chromosome 21 material exists. This results in a 15% chance of having a child with Down syndrome when the mother is affected and a less than 5% probability if the father is affected. The probability of this type of Down syndrome is not related to the mother's age. Some children without Down syndrome may inherit the translocation and have a higher probability of having children of their own with Down syndrome. In this case it is sometimes known as familial Down syndrome.
Mechanism
The extra genetic material present in Down syndrome results in overexpression of a portion of the 310 genes located on chromosome 21. This overexpression has been estimated at 50%, due to the third copy of the chromosome present. Some research has suggested the Down syndrome critical region is located at bands 21q22.1–q22.3, with this area including genes for the amyloid precursor protein, superoxide dismutase, and likely the ETS2 proto oncogene. Other research, however, has not confirmed these findings. MicroRNAs are also proposed to be involved.
The dementia that occurs in Down syndrome is due to an excess of amyloid beta peptide produced in the brain and is similar to Alzheimer's disease, which also involves amyloid beta build-up. Amyloid beta is processed from amyloid precursor protein, the gene for which is located on chromosome 21. Senile plaques and neurofibrillary tangles are present in nearly all by 35 years of age, though dementia may not be present. It is hypothesized that those with Down syndrome lack a normal number of lymphocytes and produce less antibodies which is said to present an increased risk of infection.
Epigenetics
Down syndrome is associated with an increased risk of some chronic diseases that are typically associated with older age such as Alzheimer's disease. It is believed that accelerated aging occurs and increases the biological age of tissues, but molecular evidence for this hypothesis is sparse. According to a biomarker of tissue age known as epigenetic clock, it is hypothesized that trisomy 21 increases the age of blood and brain tissue (on average by 6.6 years).
Diagnosis
Screening before birth
Guidelines recommend screening for Down syndrome to be offered to all pregnant women, regardless of age. A number of tests are used, with varying levels of accuracy. They are typically used in combination to increase the detection rate. None can be definitive; thus, if screening predicts a high possibility of Down syndrome, either amniocentesis or chorionic villus sampling is required to confirm the diagnosis.
Ultrasound
Prenatal ultrasound can be used to screen for Down syndrome. Findings that indicate increased chances when seen at 14 to 24 weeks of gestation include a small or no nasal bone, large ventricles, nuchal fold thickness, and an abnormal right subclavian artery, among others. The presence or absence of many markers is more accurate. Increased fetal nuchal translucency (NT) indicates an increased possibility of Down syndrome picking up 75–80% of cases and being falsely positive in 6%.
- Ultrasound of fetus with Down syndrome showing a large bladder
- Enlarged NT and absent nasal bone in a fetus at 11 weeks with Down syndrome
Blood tests
Several blood markers can be measured to predict the chances of Down syndrome during the first or second trimester. Testing in both trimesters is sometimes recommended and test results are often combined with ultrasound results. In the second trimester, often two or three tests are used in combination with two or three of: α-fetoprotein, unconjugated estriol, total hCG, and free βhCG detecting about 60–70% of cases.
Testing of the mother's blood for fetal DNA is being studied and appears promising in the first trimester. The International Society for Prenatal Diagnosis considers it a reasonable screening option for those women whose pregnancies are at a high likelihood of trisomy 21. Accuracy has been reported at 98.6% in the first trimester of pregnancy. Confirmatory testing by invasive techniques (amniocentesis, CVS) is still required to confirm the screening result.
Combinations
Screen | Week of pregnancy when performed | Detection rate | False positive | Description |
---|---|---|---|---|
Combined test | 10–13.5 wks | 82–87% | 5% | Uses ultrasound to measure nuchal translucency in addition to blood tests for free or total beta-hCG and PAPP-A |
Quad screen | 15–20 wks | 81% | 5% | Measures the maternal serum alpha-fetoprotein, unconjugated estriol, hCG, and inhibin-A |
Integrated test | 15–20 wks | 94–96% | 5% | Is a combination of the quad screen, PAPP-A, and NT |
Cell-free fetal DNA | From 10 wks | 96–100% | 0.3% | A blood sample is taken from the mother by venipuncture and is sent for DNA analysis. |
Efficacy
For combinations of ultrasonography and non-genetic blood tests, screening in both the first and second trimesters is better than just screening in the first trimester. The different screening techniques in use are able to pick up 90–95% of cases, with a false-positive rate of 2–5%. If Down syndrome occurs in one in 500 pregnancies with a 90% detection rate and the test used has a 5% false-positive rate, this means, of 20 women who test positive on screening, only one will not have a fetus with Down syndrome confirmed. If the screening test has a 2% false-positive rate, this means, of 50 women who test positive on screening, one will not have a fetus with Down syndrome.
Invasive genetic testing
Amniocentesis and chorionic villus sampling are more reliable tests, but they increase the risk of miscarriage by between 0.5–1%. The risk of limb problems may be increased in the offspring if chorionic villus sampling is performed before 10 weeks.
The risk from the procedure is greater the earlier it is performed, thus amniocentesis is not recommended before 15 weeks gestational age and chorionic villus sampling before 10 weeks gestational age.
Abortion rates
About 92% of pregnancies in Europe with a diagnosis of Down syndrome are terminated. As a result, there is almost no one with Down syndrome in Iceland and Denmark, where screening is commonplace. In the United States, the termination rate after diagnosis is around 75%, but varies from 61 to 93%, depending on the population surveyed. Rates are lower among women who are younger and have decreased over time. When asked if they would have a termination if their fetus tested positive, 23–33% said yes, when high-risk pregnant women were asked, 46–86% said yes, and when women who screened positive are asked, 89–97% say yes.
After birth
A diagnosis can often be suspected based on the child's physical appearance at birth. An analysis of the child's chromosomes is needed to confirm the diagnosis, and to determine if a translocation is present, as this may help determine the chances of the child's parents having further children with Down syndrome.
Management
Efforts such as early childhood intervention, therapies, screening for common medical issues, a good family environment, and work-related training can improve the development of children with Down syndrome and provide good quality of life. Common therapies utilized include physical therapy, occupational therapy and speech therapy. Education and proper care can provide a positive quality of life. Typical childhood vaccinations are recommended.
Health screening
Testing | Children | Adults |
---|---|---|
Hearing | 6 months, 12 months, then yearly | 3–5 years |
T4 and TSH | 6 months, then yearly | |
Eyes | 6 months, then yearly | 3–5 years |
Teeth | 2 years, then every 6 months | |
Celiac disease | Between 2 and 3 years of age, or earlier if symptoms occur |
|
Sleep study | 3 to 4 years, or earlier if symptoms of obstructive sleep apnea occur |
|
Neck X-rays | Between 3 and 5 years of age |
A number of health organizations have issued recommendations for screening those with Down syndrome for particular diseases. This is recommended to be done systematically.
At birth, all children should get an electrocardiogram and ultrasound of the heart. Surgical repair of heart problems may be required as early as three months of age. Heart valve problems may occur in young adults, and further ultrasound evaluation may be needed in adolescents and in early adulthood. Due to the elevated risk of testicular cancer, some recommend checking the person's testicles yearly.
Cognitive development
Some people with Down syndrome experience hearing loss. In this instance, hearing aids or other amplification devices can be useful for language learning. Speech therapy may be useful and is recommended to be started around nine months of age. As those with Down syndrome typically have good hand-eye coordination, learning sign language is a helpful communication tool. Augmentative and alternative communication methods, such as pointing, body language, objects, or pictures, are often used to help with communication. Behavioral issues and mental illness are typically managed with counseling or medications.
Education programs before reaching school age may be useful. School-age children with Down syndrome may benefit from inclusive education (whereby students of differing abilities are placed in classes with their peers of the same age), provided some adjustments are made to the curriculum. In the United States, the Individuals with Disabilities Education Act of 1975 requires public schools generally to allow attendance by students with Down syndrome.
Individuals with Down syndrome may learn better visually. Drawing may help with language, speech, and reading skills. Children with Down syndrome still often have difficulty with sentence structure and grammar, as well as developing the ability to speak clearly. Several types of early intervention can help with cognitive development. Efforts to develop motor skills include physical therapy, speech and language therapy, and occupational therapy. Physical therapy focuses specifically on motor development and teaching children to interact with their environment. Speech and language therapy can help prepare for later language. Lastly, occupational therapy can help with skills needed for later independence.
Other
Tympanostomy tubes are often needed and often more than one set during the person's childhood. Tonsillectomy is also often done to help with sleep apnea and throat infections. Surgery does not correct every instance of sleep apnea and a continuous positive airway pressure (CPAP) machine may be useful in those cases.
Efforts to prevent respiratory syncytial virus (RSV) infection with human monoclonal antibodies should be considered, especially in those with heart problems. In those who develop dementia there is no evidence for memantine, donepezil, rivastigmine, or galantamine.
Prognosis
Between 5–15% of children with Down syndrome in Sweden attend regular school. Some graduate from high school; however, most do not. Of those with intellectual disability in the United States who attended high school about 40% graduated. Many learn to read and write and some are able to do paid work. In adulthood about 20% in the United States do paid work in some capacity. In Sweden, however, less than 1% have regular jobs. Many are able to live semi-independently, but they often require help with financial, medical, and legal matters. Those with mosaic Down syndrome usually have better outcomes.
Individuals with Down syndrome have a higher risk of early death than the general population. This is most often from heart problems or infections. Following improved medical care, particularly for heart and gastrointestinal problems, the life expectancy has increased. This increase has been from 12 years in 1912, to 25 years in the 1980s, to 50 to 60 years in the developed world in the 2000s. Data collected between the 1985–2003 showed between 4–12% infants with Down syndrome die in the first year of life. The probability of long-term survival is partly determined by the presence of heart problems. From research at the turn of the century, it tracked those with congenital heart problems, showing 60% survived to at least 10 years and 50% survived to at least 30 years of age. The research failed to track further aging beyond 30 years. In those without heart problems, 85% studied survived to at least 10 years and 80% survived to at least 30 years of age. It is estimated that 10% lived to 70 years of age in the early 2000s. Much of this data is outdated and life expectancy has drastically improved with more equitable healthcare and continuous advancement of surgical practice. The National Down Syndrome Society provides information regarding raising a child with Down syndrome.
Epidemiology
Down syndrome is the most common chromosomal abnormality in humans. Globally, as of 2010, Down syndrome occurs in about 1 per 1,000 births and results in about 17,000 deaths. More children are born with Down syndrome in countries where abortion is not allowed and in countries where pregnancy more commonly occurs at a later age. About 1.4 per 1,000 live births in the United States and 1.1 per 1,000 live births in Norway are affected. In the 1950s, in the United States, it occurred in 2 per 1,000 live births with the decrease since then due to prenatal screening and abortions. The number of pregnancies with Down syndrome is more than two times greater with many spontaneously aborting. It is the cause of 8% of all congenital disorders.
Maternal age affects the chances of having a pregnancy with Down syndrome. At age 20, the chance is 1 in 1,441; at age 30, it is 1 in 959; at age 40, it is 1 in 84; and at age 50 it is 1 in 44. Although the probability increases with maternal age, 70% of children with Down syndrome are born to women 35 years of age and younger, because younger people have more children. The father's older age is also a risk factor in women older than 35, but not in women younger than 35, and may partly explain the increase in risk as women age.
History
English physician John Langdon Down first described Down syndrome in 1862, recognizing it as a distinct type of mental disability, and again in a more widely published report in 1866. Édouard Séguin described it as separate from cretinism in 1844. By the 20th century, Down syndrome had become the most recognizable form of mental disability.
Due to his perception that children with Down syndrome shared facial similarities with those of Blumenbach's Mongoloid race, John Langdon Down used the term "mongoloid". He felt that the existence of Down syndrome confirmed that all peoples were genetically related. In the 1950s with discovery of the underlying cause as being related to chromosomes, concerns about the race-based nature of the name increased.
In 1961, a group of nineteen scientists suggested that "mongolism" had "misleading connotations" and had become "an embarrassing term". The World Health Organization (WHO) dropped the term in 1965 after a request by the delegation from the Mongolian People's Republic. While this terminology continued to be used until the late twentieth century, it is now considered unacceptable and is no longer in common use.
In antiquity, many infants with disabilities were either killed or abandoned. In June 2020, the earliest incidence of Down syndrome was found in genomic evidence from an infant that was buried before 3200 BC at Poulnabrone dolmen in Ireland. Researchers believe that a number of historical pieces of art portray Down syndrome, including pottery from the pre-Columbian Tumaco-La Tolita culture in present-day Colombia and Ecuador, and the 16th-century painting The Adoration of the Christ Child.
In the 20th century, many individuals with Down syndrome were institutionalized, few of the associated medical problems were treated, and most people died in infancy or early adulthood. With the rise of the eugenics movement, 33 of the then 48 U.S. states and several countries began programs of forced sterilization of individuals with Down syndrome and comparable degrees of disability. Action T4 in Nazi Germany saw the systematic murder of people with Down syndrome made public policy.
With the discovery of karyotype techniques in the 1950s it became possible to identify abnormalities of chromosomal number or shape. In 1959 Jérôme Lejeune reported the discovery that Down syndrome resulted from an extra chromosome. However, Lejeune's claim to the discovery has been disputed, and in 2014 the Scientific Council of the French Federation of Human Genetics unanimously awarded its Grand Prize to his colleague Marthe Gautier for her role in this discovery. The discovery took place in the laboratory of Raymond Turpin at the Hôpital Trousseau in Paris, France. Jérôme Lejeune and Marthe Gautier were both his students.
As a result of this discovery, the condition became known as trisomy 21. Even before the discovery of its cause, the presence of the syndrome in all races, its association with older maternal age, and its rarity of recurrence had been noticed. Medical texts had assumed it was caused by a combination of inheritable factors that had not been identified. Other theories had focused on injuries sustained during birth.
Society and culture
See also: List of people with Down syndromeName
Down syndrome is named after John Langdon Down. He was the first person to provide an accurate description of the syndrome. His research that was published in 1866 earned him the recognition as the Father of the syndrome. While others had previously recognized components of the condition, John Langdon Down described the syndrome as a distinct, unique medical condition.
In 1975, the United States National Institutes of Health (NIH) convened a conference to standardize the naming and recommended replacing the possessive form, "Down's syndrome", with "Down syndrome". However, both the possessive and nonpossessive forms remain in use by the general population. The term "trisomy 21" is also commonly used.
Ethics
Obstetricians routinely offer antenatal screenings for various conditions, including Down syndrome. When results from testing become available, it is considered an ethical requirement to share the results with the patient.
Some bioethicists deem it reasonable for parents to select a child who would have the highest well-being. One criticism of this reasoning is that it often values those with disabilities less. Some parents argue that Down syndrome should not be prevented or cured and that eliminating Down syndrome amounts to genocide. The disability rights movement does not have a position on screening, although some members consider testing and abortion discriminatory. Some in the United States who are anti-abortion support abortion if the fetus is disabled, while others do not. Of a group of 40 mothers in the United States who have had one child with Down syndrome, half agreed to screening in the next pregnancy.
Within the US, some Protestant denominations see abortion as acceptable when a fetus has Down syndrome while Orthodox Christianity and Roman Catholicism do not. Some of those against screening refer to it as a form of eugenics. Parents may be stigmatized whichever decision they make.
Advocacy groups
Advocacy groups for individuals with Down syndrome began to be formed after the Second World War. These were organizations advocating for the inclusion of people with Down syndrome into the general school system and for a greater understanding of the condition among the general population, as well as groups providing support for families with children living with Down syndrome. Before this individuals with Down syndrome were often placed in mental hospitals or asylums. Organizations included the Royal Society for Handicapped Children and Adults founded in the UK in 1946 by Judy Fryd, Kobato Kai founded in Japan in 1964, the National Down Syndrome Congress founded in the United States in 1973 by Kathryn McGee and others, and the National Down Syndrome Society founded in 1979 in the United States. The first Roman Catholic order of nuns for women with Down Syndrome, Little Sisters Disciples of the Lamb, was founded in 1985 in France.
The first World Down Syndrome Day was held on 21 March 2006. The day and month were chosen to correspond with 21 and trisomy, respectively. It was recognized by the United Nations General Assembly in 2011.
Special21.org, founded in 2015, advocates the need for a specific classification category to enable Down syndrome swimmers the opportunity to qualify and compete at the Paralympic Games. The project began when International Down syndrome swimmer Filipe Santos broke the world record in the 50m butterfly event, but was unable to compete at the Paralympic Games.
Paralympic Swimming
International Paralympic Committee Para-swimming classification codes are based upon single impairment only, whereas Down syndrome individuals have both physical and intellectual impairments.
Although Down syndrome swimmers are able to compete in the Paralympic Swimming S14 intellectual impairment category (provided they score low in IQ tests), they are often outmatched by the superior physicality of their opponents.
At present there is no designated Paralympic category for swimmers with Down syndrome, meaning they have to compete as intellectually disadvantaged athletes. This disregards their physical disabilities.
A number of advocacy groups globally have been lobbying for the inclusion of a distinct classification category for Down syndrome swimmers within the IPC Classification Codes framework.
Despite ongoing advocacy, the issue remains unresolved, and swimmers with Down syndrome continue to face challenges in accessing appropriate classification pathways.
Research
See also: Down syndrome research and Mouse models of Down syndromeEfforts are underway to determine how the extra chromosome 21 material causes Down syndrome, as currently this is unknown, and to develop treatments to improve intelligence in those with the syndrome. Two efforts being studied are the use stem cells and gene therapy. Other methods being studied include the use of antioxidants, gamma secretase inhibition, adrenergic agonists, and memantine. Research is often carried out on an animal model, the Ts65Dn mouse.
Other hominids
Down syndrome may also occur in hominids other than humans. In great apes chromosome 22 corresponds to the human chromosome 21 and thus trisomy 22 causes Down syndrome in apes. The condition was observed in a common chimpanzee in 1969 and a Bornean orangutan in 1979, but neither lived very long. The common chimpanzee Kanako (born around 1993, in Japan) has become the longest-lived known example of this condition. Kanako has some of the same symptoms that are common in human Down syndrome. It is unknown how common this condition is in chimps, but it is plausible it could be roughly as common as Down syndrome is in humans.
Fossilized remains of a Neanderthal aged approximately 6 at death were described in 2024. The child, nicknamed Tina, suffered from a malformation of the inner ear that only occurs in people with Down syndrome, and would have caused hearing loss and disabling vertigo. The fact that a Neanderthal with such a condition survived to such an age was taken as evidence of compassion and extra-maternal care among Neanderthals.
In popular culture
Individuals
- Jamie Brewer is an American actress and model. She is best known for her roles in the FX horror anthology television series American Horror Story. In its first season, Murder House, she portrayed Adelaide "Addie" Langdon; in the third season, Coven, she portrayed Nan, an enigmatic and clairvoyant witch; in the fourth season Freak Show, she portrayed Chester Creb's vision of his doll, Marjorie; in the seventh season Cult, she portrayed Hedda, a member of the 'SCUM' crew, led by feminist Valerie Solanas; and she also returned to her role as Nan in the eighth season, Apocalypse. In February 2015, Brewer became the first woman with Down syndrome to walk the red carpet at New York Fashion Week, for designer Carrie Hammer.
- Sofía Jirau is a Puerto Rican model with Down syndrome, working with top designers and renowned media outlets such Vogue Mexico, People, Hola!, among others. In February 2020, Jirau made her debut at New York Fashion Week. Then in February 2022, she became the first-ever model with Down Syndrome to be hired by the American retail company Victoria's Secret. She walked the LA Fashion Week runway in 2022. Jirau launched a campaign in 2021 called Sin Límites or No Limits "which seeks to make visible the challenges facing the Down syndrome community, demonstrate our ability to achieve our goals, and raise awareness about the condition throughout the world."
- Chris Nikic is the first person with Down syndrome to finish an Ironman Triathlon. He was awarded the Jimmy V Award for Perseverance at the 2021 ESPY Awards. Nikic continues to run races around the world, using his platform to promote his 1% Better message and bring awareness to the endless possibilities for people with Down syndrome.
- Grace Strobel is an American model and the first person with Down Syndrome to represent an American skin-care brand. She first joined Obagi in 2020, and continues to be an Ambassador for the brand as of 2022. She walked the runway representing Tommy Hilfiger for Runway of Dreams New York Fashion Week 2020 and Atlantic City Fashion Week. Strobel has been featured in Forbes, on The Today Show, Good Morning America, by Rihanna's Fenty Beauty, Lady Gaga's Kindness Channel, and many more. She is also a public speaker and gives a presentation called #TheGraceEffect about what it is like to live with Down syndrome.
Television and film
- Life Goes On is an American drama television series that aired on ABC from September 12, 1989, to May 23, 1993. The show centers on the Thatcher family living in suburban Chicago: Drew, his wife Libby, and their children Paige, Rebecca and Charles. Charles, called Corky on the show and portrayed by Chris Burke, was the first major character on a television series with Down syndrome. Burke's revolutionary role conveyed a realistic portrayal of people with Down syndrome and changed the way audiences viewed people with disabilities.
- Struck by Lightning, an Australian film by Jerzy Domaradzki and starring Garry McDonald, is a comedy-drama depicting the efforts by a newly appointed physical education teacher to introduce soccer to a specialized school for youths with Down syndrome.
- Champions (2023) is a film starring four main actors with Down syndrome: Madison Tevlin, Kevin Iannucci, Matthew Von Der Ahe and James Day Keith. It is an American sports comedy film directed by Bobby Farrelly in his solo directorial debut, from a screenplay written by Mark Rizzo. The film stars Woody Harrelson as a temperamental minor-league basketball coach who after an arrest must coach a team of players with intellectual disabilities as community service; Kaitlin Olson, Ernie Hudson, and Cheech Marin also star.
- Born This Way is an American reality television series produced by Bunim/Murray Productions featuring seven adults with Down syndrome with work hard to achieve goals and overcome obstacles. The show received a Television Academy Honor in 2016.
- The Peanut Butter Falcon is a 2019 American comedy-drama film written and directed by Tyler Nilson and Michael Schwartz, in their directorial film debut, and starring Zack Gottsagen, Shia LaBeouf, Dakota Johnson and John Hawkes. The plot follows a young man with Down syndrome who escapes from an assisted living facility, in order to follow his dream of being a wrestler, and befriends a wayward fisherman on the run. As the two men form a rapid bond, a social worker attempts to track them.
Music
- The Devo song "Mongoloid" is about someone with Down syndrome.
- The Amateur Transplants song "Your Baby" is about a fetus with Down syndrome.
Toys
- In 2023, Mattel released a Barbie doll with characteristics of a person having Down syndrome as a way to promote diversity.
See also
Notes
- Using the traditional numbering; the current numbering scheme retains human chromosome numbers, using 2A and 2B instead of 2 and 3 to refer to the two chromosomes that fused into chromosome 2 in humans.
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Further reading
- Fox N (2021-11-26). "'World-leading' Down's syndrome bill clears first hurdle in Parliament". BBC News. Archived from the original on 2021-11-27. Retrieved 2021-11-27.
- Thompson SB (1999). "Examining dementia in Down's syndrome (DS): decline in social abilities in DS compared with other learning disabilities". Clinical Gerontologist. 20 (3). Taylor & Francis (Routledge): 23–44. doi:10.1300/j018v20n03_04. ISSN 1545-2301. OCLC 1106716083.
- Thompson SB (2000a). "The Central Executive System in people with Down's syndrome and dementia". Clinical Gerontologist. 21 (3). Taylor & Francis (Routledge): 3–32. doi:10.1300/j018v21n03_02. ISSN 1545-2301. OCLC 1106716083. S2CID 218575706.
- Thompson SB (2000b). "Investigation into Down's syndrome and dementia". Journal of the Association of Practitioners in Learning Disability. 17 (3): 10–14.
External links
- Down's syndrome by the UK National Health Service
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