Editing Down syndrome (section)

==Other hominids==
Down syndrome may also occur in [[hominidae|hominids]] other than humans. In [[great apes]] 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 [[chromosome 2]] 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 [[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.<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 [[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.<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>