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Trisomy Spotted in Chimp

Researchers have uncovered a chimpanzee in Japan that has a Down syndrome-like disorder, Mashable reports. It's only the second such case that researchers are aware of, it adds.

In the journal Primates, Kyoto University researchers report that Kanako was born in captivity in Japan in 1992 of wild-born parents, who were young and healthy. The parents' other offspring were also healthy, save for a premature offspring of the father's that died. Kanako, though, was reported after birth to be inactive and less vocal than other newborn chimps. She later developed vision problems, becoming blind by the age of seven. She also has underdeveloped teeth and a heart defect was later noted. As Mashable points out, these are also conditions that affect people with Down syndrome.

The Kyoto researchers then conducted a chromosomal analysis of Kanako to report in their paper that she has trisomy 22 — chromosome 22 in great apes is akin to chromosome 21 in humans.

Mashable adds that the only other known chimpanzee with such a chromosomal disorder only lived to the age of two, while Kanako is 24.

"It is difficult to estimate the probability of a rare event using a small population, but given that around 500 chimpanzees have been born in captivity in Japan, the probability of this autosomal trisomy in chimpanzees may be comparable to that of trisomy 21 in humans, which occurs in up to 1 in 600 births," Kyoto's Satoshi Hirata says in a statement.