Scientists were able to diagnose Down syndrome using DNA from ancient bones. Down syndrome happens to 1 in 700 newborns today, and it results in an extra copy of chromosome 21. Down syndrome is most likely to occur when older mothers give birth in modern times. Back then, Down syndrome was rare because there were higher chances of women dying young, which made Down syndrome rare.
The first Down syndrome case using DNA from ancient bones was in 2020. The bones were found to be of a six-month-old boy who had been buried for almost 5570 years. Scientists also found an infant who had Edwards syndrome. Edwards syndrome is when there is an extra copy of chromosome 18. Researchers believe that the baby was only able to survive up to 40 weeks of gestation. This could possibly be the first case of Edwards syndrome found in the ancient remains.
This is a picture of ancient remains of infants who had Down syndrome. These bones are about 2500 years old.
References:
https://www.smithsonianmag.com/smart-news/dna-reveals-presence-of-down-syndrome-in-ancient-society-180983835/
https://www.nytimes.com/2024/02/20/science/down-syndrome-dna-bones.html