Scientists find Down syndrome 'genetic signature' in ancient bones. Scientists diagnosed Down syndrome using DNA from the ancient bones of seven babies, one of them from 5,500 years ago.
Their method may help researchers learn more about how prehistoric societies treated people with Down syndrome and other rare diseases. Down syndrome occurs in 1 in 700 babies today and is caused by an extra copy of chromosome 21. The extra chromosome produces additional proteins that can cause a series of disorders, such as heart defects and learning difficulties.