There is a good chance you have met or know someone with Down syndrome, one of the most common chromosomal conditions. But there is so much to learn about it beyond its physical traits. For one thing, ...

Understanding the Context

Edwards syndrome, also known as trisomy 18, describes a rare genetic condition where a person has three copies of chromosome 18. Having an extra copy of this chromosome causes a variety of symptoms ... The team identified six cases of Down syndrome and one case of Edwards syndrome in human populations that were living in Spain, Bulgaria, Finland, and Greece from as long ago as 4,500 years before ...