Re: What is the cause for down syndrome?

Jeanette,
There is only one form of Down syndrome known to be hereiditary and it happens in only a very small portion (3 to 4%) of individuals with Down syndrome. It is called Translocation Down syndrome. If your uncle is 30, chances are he never had a chromosome study. If you are anxious about it, talk to a geneticist. Testing could be done easily to rule it out. The other, greater incidence of Down syndrome has only been proven to be age related and again, a geneticist could explain what those risks would be for your age. Unlike, one of the replies below, this age relation has not altered and is still very much tracked today. If you want more info on Down syndrome, my suggestion is that you check out the two most reputable organizations (in America), the National Down Syndrome Society ( www.ndss.org ) and the National Down Syndrome Congress ( www.ndsccenter.org ). Tweet