Know anything about Chiari malformations?

Question

I have an Arnold Chiari Malformation, type 1. My son's biological sister got diagnosed with the same thing last month. We're trying to find statistics on how rare it is, how many people per thousand are diagnosed, or whatever. And we're also wondering, is it genetic or hereditary? Links appreciated.

Answer 1

I saw a special on that about a year ago...
I remember that they weren't sure how rare it is, but that it seemed to be more common than had previously believed and that it did seem to run in families.

Best of luck!