She could have a mutation or something that no one else in the family has. I would consult with a ped. geneticist and see if there is any simple testing that can be done (like a karyotype) or maybe the geneticist will suspect something just by looking at her. Certain syndromes produce certain physical characteristics that may mean nothing alone, but combined they could mean something. DS has "cup-shaped ears" that can be a part of so many genetic disorders, but then I realized my dad has the same exact ears. He also has dimples in his shoulders that could signify something, but then I saw that Dh has "indentations" in his shoulders that aren't full-on dimples, but DS must have a more full-blown version. Anyway, my point is that a geneticist would be able to see things like that and there may be something that screams a certain disorder, and then they would know what to test for. In our case, it is a balanced translocation and they are all pretty much unique, except for members in the same family often having the same translocation (but there is always person who is "first" and no one else has it).
