I would say you are correct. The DNA test can be done to test for the more common CAH genes. If you and your husband are carriers of a , for lack of a better word, "funkier" CAH gene then maybe your relatives are also carriers of the same one which could be why they would want to know what they are looking for.  Chances are though that they know what kind of CAH your child has so they would, I guess, check for those common mutations first.

I would try a different lab. Maybe Cornell. I think there is another one in Oklahoma that is a little less expensive. We had all of ours done in Cornell.

Good luck.

Sandra