There are a lot of mutations of DNA that can cause CAH. I think that there are 10 ’common’ ones and then a whole slew of uncommon ones. From what I can tell, most labs can only identify mutations that have already been identified because of the techniques they use. So perhaps you have a mutation that has not already been identified, have an uncommon mutation that the lab does not test for, or the lab goofed (it happens!)
Finding a lab that does complete sequencing is a good idea. I really don’t know why most genetic testing places don’t do this. It really isn’t that hard to amplify a section of DNA, have it sequenced, and then throw the sequence onto NCBI BLAST. BLAST is a program that will take a sequence of DNA and compare it to other known DNA sequences. It makes sense to me but... who knows. I suspect that this is what your genetics person is going to do. If she has trouble finding someone to sequence the DNA, ask her about universities in the area. The university I work at has a DNA sequencing and synthesizing facility and I suspect would take samples from outside the university- I don’t see why not as long as they get paid! On the other hand, it might be hard to get insurance to pay something like that, but depending on who you find it can be cheap (UGA is $17 per sample, for example)
Good luck!
Martha