I’m curious to know how your son came to be diagnosed, to begin with. Was it through newborn screening, followed up with DNA to confirm?
I agree with you that DNA is not the best way to make the diagnosis of CAH. BUt I also think that (with DNA) mistakes---when they happen---are more likely to happen in the opposite situation of yours. i.e. the child really has CAH, but the DNA doesn’t turn up any mutations. Unfortunately, I think it’s much less likely to be a mistake if they DO find mutations.
Often, I think, a lot of confusion could be avoided, if there were just better communication between doctors and parents. If your child has already been treated for a couple of years, and the doctors are still sure that he has CAH, they really should be able to tell you why. And they should be able to back up their position with your child’s lab tests of the last couple of years.
When something isn’t explained thoroughly, I think you often end up with even more questions. I wonder if that might not be part of the problem, in your situation.