I do believe it is possible to have siblings with different presentations of CAH---it all depends on the genetic make-up of the parents. In your case, I believe it would mean that at least one of you (you or your husband) would have to carry at least two CAH defects, one a salt-wasting defect and the other, a non-saltwasting defect. Our family has been genetically tested, and from what the counsellor told us, the "better" gene dominates. For example, if your son is a salt-waster, it would mean that both you and your husband are carriers of salt-wasting defects. When your son was conceived, he got SW genes from both of you, thus he presents as a salt-waster. If your daughter also has CAH, but is not a salt-waster, it would mean that at least one of you (you or your husband) also carries a milder, non-saltwasting defect. When your daughter was conceived, if she got the SW gene from one of you, and the milder non-salt gene from the other of you, she would end up presenting as a non-salt waster, because the "better" gene dominates. When I was tested, I was found to have two defects, both salt-wasting. Fortunately, my husband only has one defect, which is a non-salt defect. When we conceived my son, he received CAH genes from both of us, but luckily, because the "better" gene dominates, the non-salt gene he got from my husband won out, and he is a non-salt waster. Theoretically, for us, we could never have a salt-wasting CAH child, because my husband doesn't carry the SW gene. If my husband had had another defect, which was salt-wasting, and one of my two defects was a non-salt (instead of both being SW), then we could have had either a SW child, or a non-salt waster, depending on how the genes combined, as may be the case with your children. At any rate, the only way to know with your daughter is to have her tested for CAH. Since she does have some signs of early puberty, and you already have a child with the condition, there is certainly plenty of reason to proceed with some tests. Good luck!!