Congenital adrenal hyperplasia (CAH) describes a group of genetic disorders affecting your adrenal glands. You have one adrenal gland on top of each kidney. The adrenal glands produce several important hormones your body needs.
In CAH, genetic mutations (changes) cause shortages of certain enzymes, such as 21-hydroxylase, that help your body produce needed hormones. For many people with CAH, the enzyme shortage causes the adrenal glands to overproduce other hormones, like testosterone.
There are two main types of CAH: classic CAH and nonclassic CAH. The symptoms depend on the type of CAH you have. There are much more rare forms of CAH with different symptoms.