The basic cause is a genetic defect that prevents the adrenal glands from manufacturing the steroid hormone cortisol. The low level of steroids in the blood causes a gland in the brain (the pituitary) to produce large quantities of a hormone to try to stimulate the adrenal glands to produce more cortisol. Instead, they can only produce large quantities of the male sex hormone.

Causes

The basic cause is a genetic defect that prevents the adrenal glands from manufacturing the steroid hormone cortisol. The low level of steroids in the blood causes a gland in the brain (the pituitary) to produce large quantities of a hormone to try to stimulate the adrenal glands to produce more cortisol. Instead, they can only produce large quantities of the male sex hormone

Treatment

Congenital adrenal hyperplasia can be effectively treated by regular doses of the drug hydrocortisone. This is identical to the natural steroid cortisol produced by the adrenal glands, and the presence of it in the blood immediately stops the pituitary gland from sending out too much of its own hormones. Hydrocortisone, or another steroid drug, is given by injection to infants, but later in life can be taken in tablet form by mouth.

In girls, surgery may be necessary along with treatment with hydrocortisone to restore a feminine appearance. Normal menstrual periods and even pregnancy may be possible. In boys, hydrocortisone suppresses the excess male hormone production and allows a normal puberty to occur at the right time.