Adrenal hyperplasia, congenital

An uncommon genetic disorder in which an enzyme defect blocks the production of corticosteroid hormones from the adrenal glands. Excessive amounts of androgens (male sex hormones) are produced, which can result in abnormal genital development in an affected fetus. Other effects include dehydration, weight loss, low blood pressure, and hypoglycaemia. Hyperplasia (enlargement) of the adrenal glands occurs and there is excessive skin pigmentation in skin creases and around the nipples. In severe cases, the disorder is apparent soon after birth. In milder cases, symptoms appear later, sometimes producing premature puberty in boys and delayed menstruation, hirsutism, and potential infertility in girls. Congenital adrenal hyperplasia is confirmed by measuring corticosteroid hormones in blood and urine. Treatment is by hormone replacement. If this is started early, normal sexual development and fertility usually follow.