Antenatal diagnosis and treatment of congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) is a family of monogenic autosomal recessive disorders of steroidogenesis in which enzymatic defects result in impaired synthesis of cortisol by the adrenal cortex. The adrenal 21-hydroxylase (21-OH) enzyme is one of five enzymes necessary for the synthesis of cortisol from cholesterol, and its deficiency is the most common enzymatic defect causing CAH. 21-OH deficiency (21-OHD) occurs in a classical form that can cause genital ambiguity at birth in genetic females. Newborn males have normal genitalia. Prenatal treatment of 21-hydroxylase deficiency with dexamethasone has been used for approximately 15 years. An algorithm was developed for prenatal diagnosis and treatment.