Prenatal Detection of Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) is a family of autosomal recessive disorders of adrenal steroidogenesis in which there is a deficiency of one of the enzymes necessary for Cortisol synthesis. Consequent to the enzyme deficiency, there is increased ACTH via the negative feedback effect, adrenal hyperplasia and overproduction of precursor steroids produced prior to the enzymatic block, and overproduction of the adrenal hormones not requiring the deficient enzymatic step. A deficiency of each of the enzymes required for Cortisol synthesis has been described: cholesterol desmolase, 3β-hydroxysteroid dehydrogenase (3BHSD), 21-hydroxylase (21-OH), 11β-hydroxylase (11-βOH), and 17-hydroxylase. The symptoms of the enzymatic disorder depend upon which steroids are deficient and which are produced in excess (Bongiovanni et al., 1967; Bongiovanni, 1972; New et al., 1981b). Classical and nonclassical forms of several enzyme deficiencies have been described (3βHSD, 21-OH, 11β-OH), suggesting that different degrees of enzymatic deficiencies occur. Prenatal diagnosis has been reported in 21-OH deficiency and 11β-OH deficiency (New and Levine, 1984).