21-Hydroxylase Deficiency

Excerpt

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder, caused by the deficiency of one of the enzymes required for the synthesis of cortisol in the adrenal glands. 21-hydroxylase deficiency is the most common cause of congenital adrenal hyperplasia (more than 90% of the cases). Glucocorticoid and mineralocorticoid replacement are the mainstays of treatment.

Prenatal diagnosis and treatment of affected females are very important, to minimize genital virilization. Because 21-hydroxylase deficiency is often undiagnosed in affected males until they have severe adrenal insufficiency, all US states and many other countries have instituted newborn screening programs that measure 17-hydroxyprogesterone concentration). Newborn screening can detect almost all infants with classic CAH and some infants with nonclassic CAH. Although false-negative results are uncommon, false-positive results are usually seen in premature infants; therefore, serial measurements of 17-hydroxyprogesterone are advised for premature infants. A positive newborn screening test for CAH must be confirmed by a second plasma sample (17-hydroxyprogesterone), and serum electrolytes should be measured.

This activity highlights the diagnosis and treatment of 21 hydroxylase deficiency.