Newborn screening, prenatal diagnosis, and prenatal treatment of congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency can be detected by newborn screening. Benefits of screening for affected newborns include the prevention of severe adrenal crisis, its sequelae, and progressive signs of androgen excess. First-trimester prenatal diagnosis is possible by HLA typing and/or DNA analysis of genes within the HLA complex of chorionic villus cells; for second-trimester diagnosis, hormonal measurement o f amniotic fluid and HLA typing or DNA analysis of amniotic cells are used. Results of prenatal treatment of CAH have varied, and the efficacy of prenatal treatment by maternal glucocorticoid therapy requires further investigation.