Nonclassic Congenital Adrenal Hyperplasia: What Do Endocrinologists Need to Know?

Congenital adrenal hyperplasia encompasses a group of autosomal recessive defects in cortisol biosynthesis, and 21-hydroxylase deficiency accounts for 95% of such cases. Non-classic 21-hydroxylase deficiency is due to partial enzymatic defects, which present with normal cortisol synthesis, but excessive production of adrenal androgens, including 11-oxygenated androgens. Non-classic 21-hydroxylase deficiency is relatively common, and its phenotype resembles closely that of polycystic ovary syndrome. This review focuses primarily on non-classic 21-hydroxylase deficiency, its clinical features, diagnosis, and management.