Clitoromegaly is most commonly associated with which metabolic defect?

• A. Caudal regression
• B. Congenital adrenal hyperplasia
• C. Maternal diabetes
• D. Phenylketonuria

Answer: (B)

Clitoromegaly in a newborn girl is a sign of exposure of the female fetus to excess androgens. The condition that most commonly causes this androgen excess is congenital adrenal hyperplasia, typically from 21-hydroxylase deficiency. This enzyme defect reduces cortisol production, which raises ACTH, leading to adrenal enlargement and overproduction of adrenal androgens. Those androgens virilize external genitalia, producing clitoromegaly and often labioscrotal fusion.

Other options don’t usually cause virilization: maternal diabetes is linked to a range of congenital anomalies (such as caudal regression) but not specifically clitoromegaly; phenylketonuria is a metabolic disorder affecting phenylalanine metabolism with neurodevelopmental effects rather than genital virilization.