Congenital adrenal hyperplasia in monozygotic twins with variable clinical manifestations.

The first cases of congenital adrenal hyperplasia III with variable clinical manifestations in female monozygotic twins are presented. Twin "A" revealed severe hypertrophy of the clitoris, labial fusion and a visible introitus. However, twin "B" manifested moderate clitoral hypertrophy, a visible introitus and no labial fusion. Neither infant had palpable gonads.