Unusual heterozygotes of congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

Three otherwise healthy relatives of patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency and salt-wasting presented with clinical and/or biochemical findings, which exceeded those usually seen in heterozygotes: Two females (1 mother and 1 prepubertal sister of a patient with CAH) had marked hypertrichosis and hirsutism and excreted pregnanetriolone in their urine. The mother had increased basal plasma 17alpha-OH-progesterone (296 ng/100 ml), which increased to 7170 ng/100 ml after ACTH as in homozygotes of CAH. One adult male (brother of a patient with CAH) was clinically normal, but also excreted pregnanetriolone and had a high plasma 17alpha-OH-progesterone (1905 ng/100 ml), which increased further to 6352 ng/100 ml after ACTH. It is concluded that these subjects represent unusually marked heterozygotes of CAH rather than mild homozygotes. In females, this condition should be included in the differential diagnosis of idiopathic hirsutism, in males, it will pass unnoticed, unless relatives of patients with CAH are systematically tested.