A 12-day-old 46,XX neonate has ambiguous genitalia with clitoromegaly and partial labial fusion. Blood pressure is 105/70 mmHg (elevated for age). Serum sodium is 136 mEq/L, potassium is 4.8 mEq/L. 17-hydroxyprogesterone is modestly elevated, deoxycorticosterone and 11-deoxycortisol are markedly elevated. Which enzyme deficiency is most likely?

• A 21-hydroxylase
• B 3-beta-hydroxysteroid dehydrogenase
• C 17-alpha-hydroxylase
• D 11-beta-hydroxylase ✓

Explanation

Accumulation of 11-deoxycortisol and deoxycorticosterone, a potent mineralocorticoid, causes hypertension with normal or high sodium and suppressed aldosterone. Virilization occurs from shunting into androgens. The tempting distractor is 21-hydroxylase deficiency, but that enzyme block produces salt wasting with hyponatremia, hyperkalemia, and hypotension, never hypertension. 17-alpha-hydroxylase deficiency causes hypertension too, but presents with undervirilization rather than virilized genitalia.

Reference: Nelson Textbook of Pediatrics, 22nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.