A 5-year-old child with 46,XX karyotype presents with clitoromegaly and accelerated growth. Blood pressure is 140/95 mmHg. Serum sodium is 140 mEq/L, potassium 3.2 mEq/L, renin is low, and 11-deoxycortisol is markedly elevated. Which enzyme deficiency is responsible?

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

Explanation

11-beta hydroxylase deficiency blocks conversion of deoxycorticosterone and 11-deoxycortisol, causing accumulation of mineralocorticoid-active deoxycorticosterone. This produces hypertension with hypokalemia and low renin, plus virilization from excess adrenal androgens. The key distractor is 21-hydroxylase deficiency, but that enzyme defect causes salt wasting with hyponatremia and hyperkalemia, never hypertension. Elevated 11-deoxycortisol specifically localizes the block above 11-deoxycortisol in the steroid pathway.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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