A 6-year-old girl is brought for ambiguous genitalia noted since birth, progressive clitoromegaly, and accelerated growth. Blood pressure is 138/92 mmHg. 17-hydroxyprogesterone is only mildly elevated, while 11-deoxycortisol is markedly elevated. Which enzyme deficiency is responsible?
- A 21-hydroxylase deficiency
- B 17-alpha-hydroxylase deficiency
- C 11-beta-hydroxylase deficiency ✓
- D 3-beta-hydroxysteroid dehydrogenase deficiency
Correct answer: C. 11-beta-hydroxylase deficiency
Explanation
Virilisation combined with hypertension points to 11-beta-hydroxylase deficiency, where accumulated 11-deoxycorticosterone acts as a mineralocorticoid and raises blood pressure while shunting precursors into androgens. Classic 21-hydroxylase deficiency, the commonest form, causes salt-wasting with hypotension and a markedly elevated 17-hydroxyprogesterone. 17-alpha-hydroxylase deficiency causes sexual infantilism with hypertension, and 3-beta-HSD deficiency causes incomplete virilisation with salt wasting.
Reference: Williams Textbook of Endocrinology, 14th ed.
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