A newborn girl has ambiguous genitalia, vomiting, dehydration, hyponatraemia and hyperkalaemia. Both adrenal glands are massively enlarged with wrinkled, cerebriform cut surface. Enzyme deficiency responsible and the accumulated steroid precursors are:

• A 11-beta hydroxylase deficiency with accumulation of 11-deoxycortisol
• B Aldosterone synthase deficiency with accumulation of corticosterone
• C 5-alpha reductase deficiency with accumulation of testosterone
• D 21-hydroxylase deficiency with accumulation of 17-hydroxyprogesterone ✓

Explanation

21-hydroxylase deficiency accounts for about 90 percent of congenital adrenal hyperplasia. The block diverts precursors into the androgen pathway causing virilisation of female infants, while aldosterone and cortisol deficiency cause salt wasting with hyponatraemia and hyperkalaemia. 17-hydroxyprogesterone is the hallmark elevated precursor. 11-beta hydroxylase deficiency causes hypertension from 11-deoxycorticosterone excess, and 5-alpha reductase deficiency affects external genitalia without adrenal pathology.

Reference: Williams Textbook of Endocrinology, 14th ed.

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Written and medically reviewed by the StethoPrep medical team.