A newborn presents with ambiguous genitalia, salt wasting, and hypotension. Laboratory tests show elevated 17-hydroxyprogesterone levels. Which enzyme deficiency is most likely responsible for this condition?

The correct answer to the question "A newborn presents with ambiguous genitalia, salt wasting, and hypotension. Laboratory tests show elevated 17-hydroxyprogesterone levels. Which enzyme deficiency is most likely responsible for this condition?" is Option A: 21-hydroxylase.

The other options — B) 11β-hydroxylase, C) 17α-hydroxylase, D) 3β-hydroxysteroid dehydrogenase — are incorrect for this USMLE Exam Prep question. As explained above: 21-hydroxylase deficiency is the most common cause of congenital adrenal hyperplasia. It leads to impaired cortisol and aldosterone synthesis (causing salt wasting) and accumulation of androgens (cau…