In congenital adrenal hyperplasia due to 17α-hydroxylase deficiency, which metabolite is reported as high?

• A. Aldosterone
• B. Cortisol
• C. 17-hydroxyprogesterone
• D. DHEA

Answer: (A)

In 17α-hydroxylase deficiency, the block stops the conversion of pregnenolone and progesterone into their 17-hydroxylated forms, so cortisol and sex steroids fall while precursors are redirected toward mineralocorticoid synthesis. This pushes the pathway toward accumulating mineralocorticoid precursors, especially 11-deoxycorticosterone and corticosterone. These substances have strong mineralocorticoid effects, leading to sodium retention, hypertension, and suppressed renin. Because of this, cortisol and DHEA are reduced, and 17-hydroxyprogesterone is also low, since the step producing it from progesterone is blocked. Aldosterone itself may be normal or reduced depending on regulation of the renin-angiotensin system, but the patient’s mineralocorticoid excess is driven mainly by the accumulated precursors like 11-deoxycorticosterone, not by aldosterone.