A 13-year-old girl is brought to the physician by her mother for her yearly physical examination. Her temperature is 36.7 C (98 F), blood pressure is 152/91 mm Hg, the pulse is 75/min, and respirations are 18/min. Physical examination shows a lack of secondary sexual characteristics and pelvic examination shows a blind vagina. Laboratory studies reveal hypokalemia and low testosterone and estradiol levels. The cytogenetic analysis shows a 46, XY karyotype. Which of the following enzymes is most likely to be deficient in this patient:
Ans. C. 17α-hydroxylase
Explanation: 17a-hydroxylase deficiency impairs the synthesis of androgens, estrogens, and cortisol but does not inhibit mineralocorticoid production. Boys appear phenotypically female at birth, but girls develop normal genitalia. Patients typically present with hypogonadism, hypertension, and hypokalemia.