Diabetes Mellitus USMLE Step 1 Practice Question
A 19-year-old man presents with infertility and gynecomastia. Vital signs are normal (BP 118/76, HR 72, RR 16, Temp 37°C). Physical examination reveals tall stature with disproportionately long limbs, small firm testes bilaterally, and mild gynecomastia. Laboratory studies show elevated FSH (18 mIU/mL), elevated LH (16 mIU/mL), and low testosterone (120 ng/dL). Semen analysis reveals azoospermia. He denies anabolic steroid use. Which karyotype best explains these findings?
Answer choices
- A47 XYY
- B45 XO
- C46 XY
- DMosaic trisomy 21
- E47 XXYCorrect answer
- F46 XX with testicular feminization
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