Diabetes Mellitus USMLE Step 1 Practice Question
A 15-year-old girl presents with primary amenorrhea and short stature. Vital signs show BP 138/82 mmHg, HR 78/min, RR 16/min, temp 37°C. Physical examination reveals webbed neck, widely spaced nipples, and cubital valgus. Laboratory studies demonstrate elevated FSH of 62 mIU/mL (normal 5-25) and low estrogen at 8 pg/mL. Karyotype analysis shows 45,X. Cardiac ultrasound is normal. She takes no medications. Which chromosomal abnormality best explains these findings?
Answer choices
- AHypothalamic GnRH deficiency with anosmia
- BActivating mutation in Gs alpha
- C46 XY karyotype with androgen receptor defect
- D45 XO karyotype with streak ovariesCorrect answer
- E47 XXY karyotype with seminiferous tubule dysgenesis
- F46,XY pure gonadal dysgenesis (Swyer syndrome)
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