A 14-year-old girl presents with short stature (below the 3rd centile), primary amenorrhoea, absent breast development, a low posterior hairline, widely spaced nipples, cubitus valgus, and hypertension. Echocardiography shows a bicuspid aortic valve. What is the best confirmatory investigation?
- A Serum FSH and LH levels
- B Karyotype from peripheral blood lymphocytes ✓
- C Pelvic ultrasonography
- D Growth hormone stimulation testing
Correct answer: B. Karyotype from peripheral blood lymphocytes
Explanation
The phenotype of short stature, primary amenorrhoea, cubitus valgus, low hairline, and left-sided cardiac lesion points to Turner syndrome, confirmed by karyotype showing 45,X or mosaicism such as 45,X/46,XX. Gonadotropins will be elevated because of streak ovaries, but they support rather than confirm the diagnosis, and ultrasound showing a hypoplastic uterus cannot distinguish Turner syndrome from other causes of ovarian failure.
Reference: Nelson Textbook of Pediatrics, 22nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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