A 16-year-old girl has never menstruated. She has normal secondary sexual characteristics (Tanner stage 5 breasts, scant axillary and pubic hair), a blind-ending vaginal pouch, and no uterus on ultrasound. Karyotype is 46,XY. The diagnosis is:

• A Complete androgen insensitivity syndrome (CAIS) ✓
• B Turner syndrome (45,X)
• C Congenital adrenal hyperplasia
• D Mayer-Rokitansky-Küster-Hauser syndrome

Explanation

Complete androgen insensitivity syndrome (CAIS) results from mutations in the androgen receptor gene (X-linked). 46,XY individuals cannot respond to androgens, resulting in female external phenotype, well-developed breasts (estrogen from testicular aromatization), absent/scant pubic and axillary hair, absent uterus, and a blind vaginal pouch. Testes are present intra-abdominally and carry a gonadal malignancy risk (~3–5%), so gonadectomy after puberty is recommended.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.