skip to main content

Complete AIS — RACP Paediatrics MCQ

Instant feedback + full explanation. One question, done properly.

HardEndocrineComplete AISRACP Paediatrics

A phenotypically female adolescent presents with primary amenorrhoea and breast development but absent pubic and axillary hair. Examination reveals a short blind-ending vagina and bilateral inguinal masses (testes). Karyotype is 46,XY. Testosterone levels are in the adult male range. What is the most likely diagnosis?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — 46,XY androgen insensitivity syndrome

A 46,XY individual with female external phenotype, breast development (aromatisation of testosterone to oestrogen), absent pubic/axillary hair (androgen insensitivity), inguinal testes, and primary amenorrhoea is classic complete androgen insensitivity syndrome (CAIS). It is caused by mutations in the androgen receptor gene (X-linked). Gonadectomy is recommended after puberty due to malignancy risk.

Reference: RCH Melbourne – 2023 – DSD CPG; RACP Paediatric Curriculum – Endocrine/Genetics