A 22-year-old woman presents with primary amenorrhea. Examination reveals normal secondary sexual characteristics (Tanner stage V breast development), absent uterus and upper vagina, and normal karyotype 46,XX. FSH and LH are normal. What is the most likely diagnosis and what is the embryological basis of this condition?

• A Androgen insensitivity syndrome (AIS) — 46,XY karyotype with female phenotype and absent Müllerian structures due to AMH secretion by testes
• B Turner syndrome (45,X) with absent uterus due to abnormal Müllerian development in the setting of streak gonads
• C Kallmann syndrome with uterine aplasia caused by GnRH deficiency during embryological development
• D Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome Type I — failure of Müllerian duct development causing uterovaginal aplasia with normal ovarian and external genital function ✓

Explanation

MRKH syndrome (Mayer-Rokitansky-Küster-Hauser) presents with: 46,XX karyotype, normal secondary sexual characteristics (ovaries are normal, estrogen production is intact), absent uterus, absent or rudimentary upper 2/3 of vagina, and normal FSH/LH. The embryological basis is failure of the Müllerian (paramesonephric) ducts to develop and fuse to form the uterus, cervix, and upper vagina — despite normal ovarian development (ovaries are of mesodermal-coelomic origin, not Müllerian). Type I (isolated) vs Type II (MURCS association — Müllerian aplasia, Renal aplasia, Cervicothoracic Somite dysplasia). AIS (46,XY) is the key differential — distinguished by karyotype and the absence of pubic/axillary hair in complete AIS.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

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Written and medically reviewed by the StethoPrep medical team.