Mehl. SRY and mullerian

Question 1

Mehl. Müllerian agenesis.
Aka Mayer-Rokitansky-Küster-Hauser syndrome. USMLE will never assess this name, but students have asked about this before.

Answer 1

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Question 2

Mehl. Müllerian agenesis. karyotype?

Answer 2

46XX karyotype

Question 3

Mehl. Müllerian agenesis. CP?

Answer 3

Presents identical to AIS on USMLE except they’ll say pubic/axillary hair is normal/coarse.

Question 4

Mehl. Müllerian agenesis.
Ovaries are present, since no Y chromosome is present (i.e., no SRY gene to convert primitive gonads into testes, so ovaries as the default ensue).

Answer 4

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Question 5

Mehl. Müllerian agenesis. what reproductive organs do not develop?

Answer 5

But since the Müllerian (paramesonephric) ducts don’t develop, the Fallopian tubes, uterus, cervix, and upper vagina don’t develop.

Question 6

Mehl. Müllerian agenesis. BEST NEXT STEP?

Answer 6

Next best step = ultrasound first if listed, then karyotype.

Question 7

Mehl. SRY gene translocation. karyotype?

Answer 7

46XX karyotype; phenotypically male

Question 8

Mehl. SRY gene translocation. mechanism of translocation?

Answer 8

The SRY gene from the Y chromosome is translocated usually onto one of the X chromosomes, resulting in formation of testes instead of ovaries.

Question 9

Mehl. SRY gene translocation.
The presence of testes leads to ……??

Answer 9

Testosterone and DHT -> develops male external structures; MIF production -> no Müllerian structures develop.

Question 10

Mehl. SRY gene translocation. testes, what phalus abnormalities?

Answer 10

Testes are usually small, and there can be penile abnormalities like hypo- or epispadia

Question 11

Mehl. SRY gene translocation.
Rarely, this condition can be seen in 46XY karyotype, where the SRY gene is lost, rather than gained. Testes are absent, and instead there are streak ovaries + Müllerian structures.