Per p608 in FA 2019, SRY on Y chromosome results in development of testes. DHT results in development of male external genitalia (and the prostate).
Y chromosome --> SRY gene --> Testis --> Sertoli and Leydig cells.
Sertoli cells: AMH --> involution of mullerian ducts --> no female internal organs
Leydig cells:
Everything is normal, except for external genitalia. DHT signalling is missing.
You start out as female genitalia
Then add some extra stuff to make a dick and testis.
Add Testosterone (Ley"dick" cell) + Anti-mullerian hormone (sertoli cell) => male INTERNAL genitalia
Add DHT (produced by 5-a hydroxylase) => male EXTERNAL genitalia
Since pt is lacking male external genitalia, something is wrong with DHT
I chose E) because I was thinking androgen insensitivity syndrome. However, I realize the wording of the question is which HORMONE would be reduced and in AIS, testosterone levels would not actually be reduce.
To be clear though, AIS could have the EXACT same described presentation, yes? (46.XY with male genital ducts & female external genitalia) Just want to make sure there is nothing else that could have tipped me off. Thanks.
Dang this question threw me off because it said female genitalia when I thought it would be ambiguous at birth. DHT still makes the most sense. Thanks.
Everything has been covered already, but here's to the visual learners - it's easy to see the relationship between DHT and testosterone. https://imgur.com/a/M8Y3Fdm
(ignore the whole black versus blue colors...it complicates things and I'm sure I miscolored somewhere).
submitted by โsinforslide(63)
Male internal genitalia -> Intact SRY , testes, and testosterone.
No female internal genitalia -> Presence of MIF (antimullerian hormone) and intact Sertoli cell function.
Female external genitalia -> No androgen present, which is required for male external genitalia formation.