Sexual development Flashcards
“Master switch” gene that causes differentiation into testes and what is the genes target?
SRY gene and target is SF-1
What cells secrete testosterone at 10 weeks? What stimulates them?
Leydig cells, stimulated by hCG
At 20 weeks what stimulates testosterone production from what?
LH from fetal pituitary stimulate fetal testis to produce testosterone
Anti-mullerian hormone (AMH) does what? What synthesizes it?
Regression of Müllerian ducts in normal males. Sertoli cells make in fetal testis
Testosterone is converted into what? By what enzyme?
Dihydrotestosterone (DHT) by 5alpha-reductase
What dose dihydrotestosterone do?
Develop prostate
When do ovaries develop?
9 weeks, if two X chromosomes and lack SRY gene
What genes responsible for ovarian development
DAX1 gene
Where do primordial germ cells (PGCs) migrate?
They seed gonads of both sexes, migrate from embryonic hindgut and settle along genital ridge
What does urogenital sinus form in males and females?
Males-grows prostate gland Females-grows lower 2/3 vagina
No hormonal input would result in what system forming?
Mullerian system (female)
Klinfelter syndrome (47,XXY)
- External male genitalia
- wolffian internal ducts normal
- decrease or normal testosterone
- increased LH
- really increased FSH
Ectopic pregnancy what treatment?
Methotrexate (need to be hemodynamically stable) or remove Fallopian tube
TORCH infections
Toxoplasmosis Other (syphilis, varicella, parvovirus) Rubella Cmv HSV (HIV, Hep B/C)
Genetic 46, XY DSD name 3 possible etiologies?
- Defect testosterone biosynthesis
- Defect androgen dependent target=androgen-insensitivity syndrome (AIS), receptor missing or malfunction
- 5alpha-reductase deficiency (look like male after puberty)
46,XX DSD
- Clitoromegaly 12 weeks
-
C21-hydroxylase deficiency (most common)
- Salt losing - adrenal crisis
- ACTH high
- cortisol low
- renin high-hypotension
- dx: 17-hydroxyprogesterone would be high
- tx: steroids for life
- C11-beta hydroxylase deficiency
- increased deoxycorticosterone (DOC)
- ACTH high
- salt and water retention and HTN
Congenital adrenal hyperplasia
- Autosomal recessive
- c21 hydroxylase deficiency,
- adrenal crisis risk
- female child genitalia would look ambiguous and male genitalia look normal
Female has not started period and is 16. Has shield like chest, short broad neck, high arched palate, short stature. What is the likely diagnosis?
-
Turner syndrome
- Males in family have history of fragile x
- family history Turner syndrome
- primary amenorrhea most common cause
- tx: phase 1: estrogen (low dose at 1st), phase 2: progesterone, phase 3: maintainance
Mullerian agenesis what wrong?
Lack uterus and fallopian tubes
Giving an older patient hypotonic saline can make what worse?
Hyponatremia
