Sexual development

Question 1

“Master switch” gene that causes differentiation into testes and what is the genes target?

Answer 1

SRY gene and target is SF-1

Question 2

What cells secrete testosterone at 10 weeks? What stimulates them?

Answer 2

Leydig cells, stimulated by hCG

Question 3

At 20 weeks what stimulates testosterone production from what?

Answer 3

LH from fetal pituitary stimulate fetal testis to produce testosterone

Question 4

Anti-mullerian hormone (AMH) does what? What synthesizes it?

Answer 4

Regression of Müllerian ducts in normal males. Sertoli cells make in fetal testis

Question 5

Testosterone is converted into what? By what enzyme?

Answer 5

Dihydrotestosterone (DHT) by 5alpha-reductase

Question 6

What dose dihydrotestosterone do?

Answer 6

Develop prostate

Question 7

When do ovaries develop?

Answer 7

9 weeks, if two X chromosomes and lack SRY gene

Question 8

What genes responsible for ovarian development

Answer 8

DAX1 gene

Question 9

Where do primordial germ cells (PGCs) migrate?

Answer 9

They seed gonads of both sexes, migrate from embryonic hindgut and settle along genital ridge

Question 10

What does urogenital sinus form in males and females?

Answer 10

Males-grows prostate gland Females-grows lower 2/3 vagina

Question 11

No hormonal input would result in what system forming?

Answer 11

Mullerian system (female)

Question 12

Klinfelter syndrome (47,XXY)

Answer 12

• External male genitalia
• wolffian internal ducts normal
• decrease or normal testosterone
• increased LH
• really increased FSH

Question 13

Ectopic pregnancy what treatment?

Answer 13

Methotrexate (need to be hemodynamically stable) or remove Fallopian tube

Question 14

TORCH infections

Answer 14

Toxoplasmosis Other (syphilis, varicella, parvovirus) Rubella Cmv HSV (HIV, Hep B/C)

Question 15

Genetic 46, XY DSD name 3 possible etiologies?

Answer 15

1. Defect testosterone biosynthesis
2. Defect androgen dependent target=androgen-insensitivity syndrome (AIS), receptor missing or malfunction
3. 5alpha-reductase deficiency (look like male after puberty)

Question 16

46,XX DSD

Answer 16

• 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

Question 17

Congenital adrenal hyperplasia

Answer 17

• Autosomal recessive
• c21 hydroxylase deficiency,
• adrenal crisis risk
• female child genitalia would look ambiguous and male genitalia look normal

Question 18

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?

Answer 18

• 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

Question 19

Mullerian agenesis what wrong?

Answer 19

Lack uterus and fallopian tubes

Question 20

Giving an older patient hypotonic saline can make what worse?

Answer 20

Hyponatremia