Abnormal Development of the Reproductive System Flashcards
What triggers testis development?
SRY
What secretes AMH?
Testes
What causes involution of the Mullerian duct?
AMH
What causes differentiation of the Wolffian duct?
Testosterone
What does the Wolffian duct form?
Seminal vesicles, epididymis, and vas deferens
What 3 things does DHT trigger?
- Genital tubercle → penis
- Labioscrotal folds → scrotum
- Urogenital folds → penile urethra
What triggers ovary development?
FOXL2 gene + absence of SRY
What triggers differentiation of Mullerian duct?
Absence of AMH
What 3 things does the Mullerian duct form?
Fallopian tube, uterus, and upper vagina
What causes involution of the Wolffian duct?
Absence of testosterone
What causes formation of female external genitalia?
What 4 things form from which precursors?
- Absence of DHT
- Genital tubercle → clitoris
- Folds of urogenital sinus → labia minora
- Labioscrotal folds → labia majora
- Urogenital sinus → urethra and lower vagina
What 2 genes are involved in Kallman Syndrome?
KAL 1 / 2
4 effects of gonadal dysgenesis
- Low estradiol → high FSH due to loss of neg feedback
- Primary amenorrhea
- Short stature
- If Y chromosome is present, do gonadectomy due to risk of gonadal tumors
Mullerian Agenesis (Mayer-Rokitansky-Kuster-Hauser Syndrome) Karyotype Presentation
- 46, XX
- Presents as normal female phenotype w/ absence of uterus, upper vagina, and fallopian tubes.
- Ovaries and lower vagina are still present.
- Development is normal except for lack of menses.
Imperforate hymen / Transverse vaginal septum
Presentation
Treatment
- Presents w/ hematocolpos and monthly cyclic pain b/c menses can’t drain out. Uterus / upper vagina become distended w/ blood (hematocolpos). May get endometriosis.
- Ovaries are present and development is normal.
- Treat w/ surgery to open up the vagina.
Androgen insensitivity in a fetus
Karyotype
Phenotype
- 46, XY karyotype w/ normal (undescended) testes
- But, lack of sensitivity to androgens → female phenotype
- No testosterone receptor → absence male internal genitalia (no Wolffian duct)
- Normal AMH → absent female internal genitalia
- No DHT receptor → absent male external genitalia and presence of female external genitalia (blind vaginal pouch [lower vagina])
- Overall, you get female external genitalia + undescended testes.
Androgen insensitivity during puberty
Karyotype
Presentation
Treatment
- 46, XY karyotype w/ normal (undescended) testes
- Testosterone and DHT rise during puberty, but b/c the receptors don’t work:
- No virilization or pubic hair (abnormal androgen receptor)
- Normal breast development (due to peripheral conversion of testosterone to estrogen + normal estrogen receptor)
- Amenorrhea (no uterus due to AMH)
- Overall, get breasts but no period or pubic hair
- Legally and socially female. Testes are removed after puberty due to risk of tumor development.
2 syndromes that cause blind vagina
What is the difference?
- Androgen insensitivity syndrome and mullerian agenesis.
* Main diff is that AIS is 46 XY and Mullerian agenesis is 46 XX
Classic CAH
Presentation in girls vs boys
2 variants
- Girls present w/ ambiguous external genitalia. Have ovaries and uterus.
- Boys present w/ adrenal crisis (prevent w/ newborn screen).
- 2 variants, both of which present w/ virilization in girls
- Salt wasting – more common. Impaired cortisol and aldosterone → hyponatremia, dehydration, hyperkalemia, hypotension, and shock. Presents w/ early adrenal crisis in both genders.
- Simple virilizing – adequate aldosterone function (only requires 1% of enzyme function). Both genders can have adrenal crisis. Girls have clitoral enlargement and labial fusion. Presentation is less obvious in newborn boys, but later presents w/ very early pubertal signs and risk of adrenal crisis w/ stress.
Treating CAH (2)
- Glucocorticoids for adrenal insufficiency. Also reduces androgen levels allowing for ovulation and conception in women.
- Surgery for women to fix ambiguous genitalia
