Disorders of Sex Development - Repro - USMLE Step 1
Terms in this set (10)
Testicular atrophy, eunuchoid body shape, tall, long extremities, gynecomastia, female hair distribution. May present with developmental delay. Presence of inactivated X chromosome (barr body). Common cause of hypogonadism seen in infertility work-up.
(45,XO) or mosaicism (e.g. 45,XO/46,XX)
Short stature (if untreated), ovarian dysgenesis (streak ovary), shield chest, bicuspid aortic valve, preductal coarctation (femoral < brachial pulse), lymphatic defects (result in webbed neck or cystic hygroma; lymphedema in feet, hands), horseshoe kidney. Most common cause of primary amenorrhea. No barr body.
Double Y males
Phenotypically normal (usually undiagnosed), very tall. Random nondisjunction event (paternal meiosis II); noninherited; normal fertility. May be associated with severe acne, learning diability, autism spectrum disorders, and antisocial personality disorder.
(46,XX) or (47,XXY)
Also called ovotestitular disorder of sex development. Both ovarian and testicular tissue present (ovotestis); ambiguous genitalia.
Ovaries present, but external genitalia are virilized or ambiguous. Due to excessive and inappropriate exposure to androgenic steroids during early gestation (e.g. congenital adrenal hyperplasia or exogenous administration of androgens during pregnancy).
Inability to synthesize estrogens from androgens. Masculinization of female infants (ambiguous genitalia). Can present with maternal virilization during pregnancy (fetal androgens cross the placenta).
Testes present, but external genitalia are female or ambiguous. Most common form is androgen insensitivity syndrome (testicular feminization).
Androgen insensitivity syndrome
Defect in androgen receptor resulting in normal-appearing female; female external genitalia with scant sexual hair, rudimentary vagina (urogenital sinus forms lower 2/3 of vagina but, due to presence of MIF, upper 1/3 and other more proximal structures are absent --> uterus and fallopian tubes absent). Patients develop testes (often found in the labia majora); surgically removed to prevent malignancy.
Autosomal recessive; Inability to convert testosterone to DHT. Ambiguous genitalia until puberty, when increased testosterone causes masculinization/increased growth of external genitalia. Normal internal genitalia.
Increased or NORMAL LH
Failure to complete puberty; a forms of hypogonadotropic hypogonadism. Defective migration of GnRH cells and formation of olfactory bulb; decreased synthesis of GnRH in the hypothalamus; anosmia. Defect of X-linked KAL chain. Infertility (low sperm count in males; amenorrhea in females).