Cause:Genetic mutation or transmitted as? "X-linked or autosomal dominant expressed only in male". No incr w advanced maternal age.
Pathophys:Part of mixed gonadal dysgenesis (see above); XO, X with partial X or Y deletion, isochromosome of X or Y, ring chromosome with deletion of X or Y. Lymphatic hypoplasia causes edema
Rare, incid = 1/1500-2500 females, prevalence = 50-75 000 in US; more common in miscarriage fetuses
Sx:Short stature (90% are <5 ft); primary amenorrhea; multiple moles appear between age 4 and 15 yr
Si:Normal female genitalia; ankle edema; low hairline at base of neck; neck webbing (20%); multiple nevi and nail anomalies; increased carrying angle of elbow, short 4th metacarpal
Diabetes mellitus; Hashimoto's thyroiditis in up to 50%; congenital cardiovascular abnormalities, esp coarctation of the aorta (15%) and bicuspid aortic valve; renal and gi congenital abnormalities occasionally; tumors in streak gonads if present; renal HT; scoliosis (10%); OM from malformations of mouth/nose; hypothyroidism (20%); stabismus
Lab:
Path:Streak gonads w gonadal dysgenesis
Chromosome preps are Barr body-negative; get full karyotype to r/o XO-XY mosaicism with increased gonadal cancer incidence
Chem:FSH and LH increased (unlike hypogonadotrophic hypogonadism)
Xray:
Prenatal ultrasound may show lymphedema, thickened nuchal fold, cystic hygroma, horseshoe kidney
Knee films show overgrowth of medial tibial condyle