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638 SectioN iii RepRoductive ` REPRODUCTIVE—PATHOlOgy RepRoductive ` REPRODUCTIVE—PATHOlOgy
` REPRODUCTIVE—PATHOlOgy
Sex chromosome Aneuploidy most commonly due to meiotic nondisjunction.
disorders
Klinefelter syndrome Male, 47,XXY. Dysgenesis of seminiferous tubules
A Testicular atrophy, eunuchoid body shape, inhibin B FSH.
tall, long extremities, gynecomastia, female Abnormal Leydig cell function testosterone
hair distribution A . May present with LH estrogen.
developmental delay. Presence of inactivated
X chromosome (Barr body). Common cause of
hypogonadism seen in infertility work-up.
Turner syndrome Female, 45,XO. Menopause before menarche.
B Short stature (associated with SHOX gene, estrogen leads to LH, FSH.
preventable with growth hormone therapy), Sex chromosome (X, or rarely Y) loss often due to
ovarian dysgenesis (streak ovary), shield nondisjunction during meiosis or mitosis.
chest B , bicuspid aortic valve, coarctation Meiosis errors usually occur in paternal gametes
of the aorta (femoral < brachial pulse), sperm missing the sex chromosome.
lymphatic defects (result in webbed neck Mitosis errors occur after zygote formation loss
or cystic hygroma; lymphedema in feet, of sex chromosome in some but not all cells
hands), horseshoe kidney, high-arched palate, mosaic karyotype (eg. 45,X/46XX).
shortened 4th metacarpals. (45,X/46,XY) mosaicism associated with
Most common cause of 1° amenorrhea. No Barr increased risk for gonadoblastoma.
body. Pregnancy is possible in some cases (IVF,
exogenous estradiol-17β and progesterone).
Double Y males 47, XYY.
Phenotypically normal (usually undiagnosed),
very tall. Normal fertility. May be associated
with severe acne, learning disability, autism
spectrum disorders.
Ovotesticular disorder 46,XX > 46,XY.
of sex development Both ovarian and testicular tissue present
(ovotestis); ambiguous genitalia. Previously
called true hermaphroditism.
FAS1_2019_15-Repro.indd 638 11/7/19 5:52 PM
