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Pathophys and Cause ⬇

Cause:Genetic; mutation, in case of mosaics, in postconception fetus

Pathophys:XXY, XXXY in at least some body cells (mosaicism)

Epidemiology ⬆ ⬇

1/250 male births and 1/20 aspermic males (Nejm 1969;281:969)

Signs and Symptoms ⬆ ⬇

Sx:Sexual immaturity, sterility

Si:Aspermic/hypospermic, male phenotype; small testes (<2.5 cm diameter); gynecomastia; diminished intelligence (IQ); vertical creases on upper lip as age (present in all females without ovaries)

Complications ⬆ ⬇

Breast cancer incidence is the same as for women (Nejm 1980;303:795)

r/o "SUPERMALE" = XXYY, XYY; tall, aggressive; have varicose veins; may present looking like a Klinefelter's

Lab and Xray ⬆ ⬇

Lab:

Chem:FSH and LH elevated (unlike hypogonadotropic hypogonadism)

Path:

  • Testicular bx shows hyalinized tubules with clumped Leydig cells, r/o mumps orchitis
  • Chromosome preps show buccal Barr body-positive (85%); XXY or XXYY by full karyotype, unless miss in a mosaic

Treatment ⬆

Rx:

Testosterone 200 mg im in oil q2-4wk or pulse

Paternity possible w testicular sperm aspiration and in vitro fertilization (Nejm 1998;338:588)