Medical Condition:
Syndrome, Klinefelter
A SEX CHROMOSOME DISORDER characterized by small testes, underdevelopment of secondary sexual characteristics, infertility (INFERTILITY, MALE), hyalinization and fibrosis of the seminiferous tubules, and elevated levels of gonadotropin. Patients tend to have long legs and a slim, tall stature. GYNECOMASTIA is present in many of the patients. The classic form has the karyotype 47,XXY. Several variants include those with the karyotpes 48,XXYY; 48,XXXY; 49,XXXXY, and several mosaic patterns ( 46,XY/47,XXY; 47,XXY/48,XXXY, etc.).