摘要
Klinefelter syndrome(KS),described for the first time in 1942,is the most common chromosome aneuploidy in men,affecting from 1/500 to 1/1000 newborn males,and it frequently causes azoospermia.In the majority of cases,KS patients present a nonmosaic karyotype 47,XXY or a mosaic 47,XXY/46,XY karyotipe.1 KS is characterized usually by gynecomastia,small testes,and alteration of germinal epithelium and Sertoli cell.
