Progressive depletion of germ cells in a man with nonmosaic Klinefelter's syndrome: optimal time for sperm recovery.

We describe a sequential deteriorated change of sperm count in a 30-year-old infertile man with nonmosaic Klinefelter's syndrome. His initial semen analysis revealed oligozoospermia; however, the sperm count decreased progressively, which resulted in azoospermia over a period of 3 years. By testicular sperm extraction, a few spermatozoa were recovered. We analyzed the germ cells with three-color fluorescence in situ hybridization, and the presence of a 46,XY lineage was found. We suggest that progressive depletion of germ cells might occur in men with nonmosaic Klinefelter's syndrome and that these men should undergo semen cryopreservation or sperm recovery as early as possible.