Differences in clinical outcomes between men with mosaic Klinefelter syndrome and those with non-mosaic Klinefelter syndrome

Purpose: This study compared the clinical outcomes of men with Klinfelter syndrome based on karyotype.

Methods: The authors analyzed the outcomes of microdissection testicular sperm extraction (micro-TESE) performed on 57 patients with Klinfelter syndrome (KS) at our clinic.

Results: The average ages of the non-mosaic and mosaic KS groups were 32.2 ± 4.8 and 45.9 ± 13.1 years, respectively. The sperm retrieval rates of the non-mosaic and mosaic KS groups were 46.5% (20/43) and 50.0% (7/14), respectively. The fertilization rates after intracytoplasmic sperm injection did not significantly differ between the non-mosaic and mosaic KS groups. The mosaic KS group had higher cleavage and blastocyst development rates than the non-mosaic KS group (72.2% vs. 96.2% and 30.5% vs. 44.7%, respectively). The group using motile sperm had better outcomes than the group using immotile sperm. The embryo transfer outcomes of the non-mosaic and mosaic KS groups did not significantly differ (clinical pregnancy rate: 28.0% vs. 20.7%, miscarriage rate: 14.3% vs. 33.3%, production rate per transfer: 22.0% vs. 13.8%, and production rate per case: 58.8% vs. 57.1%).

Conclusions: Compared with the non-mosaic KS group, the mosaic KS group had significantly better intracytoplasmic sperm injection outcomes because of the higher utilization rate of motile sperm.