研究開発・学会発表

Introduction: Klinefelter syndrome (KS) is a sex chromosome disorder characterized by the presence of an extra X chromosome. The mosaic form includes cells with both normal and KS karyotypes. We previously reported a 40% sperm retrieval rate in KS using microdissection testicular sperm extraction (MD-TESE). In this study, we aimed to compare culture and pregnancy outcomes between mosaic and non-mosaic KS cases.

Methods: This retrospective study analyzed 27 KS cases that underwent MD-TESE and intracytoplasmic sperm injection (ICSI) between January 2011 and December 2021. Peripheral blood karyotype analysis using G-banding was performed, identifying 20 non-mosaic cases and 7 mosaic cases. Standard procedures were followed for MD-TESE and ICSI.

Results: The age of husbands in the non-mosaic group was significantly lower than that in the mosaic group (32.2±4.8 vs 45.9±13.1 years, p<0.001). The use of motile sperm was higher in the mosaic group (100% vs 51.3%, p<0.001). Fertilization rates were similar across groups, but cleavage rates (84.6% vs 58.5% vs 96.2%) and blastocyst formation rates (31.2% vs 13.7% vs 44.7%) were significantly lower in non-mosaic cases using non-motile sperm compared to mosaic cases (p<0.05). Regarding pregnancy outcomes, there was no significant difference between non-mosaic and mosaic groups in clinical pregnancy rate (28.0% vs 20.7%) or miscarriage rate (14.3% vs 33.3%). However, the age of the wives at the time of embryo transfer was significantly lower in the non-mosaic group (33.4±4.5 vs 37.3±4.2 years, p<0.001).

Conclusions: These findings suggest that the use of motile sperm, regardless of karyotype, improves embryonic development. While no significant difference in pregnancy outcomes was observed, the age of the wife appears to influence success rates. Therefore, early diagnosis and intervention in KS are crucial to optimizing reproductive outcomes.