RESUMEN
OBJECTIVE@#To investigate the association of MTHFR C677T and MS A2756G polymorphism with semen quality in China.@*METHODS@#The experimental group included 75 males with oligospermia, asthenospermia or teratospermia. The control group included 72 fertile males with normal fertility and sperm quality. The differences in the frequency of genetic polymorphism of MTHFR C677T and MS A2756G in the 2 groups were analyzed, and the plasma homocysteine (Hcy) level in both groups was detected.@*RESULTS@#The frequency of MTHFR C677T genotypes (CT, TT and CT+TT) in the abnormal sperm group was higher than that in the control group (P0.05). The Hcy level in abnormal sperm group was higher than that in the control group. In all subjects, the Hcy level of the MTHFR genotypes (CT, TT and CT+TT) was higher than that of the CC genotype, with no difference among the three MS A2756G genotypes.@*CONCLUSION@#CT and TT genotypes of MTHFR C677T are associated with abnormal sperm, which might be part of the pathogenesis of abnormal sperms. T allele may be the risk factor in China. The one mechanism of the association between MTHFR C677T polymorphism and semen quality could be higher Hcy level. MS A2756G polymorphism may not associate with semen quality in China.