Abstract: Objective To investigate the relationship between methylenetetra- hydrofolatereductase (MTHFR) gene polymorphism and serum homocysteine (Hcy) level and subtypes of ischemic stroke (IS). Methods The study was conducted according to the matched principle of case-control design, 310 patients with IS and 330 healthy people during the same period were selected as the case group and the control group. Recycling enzyme method and the real-time fluorescent quantitative PCR (RT-qPCR) method were used to detect the level of serum Hcy and the genotypes of MTHFR C677T, respectively. Results There was a significantly difference in MTHFR C677T genotype and allele frequency between the case and control groups (P＜0.05). The correlation analysis with different subtypes indicated that the frequencies of CT genotype (38.02%), TT genotype (10.74%), and T allele (29.75%) were significantly different in the LAA group (OR=1.662,95% CI:1.058-2.608,P＜0.05;OR=2.373,95% CI:1.110-5.073,P＜0.05;OR=1.663,95% CI:1.190-2.323,P＜0.05); The frequencies of TT genotype (10.53%) and T allele (27.30%) in SAO group were also significantly different (OR=2.130,95% CI:1.046-4.336,P＜0.05;OR=1.474,95% CI:1.075-2.021,P＜0.05).Further analysis of serum Hcy level showed that LAA group (19.55±5.61) μmol/L and SAO group (16.37±5.20)μmol/L were significantly higher than the control group (14.46±4.61)μmol/L (P＜0.001); Among the patients of both subtypes the serum Hcy levels in those with CT genotypes and TT genotypes were significantly higher than those in patients of CC genotypes(P＜0.001). Conclusions The gene polymorphism of MTHFR C677T has a significant effect on Hcy level in patients with LAA and SAO stroke.

Key words: homocysteine, MTHFR C677T gene, gene polymorphism, ischemic stroke