目的:探讨亚甲基四氢叶酸还原酶(MTHFR)C677T基因多态性与缺血性脑血管病的相关性。方法:运用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术对512例缺血性脑血管病患者和500例健康对照者进行MTHFR C677T基因多态性分析。结果:缺血性脑血管病患者中突变纯合子TT基因型频率为40%,突变杂合子CT基因型频率42·6%,野生型CC基因型频率为17·4%;对照组中TT基因型频率为32·8%,CT基因型频率为34·6%,CC基因型频率为32·6%;患者组和对照组T等位基因频率分别为61·3%和51·1%,C等位基因频率分别为38·7%和49·9%,以上各频率之间均有显著性差异(P<0·05)。结论:MTHFR C677T基因多态性与缺血性脑血管病的发生有一定关系,可能是缺血性脑血管病的一个重要危险因素。 Objective: To investigate the relationship between methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism and ischemic cerebrovascular disease. Methods: MTHFR C677T gene polymorphism was analyzed in 512 ischemic cerebrovascular disease patients and 500 healthy controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: The frequency of TT homozygote was 40% in the patients with ischemic cerebrovascular disease, 42.6% in the mutant heterozygous CT genotype and 17.4% in the wild-type CC genotype. In the control group, TT gene The frequency of type C was 32.8%, the frequency of CT genotype was 34.6% and the frequency of CC genotype was 32.6%. The frequencies of T allele in patients and controls were 61.3% and 51.1% respectively, The frequency of C allele was 38.7% and 49.9%, respectively, with significant difference (P <0.05). Conclusion: The polymorphism of MTHFR C677T gene is related to the occurrence of ischemic cerebrovascular disease and may be an important risk factor of ischemic cerebrovascular disease.