中文摘要：

目的探讨N5，N10－亚甲基四氢叶酸还原酶（MTHFR）基因多态性和吸烟与缺血性卒中患病的关系。方法应用聚合酶链反应（PCR）和变性高效液相色谱（DHPLC）技术筛查454例缺血性卒中患者（患者组）和334例非缺血性卒中患者（对照组）MTHFR职基因的多态分布，依据TOAST分型及神经功能缺损评分分型分别进行MTHFR基因多态性的亚组分析，采用非条件Logistic回归模型分析MTHFR基因多态性、吸烟情况与缺血性卒中患病的关系。结果TT基因型和T等位基因与中、重型缺血性卒中，大动脉粥样硬化型和心源性栓塞型缺血性卒中相关。携带TT基因型和T等位基因的吸烟群体患缺血性卒中的相对危险度分别为4．393和2．359，而携带CC基因型的吸烟群体患缺血性卒中的相对危险度则为0．353。非吸烟群体MTHFR基因的各基因型和等位基因频率的分布与对照组相比差异均无统计学意义（P〉0．05）。结论携带T等位基因的吸烟群体容易患缺血性卒中，而携带C等位基因的吸烟群体不容易患缺血性卒中：MTHFR基因与吸烟在缺血性卒中的发病过程中存在协同作用。

英文摘要：

Objective To study the relationship between ischemic stroke （IS） and both gene polymorphisms of methylenetetrahydrofolate reductase （MTHFR） and cigarette smoking. Methods Four hundred and fifty-four patients with IS and 334 controls were recruited in our study; their gene polymorphisms of MTHFR were detected by PCR and denaturing high performance liquid chromatogram （DHPLC）. The patients were further divided into different subgroups based on TOAST criteria and scores of neurological impairments and the distribution of MTHFR genotypes were analyzed accordingly. The relationships between IS and both cigarette smoking and these genotypes were measured by odds ratios （ORs） and 95% confidence intervals （95%Cis）. The ORs and 95% CIs were calculated by unconditional logistic regression. Results TT genotype and T allele were associated with LAA type and CE type, moderate type and severe type of IS. OR of TT genotype and T allele in smoking patients with IS were 4.393 and 2.359, respectively; but the OR ofCC genotype in smoking patients with IS was 0.353. On the other hand, the OR of all genotypes and alleles in non-smoking patients with IS were not significantly different as compared with those in controls. Conclusion Cigarette smokers with T alleles are likely to suffer IS, but those cigarette smokers with C alleles are not; and there exist interactions between cigarette smoking and MTHFR gene in the pathogenesis of IS.