目的：探讨半胱氨酸代谢关键酶基因表观遗传学改变与汉族人群缺血性脑卒中（IS）的发病关系。方 法：采用病例-对照研究设计，以动脉粥样硬化性脑梗死（ATS）患者30例为病例组，另选择同期体检健康人群 30例为对照组。寻找目的基因（基因上游5 kb的区域一直到第2外显子区域）的CpG岛区域，使用重亚硫酸 盐修饰直接测序技术进行样本DNA甲基化检测，运用单因素或Logistic回归分析检测2组间DNA甲基化分 布差异。结果：胱硫醚-β-合成酶（CBS）基因4个CpG岛同源性非常高，放弃甲基化分析；5,10-亚甲基四氢叶 酸还原酶（MTHFR）基因有2个CpG岛；半胱氨酸合成酶（MTR）基因有1个CpG岛。结果显示，2组这2个基 因所有CpG岛都未发现DNA甲基化情况。结论：未发现MTHFR和MTR基因DNA甲基化改变与汉族人群 ATS相关。

To investigate the relationship between the epigenetic alterations of genes encoding the key enzymes of homocysteine (Hcy) metabolism and the risk for atherothrombotic stroke (ATS) in the Chinese Han population. Methods: This case-controlled study enrolled 30 cases with ATS and 30 healthy controls. The CpG islands region of the targeted gene (5kb upstream region to exon 2) was identified. Detection of DNA methylation was accomplished by sequencing bisulfite-altered DNA. Univariate and multivariate logistic regression analysis were used to detect the differences in DNA methylation levels between the two groups. Results: DNA methylation analysis of the cystathionine-β-synthase (CBS) gene was abandoned because of the high homology of the 4 CpG island sequences. There were respectively 2 and 1 CpG islands found in the 5, 10-methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR) genes. However, no change in DNA methylation levels was detected in the CpG islands of these two genes. Conclusion: Our study suggested no significant association between DNA methylation alterations of the MTHFR and MTR genes with ATS among the Han Chinese.