摘要： 研究背景 儿茶酚胺氧位甲基转移酶（COMT）是儿茶酚胺的主要代谢酶，催化儿茶酚胺第3 位羟基甲基化，降解儿茶酚胺，同时亦是雌激素的主要代谢酶。COMT 基因在rs4680 位点存在鸟嘌呤-腺嘌呤（G-A）点突变，使其编码的第108 和（或）158 位氨基酸由缬氨酸（Val）变为蛋氨酸（Met），导致儿茶酚胺氧位甲基转移酶活性降低。已知COMT 基因多态性与精神疾病、酒精依赖、药物不良反应等有关，而与脑梗死之间的关系尚不明确，本研究旨在探讨COMT 基因多态性与脑梗死之间的关系。方法 通过聚合酶链反应- 限制性酶切片段长度多态性方法检测181 例天津地区汉族脑梗死患者COMT Val 及Met基因型，以及不同基因型脑梗死患者血糖、总胆固醇、甘油三酯、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇，以及载脂蛋白A 和B 水平。结果 脑梗死组Val 等位基因频率（78.45%）及Val/Val纯合子基因型（61.33%）均高于正常对照组（68.24%和45.95%），差异具有统计学意义（P < 0.05 ）；进一步分析显示男性Val 等位基因频率（82.52%）与正常对照组（66.67%）之间差异亦存在统计学意义（P < 0.01 ），而女性患者组间差异（69.83%对69.07%）无统计学意义（P > 0.05 ）。脑梗死组Val/Val型与Val/Met+ Met/Met型比较，血糖、血脂水平及高血压患病率差异无统计学意义（均P > 0.05 ）。 结论 COMT Val 等位基因频率和Val/Val纯合子基因型是男性脑梗死患者的遗传学危险因素，COMT 对脑梗死的影响与血糖、血脂及血压无明显相关性。

关键词: 多态现象, 遗传, 儿茶酚O-甲基转移酶, 脑梗死, 天津, 汉族

Abstract: Background  Catechol-O-methyltransferase (COMT) has a key function in thedegradation of catecholamines and inactivating estrogen. A common polymorphism in the COMT gene is guanine-adenine (G-A) point mutation on rs4680, which causes a valine (Val) substitution to methionine (Met) in 108 and (or) 158 amino acid by this gene and is responsible for lowered activity of the enzyme. The Val/Met polymorphism has been recognized to be associated with psychiatric disorders, alcohol dependence and drug side effects, but few study has been done to examine the relationship with cerebral infarction (CI). The objective of this study is to investigate the relationship between the polymorphisms of COMT gene and CI. Methods  The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect COMT Val158Met genotype in 181 CI patients and 148 cases of controls. Meanwhile the serum levels of glucose, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C ), high-density lipoprotein cholesterol (HDL-C ), apolipoprotein B (ApoB) and ApoA in CI group were detected. Results  The frequency of Val allele (78.45%) and Val/Valgenotype (61.33%) in CI was significantly higher than that in the control group (68.24% and 45.95%, P < 0.05). Further analysis showed the frequency of Val allele in CI was significant higher in men (82.52% vs 66.67%, P < 0.01), but not in women (69.83% vs 69.07%, P > 0.05) than that in the control group. The serum levels of glucose, TC, TG, LDL-C, HDL-C, ApoB, ApoA and the frequency of hypertension had no difference between Val/Val genotype and Val/Met + Met/Met genotypes ( P > 0.05, for all). Conclusion  The frequencies of Val allele and Val/Val genotype can be considered as genetic risk factors of male CI patients. The effect of COMT on CI is not related to blood pressure, serum lipid and glucose.

Key words: Polymorphism, genetic, Catechol O-methyltransferase, Brain infarction, Tianjin, Han nationality