2型糖尿病颈动脉内中膜厚度与亚甲基四氢叶酸还原酶基因C677T多态性及血浆同型半胱氨酸水平的关系

目的探讨亚甲基四氢叶酸还原酶（MTHFR）基因C677T多态性及同型半胱氨酸水平与早期2型糖尿病（T2DM）颈动脉内中膜厚度（IMT）的关系及影响因素。方法测定T2DM患者及对照组（NC）颈动脉IMT,分为糖尿病无内中膜增厚组（DM1）和糖尿病合并内中膜增厚组（DM2）。用PCR—RFLP检测MTHFR基因C677T多态性。结果DM。组MTHFR C677T基因TT基因型频率与NC组比较明显增高（40．4％ vs 17．3％,P〈0．01）,与DM1组比较明显增高（40．4% vs 17．9％,P〈0．01）,DM1组与NC组比较无统计学差异（17．9％ vs 17．3％,P〉0．05）。T等位基因频率DMz组与NC组比较明显增高（57．0％ vs 33．7％,P〈0．01）,与DM1组比较明显增高（57．0％ vs 42．9％,P〈0．01）,差异有统计学意义。结论高同型半胱氨酸血症、T等位基因是早期糖尿病患者颈动脉内中膜增厚的危险因素之一,血浆同型半胱氨酸水平与MTHFR C677T基因多态性有关。     

N5，N10-亚甲基四氢叶酸还原酶基因多态性及血浆同型半胱氨酸与冠心病的关系

目的研究N5,N10-亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性、血浆同型半胱氨酸(Hcy)与冠心病的关系。方法选取2013年至2015年在我院住院的冠心病患者256例,按年龄分为60岁组(中青年组)107例及≥60岁组(老年组)149例,选取同期行健康体检的人群145例作为对照组,应用聚合酶链反应(PCR)技术和基因芯片分析技术检测MTHFR基因C677T多态性,应用高效液相色谱法测定血浆Hcy水平,分析不同组群之间MTHFR基因C677T多态性的分布及Hcy水平。结果 MTHFR基因分布频率:中青年组CC型、CT型、TT型基因频率分别为26.2%,43.9%,29.9%,C等位基因频率为48.1%,T等位基因频率为51.9%。中青年组CC型、CT型、TT型基因频率分别为35.6%,42.3%,22.1%,C等位基因频率为56.8%,T等位基因频率为43.2%。对照组CC型、CT型、TT型基因频率分别为37.9%,40.1%,21.4%,C等位基因频率为58.3%,T等位基因频率为41.7%。中青年组T等位基因频率明显高于对照组(χ~2=5.10,P=0.015),中青年组Hcy浓度明显高于对照组。老年组T等位基因频率与对照组比较差异无显著性(χ~2=0.147,P=0.382),两组间Hcy浓度差异无显著性。各组的TT基因型者血浆Hcy浓度均明显高于CC和TC基因型者(P0.01),而后两者间差异无显著性。结论 MTHFR基因TT型可导致Hcy水平明显升高,MTHFR基因C677T点突变仅与中青年组冠心病患者相关,与老年组冠心病患者无明显相关,Hcy水平升高及MTHFR基因T等位基因频率增高可能为中青年冠心病患者的危险因素,提示不同年龄阶段的冠心病患者发病的机制可能存在差异。     

H型高血压患者MTHFR基因C677T多态性与颈动脉内膜中层厚度的相关性研究

目的探讨H型高血压患者亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性与颈动脉内膜中层厚度(IMT)的相关性。方法选取2015年9月~2017年7月于滁州市第一人民医院心内科住院的315例高血压患者。所有患者行MTHFR基因C677T多态性(CC型、CT型或TT型)检测。以血同型半胱氨酸(HCY)水平将试验对象分为H型高血压组(HCY≥10μmol/L,A组,n=159)和非H型高血压组(HCY10μmol/L,B组,n=156)。比较两组间一般临床资料、血脂、颈动脉IMT及MTHFR基因C677T多态性。行Pearson相关分析研究颈动脉IMT与其他变量的相关性。以颈动脉IMT为因变量进一步行多元线性回归逐步分析探索其危险因素。结果两组间在年龄、性别构成、吸烟比、糖尿病发病率、体质指数、血压水平、血脂水平无显著差异(P均0.05)。A组的颈动脉IMT值显著高于B组(P=0.016)。A组中MTHFR基因C677T突变型(CT型、TT型)频率较B组高,而野生型(CC型)频率较B组低(P0.01)。相关性分析提示颈动脉IMT与MTHFR基因C677T等位基因T频数、低密度脂蛋白胆固醇(LDL-C)正相关(r分别为0.39、0.355,P均0.01),与高密度脂蛋白胆固醇(HDL-C)负相关(r=-0.27,P0.01)。多元线性回归分析提示T频数、LDL-C与HDL-C是颈动脉IMT的独立影响因素(回归系数B分别为0.046、0.029和-0.067,P均0.01)。结论 MTHFR基因C677T多态性与颈动脉IMT密切相关。MTHFR基因C677T突变型的出现、LDL-C增加和HDL-C降低是颈动脉内中膜增厚的独立危险因素。     

急性脑梗死患者MTHFR基因多态性与血浆同型半胱氨酸水平的关系

目的 探讨急性脑梗死（ACI）患者N5,N10-亚甲四氢叶酸还原酶（MTHFR）基因多态性与血浆同型半胱氨酸（Hcy）水平的关系.方法 采用多聚酶链反应2-限制性内切酶片段长度多态性技术（PCR2-RFLP）检测48例ACI患者MTHFR基因C677T位点多态性,同时测定血浆总Hcy及血清叶酸、维生素B12、尿酸（UA）.结果 ACI患者MTHFR基因T/T型频率为35.43％,T/C型频率为56.32％,C/C型频率为8.25％;T等位基因频率为63.59％,C等位基因频率为36.41％.MTHFR基因T/T型ACI患者血浆Hcy显著高于其他两型,T/C型与C/C型血浆Hcy水平较比较无显著差异.Hcy中度与轻度增高者MTHFR基因分布比较,P≤0.05.3组基因型间叶酸、维生素B12及UA水平均无显著差异.结论 ACI患者MTHFR基因C677T突变与Hcy水平显著相关,MTHFR基因纯合突变可能是引起高Hcy的一个重要遗传因素.     

亚甲基四氢叶酸还原酶基因多态性与老年高血压伴高同型半胱氨酸血症及颈动脉硬化的相关性研究

目的探讨5,10-亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)基因多态性与血浆同型半胱氨酸(homocysteine,Hcy)水平的关系及对老年H型高血压患者颈动脉内膜中层厚度(intima-media thickness,IMT)的影响。方法选择2016年1月~2017年6月在武警后勤学院附属医院心内科住院的老年高血压患者260例,根据血浆Hcy水平将患者分为H型高血压组117例(Hcy≥15μmol/L),普通高血压组143例(Hcy15μmol/L),同期选取我院体检的老年正常血压对照组99例(Hcy15μmol/L),进行血浆Hcy及MTHFR基因C677T多态性检测,并采用超声检查测量颈动脉IMT。结果 H型高血压组和普通高血压组收缩压、舒张压水平明显高于对照组,差异有统计学意义(P0.05)。H型高血压组Hcy、颈动脉IMT明显高于普通高血压组和对照组,差异有统计学意义(P0.05)。3组CC、CT、TT基因型及C、T等位基因频率比较,差异有统计学意义(P0.05)。H型高血压组TT基因型及T等位基因频率明显高于普通高血压组及对照组(29.1%vs 18.2%,16.2%;49.1%vs 36.4%,32.3%,P0.05),CC基因型及C等位基因频率明显低于普通高血压组及对照组(30.8%vs45.5%,51.5%;50.9%vs 63.6%,67.7%,P0.05)。H型高血压组和普通高血压组不同基因型血浆Hcy水平比较,差异有统计学意义(P0.05)。多因素逐步回归分析显示,年龄、收缩压、空腹血糖、Hcy、LDL-C是颈动脉IMT增厚的独立危险因素(P0.05,P0.01)。结论 MTHFR基因C677T多态性与血浆Hcy水平相关,可能通过升高血浆Hcy水平,间接参与颈动脉粥样硬化的发生和发展。     

亚甲基四氢叶酸还原酶基因多态性与糖尿病微血管并发症相关性研究

目的：探讨亚甲基四氢叶酸还原酶(MTHFR)基因多态性与中国人2型糖尿病微血管并发症的关系。方法：运用PCR—RFLP检测263例中国人(206例为2型糖尿病，其中148例合并肾病或视网膜病变，57例为正常对照组)MTHFR基因C677T位碱其突变，比较各组间等位基因频率和基因型频率。结果：(1)同时合并肾病和视网膜病变的2型糖尿病组与无微血管并发症的2型糖尿病组及正常对照组相比，TT基因型频率显著增加，突变等位基因T频率也明显升高。(2)2型糖尿病合并肾病组TT基因型频率及T等位基因频率明显高于不伴有肾病的2型糖尿病组及正常对照组。(3)2型糖尿病合并视网膜病组与无视网膜病的2型糖尿病及正常对照组相比，TT基因型频率及T等位基因频率明显升高。结论：MTHFR基因C677T碱基突变是促进中国人2型糖尿病患者并发微血管并发症的危险因子，突变T等位基因是糖尿病微血管并发症的易感基因。     

N5，10-亚甲基四氢叶酸还原酶基因多态性与蒙古族原发性高血压病的关系

目的探讨N5,10-亚甲基四氢叶酸还原酶(MTHFR)C677T位点突变与蒙古族高血压病患者之间的关系。方法采用Sequenom系统检测110例高血压病患者及115例健康对照组MTHFR基因多态性。结果蒙古族高血压人群MTHFR基因TT基因型频率及T等位基因频率(0.15,0.32)与正常人群(0.10,0.29)相比差异无显著性(P>0.05);单纯收缩压增高人群MTHFR基因型TT基因型及T等位基因频率(0.23,0.40)高于正常人群,差异有显著性(P<0.05)。结论MTHFR C677T位点TT基因型及T等位基因突变增加蒙古族人群单纯收缩压增高的危险性,可能是单纯收缩期高血压病的易感基因。     

N5,10-亚甲基四氢叶酸还原酶基因多态性与蒙古族原发性高血压病的关系

目的探讨N5,10-亚甲基四氢叶酸还原酶(MTHFR)C677T位点突变与蒙古族高血压病患者之间的关系.方法采用Sequenom系统检测110例高血压病患者及115例健康对照组MTHFR基因多态性.结果蒙古族高血压人群MTHFR基因TT基因型频率及T等位基因频率(0.15,0.32)与正常人群(0.10,0.29)相比差异无显著性(P＞0.05);单纯收缩压增高人群MTHFR基因型TT基因型及T等位基因频率(0.23,0.40)高于正常人群,差异有显著性(P＜0.05).结论MTHFR C677T位点TT基因型及T等位基因突变增加蒙古族人群单纯收缩压增高的危险性,可能是单纯收缩期高血压病的易感基因.     

同型半胱氨酸相关酶基因多态性与高血压伴周围动脉闭塞性疾病的关系

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因C677T、胱硫醚B合成酶(CBS)基因844ins68和甲硫氨基合成酶(MS)基因A2756G3种同型半胱氨酸(Hcy)代谢相关酶基因多态性与北京社区汉族老年人群中原发性高血压(EH)、EH伴周围动脉闭塞性疾病(PAOD)易感性的关系。方法PCR扩增老年EH(EH组)、老年EH伴PAOD(EH—PAOD组)患者和老年健康对照组的MTHFR C677T、CBS 844ins68、MS A2756G基因突变点，直接或经限制性内切酶消化后行凝胶电泳，确定基因型并统计基因突变频率。结果EH组100例MTHFR基因3种基因型频率为：C／C29．0％，C／T45．0％，T／T26．0％；EH—PAOD组59例为：C／C15．9％，C／T35．5％，T／T48．6％；对照组100例为：C／C31．0％，C／T50．0％，T／T19．0％。3组MTHFR基因的C677T单核苷酸突变中T突变位点的频率分别为48．5％、64．4％、44．0％。EH—PAOD组与对照组和EH组比较，MTHFR T／T基因型频率和T等位基因频率差异均有统计学意义。而CBS 844ins68、MS A2756G各种基因型频率和等位基因频率在EH组、EH—PAOD组和对照组之间差异无统计学意义。结论MTHFR基因C677T单核苷酸突变可能是北京社区汉族老年人PAOD的遗传性危险因素之一，可能与EH无关。且CBS基因844ins68、MS基因A2756G的突变可能都不足以成为EH和PAOD的遗传危险因子。     

老年H型高血压患者颈动脉内膜中层厚度与MTHFR基因多态性的关系

目的探讨老年H型高血压患者颈动脉内膜厚度与亚甲基四氢叶酸还原酶(MTHFR)基因多态性的关系。方法274例老年高血压患者,将其分为H型高血压组和非H型高血压组;根据超声结果将H型高血压组分为伴有颈总动脉内膜中层厚度(IMT)增加的H1组和未见IMT增加的H2组。另选择同期体检者作为对照组。采集血液检测各组研究对象的生化指标;酶联免疫吸附试验(ELISA)检测同型半胱氨酸(Hcy)水平;检测MTHFR基因的多态性和IMT;采用Spearman相关分析及Logistic回归法分析H型高血压患者IMT与基因型的相关性。结果H型高血压组Hcy水平显著高于非H型高血压组和对照组,H1组显著高于H2组(P<0.05);H1组、H2组、非H型高血压组的IMT显著高于对照组,H1组的IMT显著高于H2组(P<0.05);H1组、H2组、非H型高血压组的三酰甘油(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-L)、高密度脂蛋白胆固醇(HDL-C)水平比较无显著差异(P>0.05),但三组TG、TC、LDL-L、HDL-C水平均显著高于对照组。H1组的T/T基因型频率、等位基因T频率均显著高于H2组、非H型高血压组和对照组(P<0.05);H2组T/T基因型频率显著高于对照组,与非H型高血压组无显著差异(P>0.05),其等位基因T也显著高于对照组和非H型高血压组(P<0.05)。H1组、H2组中T/T基因型的Hcy水平和IMT显著高于C/T、C/C基因型,CT基因型显著高于CC基因型;非H型高血压组T/T基因型的Hcy水平和IMT显著高于C/C基因型(P<0.05)。Spearman相关分析显示MTHFR C677T基因型与Hcy水平呈正相关,Hcy水平与IMT呈正相关,Logistic多因素分析显示TT基因型患者H型高血压合并颈动脉内膜增厚及存在颈动脉粥样硬化斑块的风险是CC基因型和CT基因型的2.090倍。结论血浆Hcy水平升高、MTHFR基因突变与IMT的变化相关。     

亚甲基四氢叶酸还原酶基因多态性与糖尿病肾病相关性研究

目的：研究亚甲基四氢叶酸还原酶（MTHFR）基因多态性与2型糖尿病肾病的关系。方法：运用聚合酶链反应－限制性片段长度多态性技术（PCR－RFLP）检测85例2型糖尿病患者（其中39例伴糖尿病肾病）及57例正常对照组MTHFR C677T基因型,采用高效液相色谱法测定血浆同型半胱酸水平。结果：糖尿病肾病组MTHFR基因TT纯合基因型,CT杂合基因型及T等位基因频率（分别为38．21％,51．28％,53．85％）均明显高于糖尿病不伴肾病组（分别为19．57％,28．26％,33．70％）及正常对照组（分别为17．54％,28．07％,31．58）,基因型和等位基因频率分布差异均有统计学意义（P＜0．05）,而MTHFR基因该多态性在不伴肾病组与正常对照组之间差异无显著性（P＞0．05）,T等位基因与糖尿病肾病的发生密切相关（OR＝2．30,95％可信区间;1．24－4．26）。糖尿病肾病组,糖尿病不伴肾病组及正常对照组中,MTHFR基因有C677T突变者血浆同型半胱氨酸水平均显著高于无基因突变者。结论：MTHFR基因C677T位碱基突变致血浆同型半胱氨酸水平高是糖尿病肾病发病的重要遗传因素。     

Genetic polymorphism of methylenetetrahydrofolate reductase as a risk factor for diabetic nephropathy in Chinese type 2 diabetic patients

OBJECTIVE: Genetic predisposition has been implicated in diabetic nephropathy (DN). The C677T variant of the methylenetetrahydrofolate reductase (MTHFR) gene, one of the key enzymes catalyzing remethylation of homocysteine, may play a role in the development of not only vascular disease but also diabetic microangiopathies. In this study, we examined the distribution of the MTHFR genotypes in the Chinese population and the association between the C677T variant and diabetic nephropathy. METHODS: 220 unrelated patients with type 2 diabetes mellitus and 130 controls were recruited. The MTHFR genotype was analyzed by PCR followed by HinfI digestion. Plasma total homocysteine levels were measured using high-performance liquid chromatography (HPLC) with fluorescence detection. RESULTS: In 130 healthy control subjects, the frequency of the mutant T allele was 30.0%, comparable to that of a Hong Kong (Chinese) population. The distribution of the three genotypes was as follows: TT genotype, 16.9%; CT genotype, 26.2%; and CC genotype, 56.9%. This genotype distribution did not differ between control subjects and type 2 diabetic patients in which 19.1% were TT, 34.5% were CT and 46.4% were CC (2=3.85, P>0.05). The frequency of the mutant T allele was 42.3% in diabetic patients with nephropathy (n=124) versus 28.6% in those without nephropathy (n=96). The genotype frequencies were TT, 21.0%; CT, 42.7%; CC, 36.3% in diabetic patients with nephropathy versus TT, 16.7%; CT, 23.9%; CC, 59.4% in those without nephropathy. The MTHFR genotype and allele frequencies were different between diabetic patients with and without nephropathy (chi2=12.27, P<0.005; chi2=8.77, P<0.005, respectively). Moreover, plasma homocysteine levels were markedly higher in individuals with TT genotype than those with CC or CT genotype. CONCLUSIONS: The C677T mutation of MTHFR gene is common in the Chinese population. MTHFR C677T gene polymorphism associated with a predisposition to increased plasma homocysteine levels may represent a genetic risk factor for diabetic nephropathy in Chinese type 2 diabetic patients.     

Serum Homocysteine,MTHFR Gene Polymorphism,and Carotid Intimal-Medial Thickness in NIDDM Subjects

We assessed the contribution of serum homocysteine levels, an independent risk factor for vascular disease, and of the methylenetetrahydrofolate reductase (MTHFR) C677T mutation to the variability of carotid intimal-medial thickness (IMT) in patients with non–insulin-dependent diabetes mellitus (NIDDM). Ninety-five patients (33 males and 62 females, mean age 53 ± 10 years) without nephropathy or other vascular complications were enrolled. Fasting total serum homocysteine and other biochemical analytes were measured. The MTHFR polymorphism was determined by the polymerase chain reaction. Common carotid IMT and plaques or stenoses in the carotid district were measured by ultrasonography. Serum total homocysteine concentrations were higher in subjects with the mutant (Val/Val) genotype than in those with the Ala/Val plus Ala/Ala genotypes (P = 0.02). On univariate analysis, carotid IMT was significantly associated with age, body mass index (BMI), systolic blood pressure, and total cholesterolemia. No significant association was found between IMT and serum homocysteine or the MTHFR polymorphism, although a slightly greater IMT was observed in the homozygous Val genotypes. On multiple regression analysis, only age and BMI were independently associated with IMT and explained about 40% of IMT variability. The results did not change when the analysis was restricted to the subgroups with or without atherosclerotic plaques in the carotid district. In 95 Italian NIDDM patients without nephropathy, neither basal levels of serum total homocysteine nor the MTHFR C677T polymorphism predicted significant changes in common carotid intimal-medial thickness.     

Methylenetetrahydrofolate reductase polymorphism associated with susceptibility to coronary heart disease in Chinese type 2 diabetic patients

OBJECTIVE: Epidemiological studies have identified hyperhomocyst(e)inemia as an independent risk factor for atherosclerosis. The C677T variant of the methylenetetrahydrofolate reductase (MTHFR) gene, one of the key enzymes catalyzing remethylation of homocysteine, might play a role in the development of coronary heart disease (CHD). In this study, we examined the distribution of the MTHFR genotypes in the Chinese population and the association between the C677T variant and CHD in Chinese type 2 diabetic patients. METHODS: Two hundred and twenty-eight unrelated patients with type 2 diabetes mellitus (126 with coronary heart disease) and 114 healthy control subjects were recruited. The MTHFR genotype was analyzed by PCR followed by HinfI digestion. Plasma total homocysteine levels were measured using high-performance liquid chromatography (HPLC) with fluorescence detection. RESULTS: In 114 healthy control subjects, the frequency of the mutant T allele was 38.0%, comparable to that of a Hong Kong (Chinese) population. The genotype distribution did not differ between control subjects and type 2 diabetic patients (chi(2) = 3.67, P > 0.05). Genotypic analysis revealed that type 2 diabetic patients with CHD displayed a greater prevalence of T allele (45.2%) than type 2 diabetic patients without CHD (30.4%) (chi(2) = 8.72, P < 0.005). The odds ratio for CHD in type 2 diabetic patients in presence of T allele was 1.89 (CI 95%, 1.24-2.88). The MTHFR genotype were different between diabetic patients with and without CHD (chi(2) = 11.98, P < 0.005). Moreover, plasma homocysteine levels were markedly higher in individuals with TT genotype than those with CC or CT genotype or CC plus CT genotype. CONCLUSIONS: The C677T mutation of MTHFR gene is common in the Chinese population. MTHFR C677T gene polymorphism associated with a predisposition to increased plasma homocysteine levels could constitute a useful predictive marker for CHD in Chinese type 2 diabetic patients.     

C677T methylene-tetrahydrofolate reductase mutation in type 2 diabetic patients with and without hyperhomocysteinaemia

OBJECTIVE: The aim of the study was to determine the prevalence of the C677T mutation in a cohort of type 2 diabetic patients with and without elevated total plasma homocysteine (tHcy). METHODS: 80 type 2 diabetic patients with hyperhomocysteinaemia (group 1, tHcy: 21.3 +/- 6.7 micromol/L) and 50 subjects with normal levels (group 2, tHcy 11.2 +/- 2.3 micromol/L) were studied. C677T mutation was assessed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: Homozygosity was present in 23% of patients in group 1 and 8% in group 2 (P<0.02). No significant difference in heterozygosity frequency was observed between patients with and without hyperhomocysteinaemia. T allele frequency was 0.43 in group 1 and 0.35 in group 2. CONCLUSION: C677T mutation is frequent in diabetic patients with hyperhomocysteinaemia and could contribute, besides non genetic factors, to increased levels of tHcy.     

亚甲基四氢叶酸还原酶C677T基因多态性与卵圆孔未闭并发隐源性卒中的相关性

目的 探讨同型半胱氨酸代谢酶N5,10-亚甲基四氢叶酸还原酶（N5,10-methylenetetrahydrofolate reductase,MTHFR）C677T基因多态性与卵圆孔未闭（patent foramen ovale,PFO）并发隐源性卒中（cryptogenic stroke,CS）的相关性。 方法 选择CS患者300例,均行经颅脑计算机断层扫描或磁共振成像检查。所有患者行经食管超声心动图（TEE）和（或）经胸壁多普勒超声心动图（TTE）检测有无PFO。按照有无PFO,将并发PFO的85例CS患者作为并发PFO组,按照年龄、性别相匹配,选择85例无PFO的CS患者作为对照（非PFO）组。检测两组血浆总同型半胱氨酸（total homocysteine,tHcy）水平和MTHFR C677T基因型。 结果 ①MTHFR C677T的TT基因型是PFO并发CS的独立相关因素;②PFO并发CS患者血浆Hcy水平和各因素Spearman相关分析结果显示,Hcy水平与患者性别呈负相关,而与吸烟、高Hcy、C677T基因型呈正相关。 结论 MTHFR C677T基因多态性与CS并发PFO相关。     

No association between MTHFR gene polymorphism and diabetic nephropathy in Japanese type II diabetic patients with proliferative diabetic retinopathy

The development of diabetic nephropathy shows marked variation among individuals. Not only hyperglycemia, but also genetic factors may contribute to the development of diabetic nephropathy. Methylenetetrahydrofolate reductase (MTHFR) is involved in remethylation of homocysteine to methionine. Decreased activity of MTHFR which can result in hyperhomocysteinemia may lead to cerebrovascular disease and coronary artery disease. Recently, a common C to T mutation at nucleotide position 677 of the MTHFR gene (MTHFR677C>T) has been reported to be correlated with hyperhomocysteinemia and the severity of coronary artery disease as macroangiopathy. In the present study, we recruited 173 of Japanese type II diabetic patients with proliferative diabetic retinopathy who would be exposed to long-term hyperglycemia, and examined the contribution of the MTHFR gene polymorphism to the development of diabetic nephropathy as microangiopathy. The frequency of the mutated allele was 43.3% in patients with nephropathy (n = 105) versus 41.9% in those without nephropathy (n = 68). The genotype frequencies were +/+, 16.2%; +/−, 54.3%; −/−, 29.5% in patients with nephropathy versus +/+, 13.2%; +/−, 57.4%; −/−, 29.4% in those without nephropathy (+ indicates the presence of the mutation). The MTHFR genotype and allele frequencies were not significantly different between patients with and without nephropathy. Therefore, we conclude that the MTHFR gene polymorphism is not associated with the development of diabetic nephropathy in Japanese type II diabetic patients.     

冠心病患者血浆同型半胱氨酸及亚甲基四氢叶酸还原酶C677T基因多态性

目的比较不同冠心病类型及不同冠状动脉病变支数间血浆同型半胱氨酸水平差异,分析亚甲基四氢叶酸还原酶C677T基因突变对血浆同型半胱氨酸水平影响,及其与冠心病的关系.方法对经冠状动脉造影确诊的非冠心病74例、稳定型心绞痛32例、不稳定型心绞痛104例、急性心肌梗死25例采用改良高效液相色谱法测定同型半胱氨酸,聚合酶链反应-限制性内切酶法测定亚甲基四氢叶酸还原酶C677T基因型.结果血浆同型半胱氨酸水平冠心病组较非冠心病组显著增高,急性心肌梗死、不稳定型心绞痛组均较非冠心病组、稳定型心绞痛组显著增高,冠状动脉单支病变较正常、双支、三支病变组显著高.亚甲基四氢叶酸还原酶C677T基因纯合突变患者血浆同型半胱氨酸水平显著高于正常纯合子和杂合子患者.冠心病组亚甲基四氢叶酸还原酶C677T基因突变频率较对照组高,但无统计学意义.相关分析表明亚甲基四氢叶酸还原酶C677T基因突变与冠心病、同型半胱氨酸均无相关性.二元Logistic回归分析表明,高同型半胱氨酸血症致冠心病的OR值是1.138,亚甲基四氢叶酸还原酶C677T基因突变不是冠心病的独立危险因素.结论同型半胱氨酸可能是冠心病的独立危险因素,更可能是急性冠状动脉综合征的标志物.血浆同型半胱氨酸水平不与冠状动脉病变支数成正相关.亚甲基四氢叶酸还原酶C677T基因突变可能不是冠心病的独立危险因素及血浆同型半胱氨酸水平最关键的影响因素.     

Mutations C677T and A1298C of the 5,10-methylenetetrahydrofolate reductase gene and fasting plasma homocysteine levels are not associated with the increased risk of venous thromboembolic disease.

Mild hyperhomocysteinemia is associated with homozygosity for the thermolabile variant of 5,10-methylenetetrahydrofolate reductase (MTHFR) and could increase the risk of venous thromboembolic disease (VTD). Recently, the second A1298C mutation of the MTHFR gene was described. The present study aimed to analyze both mutations of the MTHFR gene and plasma homocysteine levels in subjects with VTD. The study groups comprised 146 patients with VTD and 100 healthy subjects. There were no statistical differences in carrier frequency and allelic frequency for both A1298C and C677T mutations, nor were there any differences encountered between subjects with VTD and controls in either plasma homocysteine levels or according to C677T or A1298C genotypes of MTHFR. In our VTD patients and controls, neither MTHFR 677CT/1298CC nor MTHFR 677TT/1298CC combined genotypes were observed; double heterozygotes (A1298C/C677T) were represented only in 11% of VTD patients, and in 15% of the controls. In conclusion, the polymorphisms C677T and A1298C of MTHFR and fasting plasma homocysteine levels do not seem to be significant risk factors for venous thromboembolic disease.