青年缺血性脑血管疾病独立危险因子与N5及N10-亚甲基四氢叶酸还原酶基因突变的关系

背景：血浆同型半胱氨酸浓度升高是动脉粥样硬化性血栓性脑梗死的独立危险因素，同型半胱氨酸在转硫化和再甲基化过程中的代谢酶Ns，N10-亚甲基四氢叶酸还原酶（methylene tetrahydrofolate reduetase，MTHFR）基因突变可致血浆同型半胱氨酸浓度升高。 目的：探讨同型半胱氨酸血症、同型半胱氨酸代谢关键酶MTHFR基因突变与青年缺血性脑血管疾病的关系。 设计：病例-对照观察。 单位：吉林大学中丑联谊医院神经内科。 对象：于2003-04／2004-12吉林大学中丑联谊医院神经内科收治发病2d内住院的青年脑梗死患者100例，为病例组，男73例，女27例；年龄27-45岁，平均（42&;#177;5）岁。对照组100例为同期健康体检者：男70例，女30例；年龄18～45岁，平均（39&;#177;4）岁。 方法：以高效液相色谱法测定受试者空腹血浆同型半胱氨酸，采用聚合酶链反应-限制性内切酶片段长度多态性分析和扩增阻滞突变体系法，对MTHFR基因C677T位点和A1298C位点进行检测。 主要观察指标：MTHFRC677T和A1298C基因检测，血浆同型半胱氨酸浓度与MTHFR基因型的关系。 结果：纳入患者100例和正常对照100例，均进入结果分析。④MTHFRC677T和A1298C基因检测：MTHFR C677T基因检测病例组和对照组基因型分布、纯合子频率和等位基因频率差异均显著（P〈0．01）。而MTHFR A1298C基因检测病例组和对照组基因型分布、纯合子频率和等位基因频率差异均无显著性（P〉0．05）。②血浆同型半胱氨酸浓度与MTHFR基因型的关系：MTHFR C677T和A1298C各基因型问血浆同型半胱氨酸浓度差异有显著性（P〈0．001）。2个位点突变结果LSD-t检验显示纯合子与杂合子，纯合子与野生型血浆同型半胱氨酸浓度均数差有统计学意义（P〈0．05）。MTHFR C677T和A1298C杂合子与野生型血浆同型半胱氨酸浓度均数差无统计学意义（P〉0．05）。 结论：MTHFR C677T和A1298C突变均导致血浆同型半胱氨酸浓度明显增高。MTHFR C677T多态性位点是青年缺血性脑血管疾病的独立危险因子。MTHFR A1298C基因突变与青年缺血性脑血管疾病发病无相关性。     

深圳青年高同型半胱氨酸血症MTHFR C677T基因无创纳米筛查及基因多态性研究

目的为深圳青年高同型半胱氨酸血症防治提供准确快速的转化医学药物服用方案指导,实现基因层面预防。方法选取深圳青年中进行MTHFR C677T基因无创纳米筛查的受检者,从中随机抽取100例基因检测结果为正常的受检者作为对照组,100例患有高同型半胱氨酸血症的患者设为病例组,对两组对象患者不同高同型半胱氨酸水平和MTHFRC6677T基因型的相关性进行对比。并将深圳地区青年高同型半胱氨酸血症MTHFR C677T基因型与其他地区患者比较。结果两组对象MTHFR基因频率(TT、CT、CC)和等位基因频率(T、C)的差异均有显著性(P0.05),病例组患者MTHFR基因频率中TT、等位基因频率中T高于对照组,而MTHFR基因频率中CT和CC、等位基因频率中C低于对照组;两组对象不同基因型(TT、CT、CC)的血浆Hcy水平具有显著差异(P0.05),且均有病例组患者血浆Hcy水平明显高于对照组;不同地区高同型半胱氨酸血症患者MTHFR C677T基因型进行比较,差异具有统计学意义(P0.05),基因型中CC最高为湖南地区(53.33%)、最低为美国(17.85%);CT最高为美国(48.07%)、最低为湖南地区(34.16%);TT最高为深圳地区(35.00%)、最低为美国(3.57%)。结论通过深圳青年高同型半胱氨酸血症MTHFR C677T基因多态性表现的研究,能够达到对高同型半胱氨酸血症高危人群早期基因预警筛查目的。     

中国西北地区人群高同型半胱氨酸血症、亚甲基四氢叶酸还原酶多态性与缺血性脑卒中的关系

背景血浆中总同型半胱氨酸水平增高是缺血性脑卒中的一项危险因素,5,10-亚甲基四氢叶酸还原酶是同型半胱氨酸代谢途径中的关键酶.关于5,10-亚甲基四氢叶酸还原酶与缺血性脑卒中的关系还存在争议.目的通过检测中国西北地区汉族人群中缺血性脑卒中患者血浆中总同型半胱氨酸水平和5,10-亚甲基四氢叶酸还原酶基因两个位点C677T和A1298C的基因表型,探讨三者之间的关联性.设计病例-对照实验.单位吉林大学第一附属医院神经内科,解放军第四军医大学西京医院神经内科.对象病例组随机选取2001-11/2002-05解放军第四军医大学西京医院神经内科经CT或磁共振确诊的缺血性脑卒中患者97例,男71例,女26例.对照组94例,无脑卒中病史,其中男58例,女36例.以上两组受试者有脑出血,癌症,肾功能障碍及服用维生素和雌激素的排除在外.方法血浆总同型半胱氨酸水平用全自动荧光偏振免疫分析法检测,5,10-亚甲基四氢叶酸还原酶基因两个位点C677T和A1298C的基因表型用聚合酶链式反应-限制性片段多态性分析法检测.主要观察指标脑卒中患者C677T和A1298C的基因型频率,血浆总同型半胱氨酸水平.结果677T等位基因在病例组的分布明显高于对照组(59.3%,44.7%,P=0.006),但是1298C等位基因的频率在两组间较接近(22.7%,19.7%,P＞0.05).677TT纯合子与高同型半胱氨酸血症显著相关(P＜0.01).Logistic分析表明,C677T突变及高同型半胱氨酸血症者患缺血性脑卒中的OR值分别是1.87和1.03(P＜0.05).结论高同型半胱氨酸血症是缺血性脑卒中的危险因素.C677T基因突变与缺血性脑卒中的发生相关,显著影响血浆总同型半胱氨酸水平,可能是缺血性脑卒中的一个独立的遗传危险因素.     

同型半胱氨酸及其代谢酶MTHFR A1298C基因多态性与新疆哈萨克族原发性高血压的关系

目的探讨同型半胱氨酸(Hcy)及MTHFRA1298C多态性与新疆哈萨克族原发性高血压的关系。方法应用特异引物PCR检测MTHFRA1298C基因型;酶标免疫吸附法检测血浆Hcy水平。结果 (1)高血压组血浆Hcy水平明显高于对照组(P0.01)。两组男性血浆Hcy水平均高于同组女性(P0.05)。(2)MTHFRA1298C的基因型和等位基因频率分布在两组间差异无统计学意义;MTHFR A1298C三种基因型的血浆Hcy水平差异无统计学意义。(3)Logistic回归分析,MTHFR A1298C基因多态性、血浆Hcy水平不是新疆哈萨克族高血压发病的独立危险因素。结论 (1)血浆Hcy可能与新疆哈萨克族高血压发病相关。(2)MTHFR A1298C基因多态性与新疆哈萨克族高血压的发生无明显的相关关系。MTHFR基因A1298C点突变可能不是影响血浆Hcy水平的重要遗传因素。     

中老年高同型半胱氨酸血症基因多态性与叶酸治疗效果的关联性研究

目的 探讨中老年高同型半胱氨酸血症(HHcy)相关基因多态性与叶酸补充效果的关联性。方法 2020年1~12月于宜宾市第一人民医院确诊的中老年HHcy患者334例,采用问卷收集一般资料,抽取清晨空腹血测定同型半胱氨酸(Hcy)浓度,采用PCR荧光探针法和实时定量荧光PCR(RT-PCR)法检测外周血基因组DNA中MTHFR基因C677T(rs1801133)、A1298C(rs1801131)和MTRR基因A66G (rs1801394)多态性位点,比较不同情况HHcy患者MTHFR基因C677T、A1298C和MTRR基因A66G基因型构成比和等位基因频率。结果 MTHFR基因C677T位点TT型、A1298C位点CC型和MTRR基因A66G位点GG型占比分别为46.7%、16.2和13.5%,rs1801133 T等位基因、rs1801131 C等位基因和rs1801394 G等位基因占比分别为63.3%、29.0%和29.0%。不同居住地、民族和吸烟饮酒史的rs1801131基因型分布比较,差异有统计学意义(P<0.05),不同居住地、BMI及吸烟饮酒史的rs1801394基因型分布比较,差异有统计学意义(P<0.05)。叶酸治疗无效组MTHFR基因T677T和C1298C频率及rs1801133 T等位基因和rs1801131 C等位基因频率高于有效组(P<0.05)。结论 MTHFR的T677T和C1298C患者叶酸治疗效果差。     

亚甲基四氢叶酸还原酶(MTHFR)C677T基因多态性与血压变化的相关性研究

高血压和高同型半胱氨酸血症是冠状动脉粥样硬化性心脏病(简称冠心病CVD)的独立危险因素。同型半胱氨酸浓度主要受亚甲基四氢叶酸还原酶(MTHFR)C677T基因多态性的影响,尤其受纯合子(即TT基因型)的影响。本综述旨在研究MTHFR C677T基因多态性与血压变化的关系。     

血浆同型半胱氨酸水平与MTHFR基因变异的关联研究

目的本研究的目的是探讨高同型半胱氨酸血症和MTHFR基因变异之间的关系。方法本研究随机抽取466例受试者。根据受试者同型半胱氨酸水平,将其分为高同型半胱氨酸(n=206)和正常同型半胱氨酸(n=260)。采用聚合酶链式反应-高分辨溶解曲线进行基因型检测并运用统计学软件处理数据。结果高同型半胱氨酸血症与MTHFR 677T和1298A相关,差异有统计学意义(P0.01,OR(CI)=1.842(1.418-2.394)1)。结论本研究证实高同型半胱氨酸血症与MTHFR 677T和1298A基因突变有关。     

血清同型半胱氨酸及亚甲基四氢叶酸还原酶与先兆流产相关性研究

目的探讨血清同型半胱氨酸(Hcy)水平及亚甲基四氢叶酸还原酶基因(MTHFR)C677T、A1298C位点多态性与先兆流产的关系。方法以93例先兆流产患者为病例组,99例健康孕妇为对照组,采用荧光定量PCR技术检测MTHFR基因C677T和A1298C位点多态性,同时应用酶循环法测定血清Hcy水平。比较病例组和对照组间基因型分布频率和血清Hcy水平差异。结果病例组血清Hcy水平明显高于对照组;高Hcy是先兆流产的危险因素(OR=2.056,P=0.016);MTHFR C677TT基因型携带者血清Hcy水平明显高于其他基因型;A1298CC基因型携带者血清Hcy水平明显高于AA野合型;病例组A1298CC纯合基因频率明显高于对照组;差异均有统计学意义(P0.05)。结论 Hcy升高是导致先兆流产的重要危险因素;MTHFR A1298CC纯合突变可致血清Hcy水平升高与先兆流产的发生有一定的相关性。     

叶酸基因多态性与多囊卵巢综合征的分子流行病学研究

目的探讨调控叶酸的亚甲基四氢叶酸还原酶(MTHFR)C677T位点、MTHFR A1298C位点及调控同型半胱氨酸(Hcy)的甲硫氨酸合成还原酶(MTRR)A66G位点的单核苷酸多态性(SNP)与多囊卵巢综合征(PCOS)的关系。方法选取PCOS患者250例(PCOS组)及体检健康者250名(正常对照组),分别采用化学发光免疫分析法和循环酶法检测血浆叶酸及Hcy水平,同时对外周血白细胞DNA进行基因测序,分析MTHFR和MTRR基因多态性与叶酸、Hcy水平及PCOS的关联;同时采用多元Logistic回归分析评估各等位基因对PCOS的影响程度。结果 PCOS组血浆叶酸及Hcy水平均显著高于正常对照组(P0.05)。PCOS组MTHFR C677T位点的TT基因型频率与CC基因型频率均显著低于正常对照组(P0.05),CT基因型频率2个组之间差异无统计学意义(P0.05);PCOS组T等位基因频率显著高于正常对照组(P0.05)。PCOS组MTHFR A1298C位点的各基因型频率、C等位基因频率与正常对照组比较差异无统计学意义(P0.05)。PCOS组MTRR A66G位点AG、GG基因型频率显著高于正常对照组(P0.05),AA基因型频率显著低于正常对照组(P0.05),G等位基因频率显著高于正常对照组(P0.05)。MTHFR C677T位点TT基因型与MTRR A66G位点AG或GG基因型同时存在的PCOS患者的血浆叶酸及Hcy水平显著高于其他PCOS患者(P0.05)。多元Logistic回归分析显示MTHFR C677T位点TT基因型对PCOS的影响最大,其次为MTRR A66G位点GG基因型和AG基因型。结论 MTHFR C677T位点及MTRR A66G位点的SNP会影响叶酸、Hcy水平,与PCOS的发生有一定关联,且二者的基因型具有一定的协同作用。     

MTHFR C677T/MS A2756G基因多态性及血浆Hcy水平与阿尔茨海默病的关系

目的:探讨亚甲基四氢叶酸还原酶(MTHFR) C677T、蛋氨酸合成酶(MS) A2756G基因多态性及血浆同型半胱氨酸(Hcy)水平与阿尔茨海默病(AD)的关系.方法:用多聚酶链反应技术分析75例AD患者(AD组)及71例健康老人(对照组)的MTHFR C677T、MS A2756G基因多态性及测定血浆Hcy、叶酸和VitB12水平.结果:(1)两组MTHFR C677T、MS A2756G的基因型频率及等位基因频率分布差异无统计学意义(P＞0.05);(2)对照组携带MTHFR T等位基因者血浆Hcv水平升高(P＜0.05);两组血浆Hcy水平与MS基因A2756G基因型不相关(P＞0.05) 结论:MTHFR基因C677T及MS基因A2756G多态性与AD发生不相关,AD患者血浆Hcy水平升高可能主要与体内叶酸、VitB12不足有关     

胱硫醚β-合成酶基因突变与青年缺血性脑血管疾病的相关性

背景:高半胱氨酸与脑梗死发病相关,胱硫醚β-合酶是同型半胱氨酸代谢关键酶,其基因突变是不是脑梗死的潜在的遗传候选因素尚不清楚。目的:从遗传基因变异的角度观察胱硫醚β-合酶基因T833C位点、G919位点碱基突变与青年缺血性脑卒中发病之间的关系。设计:病例-对照分析。单位:吉林大学中日联谊医院神经内科。对象:病例组:100例,为2003-04/2004-12吉林大学中日联谊医院住院患者。均是发病2d内住院、年龄≤45岁的青年脑梗死患者。对照组:100例,为同期来院体检的正常青年人。方法:以高效液相色谱法测定受试者空腹及负荷后血浆同型半胱氨酸水平,采用聚合酶链-限制性内切酶片段长度多态性分析和扩增阻滞突变体系法,对所有受试者的胱硫醚β-合酶基因T833C位点,G919A位点进行检测。结果:200例均进入结果分析。①胱硫醚β-合酶基因T833C位点,G919A位点基因检测病例组和对照组基因型分布、纯合子频率和等位基因频率差异均没有统计学意义(P>0.05)。②血浆同型半胱氨酸浓度:G919A,T833C各基因型间有显著差异(P<0.001);二个位点突变结果LSD-t检验显示:纯合子与杂合子,纯合子与野生型,C杂合子与野生型间差异均有显著性意义(P<0.05)。结论:①胱硫醚β-合酶基因T833C,G919A位点突变均可导致血浆同型半胱氨酸浓度明显增高。②胱硫醚β-合酶基因G919A和T833C基因突变与青年脑血管病发病无直接相关性。     

5,10-Methylenetetrahydrofolate reductase 677C-->T and 1298A-->C mutations are genetic determinants of elevated homocysteine

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) is one of the main regulatory enzymes of homocysteine metabolism. Elevated plasma total homocysteine (tHcy) is a major risk for cardiovascular disease. A common 677C-->T mutation in the MTHFR gene results in decreased enzymic activity, and contributes to increased plasma tHcy, in association with low plasma folate. A recently described 1298A-->C mutation in the MTHFR gene clearly reduces MTHFR activity (although to a lesser extent than the 677C-->T) but its effect on plasma tHcy levels is not yet clear. AIM: To investigate the frequency of these two MTHFR polymorphisms in a Portuguese population, and to correlate the MTHFR genotype with the biochemical phenotype at the level of homocysteine and folate concentrations. DESIGN: Prospective population survey. METHODS: We studied 117 healthy volunteers (71 females, 46 males). The 677C-->T and 1298A-->C mutations were screened by PCR-RFLP. Levels of plasma tHcy and folate, and red blood cell folate, were determined. RESULTS: The allele frequencies of the 677C-->T and 1298A-->C mutations were 0.33 and 0.28, respectively. Homozygotes for the 677C-->T mutation had significantly elevated plasma tHcy and RBC folate levels and significantly lowered plasma folate concentrations than subjects without the mutation. The 1298A-->C mutation showed a significant effect on plasma tHcy, but not on plasma folate or RBC folate levels. DISCUSSION: The observed 677T allele frequency is not consistent with the idea of a north-south gradient as previously suggested. The 1298A-->C mutation is common in Portugal. Both MTHFR mutations showed effects on plasma tHcy levels.     

Metabolic effects of C677T and A1298C mutations at the MTHFR gene in Brazilian children with neural tube defects

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) deficiency leads to impairment in folate metabolism and is implicated as a risk factor for neural tube defects (NTDs). Both C677T and A1298C MTHFR mutations are associated with NTDs, in some populations. METHODS: The frequencies of the C677T and A1298C MTHFR mutations were determined in 25 children with NTDs, case mothers and 75 healthy individuals from Sao Paulo City. Both C677T and A1298C mutations were analyzed by PCR-FLRP. The effects of MTHFR mutations on folate, vitamin B12 and homocysteine concentrations were also evaluated. RESULTS: C677T and A1298C allele frequencies in NTDs children and mothers were similar to that found in controls. Eleven in 23 NTDs patients and 10 in 21 NTDs mothers had folate or vitamin B12 concentrations in the lower end of the normal range. In NTDs children, C677T MTHFR genotypes did not affect vitamins and homocysteine concentrations, but plasma homocysteine was higher (p=0.028) in patients with 1298AA MTHFR genotype. Moreover, 677CT/1298AA haplotype was associated with lower vitamin B12 concentrations (p<0.05) in NTDs children. CONCLUSIONS: MTHFR gene mutations may affect vitamin B12 and homocysteine metabolism in Brazilian children with NTDs.     

急性淋巴细胞白血病患儿亚甲基四氢叶酸还原酶基因多态性与甲氨蝶呤动态血药浓度相关性的研究

目的本研究旨在探讨亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C基因多态性对急性淋巴细胞白血病(ALL)患儿使用大剂量甲氨蝶呤(HD-MTX)化疗期间的MTX动态血药浓度的相关关系。方法 35例ALL患儿外周血,提取基因DNA,应用PCR-RFLP方法检测MTHFR C677T、A1298C基因型;应用荧光偏振免疫分析法(FPIA)24h、48h、72h监测患儿外周血中甲氨蝶呤动态血药浓度。结果 MTHFR C677T各基因型间24 h MTX浓度有差异(P0.05),携带CT型者明显高于携带CC型和TT型者;MTHFR C677T各基因型48 h、72 h的MTX浓度未见差异。MTHFR A1298C各基因型24 h、48 h7、2 h的MTX浓度未见差异(P0.05)。结论 MTHFR C677T基因多态性影响ALL患儿HD-MTX化疗期间MTX血药浓度,提示在HD-MTX治疗时可根据检测MTHFR C677T基因型进行个体化治疗。     

C677T and A1298C polymorphisms of the methylenetetrahydrofolate reductase gene: incidence and effect of combined genotypes on plasma fasting and post-methionine load homocysteine in vascular disease

BACKGROUND: Moderately increased plasma concentrations of total homocysteine (tHcy) have been shown to be an important risk factor for vascular diseases. Two common polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene, the thermolabile C677T and a more recently reported A1298C polymorphism, may contribute to hyperhomocysteinemia. METHODS: Using PCR and restriction fragment length polymorphism analysis, we studied the prevalence of the C677T and A1298C MTHFR genotypes and the combined effect of these polymorphisms on plasma tHcy concentrations, as measured by HPLC with fluorometric detection, both fasting and post-methionine load (PML), in 1238 individuals. RESULTS: The prevalences of the C677T and A1298C genotypes did not differ significantly in 772 individuals with documented coronary artery disease (CAD), 137 individuals with deep-vein thrombosis (DVT), and 329 individuals without documented vascular disease. Individuals homozygous for the 677T allele had significantly increased fasting tHcy, particularly in the presence of low folate, compared with individuals homozygous for the wild-type allele. Neither the 1298AC nor the 1298CC genotype was associated with significantly increased fasting or PML tHcy concentrations irrespective of serum folate. Of the nine combined MTHFR genotypes, six were present in >10% of the population. Of these, the difference in mean fasting tHcy reached statistical significance (P<0.005) only in individuals with the 677TT/1298AA genotype compared with individuals with the wild-type 677CC/1298AA genotype. Differences in mean fasting tHcy did not reach statistical significance in individuals heterozygous for both MTHFR variants. We detected two 677CT/1298CC and three 677TT/1298AC individuals; only one, an 677TT/1298AC individual, had increased tHcy (both fasting and PML). No individuals had the 677TT/1298CC genotype. CONCLUSIONS: The prevalences of the C677T and A1298C polymorphisms did not differ among individuals with CAD, DVT, or those without documented vascular disease. In contrast to the C677T polymorphism, the A1298C polymorphism is not associated with increased fasting tHcy. Although the two polymorphisms usually exist in trans configuration, crossover may occur rarely to form recombinant chromosomes.     

缺血性心脑血管病患者血浆同型半胱氨酸水平及其代谢相关酶基因多态性分析

目的　了解缺血性心脑血管病患者血浆同型半胱氨酸 (Hcy)水平的变化 ,分析该变化与Hcy代谢相关酶基因变异的相关性。方法　用高效液相色谱结合荧光检测法测定 80名正常人 ,86例脑梗死 ,6 6例心肌梗死患者血浆总同型半胱氨酸 (tHcy)浓度 ,分析血浆tHcy水平与缺血性心脑血管疾病与胱硫醚 β 合成酶 (CBS)基因 844ins6 8、甲硫氨酸合成酶 (MS)基因A2 75 6G、亚甲基四氢叶酸还原酶(MTHFR)基因C6 77T三种Hcy代谢相关酶基因突变之间的相关性。结果　缺血性心脑血管病患者血浆tHcy水平 [脑梗死组 (19.5 9± 10 .6 5 ) μmol/L ,心肌梗死组 (2 1.13± 9.5 7) μmol/L]较正常对照组[(13.73± 4.78) μmol/L]显著升高 (P <0 .0 5 ) ;MTHFRC6 77T纯合突变者血浆tHcy水平无论在正常对照组或患者组均较野生型及杂合突变者明显升高 (P <0 .0 5 )。MSA2 75 6G ,CBS 844ins6 8基因突变者血浆tHcy水平差异无显著性。结论　高Hcy血症是缺血性心脑血管病的重要危险因子 ,MTHFRC6 77T纯合突变可能是导致血浆Hcy水平轻、中度增高的遗传决定簇。     

探讨MTHFR基因多态性与新疆地区人群唇腭裂发病的关系

目的 探讨亚甲基四氢叶酸还原酶（MTHFR）基因C677T和A1298C多态性与新疆地区部分人群非综合征性唇腭裂（NSCL/P）发病的关系.方法 采用病例对照设计,试验组为新疆地区NSCL/P患儿44例（维吾尔族12例,汉族32例）;对照组为非唇腭裂患儿62例（维吾尔族26例,汉族36例）.应用聚合酶链式反应-限制性片段长度多态性方法（PCR-RFLP）对MTHFR基因C677T和A1298C进行多态性检测.结果 新疆地区汉族NSCL/P的MTHFR C677T和A1298C位点基因型及等位基因频数与对照组差异无统计学意义（x2=0.07,P ＞0.05;X2 =0.30,P＞0.05）;维吾尔族NSCL/P的MTHFR C677T位点基因型及等位基因频数与对照组差异无统计学意义（X2=0.12,P ＞0.05）,而MTHFR A1298C位点基因型及等位基因频数与对照组比较其差异有统计学意义（X2=8.90,P ＜0.01）.结论 新疆地区汉族MTHFR基因C677T和A1298C位点多态性可能与NSCL/P的发生无关;维吾尔族MTHFR基因C677T位点多态性与NSCL/P的发生可能无关,而A1298C位点多态性与NSCL/P的发生相关,可能是NSCL/P发病的易感因素.     

Methylenetetrahydrofolate reductase (MTHFR) c677t gene variant modulates the homocysteine folate correlation in a mild folate-deficient population

Background: A large body of evidence links plasma concentrations of homocysteine and cardiovascular disease. Several genetic and environmental variables may modulate such relationship. We investigated the influence of methylenetetrahydrofolate reductase (MTHFR) gene variants C677T, A1298C, and T1317C on homocysteine, folate, and cobalamin concentrations in a sample of individuals from a mild folate deficiency population to better clarify the complex interactions existing among these variables. Methods: In the present study, 209 individuals belonging to an admixed urban population characterized by mild folate deficiency were investigated. MTHFR gene variants C677T, A1298C, and T1317C were genotyped and homocysteine-, folate-, and cobalamin-determined for each individual. Results: Univariate analyses showed a significant association between the C677T variant with homocysteine (P<0.001) and cobalamin (P=0.005) as well as a significant relationship between the T allele and serum folate concentrations (P<0.05). The TT genotype of the C677T polymorphism remained significantly associated with log-transformed homocysteine even after adjustment for age, sex, smoking status, ethnicity, folate, and cobalamin concentrations (P<0.01). Both univariate and multivariate analysis have failed to show any effect of the A1298C and T1317C genetic variants in homocysteine concentrations in this population. Finally, a significant interaction between folate and C677T polymorphism in the determination of homocysteine was also disclosed (P<0.005). Conclusions: Taken together, these results demonstrate a significant interaction between serum folate and MTHFR genotype in predicting homocysteine concentrations. One may consider that a differential response of homocysteine to folic acid supplementation may depend on MTHFR genotype which may have important implications when attempting to lower homocysteine concentrations in populations with mild folate deficiency.     

Patterns of co-occurrence of three single nucleotide polymorphisms of the 5,10-methylenetetrahydrofolate reductase gene in kidney transplant recipients

BACKGROUND: Recently, a new mutation of the 5,10-methylenetetrahydrofolate reductase (MTHFR) encoding gene was first described (1793G > A). Only few reports have studied the prevalence of this polymorphism, especially in combination with other MTHFR mutations (677C > T, 1298A > C). METHODS: We cross-sectionally identified the novel MTHFR 1793G > A polymorphism in 730 kidney transplant recipients. MTHFR 677C > T and 1298A > C were also assessed and the frequency of each was described individually as well as in cross-tabulation with the other MTHFR genotypes. The expected number of patients for each MTHFR genotype combination was calculated and contrasted with the observed numbers. Fisher's exact test was used for statistical inference. RESULTS: The allelic frequency of MTHFR 1793G > A was 0.052. Seventy-two patients (9.9%) were heterozygous and two patients (0.3%) were homozygous. From the cross-tabulations, we identified 53 patients (expected: 33.6) with the MTHFR 1298AC/1793GA genotype and 17 patients (expected: 6.7) with the MTHFR 1298CC/1793GA genotype. Furthermore, we found two patients with double homozygosity for MTHFR 1793G > A and MTHFR 1298A > C (MTHFR 1793AA/1298CC genotype). The frequencies of these genotype combinations were substantially larger than could be expected (P < 0.001). CONCLUSIONS: These findings suggest a selection or survival advantage for individuals with combined MTHFR 1793G > A and MTHFR 1298A > C genotypes, possibly owing to a mutually stabilizing effect on MTHFR enzyme activity.