MTHFR、MTRR基因多态性与反复流产的相关性分析

目的探讨叶酸代谢相关基因5,10-亚甲基四氢叶酸还原酶(MTHFR)、甲硫氨酸合成酶还原酶(MTRR)多态性与反复流产的关系,分析基因多态性对红细胞叶酸水平的影响。方法选取2016年12月至2018年6月来唐山市妇幼保健院遗传咨询门诊,要求进行常规孕前检查,汉族非妊娠健康女性424例为研究对象。依据不良孕产史分为两组,其中病例组216例和对照组218例。采集静脉血,提取DNA,荧光定量PCR法进行MTHFR、MTRR基因多态性检测。化学发光法进行红细胞叶酸定量检测。采用SPSS19.0软件进行统计学分析。比较两组MTHFR、MTRR基因多态性分布频率、不同基因类型红细胞叶酸水平。探讨基因多态性、红细胞叶酸水平与反复流产的关系。结果MTHFR A1298C和MTRR A66G两位点多态性在病例组和对照组间的分布,差异无统计学意义。MTHFR C677T位点多态性,在病例组中的分布频率明显高于对照组,差异具有统计学意义。病例组中MTHFR C667T位点TT型基因突变的患者红细胞叶酸水平远低于正常和杂合型。结论MTHFR C677T基因突变与反复流产的密切相关,MTHFR C667T位点TT型基因突变影响机体红细胞叶酸代谢水平。     

贵州省荔波县汉族和布依族女性MTHFR与MTRR多态性的分布

目的针对贵州省荔波县汉族和布依族女性开展分子流行病学调查,研究叶酸代谢关键酶亚甲基四氢叶酸还原酶(MTHFR)和甲硫氨酸合成酶还原酶(MTRR)的基因多态性分布。方法以在荔波县人民医院进行围孕期保健的1 342名健康女性为研究对象,其中汉族236人、布依族1 106人。采集口腔黏膜上皮脱落细胞,抽提基因组DNA,使用荧光定量PCR检测MTHFR C677T、A1298C和MTRR A66G基因多态性,进行统计分析。结果 1)入组对象的基因多态性分布符合遗传平衡。2)汉族女性MTHFR 677CC、CT和TT的基因型频率分别为49.6%、39.8%和10.6%,布依族女性为61.8%、33.7%和4.4%;汉族女性MTHFR 1298AA、AC和CC的基因型频率分别为62.3%、33.1%和4.7%,布依族女性为47.4%、42.9%和9.7%,两位点均有差异(P0.05)。汉族女性MTRR 66AA、AG和GG的基因型频率分别为56.4%、37.4%和5.9%,布依族女性为57.0%、36.0%和7.1%,差异无统计学意义。3)汉族和布依族女性MTHFR C677T与A1298C两位点连锁均有6种组合,没有CT/CC、TT/AC和TT/CC。汉族女性频率最高的是CT/AA,布依族女性频率最高的是CC/AC。两个位点构建的单倍型存在CA、TA和CC 3种组合,两位点间存在完全连锁不平衡。结论获取荔波县汉族和布依族女性MTHFR与MTRR多态性的群体遗传学特征,为指导科学增补叶酸营养、实施个性化孕期保健提供依据。     

建始地区汉族女性叶酸代谢通路关键酶基因MTHFR、MTRR单核苷酸多态性分布特征调查

目的调查湖北省建始县汉族女性叶酸代谢障碍关键酶基因5,10-亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C及甲硫氨酸还原酶(MTRR)A66G位点基因多态性分布情况,分析其遗传风险分布地域性特征,为指导孕龄妇女个性化增补叶酸及出生缺陷一级预防提供依据。方法随机以湖北省恩施州建始县248位汉族女性为研究对象,检测其MTHFR C677T、A1298C及MTRR A66G基因位点多态性,采用统计学方法分析该地区基因的多态性分布特征,并与我国南北方具有代表性的若干地区进行比较。结果本地区的汉族女性MTHFR 677TT纯合突变基因型频率(14.1%),显著高于我国我们南方城市南宁、琼海和惠州(P0.05),显著低于北方城市乌鲁木齐、尚志、延边、银川、廊坊、烟台、济源、镇江和湘潭(P0.05);等位基因T频率为40.5%,与我国其他地区的比较,结论和C677T位点基因型的情况类似;MTHFR A1298C基因型分布情况与尚志、延边、廊坊、烟台、镇江、湘潭、南宁、惠州和琼海地区的人群差异有统计学意义;MTRR A66G位点的基因型频率和等位基因频率与其它地区比较均无统计学差异(P0.05)。结论建始县的汉族女性MTHFR基因多态性频度分布具有显著的地区特异性,MTRR基因多态性频度分布不具备显著的地区特异性。     

新余市汉族女性MTHFR与MTRR基因多态性分布研究

目的针对新余市汉族女性开展分子流行病学调查,研究叶酸代谢关键酶甲硫氨酸合成酶还原酶(MTRR)和5,10-亚甲基四氢叶酸还原酶(MTHFR)的基因多态性分布。方法以孕期保健的521名汉族健康女性为研究对象,采集口腔黏膜上皮脱落细胞,提取基因组DNA,使用荧光定量PCR方法检测MTHFR C677T、A1298C和MTRR A66G基因多态性,进行统计分析。结果 (1)入组对象的基因多态性分布符合遗传平衡。(2)汉族女性MTHFR 677CC、CT、TT的基因型频率分别为38.6%、47.6%、13.8%,C、T等位基因频率分别为62.4%、37.6%;MTHFR 1298AA、AC、CC的基因型频率分别为65.1%、31.9%、3.07%,A、C等位基因频率分别为81.0%、19.0%;MTRR 66AA、AG、GG的基因型频率分别为60.3%、35.1%、4.61%,A、G等位基因频率分别为77.8%、22.2%。(3)汉族女性MTHFR C677T和A1298C两位点连锁有7种组合,频率最高的是CT/AA(30.5%),没有TT/AC和TT/CC组合。两位点间存在完全连锁不平衡(D'=1.0,r~2=0.124)。结论获取新余市汉族女性MTHFR和MTRR基因多态性的群体遗传学特征,其中关键基因位点MTHFR C677T的高风险TT基因型比例为13.8%,低于已报道的山东淄博、河南新乡、辽宁沈阳等地,高于广东佛山市,说明叶酸利用能力中等,对于高风险人群还需加强孕期管理,同时本研究也为当地人群进行个体化增补叶酸提供理论依据。     

临沂市汉族女性MTHFR和MZRR基因多态性分布及其与同型半胱氨酸水平的相关性

目的 分析山东省临沂市汉族女性亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)677C/T、1298A/C及甲硫氨酸合成酶还原酶(methionine synthase reductase,MTRR)66A/G基因多态性的分布特征,及其与同型半胱氨酸(homocysteine,Hcy)水平的相关性.方法 采用横断面调查研究方法,以临沂市825名汉族女性为研究对象,采集口腔黏膜上皮细胞,提取基因组DNA,采用Taqman-MGB技术进行MTHFR和MTRR基因多态性检测.统计分析基因多态性的分布特征,并与其他地区(山东省潍坊市、河南省郑州市、四川省德阳市及海南省)的数据进行比较.采用酶转换法检测281名研究对象的血浆Hcy浓度,根据MTHFR基因多态性将其分为MTHFR酶活性基本正常组和显著降低组,分析Hcy水平与MTHFR酶活性的相关性.结果 (1)临沂市汉族女性的MTHFR677CC、CT、TT的基因型频率分别为16.7%、48.3%和35.0%,TT纯合突变高于四川德阳和海南地区(P<0.01).MTHFR 1298AA、AC、CC的基因型频率分别为76.0%、21.6%和2.4%,CC纯合突变基因型频率低于四川德阳和海南地区(P<0.01).MTRR 66AA、AG、GG的基因型频率分别为54.7%、39.4%和5.9%,GG纯合突变基因型频率低于海南地区(P<0.01).(2)MTHFR酶活性显著降低组的Hcy水平高于酶活性基本正常组,差异有统计学意义(P<0.05).结论 (1)临沂市汉族女性有不同于其他地区的MTHFR和M7RR基因多态性分布特征.(2)MTHFR基因多态性导致的酶活性降低是Hcy水平升高的风险因素.     

张家港市汉族女性MTHFR与MTRR基因多态性分布

目的探讨张家港市汉族女性MTHFR、MTRR基因多态性的频率特征,以指导孕妇增补叶酸和出生缺陷一级预防。方法以张家港市4008例汉族女性为研究对象,检测MTHFR C677T、A1298C和MTRR A66G的基因分型。统计分析基因多态性的频率特征,并与已报道的其他地区汉族女性的数据进行比较。结果张家港市汉族女性的MTHFR C677T位点CC、CT和TT基因型频率分别为32.2%、49.5%和18.3%。C等位基因频率为64.3%,T等位基因频率为35.7%。MTHFR A1298C位AA、AC和CC基因型频率分别为68.7%、28.7%和2.5%。A等位基因频率为80.8%,C等位基因频率为19.2%。MTRR A66G位点AA、AG和GG基因型频率分别为54.4%、38.5%和7.1%。A等位基因频率为76.3%,G等位基因频率为26.4%。结论张家港市汉族女性MTHFR和MTRR基因多态性频率具有地域特异性。     

MTHFR基因多态性与银屑病的遗传易感性

【摘要】　目的　探讨亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)基因单核苷酸多态与中国北方地区银屑病的关系。方法　针对123例寻常型银屑病患者和129名正常对照个体,分别用PCR-RFLP和AS-PCR的方法,分析C677T、G1793A和A1298C 3个多态位点基因型,并进行统计分析。 结果 在病例组中,MTHFR 677 C、T等位基因频率分别为45.13%、54.87%,1298A、C等位基因频率为88.37%、11.63%,1793G、A等位基因频率为95.12%、4.88%。在正常对照组中,677 C、T等位基因频率分别为44.96%、54.87%,1298A、C等位基因频率为86.44%、13.56%,1793G、A等位基因频率为96.12%、3.88%。经统计学分析,MTHFR C677T 、A1298C、G1793A 各多态位点基因型、等位基因频率在病例组和对照组中的分布差异无显著性意义,C677T与A1298C基因型联合分析也未发现有统计学意义。结论 MTHFR基因的3个多态位点（C677T、A1298C、G1793A）与寻常型银屑病无明显的相关关系,可能与寻常型银屑病的易感性无关。     

洛阳市汉族女性MTHFR与MTRR基因多态性研究

目的探讨洛阳市汉族女性MTHFR、MTRR基因多态性的频率特征,以指导孕妇增补叶酸和出生缺陷一级预防。方法以洛阳市619例汉族女性为研究对象,检测MTHFR 677T、A1298C和MTRR A66G的基因分型。统计分析基因多态性的频率特征,并与已报道的其他地区汉族女性的数据进行比较。结果洛阳市汉族女性的MTHFR C677T位点TT纯合突变基因型频率为38.4%,高于湘潭、烟台、镇江、松滋、眉山、惠州、延边、琼海、乌鲁木齐、银川和南宁,差异均有统计学意义(P0.05)。MTHFR A1298C位点CC纯合突变基因型频率为1.9%,高于湘潭、镇江、松滋、眉山、惠州、琼海和南宁,差异均有统计学意义(P0.05)。MTRR A66G位点GG纯合突变基因型频率为4.7%,低于湘潭、烟台、松滋、琼海等地,差异有统计学意义(P0.05)。结论洛阳市汉族女性MTHFR和MTRR基因多态性频率分布具有地域特异性。     

女性MTHFR、MTRR基因型和等位基因频率分布与其他地区女性的比较

目的探讨易感基因MTHFR、MTRR在天津市女性中基因多态性的频率特征,以指导孕妇增补叶酸和出生缺陷一级预防。方法选取天津市467名女性检测MTHFR C677T、A1298C和MTRR A66G基因多态性,分析本地区基因多态性的频率特征,并与中国已报道地区进行比较。结果天津市女性的MTHFR 677TT基因型频率(26.7%),高于惠州(10.9%)和琼海(6.1%)(P均0.01),T等位基因频率(53.4%)高于惠州(29.5%)和琼海(22.1%)(P均0.05);MTHFR 1298CC纯合突变基因型频率(4.3%)低于琼海(7.1%)(P0.05);MTRR 66GG纯合突变基因型频率(6.1%)低于琼海(9.3%)(P0.05),G等位基因频率(23.9%)小于琼海(30.9%)(P0.05)。结论天津女性MTHFR和MTRR基因多态性频率分布具有地域特异性,对于叶酸代谢障碍有风险的孕期妇女需要通过增加叶酸补服的剂量和时间预防神经管畸形患儿的出生。     

母亲叶酸代谢相关基因多态性与唐氏综合征发生的关系

目的研究叶酸代谢相关基因多态性在浙南地区汉族妇女中的分布,探讨其与唐氏综合征(Down’s Syn-drome,DS)发生的关系。方法对84例已生育DS患儿的母亲(观察组)和120例生育过正常儿童的母亲(对照组)采用PCR扩增及DNA测序法检测亚甲基四氢叶酸还原酶(MTHFR)基因C677T、A1298C位点;甲硫氨酸合成酶(MTR)基因A2756G位点单核苷酸多态性。结果 MTHFR 677 T基因及CT、TT基因型、MTHFR 1298 C基因及AC、CC基因型、MTR 2756 G基因及AG基因型频率观察组与对照组比较均无统计学意义(P>0.05)。三个位点基因型频率联合分析两组也不存在统计学意义(OR=0.692,P>0.05)。结论浙南地区汉族妇女MTHFR C677T、FTHFR A1298C、MTR A2756G基因型不是DS发生的风险因素;三个基因型的联合频率也未见增加DS发生的风险。     

青岛地区汉族育龄妇女亚甲基四氢叶酸还原酶基因667位点多态性分布研究

目的探讨亚甲基四氢叶酸还原酶（MTHFR）基因667位点多态性在青岛市汉族育龄妇女中的分布状况。方法用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）技术检测98份育龄妇女外周血MTHFR C667T基因型分布。结果本研究人群MTHFR 677位点基因的CC、CT、TT基因型频率分别为24.5%、53.1%、22.4%,T等位基因频率为0.49。结论青岛市汉族育龄妇女MTHFR基因667位点多态性与其他地区有较大不同,调查可以为相关研究提供相应的分子生物学依据。     

Polymorphisms of methylenetetrahydrofolate reductase gene among women of childbearing age from Shiyan areaCSCD

Objective: To assess the association of methylenetetrahydrofolate reductase (MTHFR) gene 677C>T polymorphism with blood homocysteine (Hey) level among women of childbearing age from Shiyan area. Methods: PCR - chip hybridization was used to determine the genotype of MTHFR 6770T, and a biochemical assay was used to determine the total Hey level among 428 healthy women of childbearing age. Association of MTHFR 677>T with total Hey level was assessed. Results: Heterozygous CT mutation was most common form for the MTHFR 677>T polymorphisms and amounted for 49. 77% among the group, while the CC wild type and homozygous TT mutation respectively accounted for 30. 61% and 19. 63%. These gave a frequency of 44. 51% for the 677T allele. The dominant genotype among different age groups were the CT type. Of note, the proportion of MTHFR 677CC is higher in women above 30 years of age. The distribution of MTHFR 677>T genotypes has differed significantly among different age groups (P<0. 05). Compared with those with wild type alleles, carriers of MTHFR mutations had a higher plasma Hey level. The genotypic frequencies of MTHFR C677T in Shiyan region differed significantly from those of Sichuan, Hebei, Henan and Shandong (P < 0. 05) but were similar to those of Jiangsu, Guangdong, Ningxia and Xinjiang. Conclusion: The distribution of MTHFR C677T polymorphism among women of childbearing age in Shiyan area is influenced by age and is geographically specific and associated with plasma Hey level. Nearly 50% of women have carried the high risk alleles, for whom folic acid supplementation is crucial for the reduction of birth defect rate. © 2018 MeDitorial Ltd. All rights reserved.     

Serum homocysteine, vitamin B12, folic acid levels and methylenetetrahydrofolate reductase (MTHFR) gene polymorphism in vitiligo

The aim of this study was to determine serum vitamin B12, folic acid and homocysteine (Hcy) levels as well as MTHFR (C677, A1298C) gene polymorphisms in patients with vitiligo, and to compare the results with healthy controls. Forty patients with vitiligo and 40 age and sex matched healthy subjects were studied. Serum vitamin B12 and folate levels were determined by enzyme-linked immunosorbent assay. Plasma Hcy levels and MTHFR polymorphisms were determined by chemiluminescence and real time PCR methods, respectively. Mean serum vitamin B12 and Hcy levels were not significantly different while folic acid levels were significantly lower in the control group. There was no significant relationship between disease activity and vitamin B12, folic acid and homocystein levels. No significant difference in C677T gene polymorphism was detected. Heterozygote A1298C gene polymorphism in the patient group was statistically higher than the control group. There was no significant relationship between MTHFR gene polymorphisms and vitamin B12, folic acid and homocysteine levels. In conclusion, vitamin B12, folate and Hcy levels are not altered in vitiligo and MTHFR gene mutations (C677T and A1298C) do not seem to create susceptibility for vitiligo.     

5,10-亚甲基四氢叶酸还原酶基因多态性及补充叶酸与非综合征性唇腭裂的相关性

背景：对于5, 10-亚甲基四氢叶酸还原酶(5, 10-methylene tetrahydrofolate reductase, MTHFR)基因C677T位点多态性与唇腭裂相关性的研究国内外结果不一,未见结合干预因素叶酸影响的相关报道。 目的：探讨河南地区汉族人群MTHFR基因C677T位点多态性及补充叶酸与非综合征性唇腭裂的发病关系。 方法：选取2008-09/2010-03在郑州大学第一附属医院及郑州市第一人民医院整形外科就诊的非综合征性唇腭裂患者110例,采用PCR-RFLP法检测外周血中MTHFR基因C677T位点基因型并与40例健康对照比较频数差异。同时结合母孕期是否补充叶酸进行统计学分析。 结果与结论：病例组和对照组C677T基因型及等位基因频率比较差异均具有显著性意义(P < 0.01),且有家族史的患者TT基因型及T等位基因频率高于无家族史患者(P < 0.05)。对母孕期是否补充叶酸进行比较,发现非综合征性唇腭裂与叶酸摄入呈负相关(χ²=4.304,r=-0.169,P  < 0.05)。结果提示MTHFR基因C677T位点突变与河南汉族人群非综合征性唇腭裂的发生相关,母孕期补充叶酸能降低非综合征性唇腭裂的发病风险。     

Methylenetetrahydrofolate reductase C677T and A1298C variants do not affect ongoing pregnancy rates following IVF

BACKGROUND: There is concern that IVF could compromise normal imprinting and methylation of DNA. Methylenetetrahydrofolate reductase (MTHFR) regulates the flow of folic acid-derived, one-carbon moieties for methylation and is critical to early embryonic development. Therefore, we hypothesized that common polymorphisms in MTHFR could associate with IVF outcome. METHODS: MTHFR C677T and A1298C polymorphism genotyping was performed on 374 subjects for this study, representing 197 couples undergoing IVF in a university setting from July 2005 to January 2006. Analysis of variance (ANOVA), chi-square and/or multivariate analyses were used to assess whether these polymorphisms are associated with embryo quality or with ongoing pregnancy or spontaneous abortion rates. RESULTS: Allele frequencies for C677T ( p=0.67, q=0.33) and A1298C ( p=0.71, q=0.29) were in Hardy-Weinberg equilibrium. The C677T and A1298C variants, either alone or in combination, did not associate with embryo quality or short-term pregnancy outcome. CONCLUSIONS: The common polymorphisms in MTHFR are not associated with embryo quality, as defined by cell number or fragmentation score, or with short-term pregnancy outcomes. Therefore, in our population in which women receive adequate folic acid, MTHFR genotypes are not informative in explaining IVF failure. Further studies, however, examining birth outcomes and the other enzymes in the folic acid pathway are warranted.     

MTHFR基因C667T和A1298C多态位点和高同型半胱氨酸与冠心病的相关性研究

目的探讨亚甲基四氢叶酸还原酶(methylene tetrahydrofolate reductase,MTHFR)基因上C667T和A1298C多态位点与冠心病(coronary heart disease,CHD)的相关性,以及寻找冠心病的发病危险因素。方法随机选取行冠状动脉造影确诊的冠心病患者200例和同期同地区正常对照200例,运用Taqman方法对C667T和A1298C两个多态位点进行基因分型,罗氏生化和发光(Cobas8000)流水线来测定生化指标及血浆高同型半胱氨酸(homocysteine,HCY)、磷酯酶A2(phospholipase A2,PLA2)、血清叶酸水平等。结果冠心病组的体质量指数(body mass index,BMI)、收缩压(systolic pressure,SBP)、脂蛋白a(lipoprotein a,Lp a)、糖化血红蛋白(glycated hemoglobin,HbA1c)、磷脂酶A2、HCY水平均显著高于对照组;而总胆固醇(total cholesterol,TC)、低密度脂蛋白(LDL-C)、血清叶酸则显著低于对照组。对其进行单因素Logistic回归分析发现,除去上述变量,C667T多态位点也是冠心病发病的危险因素;进一步对C667T和A1298C两个多态位点进行分析时发现,C667T多态位点与冠心病存在相关性,冠心病组的T等位频率为39.0%,远高于对照组的22.0%(P=0.045);在显性模型中,CT/TT vs.CC的P值为0.029,OR=2.60,95%CI分别为1.03~6.14;不同基因型趋势检验P=0.016。而A1298C多态位点并未观察到其与冠心病存在相关性。在C667T和A1298C两个多态位点的联合单倍型分析中,发现只有当两个多态位点同时发生突变(T-G型)时,才存在统计学差异(P=0.034,OR=3.54,95%CI=1.10~11.41),单倍型的分布模式在病例和对照组之间有显著差异(P=0.037)。结论MTHFR基因上C667T多态位点与冠心病存在相关性,而A1298C多态位点并未观察到相关性,单倍型分析发现两者同时发生突变时可增加冠心病的发病风险。     

Nutritional and genetic determinants of vitamin B and homocysteine metabolisms in neural tube defects: a multicenter case-control study

Neural tube defects (NTDs) are severe congenital malformations due to failure of neural tube formation in early pregnancy. The proof that folic acid prevents NTDs raises the question of whether other parts of homocysteine (Hcy) metabolism may affect rates of NTDs. This French case-control study covered: 77 women aged 17-42 years sampled prior to elective abortion for a severe NTDs (cases) and 61 women aged 20-43 years with a normal pregnancy. Plasma and erythrocyte folate, plasma B6, B12 and Hcy were tested as five polymorphisms MTHFR 677 C --> T, MTHFR 1298 A --> C, MTR 2756 A --> G, MTTR 66 A --> G and TCN2 776 C --> G. Cases had significantly lower erythrocyte folate, plasma folate, B12 and B6 concentrations than the controls, and higher Hcy concentration. The odds ratio was 2.15 (95% CI: 1.00-4.59) for women with the MTRR 66 A --> G allele and it was decreased for mothers carrying the MTHFR 1298 A --> C allele. In multivariate analysis, only the erythrocyte folate concentration (P = 0.005) and plasma B6 concentration (P = 0.020) were predictors. Red cell folate is the main determinant of NTDs in France. Folic acid supplement or flour fortification would prevent most cases. Increased consumption of vitamins B12 and B6 could contribute to the prevention of NTDs. Genetic polymorphisms played only a small role. Until folic acid fortification becomes mandatory, all women of reproductive age should consume folic acid in a multivitamin that also contains B12 and B6.     

Prevalence of MTHFR gene polymorphisms (C677T and A1298C) among Tamilians

We have investigated the incidence of the C677T and A1298C methylene tetrahydrofolate reductase (MTHFR) gene single nucleotide polymorphisms (SNPs) in the South Indian Tamil Nadu population with a total number of 72 individuals. The MTHFR genotyping was performed using the polymerase chain reaction followed by restriction enzyme analysis. Homozygosity for the MTHFR A1298C SNP was detected in 15.3% (11/72) of the individuals tested, and 47.2% (34/72) were heterozygous for this SNP. Homozygosity for the C677T MTHFR SNP was detected in 1.38%(1/72), and the frequency of the C677T heterozygotes was 18.1%(13/72). When we analyzed the combined frequency of the two SNPs, the frequency of double heterozygosity was19.6%, and the frequency of double homozygosity was completely absent among the study group. The 'C' allele frequency for MTHFR A1298C was 0.389, and the 'T' allele frequency for C677T mutation was 0.104. Out of the 72 individuals included in the study, 52 were acute myocardial infarction (AMI) patients and 20 were healthy individuals with no documented history of heart disease. The results of this study indicate that the MTHFR A1298C SNP is more prevalent among the Tamilians when compared to the MTHFR C677T SNP, suggesting a possible role of MTHFR A1298C in the pathogenesis of heart diseases.     

Increased frequency of combined methylenetetrahydrofolate reductase C677T and A1298C mutated alleles in spontaneously aborted embryos

The pathogenesis of spontaneous abortion is complex, presumably involving the interaction of several genetic and environmental factors. The methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphisms are commonly associated with defects in folate dependent homocysteine metabolism and have been implicated as risk factors for recurrent embryo loss in early pregnancy. In the present study we have determined the prevalence of combined MTHFR C677T and A1298C polymorphisms in DNA samples from spontaneously aborted embryos (foetal death between sixth and twentieth week after conception) and adult controls using solid-phase minisequencing technique. There was a significant odds ratio of 14.2 (95% CI 1.78-113) in spontaneously aborted embryos comparing the prevalence of one or more 677T and 1298C alleles vs the wild type combined genotype (677CC/1298AA), indicating that the MTHFR polymorphisms may have a major impact on foetal survival. Combined 677CT/1298CC, 677TT/1298AC or 677TT/1298CC genotypes, which contain three or four mutant alleles, were not detected in any of the groups, suggesting complete linkage disequilibrium between the two polymorphisms. The present finding of high prevalence of mutated MTHFR genotypes in spontaneously aborted embryos emphasises the potential protective role of periconceptional folic acid supplementation.