广东地区汉族育龄妇女MTHFR基因遗传多态性

目的调查并分析广东地区汉族育龄妇女MTHFR基因多态性分布情况。方法选取2016年1月至2018年7月广东省妇幼保健院行婚检/孕检的育龄妇女13336例,采用Taqman-MGB法测定MTHFR基因C677T、A1298C位点的基因型,并采用卡方检验比较本地人群与其他人群的基因型频率/等位基因频率的分布情况。结果MTHFR基因C667T位点野生型(CC)、杂合突变型(CT)和纯合突变型(TT)分别占51.5%、38.7%和9.8%,突变T基因频率为29.2%;MTHFR基因A1298C位点中,野生型(AA)、杂合突变型(AC)和纯合突变型(CC)分别占59.3%、35.2%和5.5%,突变C基因频率为23.1%。广东地区汉族育龄妇女MTHFR基因C677T、A1298C位点基因型分布和等位基因频率分布与全国人群比较差异均有统计学意义(P<0.01)。广东地区汉族育龄妇女MTHFR基因C677T、A1298C位点的基因频率和等位基因频率与江苏、九江、齐齐哈尔和长沙等地区汉族育龄妇女人群相比差异均有统计学意义(P<0.05)。广东地区汉族育龄妇女MTHFR基因C677T、A1298C位点的等位基因频率与亚洲、东亚、南亚、欧洲、美洲地区人群等位基因频率的分布存在不同程度的差异。结论广东地区人群MTHFR基因的多态性分布与其他地区相比存在明显的差异。     

影响亚甲基四氢叶酸还原酶和甲硫氨酸合成酶还原酶基因多态性的因素分析

目的了解影响女性亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C位点和甲硫氨酸合成酶还原酶(MTRR)A66G位点基因多态性的因素。方法采用横断面调查研究方法,以湖北省内1 902例女性为对象,采集口腔黏膜上皮细胞,提取DNA,用实时荧光定量PCR技术检测MTHFR和MTRR基因,统计分析不同民族MTHFR和MTRR基因多态性的差异,与其他地区人群的MTHFR和MTRR基因多态性进行比较,并分析不同位点基因多态性之间的关联关系。结果 (1)湖北省汉族女性和少数民族女性在MTHFR C677T和MTRR基因多态性构成差异无统计学意义(P>0.05),而MTHFR A1298C位点基因多态性构成差异有统计学意义(P<0.05)。(2)MTHFR C677T位点的纯合突变基因型TT的频率从南到北呈上升趋势,MTHFR A1298C位点的纯合突变基因型CC的频率从南到北呈下降趋势,而MTRR A66G位点基因多态性在不同地区差异不大。(3)MTHFR C677T位点的纯合突变基因型TT的频率在A1298C位点的正常型、杂合型、纯合突变型中分别为15.9%、0.1%、0.0%,差异有统计学意义(P<0.01);MTHFR C677T位点的纯合突变基因型TT的频率在MTRR A66G位点的正常型、杂合型、纯合突变型中分别为9.4%、5.9%、0.7%,差异无统计学意义(P>0.05)。结论 MTHFR A1298C位点基因多态分布存在民族差异;而MTRR C677T、A1298C位点基因多态分布存在地区差异;同一基因不同位点的基因多态性有关联。     

MTHRF基因C677T多态性与ALL患儿MTX血药浓度和毒副反应的相关性

【目的】探讨亚甲基四氢叶酸还原酶（MTHFR）C677T基因多态性对急性淋巴细胞白血病（ALL）儿童甲氨蝶呤（MTX）血药浓度和毒副反应的影响。【方法】筛选50例采用大剂量MTX治疗的ALL患儿,采用多聚酶链反应一限制性内切酶片段多态性分析法（PCR-RFLP）检测MTHFRC677T多态性,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,记录相关毒副反应。【结果】24h时、48hMTX血药浓度均以突变型纯舍子（TT）最高（均P〈0．05）,突变型杂合子（CT）次元;MTHFRC677T基因型与肝损害、消化道反应和骨髓抑制相关,携带T突变基因患儿（CT＋TT组）发生肝损害的风险是野生型纯合子（CC）的5．12倍（95％CI：1．372～19．077）,发生3～4级消化道反应的风险是CC型的4．41倍（95％CI：1．066～18．266）,3～4级骨髓抑制发生率依次为TT型、CT型和CC型（均P〈0．05）。【结论】MTHFRC677T基因多态性影响ALL患儿大剂量MTX化疗期间MTX血药浓度,与肝损害、消化道反应和骨髓抑制等毒副反应相关。     

河南汉族人群MTHFR基因多态性与肺癌的关系

目的 探讨河南地区汉族人群5,10-亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase,MTHFR）氨基酸突变位点C677T和A1298C基因多态性分布与肺癌发生的关系。方法 202例肺癌患者（肺癌组）和202例体检健康者（对照组）,2组采用限制性片段长度多态性酶切技术检测MTHFR基因型,分析MTHFR基因C677T和A1298C位点基因频率分布特点。结果 肺癌组MTHFR基因C677T位点CC、CT、TT基因亚型分布频率分别为26.7%、50.5%、22.8%,对照组分别为34.2%、55.4%、10.4%,CC、CT亚型与对照组比较差异无统计学意义（P〉0.05）,TT基因亚型与对照组比较差异有统计学意义（P〈0.05）;携带TT基因型患肺癌的风险比值比为2.542,95%CI为1.453~4.444;肺癌组MTHFR基因A1298C位点AA、AC、CC基因亚型分布频率分别为27.2%、52.5%、20.3%,对照组分别为32.2%、50.5%、17.3%,2组比较差异均无统计学意义（P〉0.05）。结论 MTHFR基因C677T基因TT亚型与肺癌的发病明显相关,未发现A1298C基因多态性与肺癌的发生有相关性。     

武汉地区缺血性脑卒中患者MTHFR基因多态性分布分析

目的:探讨武汉地区缺血性脑卒中患者亚甲基四氢叶酸还原酶(MTHFR)基因多态性的分布。方法:选取缺血性脑卒中患者167例为卒中组,健康体检者110例为对照组。通过基因芯片法检测缺血性脑卒中相关的MTHFR基因677位点,并按基因型别分为野生型(C677C)、杂合型(C677T)、纯合型(T677T)。结果:卒中组中野生型22.2%,杂合型43.1%,纯合型34.7%。与对照组相比,野生型显著减少,纯合突变型显著增多,有显著性差异(P0.01)。不同性别脑卒中患者在MTHFR基因分型上差异无统计学意义(P0.05)。结论:武汉地区缺血性脑卒中患者中分布有较多的纯合突变型MTHFR基因。     

陕西省延安地区育龄女性MTHFR基因多态性和国内多地区相关报道比较分析2)

目的分析陕西省延安地区育龄女性叶酸代谢关键酶亚甲基 四氢叶酸还原酶(MTHFR)的基因多态性及地区遗传分布特征。方法 以延安市第二医疗集团1 508例育龄女性为研究对象,用荧光定量PCR法检测其MTHFR C677T ,A1298C基因位点多态性,并和国内多地区相关报道比较分析。结果”K 该地区三种表现型正常型、较弱型和弱型分别占22.5%,50.7%和26.8%。MTHFR C677T 位点CC,CT和TT基因频率分别为24.7%,48.6%和26.7%;MTHFR A1298C位点AA,AC和CC基 因频率分别为71.0%,26.7%和2.3%,与已报道的南方城市湘潭、武汉、南宁等地区相比 ,差异均有统计学意义( P <0.05)。MTHFR C677T和A1298C等位基因分布情况与其基因型 分布情况类似。结论该地区育龄女性MTHFR基因以基因型(MTHFR C6 77T/A1298C)CT/AA型为主,MTHFR C677T TT纯合突变型呈现北高南低的趋势,其T等位基因 频率也呈现随纬度的递减而降低的走向。     

亚甲基四氢叶酸还原酶基因677C／T和1298A／CSNP与肺癌的相关性研究

目的探讨我国黑龙江地区汉族人群亚甲基四氢叶酸还原酶（MTHFR）基因单核苷酸多态与肺癌的相关性。方法纳入225例肺癌患者作为实验组,以门诊体检健康人群225名为对照组,采用病例对照研究法进行MTHFR基因677C/T 、1298A/C SNP与肺癌的关联分析,以Sanger双脱氧链终止法检测基因分型。结果在对照组中,MTHFR基因C677T的野生型CC、突变杂合子CT、突变纯合子TT基因型频率分别为34.2%、55.1%、10.7%,实验组中3种基因型频率分别为26.7%、50.2%、23.1%,C677T各SNP基因型频率在实验组和对照组间分布差异有统计学意义（P＝0.002）,其中突变纯合子TT携带者发生肺癌风险是野生型CC的2.78倍[OR（95%CI）：2.78（1.54～5.02） , P＝0.001];MTHFR基因A1298C位点实验组AA、AC、CC基因型频率分别为34.2%、55.1%、10.7%,对照组分别为64.0%、32.0%、4.0%,两组间比较差异无统计学意义（P＝0.247）。单倍体分析结果显示,TA单倍型在实验组的分布频率明显高于对照组（43.1%与35.3%）,两组比较差异有统计学意义[OR（95%CI）：1.39（1.06～1.81）,P＝0.016];而CC单倍型在实验组和对照组的分布频率分别为10.6%、17.1%,差异有统计学意义[OR（95%CI）：0.58（0.39～0.85）,P＝0.005]。MTHFR基因677和1298两位点之间存在连锁不平衡关系（D＇＝0.48,P＝0.003）。对MTHFR基因C677T多态性进行基因-环境相互作用分析显示：TT与CC基因型相比,年龄大于60岁[OR（95%CI）：4.0（1.78～9.32）, P＝0.001]、男性[OR（95%CI）：5.55（2.10～14.67）,P＝0.000]、吸烟[OR（95%CI）：8.13（2.29～28.85） , P＝0.000]、小细胞肺癌[OR（95%CI）：1.28（1.10～1.44） ,P＝0.000]均可使肺癌的发病风险增加;CT与CC基因型相比,女性[OR（95%CI）：2.09（1.05～4.16）,P＝0.030]、不吸烟人群[OR（95%CI）：2.43（1.25～4.74）,P＝0.008]、小细胞肺癌[OR（95%CI）：0.31（1.16～1.59）,P＝0.000]的肺癌患病风险也增加。结论MTHFR基因C677T是肺癌发病的遗传易感基因,且与肺癌发病风险有关。     

华南地区汉族人群亚甲基四氢叶酸还原酶基因多态性分析

目的了解亚甲基四氢叶酸还原酶(MTHFR)C677T基因多态性在华南地区汉族健康人群、原发性高血压患者和高血压合并冠心病患者中的分布情况。方法采用芯片技术对359例人群的MTHFR C677T基因多态性进行检测,并统计男女间基因型频率的差异。结果野生型CC最多见占54.9%,突变型CT占33.1%和TT占12.0%,野生型与突变型在男女人群间的分布差异有统计学意义(P0.05);TT的频率在高血压合并冠心病患者与健康人群和原发性高血压患者中分布差异均有统计学意义(P0.05)。结论 MTHFR C677T的多态性分布在男女人群间有差异,也与原发性高血压患者冠心病的发生相关。     

陕西省延安地区育龄女性MTHFR基因多态性和国内多地区相关报道比较分析

目的分析陕西省延安地区育龄女性叶酸代谢关键酶亚甲基四氢叶酸还原酶(MTHFR)的基因多态性及地区遗传分布特征。方法以延安市第二医疗集团1 508例育龄女性为研究对象,用荧光定量PCR法检测其MTHFR C677T,A1298C基因位点多态性,并和国内多地区相关报道比较分析。结果该地区三种表现型正常型、较弱型和弱型分别占22.5%,50.7%和26.8%。MTHFR C677T位点CC,CT和TT基因频率分别为24.7%,48.6%和26.7%;MTHFRA1298C位点AA,AC和CC基因频率分别为71.0%,26.7%和2.3%,与已报道的南方城市湘潭、武汉、南宁等地区相比,差异均有统计学意义(P0.05)。MTHFR C677T和A1298C等位基因分布情况与其基因型分布情况类似。结论该地区育龄女性MTHFR基因以基因型(MTHFR C677T/A1298C)CT/AA型为主,MTHFR C677TTT纯合突变型呈现北高南低的趋势,其T等位基因频率也呈现随纬度的递减而降低的走向。     

亚甲基四氢叶酸还原酶基因多态性与乳腺癌新辅助化疗敏感性关系的研究探讨

目的研究叶酸代谢的关键酶亚甲基四氢叶酸还原酶（MTHFR）基因C677T、A1298C多态与乳腺癌患者对新辅助化疗敏感性的关系。方法收集经病理学或细胞学确诊的乳腺癌患者61例,均给予新辅助化疗。接受环磷酰胺、表阿霉素、5-氟尿嘧啶联合化疗方案（CAF）化疗34例,表阿霉素、紫杉醇联合化疗方案（AT方案）化疗27例。所有病例化疗前抽静脉血,提取白细胞DNA,用聚合酶链反应限制性片段长度多态性（PCR-RFLP）技术检测MTHFR基因型。化疗后均测量肿块大小进行疗效评价,手术均行病理检查,观察化疗反应分级情况。结果 61例乳腺癌患者中,使用CAF方案和AT方案的临床有效率分别为61.5%、75.0%,差异无统计学意义;Ⅰ~Ⅲ级化疗反应率分别为55.9%、74.1%,差异无统计学意义。携带MTHFR C677T T/T基因型、C/T基因型、C/C基因型的乳腺癌患者化疗的临床有效率分别为83.3%、72.4%、42.9%,Ⅰ~Ⅲ级化疗反应率分别为83.3%、65.5%、35.7%。携带T/T基因型乳腺癌患者的临床有效率和Ⅰ~Ⅲ级化疗反应率均显著高于携带C/C基因型的患者,而与携带C/T基因型患者相比差异无统计学意义。携带MTHFR A1298C A/A基因型、A/C基因型、C/C基因型的乳腺癌患者化疗的临床有效率分别为70.5%、64.7%、0.0%,Ⅰ~Ⅲ级化疗反应率分别为70.5%、47.1%、0.0%。携带MTHFR A1298C A/A基因型患者的临床有效率和Ⅰ~Ⅲ级化疗反应率与A/C及C/C基因型患者之间差异均无统计学意义。结论 MTHFR C677T基因多态性的作用与乳腺癌新辅助化疗敏感性之间存在着一定的相关性,对预测乳腺癌新辅助化疗的疗效具有良好的临床应用前景。     

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.     

Prevalence of methylenetetrahydrofolate reductase mutations in patients with venous thrombosis.

BACKGROUND: The objectives of this study are to examine the prevalence of combined methylenetetrahydrofolate reductase (MTHFR) 677C-->T and 1298A-->C mutations in patients with venous thrombosis (VT) and healthy volunteers and to determine if these mutations are in Hardy-Weinberg equilibrium. METHODS AND RESULTS: Sixty-five patients with VT and 64 healthy volunteers were assessed for MTHFR 677T and 1298C alleles using polymerase chain reaction and restriction fragment length polymorphism. Observed MTHFR genotype frequencies were compared with expected genotype combinations, and their odds ratios were determined. MTHFR allele frequency did not differ between VT and control groups; however, differences were observed for MTHFR genotype distribution. MTHFR 677T and 1298C alleles occurred in cis in our population, and therefore mutation crossover has occurred. There was deviation from the Hardy-Weinberg equilibrium for combined MTHFR genotypes, although this may at least partly be attributable to linkage disequilibrium. MTHFR 677CT/1298CC and 677TT/1298CC genotypes (P<.05) were not observed in either group. CONCLUSIONS: The absence of MTHFR 677CT/1298CC and 677TT/1298CC genotypes in both groups suggests that certain MTHFR genotypes may carry a selective advantage. Our discovery of a substantial number of MTHFR mutations in cis configuration suggests that any MTHFR allele linkage disequilibrium present is incomplete.     

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.     

Association between 5,10-methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and conotruncal heart defects.

Reports related some polymorphisms of the 5,10-methylenetetrahydrofolate reductase (MTHFR) to folate-dependent neural tube defects. In view of the common origin of the cells involved both in neural tube closure and heart septation, we analyzed the MTHFR C677T and A1298C polymorphisms in mothers of children with conotruncal heart defect (CD) and in their offspring to evaluate the association between the MTHFR genotype and the risk of CD. We genotyped 103 Italian mothers with CD offspring, 200 control mothers, 103 affected children and their fathers by restriction fragment length polymorphism analysis. No increased risk was observed for the prevalence of the 677TT genotype by itself in affected children and in their mothers. The combined maternal 677TT/1298AA and 677CC/1298CC genotypes have odds ratio of 1.73 and 1.85, respectively. The prevalence of 1298CC genotype in the affected children gives odds ratio of 1.90, that becomes 2.31 for the 677CC/1298CC genotype. However, none of the odds ratios was statistically significant. We observed a higher frequency of the 677T allele in Italy than in other European countries. No association has been demonstrated between the 677TT MTHFR genotype and CD.     

育龄女性MTHFR、MTRR基因多态性分布以及与血清叶酸和同型半胱氨酸水平的相关性研究

目的探讨叶酸代谢关键酶基因5,10-亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C和甲硫氨酸合成酶还原酶(MTRR)A66G多态性在育龄女性中的分布特征,并分析不同遗传特征对外周血叶酸和同型半胱氨酸(Hcy)水平的影响。方法选取2018年3月至2020年1月在上海计生所医院妇科就诊的汉族育龄女性2 651例,根据知情同意原则,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方法检测MTHFR C677T、A1298C和MTRR A66G基因多态性,采用化学发光法检测外周血叶酸水平,循环酶法检测血清Hcy水平。结果 (1)MTHFR C677TCC、CT、TT的基因型频率分别为33.2%、47.9%、18.9%,C、T等位基因频率分别为57.1%、42.9%;MTHFR A1298C AA、AC、CC的基因型频率分别为66.6%、30.5%、2.9%,A、C等位基因频率分别为81.8%、18.2%;MTRR A66G AA、AG、GG的基因型频率分别为56.4%、36.9%、6.8%,A、G等位基因频率分别为74.8%、25.2%。(2)MTHFR C677T和A1298C两位点连锁有7种组合,频率最高的是CT/AA(31.9%),没有CT/CC和TT/CC组合。两位点间存在完全连锁不平衡(D′=0.984,R2=0.161)。(3)MTHFR C677T不同基因型的叶酸和Hcy水平差异有统计学意义(P<0.05)。TT基因型的叶酸水平低于CC基因型,TT基因型的Hcy水平高于CC基因型。经单因素Logistic回归分析发现,MTHFR C677T TT基因型发生高Hcy血症的危险性是CC基因型的9.97倍(95%CI:3.81~26.05)。MTHFR A1298C和MTRR A66G不同基因型与血清叶酸及Hcy水平差异无统计学意义(P>0.05)。(4)经单因素回归分析,Hcy水平与叶酸水平呈负相关(R2=0.061,P<0.05),叶酸水平可解释Hcy水平个体差异的6.1%。结论获取了上海市汉族育龄女性MTHFR和MTRR基因多态性的群体遗传学特征,血清Hcy水平与MTHFR C677T基因多态性以及血清叶酸水平有关。筛查MTHFR和MTRR基因多态性并监测Hcy水平对围生期保健有重要的指导意义。