MTHFR A1298C基因多态性与直肠癌的初步探讨

目的探讨代谢叶酸的亚甲基四氢叶酸还原酶(MTHFR A1298C)基因单核苷酸多态性与直肠癌的关系.方法以聚合酶链反应和限制性片段长度多态方法,对56例直肠癌和143例正常对照组MTHFR A1298C基因型作比较.结果在正常对照中,MTHFR A1298C CC、CT、TT基因型频率分别为68.5%、24.5%和7.0%,而在直肠癌病人中分别为67.9%、23.2%和8.9%,两者无差异.结论MTHFR A1298C单核苷酸多态可能与直肠癌的遗传易感性无关.     

MTHFR A1298C基因多态性与直肠癌的初步探讨

目的探讨代谢叶酸的亚甲基四氢叶酸还原酶(MTHFR A1298C)基因单核苷酸多态性与直肠癌的关系.方法以聚合酶链反应和限制性片段长度多态方法,对56例直肠癌和143例正常对照组MTHFR A1298C基因型作比较.结果在正常对照中, MTHFR A1298C CC、CT、TT基因型频率分别为68.5%、24.5%和7.0%,而在直肠癌病人中分别为67.9%、23.2%和8.9%,两者无差异.结论 MTHFR A1298C单核苷酸多态可能与直肠癌的遗传易感性无关.     

MTHFR基因C677T多态性与冠心病患者血浆同型半胱氨酸和叶酸水平相关

目的研究宁夏地区汉族人群5,10-亚甲基四氢叶酸还原酶基因(MTHFR)C677T多态性、同型半胱氨酸水平(Hcy)及叶酸水平与冠心病(CHD)的相关性。方法用病例-对照研究方法、应用限制性片段长度多态性扩增技术(PCR-RFLP)分析宁夏地区汉族202例冠心病患者及199例正常人群MTHFRC677T基因型频率及基因频率的分布特点。荧光偏振免疫分析法测定血浆Hcy水平,化学发光免疫分析法测定血清叶酸、VitB12浓度。结果 (1)病例组与对照组MTHFRC677T基因型频率分别为CC型23.3%vs20.7%、CT型52.3%vs54.5%和TT型24.4%vs24.8%,两组间基因型及等位基因频率分布无差异。(2)冠心病患者组中MTHFR基因C677TCC基因型患者血浆Hcy浓度(10.84μmol/L)较T基因携带者(12.24μmol/L)低(P<0.01)。CC基因型患者血浆叶酸浓度(5.38μg/L)较T基因携带者(3.72μg/L)高(P<0.05)。结论 MTHFRC677T的3种基因型频率在宁夏汉族冠心病患者和正常人群中的分布无统计学意义。MTHFR基因C677T多态性与冠心病的危险因素Hc...     

徐州地区MTHFR基因C677T多态性与男性不育的相关性研究

目的探讨徐州地区亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性与男性不育的相关性。方法选取确诊的男性不育症患者715例做为本研究实验组,以有正常生育史且精液检测正常的男性572例做为对照组,根据MTHFR C677T基因多态性的结果,分析此多态性位点在两组中分布的差异。结果 MTHFRC677T位点等位基因T频率在不育症中显著高于健康对照组(P0.05)。MTHFRC677T位点CC基因型频率在不育症组中显著低于健康对照组,TT基因型频率在不育症中显著高于健康对照组(P0.05),CT基因型的频率在两组之间的差异无统计学意义(P0.05)。结论 MTHFR基因C677T单核苷酸多态性在徐州地区男性不育患者和健康人中,分布有显著差异,MTHFR基因C677T多态性与徐州地区男性不育有相关性。     

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。     

清远地区MTHFR基因多态性与原因不明复发性流产的相关性研究

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因C677T位点单核苷酸多态性与原因不明复发性流产(URSA)的发生之间的相关性。方法采用前瞻性病例对照研究,选取清远地区71例URSA患者与76例两次正常生育妇女作为对照,采用实时定量PCR分析技术检测MTHFR基因C677T位点单核苷酸多态性情况,并用χ~2检验分析URSA组与对照之间的C677T位点基因型的差异。结果 URSA组MTHFR(C677T)基因纯合突变型TT及等位基因T的频率均高于正常对照组。结论清远地区不明原因复发性流产的发生与MTHFR基因C677T位点纯合突变型TT存在相关性。     

MTHFRC677T基因多态性与RSA发生的关系

目的探讨MTHFRC677T基因多态性与RSA发生之间的关系。方法纳入RSA患者30例为观察组,同时纳入30例正常分娩的孕妇作为对照,以访谈的方式收集患者的一般资料及信息,采集并保存研究对象的血清标本进行MTHFRC677T基因多态性的检测,运用统计学方法进行相关性分析。结果经过检测发现,MTHFRC677T基因经酶切后有三种基因型,分别为CC纯合未突变基因型、CT杂合子基因型、TT纯合突变基因型。RSA组与对照组MTHFRC677T基因型的频率分布差异均具有统计学意义(P0.05)。MTHFRC677T基因多态性中TT基因型发生RSA的危险度相关(OR=20.97,95%CI:1.209-3.638)。结论MTHFRC677T基因多态性与RSA的发生具有关联性,其中TT基因能够大幅提高RSA发生几率。     

叶酸代谢酶MTHFR基因多态性与不明原因复发性流产的相关性研究

目的初步探讨亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C位点单核苷酸多态性与苏南地区不明原因的复发性流产(URSA)发生的相关性。方法采用病例对照研究的方法,对170例苏南地区不明原因复发性流产者(病例组)和170例正常妇女(对照组),利用PCR荧光探针技术检测MTHFR基因C677T、A1298C位点的单核苷酸多态性。结果病例组MTHFRC677T位点的TT基因型的发生频率显著高于对照组,T等位基因频率同样高于对照组,差异均有统计学意义(P0.05),而病例组MTHFR基因A1298C位点的CC基因型频率和C等位基因频率与对照组的相比,差异均无统计学意义(P0.05)。结论苏南地区MTHFR基因C677T位点多态性与育龄妇女发生不明原因复发性流产有一定的相关性。     

河南汉族人群亚甲基四氢叶酸还原酶基因多态性

目的了解河南汉族人亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)基因的分布特点。方法应用PCR-RFLP技术对500例健康个体的MTHFRC677T基因进行基因多态性分析,并结合文献进行了不同种族间的分析比较。结果河南汉族人群中MTHFRC677T突变纯合子TT型频率为32.8%,突变杂合子CT型频率为34.6%,野生型CC型频率为32.6%,T等位基因频率51.1%,与其他种族相比较,MTHFRC677T基因型在中国河南汉族正常人群中的分布与其他人群中的分布差异显著。结论MTHFRC677T基因多态性在不同种族间分布存在着明显的差异。     

MTHFRC677T基因多态性与出生缺陷的相关性研究

目的探讨亚甲基四氢叶酸还原酶(MTHFR)C677T位点单核苷酸多态性与出生缺陷的相关性。方法回顾性的分析97例有不良孕产史(病例组)和210例无不良孕产史育龄妇女(对照组)MTHFR C677T的基因型,用统计学方法分析该位点单核苷酸多态性与胎儿出生缺陷的关系。结果病例组MTHFR C677T位点TT基因型频率为28.9%,高于对照组(18.5%),T等位基因频率为53.6%,同样高于对照组(42.8%),两组人群中该位点基因型、等位基因分布情况差异具有统计学意义(P0.05)。病例组中B1组、B3组MTHFR C677T位点TT基因型频率及T等位基因频率均高于对照组,且差异具有统计学意义(P0.05);而病例组中B2组、B4组MTHFR C677T位点TT基因型频率及T等位基因频率与对照组比较,差异无统计学意义(P0.05)。结论 MTHFRC677T位点单核苷酸多态性与神经管缺陷及染色体疾病的发生具有一定相关性,与先天性心脏病及唇腭裂的发生无明显相关性。     

谷胱甘肽S转移酶M1基因多态性与直肠癌的相关性的初步探讨

目的探讨谷胱甘肽S转移酶M1基因多态性与直肠癌的关系。方法以聚合酶链反应方法,分析了56个直肠癌病人和性别、年龄配对的143个正常对照的谷胱甘肽S转移酶M1基因型及其对直肠癌的相关性。结果GSTM1基因缺失频率在病例组和对照组之间无有显著差异。结论GSTM1基因缺失可能不是结直肠癌发生的易感基因型。     

MTHFR C677T has differential influence on risk of MSI and MSS colorectal cancer

The majority of colorectal cancer (CRC) exhibiting the micosatellite instability (MSI) phenotype is due to hypermethylation of the hMLH1 gene promoter. We aimed to test the hypothesis that polymorphisms in genes coding for enzymes involved in folate metabolism play a role in altered promoter-specific hypermethylation and thus predispose to MSI CRC. Analysis of MSI was performed in 1685 CRCs, and polymorphism genotypes were determined in germline DNA for all cases and 2692 cancer-free controls. MSI was observed in 171 cancers (10.1%). Compared to homozygous wild-type individuals, those with MTHFR 677TT genotype were more likely to have MSI than microsatellite stable (MSS) CRC [odds ratio (OR) 1.90; 95% confidence interval (CI): 1.09-3.31]. When MTHFR C677T genotype frequencies in MSS CRC cases were compared to controls, individuals with homozygous variant genotype were at 19% reduced risk of cancer compared to wild type (OR = 0.81; 95% CI: 0.65-1.02). Conversely, when MSI CRC cases were compared to controls, individuals with one or two MTHFR 677T alleles were at 42% increased cancer risk (OR = 1.42; 95% CI: 1.02-1.96). Our observations indicate that MTHFR 677TT homozygous individuals are more likely to develop MSI CRC than those with wild-type genotype, and this common polymorphism has differential influences on MSI and MSS CRC risk. Stratification by MSI status should aid future studies investigating the complex relationships between genotype, environmental factors and CRC risk.     

Polymorphisms of methylenetetrahydrofolate reductase and methionine synthase genes and bladder cancer risk: a case–control study with meta-analysis

Folate deficiency due to the methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS) variants leads to carcinogenesis by affecting DNA synthesis, repair, and methylation. We hypothesized that the MTHFR C677T, A1298C, and MS A2756G polymorphisms are associated with risk of bladder cancer. In a case-control study of 239 bladder cancer cases and 250 cancer-free controls, we found that the MTHFR 677TT genotype was statistically significantly associated with an increased risk of bladder cancer compared with the 677CC genotype (OR = 2.06, 95% CI = 1.16-3.64). Furthermore, the TA haplotype was associated with a significantly increased bladder cancer risk (OR = 1.38, 95% CI = 1.05-1.81) than was the most common haplotype, CA (e.g., CA denotes MTHFR 677C -1298A). We also found that the combined genotypes with 4-6 variant (risk) alleles (i.e., MTHFR 677T, 1298A, and MS 2756G alleles) were associated with an increased risk of bladder cancer (OR = 1.62, 95% CI = 1.03-2.53) compared with those with 0-3 variants, and this increased risk was more pronounced among subgroup of older people (OR = 1.71, 95% CI = 1.03-2.83). A meta-analysis of seven studies did not show a significant risk of bladder cancer in the MTHFR polymorphisms. The MTHFR polymorphisms and their haplotypes appear to jointly contribute to risk of bladder cancer.     

糖尿病视网膜病MTHFR基因多态性及其与血浆同型半胱氨酸水平的关系

目的：研究亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase,MTHFR）基因多态性及血浆同型半胱氨酸水平与2型糖尿病视网膜病的关系。方法：应用聚合酶链反应－限制性内切酶片段长度多态性技术检测208例2型糖尿病患者（其中110例伴视网膜病）及57名正常对照的MTHFR C677T基因型，采用高效液相色谱法测定血浆同型半胱氨酸水平。结果：糖尿病视网膜病组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28．18％、41．82％、49．09％）均明显高于糖尿病不伴视网膜病组（分别为18．37％、29．59％、33．16％）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显著性（P＜0．01），而MTHFR基因多态性在糖尿病不伴视网膜病组与正常对照组之间差异无显著性（P＞0．05），T等位基因与糖尿病视网膜病的发生密切相关（OR＝1．94，95％CI；1．31－2．88）。糖尿病视网膜病组、糖尿病不伴视网膜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升高可能是糖尿病视网膜病发病的重要遗传因素。     

eNOS基因和MTHFR基因多态性与子痫前期发病关系的研究

目的探讨内皮型一氧化氮合酶(eNOS)基因第7外显子G894T突变和N5,N10-亚甲基四氢叶酸还原酶(MTHFR)基因C677T突变与子痫前期的关系。方法应用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术,对53例子痫前期患者(子痫前期组)和49例正常妊娠妇女(对照组)的eNOS基因G894T突变和MTHFR基因C677T突变进行检测。结果子痫前期组eNOS基因Glu/Glu、Glu/Asp、Asp/Asp基因型频率分别为71.7%、28.3%、0.0%;MTH-FR基因CC、CT、TT基因型频率分别为22.7%、39.6%、37.7%。对照组eNOS基因Glu/Glu、Glu/Asp、Asp/Asp基因型频率分别为83.7%、16.3%、0.0%;MTHFR基因CC、CT、TT基因型频率分别为20.4%、61.2%、18.4%。子痫前期患者TT基因型频率(37.7%)显著高于对照组(18.4%)(P<0.05),而CT基因型频率子痫前期组(39.6%)显著低于对照组(61.2%)(P<0.05),而eNOS基因型和等位基因频率两组比较差异均无显著性(P>0.05)。携带TT基因型个体发生子痫前期的风险增加2.69。结论eNOS基因G894T突变与子痫前期发病无关;MTHFR基因TT基因型能增加子痫前期的患病风险;eNOS基因和MTHFR基因在子痫前期发病中无协同作用。     

基质金属蛋白酶-2和-9基因多态性与结直肠癌的相关性

目的探讨基质金属蛋白酶（matrix metalloproteinase，MMP）-2和-9基因启动子区多态性与结直肠癌的关系。方法应用变性高效液相色谱法和限制性片段长度多态性分析方法分别检测126例结直肠癌患者和126名正常对照者的MMP-2—1306C/T和MMP-9—1562C／T多态性，分析其基因型与结直肠癌发病风险及临床病理参数的相关性。结果MMP-2—1306C／C基因型频率在结直肠癌组中显著高于对照组（P〈0．05），与CT＋TT基因型携带者比较，CC基因型携带者患结直肠癌的风险约增加2倍（OR：1．959；95％CI：1．055～3．637）。而且在结直肠癌中，MMP-2—1306C／T多态性与肿瘤的浸润深度之间差异有统计学意义（P〈0．05），CC基因型的肿瘤更容易浸润到外膜。MMP-9—1562C／T多态性的基因型及等位基因频率在结直肠癌组和对照组间的分布差异无统计学意义（P〉0．05）。结论MMP-2—1306C／T多态性可能与中国人群结直肠癌的遗传易感性相关，且CC基因型的肿瘤更易浸润到外膜。     

Methylenetetrahydrofolate reductase 677 C --> T polymorphism, plasma folate, vitamin B(12) concentrations, and risk of preeclampsia among black African women from Zimbabwe

We conducted a case control study at Harare Maternity Hospital, Zimbabwe. We genotyped a total of 171 cases with preeclampsia or eclampsia and 185 normotensive control subjects for the methylenetetrahydrofolate reductase (MTHFR) 677 C --> T genotype. The wild-type allele frequency among cases and controls was 91.2 and 91.3%, respectively. Only one subject (0.3%) was homozygous for the 677 C --> T MTHFR genotype and this subject had preeclampsia. After adjustment for confounding factors, there was statistically no significant association between maternal MTHFR genotype and risk of preeclampsia (adjusted odds ratio = 1.0; 95% CI, 0.5-1.9). In addition, plasma homocyst(e)ine, vitamin B(12), and folate concentrations were not statistically different between normotensive control subjects with wild-type genotype as compared with normotensive subjects who were heterozygous for the mutant allele. Conversely, there was a strong graded association between maternal plasma folate concentration and risk of preeclampsia. Women with plasma folate concentrations less than 5.7 nmol/L experienced a 10. 4-fold increase in risk of preeclampsia. There was no clear pattern of preeclampsia risk and vitamin B(12) concentrations.     

Smoking, folate and methylenetetrahydrofolate reductase status as interactive determinants of adenomatous and hyperplastic polyps of colorectum.

Most studies demonstrate increased risk of colorectal cancer (CRC) and adenomas in folate-deficient subjects or that high folate intake may afford some protection. Smoking increases such risk in some but not all studies. We investigated whether smoking, folate status and methylenetetrahydrofolate reductase (MTHFR) genotype predict the risk of adenomatous and hyperplastic polyps of colorectum. By colonoscopy, the type, number, size and extent of dysplasia of colorectal polyps were assessed in 443 subjects aged 63-72 years. We also determined RBC folate and the C667T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene. Smoking, folate status and the C677T MTHFR polymorphism were strong, interactive determinants of high-risk adenomas (HRAs, defined as adenomas > or =10 mm in diameter, adenomas with villous components or with severe dysplasia). The risk was particularly high in smokers with low folate and the CT/TT genotype (risk category T) and in smokers with high folate and the CC genotype (risk category C). With non-smokers with low folate and the CC genotype as reference, the odds ratios (OR, 95% CI) were 8.7 (2.5-29.7) in category T and 9.9 (2.6-38.4) in category C. Notably, this risk pattern was also observed for hyperplastic polyps. In conclusion, in smokers, high folate status may confer increased or decreased risk for HRAs, depending on the MTHFR genotype. These data demonstrate the strong gene-nutrition interaction involving the C677T MTHFR polymorphism.     

Influence of combined methionine synthase (MTR 2756A > G) and methylenetetrahydrofolate reductase (MTHFR 677C > T) polymorphisms to plasma homocysteine levels in Korean patients with ischemic stroke

PURPOSE: Methionine synthase (MTR) and 5,10-methylenetetrahydrofolate reductase (MTHFR) are the main regulatory enzymes for homocysteine metabolism. The present case- control study was conducted to determine whether there is an association between the MTR 2756A > G or MTHFR 677C > T polymorphism and plasma homocysteine concentration in Korean subjects with ischemic stroke. MATERIALS AND METHODS: DNA samples of 237 patients who had an ischemic stroke and 223 age and sex-matched controls were studied. MTR 2756A > G and MTHFR 677C > T genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: Frequencies of mutant alleles for MTR and MTHFR polymorphisms were not significantly different between the controls and cases. The patient group, however, had significantly higher homocysteine concentrations of the MTR 2756AA and MTHFR 677TT genotypes than the control group (p=0.04 for MTR, p=0.01 for MTHFR). The combined MTR 2756AA and MTHFR 677TT genotype (p= 0.04) and the homocysteine concentrations of the patient group were also higher than those of the controls. In addition, the genotype distribution was significant in the MTHFR 677TT genotype (p=0.008) and combined MTR 2756AA and MTHFR 677TT genotype (p=0.03), which divided the groups into the top 20% and bottom 20% based on their homocysteine levels. CONCLUSION: The results of the present study demonstrate that the MTR 2756A > G and MTHFR 677C > T polymorphisms interact with elevated total homocysteine (tHcy) levels, leading to an increased risk of ischemic stroke.     

C677T methylenetetrahydrofolate reductase gene polymorphisms in bipolar disorder: an association study in the Chinese population and a meta-analysis of genetic association studies

The methylenetetrahydrofolate reductase (MTHFR) gene variant C677T is suspected to be a risk factor for psychiatric disorders, but it remains uncertain whether the MTHFR C677T variant is associated with bipolar disorders. To investigate possible association, unrelated controls (n=461) with no history of psychiatric disorders and patients (n=501) diagnosed with bipolar disorder were recruited in this study. In addition, six association studies published up to June 2008 were included in a subsequent meta-analysis. No significant difference was found in either allele frequencies or genotype distribution between patients and controls in our association study in the Chinese population. Similarly, the meta-analysis result showed no significant association between MTHFR C677T and bipolar disorder. In conclusion, the MTHFR C677T variant is unlikely to play a major role in the susceptibility to bipolar disorder, although MTHFR plays an important role in the one-carbon metabolism and DNA methylation.