Combined effect of NAT2, MTR and MTHFR genotypes and tobacco on bladder cancer susceptibility in Tunisian population

Background: Cigarette smoking is the predominant risk factor for bladder cancer. This risk may be modified by polymorphisms in carcinogens metabolism genes; including those involving the N-acetyl transferase 2 (NAT2) which have been correlated with decreased enzyme activities. Moreover, folate insufficiency can induces carcinogenesis by decreasing DNA methylation. Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR) are enzymes that play central roles in the folate metabolic pathway. The MTHFR 677*T and MTR 2756*G variants are associated with decreased enzyme activity. Methods: In this work, we have conducted a case-control study in order to assess the combined effect of tobacco, slow NAT2 variants, MTHFR 677*T and MTR 2756*G alleles on bladder cancer development in North Tunisia. Results: For MTR A2756G, alleles and genotypic distributions differed significantly between cases and controls (p = 0.00009, OR = 3.27, CI 95% 1.76–6.12). While, in non-smokers patients the slow NAT2 did not appear to influence bladder cancer susceptibility; our results suggested that it might act with an additive contribution with tobacco as well as with that determined by MTR 2756 AG or 2756 GG genotypes (p = 0.0008). Identical cumulative effect was detected for slow NAT2 and MTHFR 677*T variant (p = 0.0003; OR = 36.6; CI 95% 3.4–935.3). Conclusion: The strongest result obtained by this study was for an additive effect between smoking status, slow NAT2 variants, MTR 2756*G and MTHFR 677*T alleles, in affecting bladder cancer risk.     

四氢叶酸还原酶基因多态性与子痫前期相关性的研究

目的:探讨四氢叶酸还原酶(MTHFR)基因C677T多态性在子痫前期发病机制中的作用.方法:选择妊娠期高血压疾病组孕妇80例,其中妊娠期高血压组19例、轻度子痫前期组25例,重度子痫前期组36例;并随机选取同期的正常晚期妊娠者60例为正常对照组.分别用过柱法提取基因型DNA,并行聚合酶链反应物-直接测序法检测和分析MTHFR基因中C677T的分型.结果:妊娠期高血压疾病组中C677/T677基因型与正常对照组比较,差异有统计学意义(P<0.05),妊娠期高血压疾病组T677等位基因频率(48.8%)高于正常对照组(32.5%),两组比较,差异有统计学意义(P<0.05);正常对照组与轻度子痫前期组及重度子痫前期组的C677/T677基因型和T677等位基因频率比较,差异有统计学意义(P<0.05),与妊娠期高血压组比较差异无统计学意义(P>0.05).结论:妊娠期高血压疾病患者的MTHFR基因C677T多态性可能是子痫前期发生的诱因之一;T677等位基因可能是子痫前期的易感基因.     

胆固醇酯转运蛋白TaqIB和亚甲基四氢叶酸还原酶MTHFR C667T基因多态性与视网膜中央静脉阻塞的关系

目的:探讨胆固醇酯转运蛋白(CETP)基因TaqIB和N5 N10-亚甲基四氢叶酸还原酶(MTHFR)基因MTHFR C667T多态性与视网膜中央静脉阻塞的关系。方法:采用多聚酶链反应-限制性内切酶片段长度多态性(PCR-RFLP)技术检测60例经视网膜荧光造影诊断的视网膜中央静脉阻塞患者和120例对照者的CETP和MTHFR基因多态性。结果:视网膜中央静脉阻塞组B1/B1基因型频率(33.3%)明显高于对照组(12.5%)(P<0.05),B1等位基因频率(51.8%)也明显高于对照组(31.8%)(P<0.05);视网膜中央静脉阻塞组T/T基因频率(30.0%)明显高于对照组(15.0%)(P<0.05),T等位基因频率(50.6%)也明显高于对照组(34.6%)(P<0.05);TaqIB基因的B1等位基因与MTHFR基因的T等位基因之间有协同作用(rs=0.954)。结论:CETP与MTHFR基因和视网膜中央静脉阻塞的发病有关,CETP和MTHFR基因之间有协同作用。     

MTHFR基因C677T多态性与缺血性脑卒中关系的研究

目的：了解亚甲基四氢叶酸还原酶（MTHFR）基因C677T多态性与中国人群缺血性脑卒中发病之间的关系。方法：利用PCR和分子杂交技术对北京地区294例缺血性脑卒中患者及280例无脑血管病对照者进行MTHFR基因C667T多态性检测和分析。结果：C677T多态性位点在两组人群中的分布均符合Hardy-Weinberg遗传平衡定律,但该位点基因型频率及等位基因频率在两组中分布无差异。结论：MTHFR基因C677T多态性不是中国人群缺血性脑卒中发病的遗传学危险因素。     

上海地区孕妇MTHFR C677T基因多态性与血浆同型半胱氨酸水平的关联性分析

目的 了解上海市孕妇MTHFR基因型的分布情况,分析MTHFR C677T基因多态性与高同型半胱氨酸血症的关联性,为高危孕妇的遗传筛查及围产期叶酸摄入的个性化提供依据。方法 选取上海市五所社区医院2015年1月~2015年6月门诊建卡孕妇1000例,随访了解基本信息、孕期危险因素暴露及叶酸摄入情况,以基因芯片法检测MTHFR基因型,循环酶法检测血浆同型半胱氨酸。结果 上海地区孕妇MTHFR C677T基因CC型、CT型、TT型的检出频率分别为33.0%、49.2%、17.8%,等位基因C、T的频率为57.6%、42.4%,样本人群处于H-W平衡状态。血浆同型半胱氨酸浓度为11.22（9.15,13.52）μmol/L,其中911例（91.6%）正常,84例（8.4%）属轻度高同型半胱氨酸血症。经多因素logistic回归分析,CT型与TT型发生高同型半胱氨酸血症的OR值分别为2.18（95%CI:1.11~4.25）和6.26（95%CI:3.13~12.53）。结论 MTHFR基因C677T多态性与孕妇血浆同型半胱氨酸水平存在关联,携带等位基因T者可视为高危孕妇,孕期叶酸补充可适量增加。     

MTHFR基因多态性及单体型与大剂量甲氨蝶呤化疗毒性反应的相关性研究

目的 探讨亚甲基四氢叶酸还原酶(MTHFR)基因多态性及其单体型与急性淋巴细胞白血病患儿大剂量甲氨蝶呤(HDMTX)化疗毒性反应的相关性.方法 采用聚合酶链反应-限制性片段长度多态性方法对HDMTX化疗后出现毒性反应(n=61)和无毒性反应的患儿(n=36)MTHFR基因677C＞T、1298A＞C单核苷酸多态性(SNP)进行基因分型和单体型分析,并应用病例对照分析方法进行相关性研究.结果 MTHFR 677C＞T不同基因型在两组患儿中的分布频率差异无统计学意义(x2=4.609,P=0.100).1298A＞C不同基因型在两组患儿中的分布频率差异有统计学意义(x2=10.192,P=0.006),1298C等位基因(AC+CC基因型)携带者出现毒性反应的风险降低(OR=0.245,95％CI:0.099～ 0.607,P=0.002).677C＞T与1298A＞C存在着强连锁不平衡(D'=0.895),CC单体型携带者出现毒性反应的风险降低(OR=0.338,95％CI:0.155～ 0.738,P=0.005),而TA单体型携带者出现毒性反应的风险增加(OR=1.907,95％CI:1.045～3.482,P=0.035).结论 MTHFR 1298C等位基因及CC单体型可能是HDMTX毒性反应的保护因素,TA单体型可能是危险因素.     

实时荧光定量PCR法检测MTHFR C677T基因多态性方法的建立和应用

目的:建立一种准确、快速、自动化程度较高的检测亚甲基四氢叶酸还原酶(MTHFR)C677T基因多态性的方法,并观察中国北方健康人群中MTHFR C677T基因频率。方法:应用MGB探针的原理建立MTHFR C677T基因多态的检测方法,与传统PCR-RFLP方法作对照,共检测标本88例,并计算各基因型频率。结果:荧光定量方法可以快速完成MTHFR C677T基因多态性的检测,检测结果得到传统PCR-RFLP方法的证实。88例北京汉族正常人群MTHFR基因的各种基因型频率为25％、42％和33％。结论:该方法准确、检测效率高,适用于临床实验室及流行病学调查研究。     

亚甲基四氢叶酸还原酶基因多态性与抑郁症的关联研究

目的 探讨亚甲基四氢叶酸还原酶(MTHFR)C677T多态性与抑郁症及症状表型的相关性.方法采用聚合酶链反应-限制性片段长度多态性技术(PCR-RFLP)研究100例抑郁症患者及100例对照组正常人的MTHFR基因的多态性分布;采用汉密尔顿抑郁量表(HAMD)评定症状表型.结果抑郁症患者组TT型、TC型、CC型基因频率分布及T、C等位基因频率分布与对照组比较差异有显著性(χ2=8.72,P<0.05;χ2=8.62,P<0.05).按性别分层后,男性抑郁症组TT基因型的频率(25.0%)明显高于对照组(6.3%),而CC基因型的频率(25.0%)显著低于对照组(55.3%)(P<0.05);患者组中症状表型在3种基因型间分布差异无显著性(P＞0.05).结论 MTHF C677T基因的多态性与抑郁症发病相关,其相关性受性别影响,而与症状表型间无明显的关联.     

Folic acid for the prevention of congenital anomalies

Paediatricians need to be aware of the broad implications that sufficient maternal folic acid intake has on the wellbeing of the embryo and fetus. There is now strong evidence that adequate periconceptional maternal folic acid supplementation during critical periods of organ formation is associated with reduction in both the occurrence and recurrence of neural tube defects, congenital heart defects (particularly conotruncal heart defects), obstructive urinary tract anomalies, limb deficiencies, orofacial clefts and congenital hypertrophic pyloric stenosis. Inadequate maternal folic acid intake is associated with preterm deliveries, intra-uterine growth retardation, placental abruption and infarction, while maternal folic acid supplementation is associated with a reduction in preterm deliveries and intra-uterine growth retardation. Recently adequate folic acid intake in adults has been associated with a reduction in adult cardiovascular disease and some cancers. A common mutation in the 5,10 methylenetetrahydrofolate reductase gene has been identified which produces a thermolabile variant of 5,10 methylenetetrahydrofolate reductase with reduced enzyme activity. The common mutation is a risk factor both for neural tube defects and adult cardiovascular diseases. Folic acid acts to increase the activity of the variant methylenetetrahydrofolate reductase thereby reducing plasma homocysteine levels. However the polymorphism does not explain all of the protective effects of folic acid. Conclusion Primary prevention of birth defects by adequate periconceptional folic acid supplementation is a major public health opportunity and has wide implications in reducing both mortality and morbidity due to birth defects and several adult diseases. It follows that there would also be a curbing of health care costs related to those disorders. Received: 2 October 1997 / Accepted in revised form: 8 December 1997