甲硫氨酸合成酶还原酶基因多态性与心血管疾病的研究进展

高同型半胱氨酸血症(h Hcy)的医学定义为高水平的血浆Hcy(Hcy≥10.0μmol/L)。大量研究证明,其和疾病的风险增加相关(包括血管和神经退行性疾病、妊娠并发症、男性不育、先天性疾病、糖尿病、肾功能疾病、骨质疏松症、神经精神疾病和癌症)。血浆Hcy水平是由环境和遗传因素共同决定的。环境因素包括叶酸、维生素B6、B12等;遗传因素主要有编码Hcy代谢相关基因多态性酶,如甲硫氨酸合成酶及甲硫氨酸合成酶还原酶等相关基因多态性。     

云南省汉族女性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分布研究

目的 分析云南省汉族女性亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C及甲硫氨酸合成酶还原酶(MTRR)A66G基因多态性的分布特征.方法 采用横断面调查研究方法,以云南省297例汉族女性为对象,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,并与已报道的其他地区的数据进行比较.结果 云南省汉族女性的MTHFR 677TT纯合突变基因型频率为14.1％,低于山东省和河南省,高于海南省,差异有统计学意义(均P＜0.01);MTHFR 1298CC纯合突变基因型频率为2.7％,低于四川省和海南省,差异有统计学意义(均P＜0.05);MTRR 66GG纯合突变基因型频率为6.4％,低于海南省,差异有统计学意义(P＜0.05).结论 云南省汉族女性有不同于其他地区的MTHFR和MTRR基因多态性分布特征.     

宁夏回族甲硫氨酸合酶基因A2756G多态性研究

目的 了解宁夏回族甲硫氨酸合酶(MS)基因A2756G的多态性的分布特点.方法 通过聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)技术分析200例宁夏回族MS基因A2756G基因型.结果 宁夏同族人群中AA、AG、GG基因型频率分别为0.8100、0.1750、0.0150,G突变基因频率为0.1025.与白种人群中的分布差异有统计学意义(P＜0.05).结论 甲硫氨酸合酶基因A2756G基因型在不同种族间的分布存在明显的差异.     

缺血性脑血管病患者蛋氨酸合成酶基因A2756G多态性检测

目的:检测缺血性脑血管病患者蛋氨酸合成酶(MS)基因A2756G多态性.方法:运用PCR-限制性片段长度多态性(RFLP)技术对512例缺血性脑血管病患者及500例健康对照者进行MS基因多态性检测.结果:缺血性脑血管病患者组MS A2756G A/A、A/G、G/G基因型频率分别为88.9%、10.7%和0.4%,A和G等位基因频率分别为94.2%和5.8%.对照组A/A、A/G、G/G基因型频率分别为84.6%、15.0%和0.4%,A和G等位基因频率分别为92.1%和7.9%.2组基因型及等位基因频率差异均无统计学意义(P＞0.05).结论:MS基因A2756G多态可能不足以构成河南汉族人群缺血性脑血管病发病中的一个独立的遗传危险因子.     

同型半胱氨酸和蛋氨酸合成酶还原酶A66G基因多态性与 Alzheimer病的关系

目的探讨同型半胱氨酸(Hcy)和蛋氨酸合成酶还原酶(MSR)A66G基因多态性与Alzheimer病的关系.方法运用多聚酶链反应限制性内切酶片段长度多态性技术(PCR-RFLP)和荧光偏振法(FPIA)检测66例Alzheimer病及143例正常人MSR A66G基因多态性和血浆总Hcy水平.结果Alzheimer病组MSR A66G基因型频率(%)分别为39.39、59.09和1.52,对照组分别为37.76、59.44和2.80,MSR A66G各种基因型频率在患者组与正常对照组之间的差异无显著性(P＞0 05).Alzheimer病病例组与对照组血浆Hcy分别为(14.72±6.2)μmol/L和(10.9±2.4)μmol/L,两者差异有显著差异(P＜0.05).Alzheimer病患者血浆总Hcy水平显著高于正常组.结论MSRA66G多态性与Alzheimer病无明显相关,高同型半胱氨酸血症与Alzheimer病发生有一定关系.     

冠心病和深静脉血栓患者蛋氨酸合成酶基因A2756G多态性检测

目的:检测冠心病(CHD)及深静脉血栓(DVT)形成患者蛋氨酸合成酶(MS)基因A2756G的多态性.方法:运用PCR-限制性片段长度多态性(RFLP)对103例DVT患者、208例CHD患者和250例健康对照进行MS基因A2756G多态性分析.结果:DVT组A/G G/G型频率为10.7%,低于对照组的19.6%(x2=4.114,P＜0.05),但2组等位基因频率差异无统计学意义(P＞0.05).结论:A/G G/G型可能对静脉血栓的形成具有保护性作用,该型的分布存在种族和地域差异.MS基因A2756G多态可能不是河南汉族人群CHD发生的遗传危险因素.     

亚甲基四氢叶酸还原酶基因多态性与先天神经管缺陷的相关性研究

目的研究亚甲基四氢叶酸还原酶基因多态性与红细胞叶酸浓度的关系。方法采用PCR法对育龄女性5128例进行亚甲基四氢叶酸还原酶基因多态性分析,并分别给予早孕者400μg、800μg叶酸口服补充1个月,比较干预前后红细胞叶酸浓度。结果纯合CC型早孕受试者口服400μg叶酸1个月后平均红细胞叶酸浓度与口服800μg叶酸者相比较,差异无统计学意义（P〉0．05）;突变基因型CT型、TT型早孕受试者差异则均具有统计学意义（P〈0．05）。结论对育龄妇女开展MTHFR基因多态性检测有利于指导补充叶酸剂量,值得临床进一步研究。     

叶酸代谢相关酶基因多态性与不良孕产发生易感性的关系

目的：分析妇女亚甲基四氢叶酸还原酶（MTHFR）C677T、A1298C 及甲硫氨酸合成酶还原酶（MTRR）A66G 基因多态性与不良孕产史的关联性。方法采用病例对照研究的方法,以549例正常妇女（对照组）及300例有不良孕产史（观察组）妇女为对象,采集口腔黏膜上皮细胞,提取基因组 DNA,采用基因测序技术,进行 MTHFR 及 MTRR 基因多态性检测。结果MTHFR 677TT 基因型在观察组的分布频率（10．00％）较对照组（3．46％）明显升高（χ2＝15．25,P ＜0．01）;MTHFR-1298CC基因型在观察组的分布频率（11．00％）较对照组（4．01％）明显升高（χ2＝15．66,P ＜0．01）;MTRR 66GG 基因型频率分布两组比较差异无统计学意义（χ2＝ 3．02,P ＝0．082）。两个基因的交互作用分析表明同时携带 MTHFR A1298C 突变位点和 MTRR A66G 突变位点增加了不良孕产发生的可能性（OR＝1．52,P ＝0．011）。结论MTHFR C677T 及 A1298C 与女性不良孕产的发生有一定的相关性。     

MTHFR基因多态与神经管缺陷的关系

目的：探讨中国东北地区正常汉族人群中神经管缺陷（NTD）家庭中的亚甲基四氢叶酸还原酶（MTHFR）基因677C→T多态的分布,以证明其是否为NTD发生的危险因素。方法：采用PCR-RFLP技术研究了29个正常家庭58名父母及28个NTD家庭55名父母中MTHFR677C→T多态情况。结果：①正常组中等位基因频率为V：0.491;NTD组中等位基因频率为V：0.636。②正常组中VV基因型占19.0%,NTD组中VV基因型占30.6%,统计结果χ^2=3.46,P＜0.01,即VV基因型在正常组和NTD组间有一定的显著性差异。结论：MTHFR677C→T多态很可能是NTD的一个危险因素。     

MTHFR基因A1298C多态性与神经管畸形的关系

目的:分析神经管畸形患儿核心家庭MTHFR基因第1298位点的多态性分布,探讨其与神经管畸形发生的关系。方法:应用PCR扩增技术,其扩增产物经限制性核酸内切酶MboⅡ消化后,进行非变性聚丙烯酰胺凝胶电泳,分析MTHFR基因第1298位核苷酸基因型的分布情况。结果:26个核心家庭中(78个成员)未发现突变纯合型。经χ2检验,患儿及其母亲基因型构成与对照组比较,差异均无统计学意义(分别为P>0.30,P>0.90)。患儿父亲杂合突变型低于正常对照(P<0.05)。等位基因频率比较采用u检验,患儿与对照间差异无统计学意义(P>0.50),患儿父母均高于正常对照(P<0.01)。结论:MTHFR基因A1298C多态性与神经管畸形发生无直接关系。     

Interaction between maternal 5,10-methylenetetrahydrofolate reductase C677T and methionine synthase A2756G gene variants to increase the risk of fetal neural tube defects in a Shanxi Han population

Background  The 5,10-methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS) are attractive candidates for screening for risk of neural tube defects (NTDs). The aim of the current study was to investigate maternal MTHFR and MS polymorphisms and the interaction between them and their influence on children with NTDs in the Shanxi Province of northern China.     

Methods  Fifty-one mothers who previously had children with NTDs constituted the case group and 51 age-matched mothers with children that were unaffected by any birth defects constituted the control group. All subjects were genotyped for MTHFR C677T and MS A2756G polymorphisms. SPSS 11.5 software package was used for all analyses.

Results  There was a significant difference for MTHFR genotype distribution for one site (C677T) between the case and control groups. The T allele frequencies were significantly higher in the case group than in the control group (55.9% vs. 35.3%, P <0.05). A lack of association was observed for the MS A2756G polymorphism. There was an interaction between the maternal MTHFR C677T genotype and MS A2756G genotype.

Conclusion  Genetic interaction between MTHFR and MS genes raises the probability of neural tube defects.

     

育龄妇女人群实施神经管缺陷综合干预措施的效果分析

目的了解国内在育龄妇女人群中实施神经管缺陷(NTDs)综合干预措施的预防效果。方法全面搜集国内发表的关于在育龄妇女人群中实施NTDs综合干预措施文献,共有12篇文献符合纳入标准(累计381?561人接受综合干预措施)。将纳入文献按南北地域归类,分别汇总文献的总体效应值。采用Woolf法对文献研究结果进行齐性检验,根据结果选取汇总纳入文献研究结果总体效应值的分析方法,研究结果趋于一致时,采用Peto法;研究结果间差异较大时,采用D L法。结果① 12篇文献的研究结果差异较大(Q=20443?6, P＜005),综合干预措施效应强度RR为0556?5(95％CI:0544?6～0568?7),保护率(PR)为4435％;② 南方地域的2篇文献研究结果趋于一致(Q=0068?4,P＞005),综合干预措施效应强度RR为0673?5(95％CI:0576?7～0786?5),PR为3265％。北方地域的10篇文献研究结果趋于一致(Q=16553?8,P＞005),综合干预措施效应强度RR为0513?1(95％CI:0428?3～0614?6),PR为4869％;结论目前国内在育龄妇女人群中综合干预措施可降低NTDs的发病风险,但预防率仍然较低。北方地域综合干预措施预防率高于南方地域。在育龄妇女中开展的NTDs综合干预措施尚需进一步完善。     

Single nucleotide polymorphisms of the maternal Msx2 gene and their association with fetal neural tube defects in Han ethnic group in Shanxi Province, China

Background  Neural tube defects are the most common human birth defects. The causes are multifactorial with complex genetic and environmental factors, although the exact genetic causes are unknown. This research was conducted to study the frequency of Msx2 gene polymorphisms in 59 women with a history of pregnancy with a neural tube defect and in 73 healthy controls. We aimed to determine the effect of this genetic polymorphism on the incidence of neural tube defects in the Han Chinese population.

Methods  We studied 59 mothers with at least one previous child with a neural tube defect (the case group) and 73 case-control subjects during the same period, from Shanxi Province, China. We analyzed the genotypic distributions and allele frequencies of Msx2 C386T polymorphisms in DNA samples from the case and control groups. A three-dimensional protein model was predicted using Swiss-Pdb Viewer software version 4.0. Disease association was analyzed using chi-square tests.

Results  Significant differences were observed in the genotypes and allele frequencies of the Msx2 C386T allele between the case and control groups (CT: 32% vs. 15%, P=0.0073 and TT 15% vs. 4%, P=0.013, respectively). Logistic regression analysis showed that the C386T mutation is a potential risk factor for neural tube defects (P <0.05; OR: 3.466; 95%CI: 1.831–6.560). Three-dimensional structure prediction revealed that the Msx2 C386T mutation results in a threonine substitution for methionine at position 129 of exon 2, which might lead to structural mutations or dysfunctions in the protein encoded by Msx2.

Conclusion  Maternal Msx2 C386T gene polymorphisms were associated with fetal neural tube defects in Han Chinese women in Shanxi Province.

     

MTR、MTRR基因多态性与先天性心脏病的相关性研究

目的分析母子甲硫氨酸合成酶(methionine synthetas,MTR)、甲硫氨酸合成还原酶(methionine synthase reductase,MTRR)基因突变与子代先天性心脏病(congenital heart disease,CHD)发生的相关性,进一步探讨CHD的发生机制。方法通过母子配对,采取病例对照方式,选择CHD患儿及其母亲60对,正常儿童及其母亲60对,采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法检测MTR 2 756位点以及MTRR 66位点的基因型,分析基因变异与CHD发生的相关性。结果①子代及母亲CHD病例组与对照组MTR基因2 756位点基因型频率分布及等位基因频率差异均无统计学意义(P>0.05)。②CHD患儿与对照儿童的MTRR 66基因型分布比较以及患儿母亲与对照组母亲基因型分布比较,差异有统计学意义(P<0.05),2组等位基因频率比较,子代之间差异无统计学意义(P>0.05),但母亲之间差异有统计学意义(P<0.01)。③儿童与母亲MTR 2756和MTRR 66位点基因型之间的差异无统计学意义(P>0.05)。④MTRR和MTR位点均发生基...     

RTX诱导神经管畸形动物模型的建立及其相关机制研究

摘要 目的 通过胸苷酸合成酶（Thymidylate synthase,TS）特异性抑制剂——雷替曲塞（RTX）干预孕鼠,建立小鼠神经管畸形（neural tube defects,NTDs）模型,探讨细胞凋亡和增殖、DNA损伤在诱导的NTDs发生中的潜在机制。方法 将孕7.5天 C57BL/6j小鼠随机分为6组,1组对照组,5组RTX干预组。对照组腹腔注射0.9%NaCl,RTX干预组分别腹腔注射不同剂量的RTX（5,10,11.5,13.5,15mg/kg body weight）,孕11.5天取胚胎并观察其发育情况。苏木精-伊红（H& E）染色观察神经管闭合情况,放射性法测定TS活性,高效液相色谱检测胸苷酸(dTMP)及尿苷酸(dUMP）含量,Western-blot分析复制蛋白A2(RPA2)、γ-H 2 AX和caspase-3表达,免疫组化检测细胞增殖。结果 RTX注射剂量为11.5mg/kg时,NTDs胚胎发生率最高;RTX干预后,TS活性较对照组显著降低,dUMP含量逐渐升高,dTMP含量逐渐下降;RTX建立的NTDs模型中,RPA2和γ-H 2 AX磷酸化水平显著升高;caspase-3表达量增加,细胞增殖减少。结论 通过RTX干预孕鼠可建立小鼠NTDs模型,dTMP合成障碍导致DNA损伤、细胞凋亡与增殖失调可能是叶酸缺乏导致NTDs的重要机制之一。     

中国妇女妊娠前后单纯服用叶权对神经管畸形的预防效果

目的 评价妇女在妊娠前后服用单纯４００μｇ叶酸增补剂对胎／婴儿神经管畸形（ＴＮＤｓ）的预防效果。方法 １９９３￣１９９５年在中国北方的ＴＮＤｓ高发地区和南方的ＮＴＤｓ低发地区妇女增补叶酸的推广项目中,共募集从孕前或孕后任何时间开始服药的妇女１１７６８９名;设计的服药方法从婚栓时开始到孕满３个月为止,每天服用单纯叶酸片４００μｇ;最后对妇女的分娩结局进行监测并进行预防效果的对比评价研究。结果 服药组     

Maternal periconceptional consumption of pickled vegetables and risk of neural tube defects in offspring

Background  Maternal exposure to nitrate, nitrite, and N-nitroso compounds from drinking water or diet has been associated with an increased risk of neural tube defects (NTDs) in some studies. Pickled vegetables contain relatively large amounts of nitrite and N-nitroso compounds. We examined the association between maternal periconceptional consumption of pickled vegetables and NTDs in Shanxi Province of northern China.

Methods  Data were derived from a population based case-control study of major external birth defects in four counties of Shanxi Province. Participants included 519 NTDs cases identified between 2003 and 2007 and 694 healthy controls. Exposure information was collected within 1 week after delivery. Multivariable non-conditioanal Logistic regression model was used to estimate the adjusted odds ratio (OR) controlling for potential confounding variables.

Results  The risk of NTDs was positively associated with the frequency of the consumption of pickled vegetables by the mother. Compared with pickled vegetables consumption at <1 meal/week, the adjusted OR for consumption at 1–3, 4–6, and >6 meals/week were 1.3 (95% confidence interval (CI): 1.0, 1.8), 1.9 (1.1, 3.2), and 3.6 (1.9, 6.9), respectively. A protective effect was found for maternal meat consumption at ≥1 meal/week (adjusted OR: 0.6, 95% CI: 0.4, 0.7) and egg or milk consumption at ≥1 meal/week (adjusted OR: 0.6, 95% CI: 0.4, 0.8).

Conclusion  Maternal periconceptional consumption of pickled vegetables may increase the risk for NTDs in Shanxi Province.