MTRR 66A／G多态性与先天性心脏病易感性的Meta分析

目的探讨MTRR 66A／G多态性与先心病易感性之间的关系。方法全面检索相关文献,收集2013年3月前有关MTRR 66A／G多态性与先心病易感性的病例对照研究和核心家系的连锁不平衡检验研究,使用R软件Catmap软件包进行Meta分析。结果最终纳入8项研究,Meta分析的OR值及95％CI为1.35（95％CI=1.14-1.59,P〈0.001,Pheterogeneity=O.073）。敏感性分析显示所得结果稳定,且按研究方法和种族所进行的分层分析中,除连锁不平衡检验研究亚组外,其余所有亚组OR值均达到显著性水平。结论MTRR 66A／G多态性与先心病易感性之间具有显著关联。     

湖北松滋市汉族女性 MTHFR 和 MTRR 基因多态性分布

目的分析湖北省松滋地区女性亚甲基四氢叶酸还原酶（methylenetetrahydrofolatereductase,MTHFR）C677T、A1298C及甲硫氨酸合成酶还原酶（methioninesynthasereductase,MTRR）A66G基因多态性的分布特征。方法采用现况研究方法,以松滋市1077例女性为研究对象,提取其口腔黏膜上皮细胞的基因组DNA,通过荧光定量PCR方法检测MTHFR和MTRR基因多态性。统计分析本地区基因多态性的分布特征,并与已报道其他地区进行比较。结果松滋市女性的MTHFR677TT纯合突变基因型频率为15．41％,与四川省德阳市（13．80％）基本一致,差异无统计学意义（P〉0．05）;高于广东省惠州市（10．86％）、海南省琼海市（6．14％）,低于江苏省镇江市（21．84％）、河南省郑州市（34．5％）、山东省临沂市（35．03％）,均有极显著性差异（P〈0．01）。MTHFR1298CC纯合突变基因型的分布百分数为2．60％,与四川省德阳市（6．26％）基本一致,差异均无统计学意义（P〉0．05）;低于海南省琼海市（7．13％）、广东省惠州市（7．24％）,高于山东省临沂市（2．42％）,差异均有统计学意义（P〈0．01）。MTRR66GG纯合突变基因型频率为6．41％,与琼海市比较,差异有统计学意义（P〈0．01）。结论松滋市女性MTHFR和MTRR基因多态性分布具有地域特异性。     

No association between MTHFR A1298C and MTRR A66G polymorphisms, and MS in an Australian cohort

Multiple sclerosis (MS) is a complex neurological disease that affects the central nervous system (CNS) resulting in debilitating neuropathology. Pathogenesis is primarily defined by CNS inflammation and demyelination of nerve axons. Methionine synthase reductase (MTRR) is an enzyme that catalyzes the remethylation of homocysteine (Hcy) to methionine via cobalamin and folate dependant reactions. Cobalamin acts as an intermediate methyl carrier between methylenetetrahydrofolate reductase (MTHFR) and Hcy. MTRR plays a critical role in maintaining cobalamin in an active form and is consequently an important determinant of total plasma Hcy (pHcy) concentrations. Elevated intracellular pHcy levels have been suggested to play a role in CNS dysfunction, neurodegenerative, and cerebrovascular diseases. Our investigation entailed the genotyping of a cohort of 140 cases and matched controls for MTRR and MTHFR, by restriction length polymorphism (RFLP) techniques. Two polymorphisms: MTRR A66G and MTHFR A1298C were investigated in an Australian age and gender matched case-control study. No significant allelic frequency difference was observed between cases and controls at the α = 0.05 level (MTRR χ² = 0.005, P = 0.95, MTHFR χ² = 1.15, P = 0.28). Our preliminary findings suggest no association between the MTRR A66G and MTHFR A1298C polymorphisms and MS.     

Polymorphism of genes encoding homocysteine metabolism–related enzymes and risk for cardiovascular disease

The aim of this review is to present a general overview of the relationships among homocysteine metabolism, polymorphism of the genes encoding homocysteine metabolism–related enzymes, and the nutrients influencing the plasma homocysteine level. Combining these factors creates a profile of an individual's susceptibility to complex diseases associated with hyperhomocysteinemia. Homocysteine is an amino acid derived from the demethylation of methionine. Hyperhomocysteinemia is associated with an increased risk of several complex diseases, including cardiovascular diseases. The level of plasma homocysteine depends on the combined effects of genetic and environmental factors. Polymorphisms of genes encoding homocysteine metabolism–related enzymes, such as methylenetetrahydrofolate reductase, methionine synthase, methionine synthase reductase, and cystathionine β-synthase, influence plasma homocysteine concentration and thereby cardiovascular health. On the other hand, homocysteine metabolism may be modulated by dietary intake of the nutrients involved in homocysteine metabolism (ie, folates, vitamin B₆, and vitamin B₁₂). Thus, the appropriate health-promoting doses of these nutrients may vary among certain groups of individuals, depending on their genotypes and other risk factors for complex diseases. Better understanding of the relationship between genotype and nutrition influencing the plasma total homocysteine level and cardiovascular health may improve the cardiovascular diagnostic tests (ie, measurement of biologic markers). It could be possible to define the level of progression, severity, and susceptibility to disease much earlier than it is done now. In conclusion, the introduction of combined dietary and pharmacologic treatment would be possible at the initial stages of disease.     

Polymorphic background of methionine synthase reductase modulates the phenotype of a disease-causing mutation

Methionine synthase reductase (MTRR) is the locus of the cblE class of inborn errors of cobalamin metabolism that is characterized by megaloblastic anemia and homocystinuria. Two highly prevalent SNPs, c.66A>G (p.Ile22Met) and c.524C>T (p.Ser175Leu), are found in the MTRR gene. On the basis of the allele frequency of these amino acids and sequence comparison with members of the same family of proteins, the p.Ile22/p.Ser175 sequence is designated as wild type. While characterizing a pathogenic methionine synthase reductase (MSR) mutation, c.166G>A (p.Val56Met), we discovered an interaction between the mutation and one of the polymorphic sites. Thus, when the p.Val56Met mutant was initially expressed in the p.Ile22/p.Ser175 background, we were surprised to find that kinetically, it was virtually indistinguishable from wild-type protein. To determine if the polymorphisms interacted with the p.Val56Met mutation, it was expressed in all four possible genetic backgrounds. We found that in the p.Ile22Met background, the p.Val56Met mutation impacted the kinetics of MSR and an approximately three- to 10-fold higher concentration of the p.Ile22Met/p.Val56Met mutant was required for maximal activation of methionine synthase vs. the range seen with wild-type MSR variants. A comparable (three- to seven-fold) diminution in MSR activity was observed in extracts of fibroblast cells from patients carrying the p.Val56Met mutation on one MSR allele and a null mutation on the other. These results predicted that the patient allele encodes the p.Val56Met mutation and the p.Ile22Met variation, which was confirmed by sequence analysis. This study reveals how a genetic variation can modulate phenotypic expression of a disease-causing mutation.     

MTHFR与MTRR基因相关突变与H型高血压相关性分析

目的 探讨亚甲基四氢叶酸还原酶(MTHFR)、甲硫氨酸合成酶还原酶(MTRR)基因多态性与H型高血压的相关性。方法 选取2017-04~2017-10西安北方医院55例H型高血压患者样本做为病例组,37例孕妇样本作为健康对照组,使用PCR熔解曲线法检测两组人群MTHFR基因677C＞T、1298A＞C和MTRR基因66A＞G位点的多态性,分析两组人群的基因型及分布,采用循环酶法检测血清同型半胱氨酸(Hcy)水平。结果 与孕妇健康对照组相比,H型高血压组MTHFR677C＞T的T等位基因频率显著升高(χ²=10.172,P<0.01),而MTHFR1298A＞C和MTRR66A＞G差异无统计学意义(P>0.05)。此外,H型高血压组血清Hcy明显高于孕妇健康对照组(P＜0.01),血清Hcy水平在MTHFR677C＞T的基因型间差异有统计学意义(P＜0.05),但在MTHFR1298A＞C和MTRR66A＞G的基因型间差异无统计学意义(P>0.05)。结论 MTHFR677C＞T中T等位基因与H型高血压密切相关,也与Hcy水平升高相关,但未发现MTHFR1298A＞C和MTRR66A＞G与H型高血压及Hcy水平升高有关。     

湖北省英山县汉族女性MTHFR和MTRR的遗传多态性分析

目的分析湖北省黄冈市英山县汉族育龄女性叶酸代谢相关酶5,10-亚甲基四氢叶酸还原酶(MTHFR)和甲硫氨酸合成酶还原酶(MTRR)的基因多态性分布特征,以指导育龄女性增补叶酸和出生缺陷的一级预防。方法以英山县319例汉族女性为研究对象,提取口腔黏膜上皮细胞基因组DNA,通过荧光定量PCR法对MTHFR和MTRR的多态性位点进行分析,获得英山县妇女该基因的分布特征,并与已报道的其他地区的数据进行比较。结果英山县汉族女性MTHFR C677T基因型构成与淄博、济源、张家口、延边、乌鲁木齐、银川、眉山、南宁、琼海数据相比差异有统计学意义(x^2值为181.41~13.46,均P<0.05),与松滋、湘潭、惠州相比无统计学意义(x^2值为0.12~5.87,均P>0.05)。英山县汉族女性MTHFR A1298C基因型构成与淄博、济源、张家口、延边、银川、眉山、松滋、湘潭数据的差异均有统计学意义(x^2值为76.94~7.31,均P<0.05),与乌鲁木齐、惠州、南宁、琼海相比无统计学意义(x^2值为5.19~0.97,均P>0.05)。英山县汉族女性MTRR A66G的基因型构成与延边和琼海的差异有统计学意义(x^2值分别为6.10、17.10,均P<0.05),与淄博、济源、张家口、乌鲁木齐、银川、眉山、松滋、湘潭、惠州、南宁的差异均没有统计学意义(x^2值为0.95~5.48,均P>0.05)。结论英山县汉族女性MTHFR和MTRR基因多态性频率分布具有地域特异性。     

育龄女性基因多态性对补充叶酸降低HCY的影响

目的阐明MTHFRC677T、A1298C和MTRRA66G多态性在河南汉族育龄女性中的分布特征及其对补充叶酸降低HCY的影响。方法选取2011年7月至2013年4月在郑州大学第三附属医院进行优生咨询的育龄女性425名。荧光定量PCR检测MTHFRC677T、A1298C和MTRRA66G的基因多态性;化学发光法测定血叶酸浓度;循环酶法测定血HCY浓度。结果①河南地区汉族育龄女性中MTHFR677T、1298C和MTRR66G等位基因频率分别为62．1％、13．1％、23．7％。②补充叶酸前MTHFRC677T基因型叶酸浓度Tr〈CT〈CC,TT基因型HCY浓度远高于CC和CT基因型（P〈0．001）。400μg／d补充后HCY浓度迅速下降（TT〉CT〉CC）,但6．3％CT、16．9％TT基因型HCY浓度没有降低至正常范围。结论河南地区汉族育龄女性具有其他省份不同的遗传特征,MTHFRC677T各基因型对补充叶酸降低HCY的反应不同。     

四川仁寿县孕前及孕早期妇女叶酸代谢障碍相关基因位点分布研究

目的调查四川省仁寿县孕前及孕早期女性叶酸代谢障碍相关酶基因(MTHFR和MTRR)多态性的分布特点,为预防出生缺陷提供科学指导。方法以仁寿县2 286例孕前及孕早期女性为研究对象,采用实时荧光定量PCR检测叶酸代谢障碍相关基因位点MTHFR C677T、A1298C和MTRR A66G的基因型,分析数据得出仁寿县妇女该基因的分布特征,并与文献已经报道的其他地区进行统计学分析比较。结果仁寿县女性MTHFR 677TT纯合突变基因型频率为15.00%,低于北方区域(淄博43.60%、郑州36.80%、辽源28.80%),高于南方区域(南宁7.70%、广州7.40%、琼海6.10%),差异有统计学意义(P0.01)。而与相近区域德阳、郫县差异无统计学意义(P0.01)。MTHFR 1298CC纯合突变基因型频率为3.00%,与北方区域、南方区域和四川相近区域差异均有统计学意义(P0.05),且德阳与郫县相比差异有统计学意义(P=0.002),该基因位点可能在四川区域具有更加明显的地域特性。MTHFR A66G纯合突变GG型仅与南方区域相比差异有统计学意义(P0.01)。结论四川省仁寿县地区女性的叶酸代谢相关基因MTHFR和MTRR的分布具有地域特异性。