阿尔茨海默病患者同型半胱氨酸代谢相关酶基因突变频度的研究

目的探讨胱硫醚β合成酶(CBS)基因844ins68、甲硫氨酸合成酶(M S)基因A2756G、亚甲基四氢叶酸还原酶(MTHFR)基因C677T三种同型半胱氨酸代谢相关酶基因突变在阿尔茨海默病(AD)发病中的意义.方法 PCR扩增AD 66例及143例对照者的CBS、MS、MTHFR基因突变点,直接或经限制性内切酶消化后行凝胶电泳确定其基因型.结果 AD病人MTHFR基因中,基因型C/T占56.06%,明显高于对照组(p<0.01),C/C明显低于对照组(p <0.01),T/T与对照组无明显差异(p>0.05). AD病人中MTHFR基因等位基因C的频率相对危险率(RR),T的频率与对照组的差异有显著性(p<0 .05).CBS 844ins68、MS A2756G各种基因型频率在AD组与对照组之间无差异 .结论 AD病人中MTHFR*T频率明显高于正常人;而MTHF R *C频率则明显低于正常人,而CBS 844ins68、MS A2756G突变可能不足以构成阿尔茨海默病的独立遗传性危险因子.     

阿尔茨海默病与蛋氨酸合成酶基因多态性的相关性探讨

目的　探讨蛋氨酸合成酶 (MS)基因A2 75 6G突变在阿尔茨海默病 (AD)发病中的意义。方法　PCR扩增 6 6例AD患者及 14 3例对照者的MS基因突变点 ,经限制性内切酶消化后行凝胶电泳确定其基因型。结果　MS基因片段PCR扩增产物长度分别为 189bp。MSA2 75 6G突变的G等位基因PCR扩增产物经HaeⅢ消化后裂解成 15 9和 30bp两个片段 ;MAD组A2 75 6G基因型频率 (% )分别为 98 4 8、1 5 2和 0 0 0 ,对照组分别为 98 6 0、1 4 0和 0 0 0 ,MSA 2 75 6G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 0 5 )。结论　MS多态性与AD无明显相关。     

同型半胱氨酸代谢酶基因多态性与深静脉血栓的相关性研究

目的探讨亚甲基四氢叶酸还原酶（methylenetetrahydrofolate reductase，MTHFR）基因C677T、甲硫氨酸合成酶（methionine synthase，MS）基因A2756G和胱硫醚β-合成酶（cystathionine β-synthase，CBS）基因844ins68这3种基因突变在深静脉血栓发病中的意义。方法应用聚合酶链反应-限制性片段长度多态性方法对103例深静脉血栓患者和250名健康对照者进行MTHFR C677T、MS A2756G和CBS 844ins68基因多态性的分析，并进行基因型及等位基因频率的计数。对MTHFR C677T和MS A2756G两位点进行单倍型分析。结果MTHFR C677T TT基因型在深静脉血栓组的分布频率（27．2％）高于对照组（17．2％），经χ^2检验差异有统计学意义（P〈0．05）。MS A2756G AG基因型在深静脉血栓组的分布频率（9．7％）低于对照组（19．2％），经χ^2检验差异有统计学意义（P〈0．05）。单倍型分析显示病例组中677T-2756A单倍型频率明显高于对照组（P〈0．05），677C-2756A单倍型频率明显低于对照组（P〈0．05）。CBS 844ins68基因型在两组的分布频率差异无统计学意义。结论MTHFR C677T多态性中TT基因型可能是深静脉血栓形成的一个遗传风险因子，MS 2756 AG基因型可能会减少深静脉血栓的发生。677T-2756A单倍型可能是静脉血栓的危险因素，677C-2756A单倍型可能是静脉血栓的保护因素。CBS 844ins68基因突变可能存在种族或地域的差异。     

2型糖尿病患者胱硫醚-β合成酶的基因多态性研究

目的　探讨同型半胱氨酸 (Hcy)代谢过程的关键酶之一胱硫醚 - β合成酶 (CBS)基因多态性与 2型糖尿病的关系 .方法　PCR扩增 5 2例 2型糖尿病和 12 4例正常人的CBS 84 4ins6 8基因突变点 ,直接行琼脂糖凝胶电泳确定其基因型 .结果　病例组与对照组CBS基因分布频率和等位基因频数分布差异无显著性 (p >0 .0 5 ) .结论　CBS84 4ins 6 8突变可能不足以构成 2型糖尿病的独立遗传性危险因子     

胱硫醚β-合成酶基因844ins68多态性的检测

目的了解广东汉族人胱硫醚β-合成酶基因844ins68的分布特点.方法 PCR扩增124例广东正常人的CBS 844ins 68基因突变点,直接行聚琼脂糖凝胶电泳确定其基因型.结果广东汉族人CBS 844ins 68基因表型频率:野生型(D/D)0.7820,纯合子突变型(I/I)0.1930, 杂合子突变型(D/I)0.0250,CBS 844ins 68基因频率:D 0.8790;I 0.1210.结论 CBS844ins 68基因突变存在一定的人种或地域差异.     

胱硫醚β-合成酶基因844ins68多态性的检测

目的 了解广东汉族人胱硫醚β-合成酶基因844ins68的分布特点．方法 PCR扩增124例广东正常人的CBS 844ins 68基因突变点，直接行聚琼脂糖凝胶电泳确定其基因型．结果 广东汉族人CBS 844ins 68基因表型频率：野生型(D／D)0．7820。纯合子突变型(I／I)0．1930，杂合子突变型(D／I)0．0250。CBS 844ins 68基因频率：D0．8790；I0．1210．结论 CBS844ins 68基因突变存在一定的人种或地域差异．     

同型半胱氨酸代谢酶基因突变多态性与妊娠高血压综合征遗传易感性研究

目的探讨同型半胱氨酸代谢酶—甲基四氢叶酸还原酶(MTHFR)、蛋氨酸合成酶(MS)和胱硫醚-β合成酶(CBβS)基因多态性在妊娠高血压综合征(妊高征)发病中的作用地位。方法荧光偏振免疫分析法测定血浆总Hcy浓度;聚合酶链反应-限制性片段长度多态性技术(PCR-RFLP)检测MTHFRC677T、MSA2756G、MTRRA66G和CBβS844ins68基因多态性。结果病例组MTHFRC677TC/T基因型频率显著高于正常对照组,总的突变T等位基因频率显著高于对照组(P<0.05);病例组MS野生型A等位基因频率明显高于对照组,而突变型G等位基因频率显著低于对照组。结论MTHFRC677T基因突变是妊高征发生的遗传风险因素;MSA2756多态性改变是妊高征的保护因子。二者均可作为妊高征预后的检测指标。     

2型糖尿病患者胱硫醚-β合成酶的基因多态性研究

目的探讨同型半胱氨酸(Hcy)代谢过程的关键酶之一胱硫醚-β合成酶(CBS)基因多态性与2型糖尿病的关系.方法 PCR扩增52例2型糖尿病和124例正常人的CBS 844ins 68基因突变点,直接行琼脂糖凝胶电泳确定其基因型.结果病例组与对照组CBS基因分布频率和等位基因频数分布差异无显著性(p>0.05).结论 CBS 844ins 68突变可能不足以构成2型糖尿病的独立遗传性危险因子.     

同型半胱氨酸和胱硫醚-β合成酶基因多态性与颅内动脉瘤的关系

目的 探讨同型半胱氨酸和胱硫醚-β合成酶基因(CBS)844ins 68基因多态性与颅内动脉瘤的关系.方法 运用多聚酶链反应技术和荧光偏振法(FPIA)检测76例颅内动脉瘤及143例正常人CBS 844ins 68基因多态性和血浆总Hcy水平.结果 ①AD组CBS844ins 68 D/D、D/I、I/I基因型频率(%...     

2型糖尿病与蛋氨酸合成酶基因多态性的相关性探讨

目的　探讨甲硫氨酸合成酶 (MS)基因A2 75 6G突变在 2型糖尿病发病中的意义 .方法　PCR扩增 6 6例 2型糖尿病 (DM)患者及 14 3例对照者的MS基因突变点 ,经限制性内切酶消化后行凝胶电泳确定其基因型 .结果　MSA2 75 6G各种基因型频率在DM组与正常对照组之间无差异 .结论　MSA2 75 6G突变可能不足以构成 2型糖尿病的独立遗传性危险因子     

同型半胱氨酸和MTHFR基因多态性与Alzheimer病的关系

目的探讨同型半胱氨酸(Hcy)和5,10 亚甲基四氢叶酸还原酶(MTHFR)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例阿尔茨海默病及143例正常人MTHFR基因多态性和血浆总Hcy水平.结果 (1)AD病人甲基四氢叶酸还原酶基因中,基因型C/T占56.06%,明显高于对照组的34.97%(P<0.01,RR=0.355),C/C占39.39%,明显低于对照组的62.94%(P<0.01),T/T占4.25%,与对照组2.09%无明显差异(P>0.05). AD病人中甲基四氢叶酸还原酶基因等位基因C的频率为67.43%、相对危险率(RR)为0.594,T的频率为32.57%、与对照组的C为80.42%、T为19.58%有显著性差异(P≤0.05).(2)AD病例组与对照组血浆Hcy分别为14.72±6.2μmol/L和10.9±2.4μmol/L,两者差异有显著差异(P<0.05).AD患者血浆总Hcy水平显著高于正常组.结论 MTHFR基因突变及高同型半胱氨酸血症与Alzheimer病发生有一定关系.     

The allele frequencies of three polymorphisms in genes involved in homocysteine metabolism in a group of unrelated healthy Singaporeans

The cystathionine β-synthase (CBS) 844ins68 polymorphism, methionine synthase (MS) A2756G SNP, and 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T SNP are associated with homocysteine (Hcy) level in humans. Elevated Hcy level is considered a risk factor for atherosclerotic diseases among Asian populations. Therefore, the three polymorphisms may vary the risk for developing such diseases in Singaporeans. In this study, the three polymorphisms were determined in a group of unrelated healthy Singaporeans (273 Chinese, 127 Indians, and 156 Malays). Regarding allele frequencies, Indians had the highest frequencies of the CBS insertion allele (2.0%) and the MS 2756G allele (26.4%), while Chinese had the highest MTHFR 677T allele frequency (27.5%). In addition, the MTHFR 677T allele was found significantly lower in Chinese males than in their female counterparts. As the CBS insertion allele was suggested to be associated with lower Hcy level, whereas the MS 2756G allele and the MTHFR T/T genotype were related to higher Hcy level, the MS A/G or G/G genotype and the MTHFR T/T genotype were considered double genetic risk factors for elevated Hcy level. The frequency of such double genetic risk was 0.7% (4 subjects) in the total population consisting of 3 Chinese (1.1%) and 1 Malays (0.6%). No MTHFR T/T genotype was found in Indians. Such results suggested that Chinese could have higher Hcy levels than Malays while the situation for Indians was complicated. Since human Hcy levels are also affected by environmental factors, further studies are required to better evaluate the association between these three polymorphisms and Hcy levels and/or disease susceptibilities in Singaporeans.     

MTHFR和CBS基因多态性与低出生体重的关系研究

目的探讨母亲亚甲基四氢叶酸还原酶（MTHFR）基因C677T、胱硫醚β-合酶（CBS）基因T833C与子代低出生体重发生之间的关系。方法运用聚合酶链反应（PCR）-限制性片段长度多态性与PCR-扩增阻滞突变体系技术分别检测母亲的MTHFR、CBS基因型,对MTHFR基因型、CBS基因型、基因型的交互作用与低出生体重的关系进行分析。结果MTHFR基因突变型、CBS基因突变型对低出生体重影响无统计学意义（P〉0．05）,但MTHFR基因突变型与CBS基因突变型对低出生体重的影响存在交互作用（OR=3．155,95％CI：1．229—8．528）。结论母亲MTHFR基因C677T、CBS基因T833C,与子代低出生体重发生无关,但MTHFR基因突变型与CBS基因突变型存在交互作用,其能增加子代低出生体重发生的危险。     

叶酸代谢酶基因多态性与反复自然性流产易感性的研究

目的探讨叶酸代谢相关酶基因多态性在不明原因反复自然流产遗传易感性中的作用地位。方法运用聚合酶链反应-限制性片段长度多态性技术（PCR—RFLP）检测蛋氨酸合成酶还原酶（MTRR）A66G,蛋氨酸合成酶（MS）A2756G,N5,10-亚甲基四氢叶酸还原酶（MTHFR）C677T,胱硫醚β-合成酶（CBβS）844ins68基因多态性。结果不明原因反复自然流产患者MTHFR的T等位基因突变频率较正常对照组明显升高。而MS、MTRR和CBβS突变频率在病例组与对照组之间无显著差异。结论MTHFR C677T基因突变多态性可作为不明原因反复自然流产预后的检测指标。     

No association of C677T methylenetetrahydrofolate reductase and an endothelial nitric oxide synthase polymorphism with recurrent pregnancy loss

PROBLEM: It is controversial whether polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and the endothelial nitric oxide synthase (eNOS) are associated with recurrent pregnancy loss. METHOD OF STUDY: We studied the frequency of the C677T polymorphism of MTHFR and a eNOS gene polymorphism, as well as the plasma levels of homocysteine and NO, in 85 cases with a history of two or more unexplained embryonal losses, 40 patients suffering fetal loss and 76 controls. RESULTS: The frequency of the MTHFR gene T allele, which has been reported to be associated with miscarriages, in patients suffering fetal loss was rather significantly lower than in controls whereas there was no difference in the frequency of the eNOS gene A allele. There were no differences in the plasma homocysteine levels among the three groups. However, the NO concentrations in the embryonal loss and fetal loss groups were significantly higher than that in controls. CONCLUSION: We conclude that the NO concentration but not the polymorphism of MTHFR and eNOS gene and hyperhomocysteinemia are associated with recurrent pregnancy loss in Japanese.     

青岛地区汉族育龄妇女亚甲基四氢叶酸还原酶基因667位点多态性分布研究

目的探讨亚甲基四氢叶酸还原酶（MTHFR）基因667位点多态性在青岛市汉族育龄妇女中的分布状况。方法用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）技术检测98份育龄妇女外周血MTHFR C667T基因型分布。结果本研究人群MTHFR 677位点基因的CC、CT、TT基因型频率分别为24.5%、53.1%、22.4%,T等位基因频率为0.49。结论青岛市汉族育龄妇女MTHFR基因667位点多态性与其他地区有较大不同,调查可以为相关研究提供相应的分子生物学依据。     

Prevalence of MTHFR gene polymorphisms (C677T and A1298C) among Tamilians

We have investigated the incidence of the C677T and A1298C methylene tetrahydrofolate reductase (MTHFR) gene single nucleotide polymorphisms (SNPs) in the South Indian Tamil Nadu population with a total number of 72 individuals. The MTHFR genotyping was performed using the polymerase chain reaction followed by restriction enzyme analysis. Homozygosity for the MTHFR A1298C SNP was detected in 15.3% (11/72) of the individuals tested, and 47.2% (34/72) were heterozygous for this SNP. Homozygosity for the C677T MTHFR SNP was detected in 1.38%(1/72), and the frequency of the C677T heterozygotes was 18.1%(13/72). When we analyzed the combined frequency of the two SNPs, the frequency of double heterozygosity was19.6%, and the frequency of double homozygosity was completely absent among the study group. The 'C' allele frequency for MTHFR A1298C was 0.389, and the 'T' allele frequency for C677T mutation was 0.104. Out of the 72 individuals included in the study, 52 were acute myocardial infarction (AMI) patients and 20 were healthy individuals with no documented history of heart disease. The results of this study indicate that the MTHFR A1298C SNP is more prevalent among the Tamilians when compared to the MTHFR C677T SNP, suggesting a possible role of MTHFR A1298C in the pathogenesis of heart diseases.     

The C677T polymorphism in the methylene tetrahydrofolate reductase gene among Tunisian population

The 5,10 methylene tetrahydrofolate reductase (MTHFR) is an enzyme that catalyzes the irreversible reduction of 5,10 methylene tetrahydrofolate into 5 methyl tetrahydrofolate. It is coded by a gene where several polymorphisms have been identified. The most common is the C677T polymorphism described as presenting an heterogeneous worldwide distribution and associated with different disorders such as cardiovascular and cancerous diseases. The aim of this work was to determine the allelic and genotypic frequencies of the C677T polymorphism among a Tunisian healthy population. The study concerned 185 subjects apparently healthy. It was carried out by the PCR/RFLP method, using the restriction enzyme Hinf I. The results has showed an allelic frequency of 17.8% with a genotype frequency of 5.4%. These values are intermediate between those observed in Africa and those observed in Western countries. They must be considered in the evaluation of the clinic significance of a predisposition to diseases.