同型半胱氨酸相关酶基因多态性与高血压伴周围动脉闭塞性疾病的关系

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因C677T、胱硫醚B合成酶(CBS)基因844ins68和甲硫氨基合成酶(MS)基因A2756G3种同型半胱氨酸(Hcy)代谢相关酶基因多态性与北京社区汉族老年人群中原发性高血压(EH)、EH伴周围动脉闭塞性疾病(PAOD)易感性的关系。方法PCR扩增老年EH(EH组)、老年EH伴PAOD(EH—PAOD组)患者和老年健康对照组的MTHFR C677T、CBS 844ins68、MS A2756G基因突变点，直接或经限制性内切酶消化后行凝胶电泳，确定基因型并统计基因突变频率。结果EH组100例MTHFR基因3种基因型频率为：C／C29．0％，C／T45．0％，T／T26．0％；EH—PAOD组59例为：C／C15．9％，C／T35．5％，T／T48．6％；对照组100例为：C／C31．0％，C／T50．0％，T／T19．0％。3组MTHFR基因的C677T单核苷酸突变中T突变位点的频率分别为48．5％、64．4％、44．0％。EH—PAOD组与对照组和EH组比较，MTHFR T／T基因型频率和T等位基因频率差异均有统计学意义。而CBS 844ins68、MS A2756G各种基因型频率和等位基因频率在EH组、EH—PAOD组和对照组之间差异无统计学意义。结论MTHFR基因C677T单核苷酸突变可能是北京社区汉族老年人PAOD的遗传性危险因素之一，可能与EH无关。且CBS基因844ins68、MS基因A2756G的突变可能都不足以成为EH和PAOD的遗传危险因子。     

同型半胱氨酸代谢关键酶基因多态性与2型糖尿病合并冠心病的关系

目的探讨我国北方地区汉族人同型半胱氨酸(Hcy)代谢相关酶(MTHFR C677T、CBS844ins68)基因多态性的特点及基因多态性与2型糖尿病(T2DM)合并冠心病(CHD)的关系。方法研究对象均为北方汉族人群,包括无血缘关系的105例T2DM合并CHD患者、125例单纯T2DM患者和91例健康对照组。应用分子生物学方法分析MTHFR C677T、CBS844ins68基因多态性。结果T2DM合并CHD组的T等位基因频率明显高于与对照组(45.3%vs34.6%,P<0.05),其中CT基因型频率高于对照组(58.1%vs38.5%,P<0.05),CC型频率明显低于对照组(25.7%vs46.2%,P<0.05)。CBS844ins68多态性三组CBS844ins68的基因型及等位基因频率差别均无统计学意义(均P>0.05)。Logistic回归分析显示MTHFR基因型的OR值为1.394,95%CI0.989-1.965(P=0.058);MTHFR677携带T基因(MTHFR CT基因型和TT基因型)的OR值为1.939,95%CI1.159-3.243(P=0.012);CBS的OR值为0.52,95%CI0.108-2.495(P=0.414)。结论MTHFR677携带T基因是我国北方地区汉族人T2DM合并CHD发生的独立危险因素,筛查MTHFR677T基因型可能在预防糖尿病合并冠心病的发生、发展过程中起到一定作用。     

同型半胱氨酸及代谢酶基因多态性与脑卒中的相关性研究

目的 进一步确定亚甲基四氢叶酸还原酶(MTHFR)基因C677T、胱硫醚β-合成酶(CBS)基因844ins68、T27796C和甲硫氨酸合成酶(MS)基因A2756G这4种基因突变在脑卒中发病中的意义。方法 选择年龄及性别基本匹配的脑梗死组78例、脑出血组26例、神经系统其他疾病组29例和健康老年组50例，采用酶联免疫分析法测定受检者血浆同型半胱氨酸(Hcy)浓度，并运用多聚酶链反应-限制性内切酶片段长度多态性技术，检测基因表型。结果 脑梗死组和脑出血组血Hcy浓度明显高于神经系统其他疾病组和健康老年组。CBS844ins68及MSA2756G突变频率较国外报道明显低。此外，C677T纯合突变型的Hcy水平均高于野生型和杂合突变型，CBST27796C基因杂合子突变则可能使Hcy水平降低；而4种基因各组之间基因型频率差异无统计学意义。结论 Hcy水平与脑卒中的发生有一定联系。CBS844ins68和MSA2756G突变可能存在种族或地域差异，MTHFRC677T纯合子突变可能是导致血浆总Hcy(tHcy)水平升高的遗传决定簇，而CBST27796C基因杂合子突变可能引起tHcy水平的降低；4种基因突变符合遗传平衡定律。     

血浆Hcy及其代谢酶基因多态性与Alzheimer病的关系

目的探讨血浆同型半胱氨酸(homocysteine,Hcy)及其相关代谢酶N5,N10-亚甲基四氢叶酸还原酶(N5,N10-methylenetetrahydrofolatereductase,MTHFR)胱硫醚β-合成酶(cystathionineβ-synthase,CBS)基因多态性与阿尔茨海默病(Alzheimersdisease,AD)的关系。方法对104例AD患者、100例健康对照组运用高压毛细管电泳紫外检测法测定血浆Hcy水平,采用多聚酶链反应-限制性片段长度多态性(PCR-RELP)方法检测MTHFR基因第4外显子C677T、CBS基因第8外显子844ins68的多态性。结果AD患者血浆Hcy(16.18±3.35)μmol/L非常显著高于健康对照者Hcy(12.24±3.96)μmol/L。AD组和对照组受试者间MTHFRC677T和CBS基因844ins68的各基因型分布和等位基因频率均无显著性差异,仅MTHFR的T等位基因与受试者血浆Hcy水平升高有关。结论AD患者的血浆Hcy水平高于健康人群,可能与疾病的发生发展有关;并可能主要由环境因素所致,而非MTHFR和CBS基因变异引起。补充VitB12和叶酸有助于AD的治疗。     

同型半胱氨酸代谢相关酶基因多态性与先天性心脏病的关系

目的研究同型半胱氨酸相关酶中亚甲基四氢叶酸还原酶(MTHFR)、蛋氨酸合成酶(MS)和蛋氨酸合成酶还原酶(MTRR)基因的多态性与先天性心脏病(CHD)的相关性。方法采用病例对照研究方法,以132例CHD患儿(疾病组)与107名健康儿童(对照组)的血白细胞为样本,应用聚合酶链反应-限制性片段长度多态性技术检测两组的MTHFR基因第677位点、MS基因第2756位点及MTRR第66位点的多态性,比较两组各自的基因型和等位基因的分布频率。结果MTHFR的677位点CC、CT和TT基因型在疾病组中分别为22.73%、51.52%、25.76%,在对照组中分别为42.99%、44.86%、12.15%,两组的分布频率差异有统计学意义。MS基因第2756位点AA、AG和GG基因型在疾病组和对照组中的分布频率差异无统计学意义。MTRR基因第66位点AA、AG和GG基因型在疾病组分别为25.00%、63.64%、11.36%,在对照组中分别为48.60%、42.05%、9.35%,两组的分布频率差异有统计学意义。结论①MTHFR及MTRR的基因多态性与CHD的发病具有一定程度的相关性,MS基因的多态性分布与CHD的发病无关;②MTHFR基因第677位点中的C/C及MTRR第66位点中的A/A均为CHD的保护基因;③两基因变异在CHD的发病中可能有协同作用。     

同型半胱氨酸及其代谢酶基因多态性与冠心病的关系

目的探讨血浆同型半胱氨酸(Hcy)水平及其代谢酶MTHFR C677T、MTHFR A1298C、MS A2756G、MTRR A66G基因多态性与冠心病的相关性。方法在川东北地区汉族人群中221例冠心病患者(冠心病组)和与之性别、年龄匹配的210例非冠心病患者(对照组)为研究对象。采用Hcy检测试剂盒(速率法)测定两组患者血浆Hcy水平,采用改良多重连接反应检测技术(i MLDR)检测目的基因,进行单核苷酸多态性(SNP)分型,分析两组之间Hcy水平及其Hcy代谢酶基因多态性分布情况。结果 (1)冠心病组血浆Hcy水平明显高于对照组(15.39±6.89μmol/L比12.90±6.44μmol/L,P0.05),Hcy在两组之间比较OR值为1.060(95%CI 1.021~1.100),差异具有统计学意义(P0.05)。(2)MTHFR C677T、MTHFR A1298C、MS A2756G、MTRR A66G在两组之间比较,无论是基因型分布频率还是等位基因分布频率均无统计学差异(P均0.05);基因-基因间交互作用分析发现,这四个基因位点在冠心病的发病过程中不存在交互作用(P0.05);基因-环境间交互作用分析发现,MTHFR C677T与吸烟、甘油三酯之间也不存在交互作用(P均0.05)。(3)血浆Hcy水平在冠心病MTHFR TT基因型组(19.72±11.51μmol/L)最高,且分别高于CC基因型组(13.99±4.77μmol/L,P0.05)及CT基因型组(15.44±6.25μmol/L,P0.05)。结论 Hcy可能增加川东北地区汉族人群冠心病的患病风险,MTHFR C677T TT基因型的冠心病患者血浆Hcy水平较高,未发现MTHFR C677T、MTHFR A1298C、MS A2756G、MTRR A66G基因多态性与冠心病发病相关。     

MTHFR C677T基因多态性与缺血性脑血管病的相关性

目的:探讨亚甲基四氢叶酸还原酶(MTHFR)C677T基因多态性与缺血性脑血管病的相关性。方法:运用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术对512例缺血性脑血管病患者和500例健康对照者进行MTHFR C677T基因多态性分析。结果:缺血性脑血管病患者中突变纯合子TT基因型频率为40%,突变杂合子CT基因型频率42·6%,野生型CC基因型频率为17·4%;对照组中TT基因型频率为32·8%,CT基因型频率为34·6%,CC基因型频率为32·6%;患者组和对照组T等位基因频率分别为61·3%和51·1%,C等位基因频率分别为38·7%和49·9%,以上各频率之间均有显著性差异(P<0·05)。结论:MTHFR C677T基因多态性与缺血性脑血管病的发生有一定关系,可能是缺血性脑血管病的一个重要危险因素。     

亚甲基四氢叶酸还原酶和胱硫醚-β-合成酶基因多态与唐氏综合征发生的关系

目的探讨母体5,10-亚甲基四氢叶酸还原酶(MTHFR)基因和胱硫醚-β-合成酶(CβS)基因多态性与唐氏综合征(DS)发生的关系。方法应用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法检测70例DS患儿母亲和117例对照女性的MTHFR两个多态位点(C677T、A1298C),利用SHEsis在线分析软件进行单体型和连锁不平衡分析;PCR法检测CβS 844Ins68基因型。Pearsonχ2检验各基因和基因型频率分布的差异。计算比值比评价相对危险度。结果 MTHFR基因两个多态位点及CβS 844Ins68突变基因频率和基因型频率在病例组和对照组中分布无显著差异(P0.05)。MTHFR 677T/T/1298(C/C+C/A)联合基因型显著地增加DS发生风险(OR=8.46,95%CI:0.90~79.51,P0.05)。MTHFR两个多态位点存在连锁不平衡(D'=0.68);677T-1298C单体型与DS发生显著相关(OR=5.22,95%CI:1.37~19.94,P0.01)。结论 MTHFR两个位点变异联合分析及677T-1298C单体型可能是DS发生的风险因素,不能排除叶酸代谢酶基因多态在DS发生中的作用。     

内皮型一氧化氮合酶和N5，N10-亚甲基四氢叶酸还原酶基因多态性与苏皖地区汉族人群早发冠心病易感性的相关关系

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突变与苏皖地区汉族人群早发冠心病(PCAD)发病的关系.方法 采用病例对照研究的方法,应用聚合酶链反应-限制性片长多态性(PCR-RFLP)技术,分别检测131例PCAD患者(PCAD组)和131例年龄、性别相匹配的无冠心病者(对照组)的eNOS和MTHFR基因的单核苷酸多态性,判定其基因型并统计各基因型及等位基因的频率.结果 eNOS基因G894T多态性在PCAD组和对照组中的基因型分布(x2=2.072,P=0.355)和T等位基因频率(x2=0.727,P=0.394)差异均无统计学意义.MTHFR基因C677T基因型在PCAD组CT和TT型分布均高于对照组(x2 =14.290,P=0.001),T等位基因频率亦高于对照组(x2=16.339,P =0.000),差异有显著性(P＜0.05).Logistic回归分析显示,携带MTHFR基因C677TTT基因型是PCAD发病的独立危险因素.结论 eNOS基因G894T多态性可能与苏皖地区汉族人群PCAD发病无关;MTHFR基因677C/T多态性的TT基因型可能增加苏皖地区汉族人群PCAD的患病风险,T等位基因可能是PCAD的遗传易感基因.     

MTHFR基因多态性与肺血栓栓塞症的关系

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因多态性与肺栓塞的关系。方法选取肺栓塞患者102例及同期住院或门诊患者及健康体检者120例,应用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法进行检测两组MTHFR基因C677T、A1298C位点的多态性,比较两组基因型和等位基因分布频率。结果 1在肺栓塞组中,MTHFR C677T位点CC、C/T、TT基因型频率分别为20.6%、31.4%、48%,在对照组中分别为29.2%、39.1%、31.7%,在两组中TT基因型频率差异有统计学意义(P=0.013)。在两组间,T等位基因分布频率差异有统计学意义(P=0.008)。2在肺栓塞组中,MTHFR A1298C位点AA、A/C、CC基因型频率分别为23.5%、31.4%、45.1%,在对照组中分别为31.7%、37.5%、30.8%,在两组中CC基因型频率差异有统计学意义(P=0.029),等位基因C分布频率两组间差异有统计学意义(P=0.018)。结论MTHFR基因C677T位点的TT基因型及A1298C位点的CC基因型多态性可能为肺血栓栓塞症的高危因素。     

Effect of polymorphisms on key enzymes in homocysteine metabolism, on plasma homocysteine level and on coronary artery-disease risk in a Tunisian population

BACKGROUND: Hyperhomocysteinemia is known as an independent-risk factor for coronary-artery disease (CAD). However, the effect of homocystein metabolic enzymes polymorphisms on CAD is still controversed. We investigated the relation between homocystein metabolic key enzymes polymorphisms, homocystenemia and coronary stenosis in a Tunisian population. METHODS: Samples were collected from 251 CAD patients documented by angiography. Genotyping were performed for C677T methylene-tetrahydrofolate reductase (MTHFR), A2756G methionine-synthase (MS) and 844ins 68 cystathionine-beta-synthase (CBS). We measured fasting plasma tHcy, folate and vitamin B12. RESULTS: There was significant increase in homocysteinemia for homozygous genotypes of C677T MTHFR (p<0.001) and A2756G MS (p=0.01), but not for 844ins68 CBS (p=0.105). Potential confounders adjusted odds-ratios for significant coronary stenosis, associated with MTHFR TT, MS GG and CBS insertion, were respectively 1.78 (p=0.041); 2.33 (p=0.036) and 0.87 (p=0.823). The effect of mutated MTHFR genotype was more pronounced on homocysteinemia (21.4+/-9.1mumol/L; p<0.001) and coronary stenosis (OR=2.73; p=0.033) at low folatemia (相似文献   

N5,N10-亚甲四氢叶酸还原酶基因多态性及血浆同型半胱氨酸水平与心肌梗死的关系

研究N^5,N^10-亚甲四氢叶酸还原酶基因多态性及血浆同型半胱氨酸水平与心肌梗死的关系。运用多聚酶链反应-限制片长多态性技术检测178例心肌梗死患者及178例正常人N^5,N^10-亚甲四氢叶酸还原酶基因多态性，用高效液相色谱仪和荧光检测仪测定血浆总同型半胱氨酸水平。结果发现，N^5,N^10-亚甲四氢叶酸还原酶有3种基因型，即纯合子突变型（TT），杂合子突变型（TC）及正常型（CC），心肌梗死组TT型频率为35.4%，TC型频率为53.8%。CC型频率为10.8%。T等位基因频率为62.3%。C等位基因频率为37.7%，正常组中TT型频率为20.1%。TC型频率为55.8%。CC型频率为24.1%。T等位基因频率为32.1%,C等位基因频率为67.9%，且心梗死组TT高于正常组。正常人群中TT基因型者血浆总同型半胱氨酸水平明显高明于（TC CC）基因型者，心肌梗死患者血浆总同型半胱氨酸水平显著高于正常组，多因素分析显示，N^5,N^10-亚甲四氢叶酸还原酶基因突变型TT可能是心肌梗死发病一个危险因素，结论提示，N^5,N^10-亚甲四氢叶酸还原酶TT基因型突变可能升高个体血浆总同型半胱氨酸水平，N^5,N^10-亚甲四氢叶酸还原酶基因可能是心肌梗死的易感基因之一，N^5,N^10-亚甲四氢叶酸还原酶基因突变型TT及高同型半胱氨酸血症可能是心肌梗死发病的一个危险因素。     

A polymorphism in the methylenetetrahydrofolate reductase gene predisposes to colorectal cancers with microsatellite instability

BACKGROUND: The enzyme methylenetetrahydrofolate reductase (MTHFR) catalyses the formation of folate intermediates that are vital to methylation reactions. A polymorphic variant (TT) has been linked to reduced levels of plasma folate, aberrant DNA methylation in leucocytes, and increased risk of colorectal cancer (CRC) under conditions of low folate intake. The cystathionine beta-synthase (CBS) enzyme reduces homocysteine levels and thus may protect against CRC. The CBS gene has a variant, 844ins68, that has been linked with increased activity. These variants may be involved in the development of the subgroup of CRC displaying aberrant DNA methylation and frequently associated with microsatellite instability (MSI). AIM: To investigate the frequencies of the TT and 844ins68 genotypes in CRC patients with MSI+ tumours compared with those with MSI- tumours and a control population. SUBJECTS: Patients with CRC (n=501) and healthy control subjects (n=1207) were studied. CRC cases were classified as MSI+ (n=75) or MSI- (n=426) based on deletions within the BAT-26 mononucleotide repeat. METHODS: Subjects were genotyped for MTHFR using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and PCR-restriction fragment length polymorphism (PCR-RFLP) techniques, and for CBS using PCR. RESULTS: The MTHFR TT genotype was more frequent in older CRC patients (>or=70 y) compared with equivalent aged controls (p=0.03), was associated with a significantly later age of diagnosis in patients with proximal colon tumours (p=0.02), and was almost twice as frequent in MSI+ than in MSI- tumours (p=0.05). Compared with normal controls, the 844ins68 variant of CBS was less frequent in patients with proximal tumours (p=0.02). CONCLUSIONS: The TT genotype of MTHFR is associated with an increased risk of CRC in older populations, possibly due to age related disturbances in folate metabolism. The TT genotype appears to predispose to CRC that is MSI+. This may reflect the involvement of aberrant DNA methylation frequently associated with MSI+. The 844ins68 CBS polymorphism may protect against proximal tumours.     

Genetic risk factors in young adults with 'cryptogenic' ischemic cerebrovascular disease.

Mutations such as factor V Leiden G1691A (FVL), prothrombin G20210A (FIIM), methylenetetrahydrofolate reductase (MTHFR) C677T, cystathionine beta-synthase (CBS) 844ins68 and endothelial cell protein C receptor (EPCR) 4031ins23 are risk factors for thromboembolism. To assess the role of these mutations in young adults with cerebral ischemia of otherwise undetermined etiology, 93 patients younger than 50 years old with thromboembolic strokes or transient ischemic attacks were studied. One hundred and eighty-six healthy age-matched and sex-matched blood donors served as controls. The FVL mutation was detected in 15/93 patients and 13/186 controls. After adjustment for smoking, arterial hypertension, and hyperlipidemia, the association of the FVL mutation with cerebral ischemia [odds ratio (OR), 3.19; 95% confidence interval (CI), 1.38-7.39] remained significant. One of 93 patients and 6/186 controls were carriers of FIIM (OR, 0.33; 95% CI, 0.04-2.75). We detected the MTHFR TT677 genotype in 9/93 patients and 26/186 controls (OR, 0.66; 95% CI, 0.30-1.47), a CBS 844ins68 mutation in 12/93 patients and 19/186 controls (OR, 1.30; 95% CI, 0.60-2.81), and an EPCR 4031ins23 mutation in 1/93 patients and in no control individual (P = 0.33). In conclusion, in younger adults the FVL mutation is a risk factor for cerebrovascular disease. FIIM, the MTHFR TT677 genotype and the CBS 844ins68 mutation did not contribute to the risk in this group of patients. The EPCR 4031ins23 mutation is very rare, its possible role needs further investigation.     

Polygenic influence on plasma homocysteine: association of two prevalent mutations, the 844ins68 of cystathionine beta-synthase and A(2756)G of methionine synthase, with lowered plasma homocysteine levels

A moderately elevated plasma total homocysteine (tHcy), whether measured during fasting or post-methionine load (PML), is increasingly being recognized as a risk factor for coronary artery diseases (CAD). However, etiologies for moderately elevated plasma tHcy, particularly with regard to the role of genetic influence on plasma tHcy levels, are still not well understood. In the current investigation, we studied 1025 individuals with respect to the effect of the 68-bp insertion (844ins68 variant) of the cystathionine beta-synthase (CBS) gene, the A(2756)G transition of the B(12)-dependent methionine synthase (MS) gene and the C(677)T transition of the methylenetetrahydrofolate reductase (MTHFR) gene on fasting and 4 h PML tHcy. Of these individuals, 153 (14.9%) were heterozygous for the 68-bp insertion, 329 (32.1%) were heterozygous for the G(2756) allele and 122 (11.9%) were homozygous for the C(677)T transition. Individuals heterozygous for the insertion had significantly lower PML increase in tHcy concentrations, while individuals homozygous for the A(2756)G transition had significantly lower fasting tHcy levels. A 2-way ANOVA showed that there was no interaction between the 844ins68 and the A(2756)G transition for either fasting tHcy or PML increase in tHcy, confirming the fact that the effect of these two genotypes on plasma tHcy levels are additive. The effects are opposite but additive with the C(677)50% of all individuals in this study carried polymorphic traits, which predisposed them to either higher or lower plasma tHcy concentrations, thus providing new evidence of the importance of genetic influences as determinants of tHcy levels.     

Genetic and nutritional factors contributing to hyperhomocysteinemia in young adults

A modestly elevated total plasma homocysteine concentration (tHcy) is generally accepted as an independent and graded risk factor for various pathologies, including vascular diseases, neural tube defects, Alzheimer disease, and pregnancy complications. We analyzed 5 common functional polymorphisms in enzymes involved in homocysteine metabolism (ie, methylenetetrahydrofolate reductase [MTHFR] 677C>T and 1298A>C, methionine synthase [MTR] 2756A>G, cystathionine beta-synthase [CBS] 844ins68, and methionine synthase reductase [MTRR] 66A>G) in 452 young adults, and quantified their independent and interactive effects on tHcy concentrations. Serum folate, red cell folate, vitamin B(12), and tHcy concentrations were significantly influenced by MTHFR 677C>T genotypes. A particularly strong interaction was observed between the MTHFR 677TT genotype and serum folate, which led to a high tHcy phenotype that was more pronounced in males. The genetic contribution to the variance in tHcy was estimated to be approximately 9%, compared with approximately 35% that could be attributed to low folate and vitamin B(12). Our study indicates that dietary factors are centrally important in the control of tHcy levels in young adults with additional, but somewhat weaker, genetic effects. These data underscore the potential benefits that may be gained by improving the dietary status of young adults, and provide support for the implementation of folate/B-vitamin food fortification programs.     

MTHFR基因和β纤维蛋白原455G/A基因多态性与脑梗死的遗传易感性

目的探讨MTHFR基因和β纤维蛋白原455G/A(βFib 455G/A)基因多态性与脑梗死的遗传易感性。方法运用PCR-RFLP检测154例脑梗死患者(脑梗死组)和83例健康体检者(对照组)MTHFR和βFib 455G/A基因多态性,同时检测纤维蛋白原(Fib)和血浆同型半胱氨酸水平等生化指标。结果脑梗死组患者MTHFR基因的CC、CT、TT基因型频率分别为21.4%、48.1%和30.5%,对照组分别为57.8%、25.3%和16.9%,脑梗死组TT基因型相对危险性为对照组的2.16倍;脑梗死组βFib 455G/A基因GG、GA、AA基因型频率分别为51.3%、40.3%和8.4%,对照组分别为72.3%、21.7%和6.0%。与对照组比较,脑梗死组患者GA基因型和A等位基因频率明显增高(P<0.05);具有CT+AA基因型或TT+GA基因型个体易患脑梗死,相对危险性为2.7和2.2。结论MTHFR基因突变后T等位基因和βFib基因突变后的A等位基因可能是脑梗死发生的一个遗传易感基因,MTHFR基因中CC型可能是脑梗死的保护因子,MTHFR基因和βFib 455G/A基因突变间可能存在协同作用。     

动脉粥样硬化性脑梗死患者血浆同型半胱氨酸水平及亚甲基四氢叶酸还原酶基因多态性

目的 探讨血浆同型半胱氨酸水平、亚甲基四氢叶酸还原酶基因多态性与动脉粥样硬化性脑梗死之间的关系.方法 选择性别、年龄匹配的动脉粥样硬化性脑梗死患者(脑梗死组)68例及对照组50例,采用荧光偏振免疫法测定血浆同型半胱氨酸水平,聚合酶链反应-限制性片长多态性技术检测亚甲基四氢叶酸还原酶基因多态性.结果 脑梗死组TT基因型(36.8%比16.0%)及T等位基因频率(59.6%比38.0%)均显著高于对照组(P<0.05).脑梗死组血浆同型半胱氨酸水平显著高于对照组(P<0.05).脑梗死组和对照组亚甲基四氢叶酸还原酶 677TT纯合子血浆同型半胱氨酸水平均显著高于CT型和CC型者(P<0.05).结论 血浆同型半胱氨酸水平升高是动脉粥样硬化性脑梗死的危险因素.亚甲基四氢叶酸还原酶 C677T基因多态性与血浆同型半胱氨酸水平密切相关,与动脉粥样硬化性脑梗死显著相关.