N5，N10-亚甲基四氢叶酸还原酶基因多态性及血浆同型半胱氨酸与冠心病的关系

目的研究N5,N10-亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性、血浆同型半胱氨酸(Hcy)与冠心病的关系。方法选取2013年至2015年在我院住院的冠心病患者256例,按年龄分为60岁组(中青年组)107例及≥60岁组(老年组)149例,选取同期行健康体检的人群145例作为对照组,应用聚合酶链反应(PCR)技术和基因芯片分析技术检测MTHFR基因C677T多态性,应用高效液相色谱法测定血浆Hcy水平,分析不同组群之间MTHFR基因C677T多态性的分布及Hcy水平。结果 MTHFR基因分布频率:中青年组CC型、CT型、TT型基因频率分别为26.2%,43.9%,29.9%,C等位基因频率为48.1%,T等位基因频率为51.9%。中青年组CC型、CT型、TT型基因频率分别为35.6%,42.3%,22.1%,C等位基因频率为56.8%,T等位基因频率为43.2%。对照组CC型、CT型、TT型基因频率分别为37.9%,40.1%,21.4%,C等位基因频率为58.3%,T等位基因频率为41.7%。中青年组T等位基因频率明显高于对照组(χ~2=5.10,P=0.015),中青年组Hcy浓度明显高于对照组。老年组T等位基因频率与对照组比较差异无显著性(χ~2=0.147,P=0.382),两组间Hcy浓度差异无显著性。各组的TT基因型者血浆Hcy浓度均明显高于CC和TC基因型者(P0.01),而后两者间差异无显著性。结论 MTHFR基因TT型可导致Hcy水平明显升高,MTHFR基因C677T点突变仅与中青年组冠心病患者相关,与老年组冠心病患者无明显相关,Hcy水平升高及MTHFR基因T等位基因频率增高可能为中青年冠心病患者的危险因素,提示不同年龄阶段的冠心病患者发病的机制可能存在差异。     

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.     

连接蛋白37基因I1297D多态性与中国北方汉族人群早发冠心病的相关性

目的探讨连接蛋白37基因I1297D多态性与早发冠心病的关系。方法采用聚合酶链反应—限制片长多态性技术,对196例经冠状动脉造影证实的早发冠心病患者和218例健康对照者进行检测,分析连接蛋白37基因I1297D多态性的基因型和等位基因频率分布情况。结果连接蛋白37基因I1297D多态性在冠心病组以ID基因型为主,对照组以II基因型为主,两组中均以DD基因型和D等位基因为少见型。基因型(II型,ID型和DD型)分布频率在早发冠心病组分别为44.39%、47.45%和8.16%,在对照组分别为47.71%、44.04%和8.25%,两组间比较差异无统计学意义(χ2=0.51,P=0.77)。等位基因分布在人群中以I等位基因为主,两组间分布频率相似(68.11%比69.72%,P=0.62,OR=0.93,95%可信区间为0.70~1.24);D等位基因携带者(ID DD)在冠心病组和对照组分别为55.61%和52.29%,与II纯合子相比,冠心病的患病风险在两组间差异无统计学意义(χ2=0.46,P=0.50,OR=0.87,95%可信区间=0.58~1.30)。对心肌梗死患者分层分析显示,I1297D基因型和等位基因分布频率在心肌梗死组和对照组间差异无统计学意义(χ2=0.24,P=0.89;χ2=0.13,P=0.72)。Logistic回归校正性别、年龄、体重指数、吸烟、高血压、高脂血症、糖尿病等冠心病易患因素后,I1297D多态性在病例组和对照组差异无统计学意义(P>0.05)。结论连接蛋白37基因I1297D多态性与中国北方汉族人群早发冠心病易感性无明显关联。     

5,10-亚甲基四氢叶酸还原酶C677T基因多态性与老年单纯收缩期高血压的相关性研究

目的探讨5,10-亚甲基四氢叶酸还原酶(MTHFR)C677T基因多态性与老年单纯收缩期高血压(ISH)发病的相关性。方法入选220例年龄≥60岁ISH患者为ISH组,选择同期体检无高血压老年人群128例为对照组。检测入选者MTHFR C677T基因多态性及血浆同型半胱氨酸水平。结果ISH组T等位基因频率高于对照组(51.8%vs 37.5%,χ~2=13.33,P=0.000),C等位基因频率低于对照组(48.2%vs 62.5%,χ~2=13.33,P=0.000);CC基因型分布低于对照组(20.5%vs 40.6%,χ~2=16.38,P=0.000),CT基因型分布高于对照组(55.5%vs43.8%,χ~2=4.44,P=0.035);血浆同型半胱氨酸水平均高于对照组(13.35μmol/L vs 11.75μmol/L,P=0.01)。logistic回归分析显示,MTHFR C677T基因型(OR=1.910,95%CI:1.356~2.690,P=0.00)、同型半胱氨酸水平(OR=1.084,95%CI:1.031~1.140,P=0.02)、血尿酸水平(OR=1.004,95%CI:1.001~1.006,P=0.01)为老年ISH患病的独立预测因素。结论 MTHFR C677T基因多态性及血浆同型半胱氨酸水平是老年ISH发病的独立危险因素。     

SORL1基因多态性与散发性阿尔茨海默病关联分析

目的分析SORL1基因多态性与散发性阿尔茨海默病(SAD)是否存在关联。方法采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术,检测114例SAD患者及111例健康对照者的SORL1基因多态性分布特征。结果 SAD组与对照组SORL1基因型及等位基因频率分布差异无统计学意义(χ2=1.693,P=0.429,χ2=0.965,P=0.326)。不同性别的SAD组与对照组SORL1基因型及等位基因频率分布差异无统计学意义(男性:χ2=2.324,P=0.313,χ2=1.667,P=0.197;女性:χ2=2.878,P=0.237,χ2=0.058,P=0.810)。结论亚洲汉族人群SORL1基因rs641120位点的A/GSNP多态性与SAD可能无关联。     

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。     

妊娠相关蛋白A基因多态性与早发冠心病相关性研究

目的:探讨妊娠相关蛋白A(PAPP-A)第14外显子A/C(Tyr/Ser)基因多态性与我国早发冠心病的相关性.方法:早发冠心病(病例组)85例,非冠心病(对照组)93例,采用聚合酶链反应-限制性片段长度多态性方法(PCR-RFLP)分析PAPP-A基因多态性.结果:病例组PAPP-A基因型中CC型频率高于对照组,但2组总的基因型频率分布差异有统计学意义(χ2=10.302,P=0.016),A、C等位基因频率差异有统计学意义(P＜0.05).结论:PAPP-A第14外显子A/C(Tyr/Ser)基因多态性可能与我国早发冠心病的易感性有关.     

MTHFR基因多态性与法洛四联症的相关性研究

目的探讨5,10-亚甲基四氢叶酸还原酶(MTHFR)基因多态性与法洛四联症(TOF)的关系。方法选择136例TOF患儿(观察组)和277例健康儿童(对照组),应用PCR-限制性片段长度多态性结合直接测序法对两组MTHFR基因C677T位点多态性进行检测,分析两组基因型频率分布及各基因型与TOF的关系。采用SPSS13.0软件对数据进行分析。结果 MTHFR基因C677T突变基因型TT在观察组发生率显著高于对照组,P<0.05(χ2=11.89);T等位基因携带者患TOF的风险高于C等位基因携带者(OR=0.553,95%CI为0.412 3～0.741 4)。结论MTHFR基因多态性与TOF存在明显相关性,MTHFR基因可能是TOF的遗传易感基因。     

汉族脑卒中与N5,N10亚甲基四氢叶酸还原酶基因多态性的相关性研究

目的　探讨人体 N5,N1 0亚甲基四氢叶酸还原酶 (MTHFR)的基因多态性与脑卒中的遗传相关性。方法　采用限制性内切酶片段长度多态性方法 (PCR- RFLP) ,对 67例脑卒中病人和 78例健康人 MTHFR基因 C677T多态性位点进行检测。结果　病例组 MTHFR基因 T、C等位基因频率分别为 53%、47%,对照组为 39.7%、60 .3%,两组显著性差异 (χ2 =5.0 9,P<0 .0 5)。 TT型携带者较 CC型携带者罹患脑卒中的相对风险度为 2 .35(95%CI1 .0 2～ 5.43)。 T等位基因携带者较 C等位基因携带者罹患脑卒中的相对风险度为 1 .71 (95%CI1 .0 7～ 2 .74)。出血性卒中与缺血性卒中之间等位基因及等位基因型频率无明显差异。结论　脑卒中汉族人群 MTHFR基因 C677T位点多态性与脑卒中有相关性 ,MTHFR基因可能是脑卒中的一个易感基因。     

ApoE、CYP46基因多态性与阿尔茨海默病相关性分析

目的 探讨中国汉族人群山西地区载脂蛋白E( ApoE )基因与胆固醇24S-羟化酶(CYP46 )基因第二内含子T/C多态性在阿尔茨海默病(AD)发病中的作用.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40例AD患者(AD组)和36名正常老年人(对照组)ApoE基因、CYP46基因多态性,进行关联分析.结果 AD组与对照组比较,AD组等位基因ε4频率显著升高(χ2=16.151,P＜0.001),AD组与等位基因ε4呈正关联(OR=9.281,CI 2.650～32.497).AD组与对照组CYP46基因的3种基因型分布总体差异有统计学意义(χ2=6.863,P=0.032),AD组T等位基因(T/T+T/C)频率明显高于健康对照组(χ2=4.823,P=0.028).在ApoEε4携带者和非携带者中,CYP46基因T等位基因与AD无统计学意义(P＞0.05).结论 中国汉族人群中,ApoE等位基因ε4和CYP46等位基因T可能是AD发病的危险因素,ApoE基因多态性和CYP46基因多态性与AD呈正相关.     

冠心病患者亚甲基四氢叶酸还原酶基因多态性87例研究

目的探讨N5,N10-亚甲基四氢叶酸还原酶(MTHFR)基因多态性与冠心病的关系。方法对2003年11月至2005年8月贵阳医学院附属医院及贵州市第二人民医院住院的87例冠心病患者(冠心病组)及同期在门诊进行健康体检的73名健康人(对照组),采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)法检测其MTHFRC677T基因多态性。结果对照组与冠心病组MTHFR677位T等位基因的分布频率分别是18.5%,36.1%,病例组MTHFR基因C677T的CT基因型及T等位基因频率显著高于对照组,差异有显著性(P<0.05)。结论MTHFRC677T基因多态性与冠心病密切相关。     

MTHFR基因多态性与冠心病的关系

目的研究天津地区人群N^5,N^10-亚甲基四氢叶酸还原酶（MTHFR）基因C677T多态性与冠心病的关系。方法应用聚合酶链反应（PCR）技术和限制性酶切片段长度多态性（RFLP）分析技术检测50例冠心病患者（冠心病组）和50例正常人（对照组）的MTHFR基因C677T多态性,应用高效液相色谱法测定血浆同型半胱氨酸（Hcy）水平,采用125I标记放免法测定血清叶酸浓度。结果1.冠心病组与对照组MTHFR基因频率分布不同（P〈0.05）,对照组CC型、TC型、TT型基因频率分别为52.0%,28.0%,20.0%,冠心病组分别为26.0%,44.0%,30.0%。冠心病组T等位基因频率为52.0%,C等位基因频率为48.0%,与对照组比较有显著性差异（P〈0.05）。2.两组的TT基因型者血浆Hcy浓度均明显高于CC和TC基因型者（P〈0.05）,而后两者间无显著性差异（P〉0.05）。3.冠心病组Hcy浓度高于照组（P〈0.05）,两组叶酸水平无显著性差异（P〉0.05）,血浆Hcy浓度与叶酸水平呈显著负相关（r分别为-0.617和-0.588,P〈0.05）。结论MTHFR基因C677T点突变与冠心病发病密切相关,MTHFR基因纯合突变是引起高Hcy血症的一个重要的遗传因素。     

凝血因子Ⅶ基因R353Q、-323 0/10bp多态性与冠心病的相关性及在宁夏回、汉族人群中的分布特点

目的:探讨血浆凝血因子Ⅶ(coagulation factorⅦ,FⅦ)水平及其基因的多态性与回、汉族人群冠心病的关系。方法:采用候选基因及病例-对照研究的方法,以聚合酶链反应及限制性片段长度多态性技术,对420例回族冠心病患者及508名回族健康者,以及600例汉族冠心病患者和604例汉族健康者行FⅦ基因的R353Q、-3230/10bp多态性分析并确定基因型,同时采用重组可溶性组织因子法测定血浆FⅦa水平。结果:回、汉族冠心病组血浆FⅦa水平显著高于回、汉族对照组,经检验有显著差异(P0.01);回、汉族急性心肌梗死(AMI)组血浆FⅦa水平均高于不稳定型心绞痛(UAP)组(P0.01)。②回族组与汉族组相比FⅦ基因的R353Q、-3230/10bp多态性存在统计学差异(P0.01)。③回族冠心病组Q/Q基因型和Q等位基因频率明显少于对照组(P0.01),10/10基因型比例高于对照组(P=0.01),但10等位基因频率低于对照组(P0.05);汉族冠心病组10/10基因型及10等位基因频率低于对照组(P0.01)。④回族AMI组R/Q+Q/Q基因型及Q等位基因频率显著低于UAP组(P0.01);汉族AMI组10/10+0/10基因型及10等位基因频率显著低于UAP组(P0.01)。⑤血浆FⅦa水平与回族组FⅦR353Q基因多态性显著相关,RR基因型血浆FⅦa水平高于R/Q及Q/Q基因型(P0.05)。结论:回、汉族人群中存在FⅦ基因的R353Q、-3230/10bp多态性;②回族冠心病患者血浆FⅦa水平受其基因的R353Q多态性影响,Q等位基因可能是回族人群心肌梗死的遗传保护因子;③-3230/10bp多态性可能在汉族人群冠心病的的发生发展中起一定作用。     

亚甲基四氢叶酸还原酶基因多态性与原发性高血压患者合并冠心病的相关性研究

目的探讨N5,10-亚甲基四氢叶酸还原酶(MTHFR)C677T位点突变与河南豫北地区原发性高血压及其合并冠心病发病的关系。方法选择原发性高血压患者405例为高血压组,高血压合并冠心病患者400例为冠心病组,健康体检者400例为对照组。对3组MTHFR基因C677T多态性进行基因分型。结果冠心病组T等位基因频率和TT基因型频率明显高于高血压组和对照组(P<0.05)。冠心病组TT基因型患者TC和血浆同型半胱氨酸水平明显高于CC+CT基因型(P<0.05)。结论 MTHFR基因C677T多态性与原发性高血压患者冠心病的发生相关。     

C677T gene polymorphism of methylenetetrahydrofolate reductase (MTHFR) in patients with myocardial infarction

Hyperhomocysteinemia is thought to be an independent risk factor for coronary heart disease. Increased plasma homocysteine level can result from malnutrition (e.g. folate deficiency) and/or genetic-related disturbances. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the synthesis of 5-methyltetrahydrofolate, the methyl donor for homocysteine remethylation to methionine. Transition of cytosine (C) to thymidine (T) at nucleotide position 677 of MTHFR gene causes alanine 226-to-valine substitution, and in consequence results in decreased enzyme activity and increased homocysteine level. Therefore, the aim of our study was to estimate the frequency distribution of C677T MTHFR polymorphism in patients with past myocardial infarction (MI), and to evaluate the association between this polymorphism and age of MI onset or left ventricular mass (LVM). The study was performed in 100 MI patients aged from 34 to 76 years and in control group consisted of 100 age- and gender-matched non-MI subjects. Applying PCR followed by Hinf I digestion of amplification products no significant difference in the frequency distribution of C677T MTHFR genotypes has been found between both groups (MI patients: 46% CC, 45% CT and 9% TT, and control group: 39% CC, 50% CT and 11% TT, respectively). No significant association between MTHFR genotypes and age of MI onset or LVM has been found in MI group. The results of our study suggest that C677T polymorphism of MTHFR gene is not a risk factor for myocardial infarction in Polish population.     

Methylenetetrahydrofolate reductase polymorphism associated with susceptibility to coronary heart disease in Chinese type 2 diabetic patients

OBJECTIVE: Epidemiological studies have identified hyperhomocyst(e)inemia as an independent risk factor for atherosclerosis. The C677T variant of the methylenetetrahydrofolate reductase (MTHFR) gene, one of the key enzymes catalyzing remethylation of homocysteine, might play a role in the development of coronary heart disease (CHD). In this study, we examined the distribution of the MTHFR genotypes in the Chinese population and the association between the C677T variant and CHD in Chinese type 2 diabetic patients. METHODS: Two hundred and twenty-eight unrelated patients with type 2 diabetes mellitus (126 with coronary heart disease) and 114 healthy control subjects were recruited. The MTHFR genotype was analyzed by PCR followed by HinfI digestion. Plasma total homocysteine levels were measured using high-performance liquid chromatography (HPLC) with fluorescence detection. RESULTS: In 114 healthy control subjects, the frequency of the mutant T allele was 38.0%, comparable to that of a Hong Kong (Chinese) population. The genotype distribution did not differ between control subjects and type 2 diabetic patients (chi(2) = 3.67, P > 0.05). Genotypic analysis revealed that type 2 diabetic patients with CHD displayed a greater prevalence of T allele (45.2%) than type 2 diabetic patients without CHD (30.4%) (chi(2) = 8.72, P < 0.005). The odds ratio for CHD in type 2 diabetic patients in presence of T allele was 1.89 (CI 95%, 1.24-2.88). The MTHFR genotype were different between diabetic patients with and without CHD (chi(2) = 11.98, P < 0.005). Moreover, plasma homocysteine levels were markedly higher in individuals with TT genotype than those with CC or CT genotype or CC plus CT genotype. CONCLUSIONS: The C677T mutation of MTHFR gene is common in the Chinese population. MTHFR C677T gene polymorphism associated with a predisposition to increased plasma homocysteine levels could constitute a useful predictive marker for CHD in Chinese type 2 diabetic patients.     

Genetic risk factors in acute coronary disease

OBJECTIVE: We investigate whether each of the following: HPA-1, Factor V Leiden, prothrombin gene variant and the methylene tetrahydrofolate reductase gene (MTHFR) mutation, are risk factors for acute coronary disease in Portuguese patients. MATERIAL AND METHODS: 100 blood donors and 52 patients with an established diagnosis of myocardial infarction or unstable angina were evaluated for genetic risk factors, by determining HPA-1 genotype, Factor V Leiden, Prothrombin 20210 variant and MTHFR mutation. RESULTS: We found a prevalence of 2.0% for Factor V Leiden, 5.0% for the Prothrombin 20210 variant and 66% for the MTHFR mutation in blood donors. These values are similar to those found in the patients (1.9, 3.8 and 58%, respectively). We found that 28/100 controls had the PI(A2) polymorphism, a frequency statistically different from that in the patients (23/52). This difference was even more pronounced in patients less than 60 years old (27/96 vs. 13/24). CONCLUSION: Factor V Leiden, Prothrombin 20210 variant and MTHFR mutation do not seem to represent risk factors for acute coronary disease. However, the PI(A2) polymorphism could have a role in the pathogenesis of this disease. The presence of multiple genetic factors, more than single ones, could influence the development and outcome of myocardial infarction and unstable angina. Larger studies are needed in order to have a better insight into the pathophysiological mechanisms of this disease, along with its prevention and the development of new treatments.     

Angiotensin-converting enzyme gene polymorphism and coronary heart disease in Turkish type 2 diabetic patients

OBJECTIVE: It has been suggested that the insertion (I)/deletion (D) polymorphism of the angiotensin-converting enzyme (ACE) may be associated with atherosclerosis.The aim of the study was to examine the association between ACE gene polymorphism and coronary heart disease in Turkish type 2 diabetic patients. METHODS AND RESULTS: A total of 152 (97 female, 55 male) type 2 diabetic patients were included into the study. All patients underwent myocardial perfusion scintigraphic examination and forty-five of them with a perfusion defect underwent coronary angiography.Thirty-eight patients with a coronary stenosis of more than 50% on coronary angiography were considered as having coronary heart disease.The I/D polymorphism was determined by polymerase chain reaction.There was no statistically significant difference in genotypic and allelic frequencies of the ACE I/D polymorphism among patients with and without coronary heart disease (DD:ID:II (%), 32:58:11 and 39:44:17, respectively). CONCLUSIONS: ACE gene polymorphism is not a significant parameter to determine coronary heart disease in Turkish type 2 diabetic patients.     

Differing relationships of methylene tetrahydrofolate reductase genotypes with cardiovascular risk in familial and polygenic hypercholesterolaemia

BACKGROUND: Plasma homocysteine and the methylene tetrahydrofolate reductase C677T polymorphism have been suggested as being risk factors for cardiovascular disease. OBJECTIVE: To determine whether plasma homocysteine and the methylene tetrahydrofolate reductase C677T polymorphism are risk factors for coronary heart disease in patients with heterozygous familial hypercholesterolaemia as compared with those with polygenic hyperlipidaemia. METHODS: Plasma homocysteine and the methylene tetrahydrofolate reductase polymorphism were assessed with other risk factors in 112 patients with familial hypercholesterolaemia and 72 patients with polygenic hyperlipidaemia, of whom 29 (25.8%) and 30 (41%) respectively had established cardiovascular disease and in 100 healthy normal subjects. RESULTS: Plasma homocysteine was not significantly elevated in patients with and without coronary heart disease with familial hypercholesterolaemia or polygenic hyperlipidaemia compared with controls. The allele frequencies for C677T were significantly different in patients with coronary heart disease and with polygenic hyperlipidaemia (0.35 versus 0.29) (P = 0.02) as opposed to those with coronary heart disease and familial hypercholesterolaemia (0.25 versus 0.30) (P = 0.63). Methylene tetrahydrofolate reductase genotype but not homocysteine had a weak association with coronary heart disease in logistic regression analysis in patients with polygenic hyperlipidaemia (P = 0.05) but neither methylene tetrahydrofolate reductase genotype or plasma homocysteine was a risk factor in patients with familial hypercholesterolaemia. CONCLUSION: Whilst methylene tetrahydrofolate reductase genotype may be a weak risk factor for coronary heart disease in polygenic hyperlipidaemia as opposed to familial hypercholesterolaemia, homocysteine does not seem to be an important risk factor for coronary heart disease in patients in southern UK.