Methylenetetrahydrofolate reductase gene, homocysteine and coronary artery disease: the A1298C polymorphism does matter. Inferences from a case study (Madeira, Portugal)

Elevated levels of plasma homocysteine, an independent risk factor and a strong predictor of mortality in patients with coronary artery disease (CAD), can result from nutritional deficiencies or genetic errors, including methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms. The contribution of these polymorphisms in the development of CAD remains controversial. We analysed the impact of MTHFR C677T and A1298C on fasting homocysteine and CAD in 298 CAD patients proved by angiography and 510 control subjects from the Island of Madeira (Portugal). After adjustment for other risk factors, plasma homocysteine remained independently correlated with CAD. Serum homocysteine was significantly higher in individuals with 677TT and 1298AA genotypes. There was no difference in the distribution of MTHFR677 genotypes between cases and controls but a significant increase in 1298AA prevalence was found in CAD patients. In spite of the clear effect of C677T mutation on elevated homocysteine levels we only found an association between 1298AA genotype and CAD in this population. The simultaneous presence of 677CT and 1298AA genotypes provides a significant risk of developing the disease, while the 1298AC genotype, combined with 677CC, shows a significant trend towards a decrease in CAD occurrence. The data shows an independent association between elevated levels of homocysteine and CAD. Both MTHFR polymorphisms are associated with increased fasting homocysteine (677TT and 1298AA genotypes), but only the 1298AA variant shows an increased prevalence in CAD group. Odds ratio seem to indicate that individuals with the MTHFR 1298AA genotype and the 677CT/1298AA compound genotype had a 1.6-fold increased risk for developing CAD suggesting a possible association of MTHFR polymorphisms with the risk of CAD in Madeira population.     

Multidisciplinary approach of organic catatonia in children and adolescents may improve treatment decision making

Catatonia is an infrequent but severe condition in young people. Organic diseases may be associated and need to be investigated though no specific recommendations and guidelines are available. We extensively reviewed the literature of all the cases of organic catatonia in children and adolescents from January 1969 to June 2007. We screened socio-demographic characteristics, organic diagnosis, clinical characteristics and treatment. We found 38 cases of children and adolescents with catatonia due to an organic condition. The catatonic syndrome occurred in 21 (57%) females and 16 (43%) males. The mean age of patients was 14.5 years (+/-3.39) [range=7-18 years], and three died from their condition. The organic conditions included infectious diseases (N=10), neurological conditions (N=10), toxic induced states (N=12) and genetic conditions including inborn errors of metabolism (N=6). The onset was dominantly acute, and the clinical presentation most frequently stuporous. Although benzodiazepines were recommended as primary symptomatic treatment, they were rarely prescribed. In several cases, therapeutic approach was related to organic cause (e.g., plasma exchange in lupus erythematosus; copper chelators in Wilson's disease). Based on this review and on our own experience of catatonia in youth, we proposed a consensual and multidisciplinary diagnostic strategy to help practitioners to identify underlying organic diseases.     

Effects of the C677T and A1298C polymorphisms of the MTHFR gene on the genetic predisposition for diabetic nephropathy.

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) is a regulatory enzyme of homocysteine metabolism. The C677T polymorphism of the MTHFR gene has been reported to be associated with elevated plasma homocysteine in patients with low folic acid intake. A recently reported second common polymorphism, A1298C, may increase homocysteine, but only in individuals carrying the T677 allele. This study aimed to investigate the influence of the C677T and A1298C polymorphisms of the MTHFR gene on the development of diabetic nephropathy in Caucasian patients with type 2 diabetes. METHODS: We genotyped 429 type 2 diabetic patients for the C677T and A1298C polymorphisms using standard PCR-based protocols, and divided them into three groups based on renal status: 159 patients with normoalbuminuria, 149 with microalbuminuria, and 121 with persistent proteinuria and chronic renal failure (CRF). The C677T and A1298C genotype frequencies were compared among the three groups. RESULTS: Although the frequencies of the CT and TT genotypes of the C677T polymorphism tended to increase with each stage of diabetic nephropathy (53, 56 and 63% in normoalbuminuria, microalbuminuria and proteinuria/CRF, respectively), these differences were not significant. When male and female patients were analysed separately, the effect was seen only in males. The CT + TT genotype was present in 46% of male patients with normoalbuminuria, in 57% with microalbuminuria and in 68% with proteinuria/CRF (OR = 2.46; 95% CI 1.13-5.38). There were no differ-ences in the A1298C polymorphism among the three groups. CONCLUSIONS: These findings indicate that the C677T polymorphism is a risk factor for diabetic nephrop-athy in male patients with type 2 diabetes.     

孕期疾病与5,10-亚甲基四氢叶酸还原酶基因对先天性心脏病影响的病例-对照研究

目的探讨5,10-亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性、孕期疾病及其交互作用与子代先天性心脏病的关系。方法采用以医院为基础的病例对照研究设计,按照纳入和剔除标准选择144例先天性心脏病(先心病)病例与168例健康对照,通过聚合酶链反应-限制性片段长度多态性(polymerase chain reaction restricted fragment length polymorphism,PCR-RFLP)检测MTHFR C677T基因型,并对母亲孕期患病情况进行调查;采用单因素和多因素非条件logistic回归模型,分析影响因素关联强度及交互作用。结果病例组和对照组MTHFR 677TT基因型频率和T等位基因频率的差异有统计学意义(χ2=22.38,P<0.001;χ2=20.36,P<0.0001),MTHFR 677TT基因型与先心病风险的OR值为3.215(95%CI:1.958～5.280);妊高症、孕期感冒发烧是先心病的危险因素,其OR值分别为4.545(95%CI:1.788～11.553)、3.885(95%CI:1.756～8.592);MTHFR 677TT基因型与孕期两种疾病之间具有正相加交互作用,调整混杂因素前后,TT基因型与妊高症的I(AB)为5.469、6.011,AP(AB)为32.33%、33.67%,AP*(AB)为36.28%、37.54%;与孕期感冒发烧之间的I(AB)为4.165、5.951,AP(AB)为30.02%、31.36%,AP*(AB)为31.65%、33.38%。结论 MTHFR 677TT基因型是先心病的易感因素;妊高症、孕期感冒发烧是子代先心病发生的危险因素;MTHFR 677TT基因型与孕期两种疾病对先心病具有协同作用。     

Association between MTHFR variant and diabetic neuropathy

Background

Methylene-tetrahydrofolate reductase (MTHFR) gene variant may play an important role in the pathophysiology of diabetes and its complications due to its influence on plasma homocysteine levels and also its effect on scavenging peroxynitrite radicals. Diabetic peripheral neuropathy (DPN) is one of the most common diabetic chronic complications. The aim of this study was to investigate the relationship between diabetic neuropathy and MTHFR gene C677T and 1298A ?C polymorphisms.

早期糖尿病肾病患者亚甲基四氢叶酸还原酶C676T突变的相关因素及中医证型分析

目的探讨早期糖尿病肾病(DN)患者基因突变与中医证型的关系。方法应用聚合酶链反应限制性片段长度多态性的方法,检测63例早期DN患者亚甲基四氢叶酸还原酶(MTHFR)基因的677碱基多态性情况,测定患者血浆同型半胱氨酸(Hcy)、叶酸浓度、空腹血糖、餐后血糖、糖化血红蛋白(HbA1C)、尿白蛋白排泄率(UAER)及血脂,并记录患者的中医证型。结果63例早期DN患者中CC型19例,TT例17例,CT型27例,TT、TC、CC的基因型频率分别为27.00%、42.85%、30.15%;T等位基因频率为48.41%,C等位基因频率51.59%。MTHFR基因的C676T突变与Hcy水平相关(P0.01);与甘油三酯(TG)水平相关(P0.05)。中医证型与基因型具有相关性(P0.01),CC型基因多辨证为阴虚热盛,杂合子基因型CT多辨证为气阴两虚,纯合子基因型TT多辨证为阴阳两虚。结论早期糖尿病肾病患者MTHFR基因的677碱基多态性与Hcy、TG、中医证候相关。     

云南人亚甲基四氢叶酸还原酶基因型多态性与乳腺癌易感性的关联

 目的亚甲基四氢叶酸还原酶(MTHFR)是叶酸代谢的关键性酶,其催化作用决定了DNA甲基化与DNA合成之间的平衡。MTHFR基因多态性可能会影响叶酸代谢结局,从而构成肿瘤风险因子。研究分析了MTHFR各基因型在云南籍乳腺癌人群和正常人群中的分布差异,初步探索了MTH-FR多态性与乳腺癌易感性之间的关系。方法以多重PCR-RFLP技术,对125例云南籍乳腺癌患者和103例正常人群MTHFR677位点1298位点多态性进行筛查。结果未发现MTHFRC677T和A1298C基因型频率在乳腺癌和对照样本之间存在显著差异。结论在目前样本条件下,上述两个MTHFR位点基因型多态性与云南籍人群的乳腺癌易感性之间无明显相关性。