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Polymorphism (C677T) in the 5,10-Methylenetetrahydrofolate reductase (MTHFR) gene: A preliminary study on north Indian men

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An elevated level of plasma homocysteine, sulfur containing amino acid generated through demethylation of methionine has been widely accepted as a risk factor for cardiovascular disease (CVD). The increase can result from genetic and/or nutrient related disturbances in the remethylation or transsulfuration pathways for homocysteine metabolism. A common mutation (C677T) in the gene encoding for the enzyme 5, 10-methylenetetrahydrofolate reductase (MTHFR) or deficiency of the B vitamins namely folic acid, B(12), B(6) can lead to hyperhomocysteinemia.In the present study, we have investigated the incidence of the (C677T) MTHFR polymorphism in the North Indian males. 141 angiographically proven coronary artery disease (CAD) patients and 55 age and sex matched healthy volunteers were examined for the association between MTHFR gene polymorphism and CAD. The MTHFR genotyping was performed using polymerase chain reaction (PCR) followed by restriction-isotyping with Hinf 1 endonuclease. A trend for higher 'T' allele frequency (0.19) was observed in patients than in controls (0.16). However no significant association was found between C677T mutation and CAD severity. The lack of statistical significance could be due to the small sample size studied. Hence a larger study including various ethnic groups is warranted.
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... Methylenetetrahydrofolate reductase (MTHFR) is an enzyme that catalyses the reduction of 5′,10′-methylenetetrahydrofolate to 5′-methyltetrahydrofolate; a major form of folate in plasma, and a carbon donor for the remethylation of homocysteine to methionine (Kluijtmans and Whitehead, 2001;Vasisht et al., 2002). The enzyme is therefore responsible for reducing levels of homocysteine in the plasma. ...
... A common SNP at position 677 of the MTHFR gene (rs1801133) in which a cytosine is converted to thymine, results in the substitution of an alanine residue to valine in the enzyme (Anderson et al., 1997). The encoded protein has reduced activity at 37°C and higher, and thus the C677T SNP is termed "thermolabile" (Vasisht et al., 2002). The MTHFR 677 TT genotype has been linked to increased plasma homocysteine levels (Anderson et al., 1997;Clarke et al., 2012;Mehlig et al., 2013;Nienaber-Rousseau et al., 2013). ...
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Methylenetetrahydrofolate Reductase C677T polymorphism is associated with increased risk of coronary artery disease P. Ramkaran*, A. Phulukdaree*, S. Khan#, D. Moodley* and A.A. Chuturgoon* *Discipline of Medical Biochemistry and Chemical Pathology, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa #Department of Cardiology, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa Background: Methylenetetrahydrofolate reductase (MTHFR) reduces 5’,10’-methylenetetrahydrofolate to 5’-methylenetetrahydrofolate and re-methylates homocysteine to methionine, two important reactions involved in methylation pathways and folate metabolism. The common MTHFR C677T single nucleotide polymorphism (SNP) (rs1801133) has been associated with raised levels of homocysteine, a well known risk factor for coronary artery disease (CAD). There is a high prevalence of aggressive and premature CAD in our local Indian population. The MTHFR C677T SNP has not been investigated in this population. The present study therefore investigated the MTHFR C677T SNP in young Indian patients with CAD compared to age-and sex-matched Indian and Black controls. Methods: A total of 290 subjects were recruited into this study which included 106 CAD patients (confirmed on angiography, mean age 37.5, range 24 - 45 years), 100 age-, sex- and race-matched controls, and 84 age- and sex-matched Black controls. Polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) was used to genotype CAD patients and healthy controls. Data for clinical markers were obtained from pathology reports. Results: The MTHFR 677 T allele was found at a higher frequency in the total Indian group (10%) compared to the total Black population (2%) (p=0.0007, odds ratio (OR) = 4.778 95% confidence interval (CI) 1.687-13.53). The frequency of the MTHFR 677 T allele was significantly higher in CAD patients (14%) than in the control group (7%) (p=0.0353, OR=0.475 95% CI 0.2431-0.9281). The MTHFR C677T SNP did not significantly influence levels of total cholesterol, LDL, HDL, triglycerides, fasting glucose, fasting insulin or hsCRP in CAD patients compared to controls. Conclusion: The MTHFR 677 T variant allele is associated with increased risk of CAD in young patients of Indian ethnicity.
... The polymorphic variation of C677T allele (rs1801133) , the missense (point) mutation is responsible for the reduction enzymatic activity (30% -70%) followed by increase "risk factor" in the variety of disease in heterozygous condition other than CHDs, such as neural tube defects (NTD), mental retardation, miscarriage and cancers [12][13][14][15][16][17]. Only few studies have been demonstrated regarding variations of MTHFR allele in CHD cases in Indian population [18,19]. Therefore, the present study has been designed to evaluate the frequency of karyotypic variations in individual case and try to find out their correlation with penetrance of MTHFR C677T gene polymorphism as "risk factor" in CHDs cases to confirm the hypothesis that congenital anomalies are polygenic in nature. ...
... In the present study, we report for the first time the role of MTHFR C677T polymorphism and codominance of chromosome variations in CHDs cases in the Eastern region of India. Previously, few studies have been reported mutant "T'' allele of MTHFR in CHDs[18,19]. Our results indicate that the frequency of the putative risk allele C677T was 25%, which is similar to meta-analysis study performed by Xuan et al where they identified frequency of 28.99% in Caucasian children and 31.76% in the Caucasian maternal population, although higher frequency (42.28%) has been reported in Asian population ...
... Methylenetetrahydrofolate reductase (MTHFR) is an enzyme that catalyses the reduction of 5′,10′-methylenetetrahydrofolate to 5′-methyltetrahydrofolate; a major form of folate in plasma, and a carbon donor for the remethylation of homocysteine to methionine (Kluijtmans and Whitehead, 2001;Vasisht et al., 2002). The enzyme is therefore responsible for reducing levels of homocysteine in the plasma. ...
... A common SNP at position 677 of the MTHFR gene (rs1801133) in which a cytosine is converted to thymine, results in the substitution of an alanine residue to valine in the enzyme (Anderson et al., 1997). The encoded protein has reduced activity at 37°C and higher, and thus the C677T SNP is termed "thermolabile" (Vasisht et al., 2002). The MTHFR 677 TT genotype has been linked to increased plasma homocysteine levels (Anderson et al., 1997;Clarke et al., 2012;Mehlig et al., 2013;Nienaber-Rousseau et al., 2013). ...
... Methylenetetrahydrofolate reductase (MTHFR) is an enzyme that catalyses the reduction of 5′,10′-methylenetetrahydrofolate to 5′-methyltetrahydrofolate; a major form of folate in plasma, and a carbon donor for the remethylation of homocysteine to methionine (Kluijtmans and Whitehead, 2001;Vasisht et al., 2002). The enzyme is therefore responsible for reducing levels of homocysteine in the plasma. ...
... A common SNP at position 677 of the MTHFR gene (rs1801133) in which a cytosine is converted to thymine, results in the substitution of an alanine residue to valine in the enzyme (Anderson et al., 1997). The encoded protein has reduced activity at 37°C and higher, and thus the C677T SNP is termed "thermolabile" (Vasisht et al., 2002). The MTHFR 677 TT genotype has been linked to increased plasma homocysteine levels (Anderson et al., 1997;Clarke et al., 2012;Mehlig et al., 2013;Nienaber-Rousseau et al., 2013). ...
... 1,3,5 Co-existence of these SNPs with sickle cell gene can increase the homocysteine levels and thus are regarded as potential genetic risk factors for vaso-occlusive or hemolytic episodes with acute painful events in them. [6][7][8] However, very few studies are available regarding the contributory and additive effect of both the polymorphisms towards the clinical complications witnessed in SCA patients in pediatric age group who are most vulnerable for the varied manifestations of the disorder and register a high morbidity and mortality. 9,10 Taking into account the above facts, the study was intended primarily to determine the interaction of the combined haplotypes of MTHFR SNPs on the clinical presentations in children diagnosed with sickle cell disorder. ...
Article
BACKGROUND Methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C variants are considered as potential genetic risk factors for vaso-occlusive complications in sickle cell disorder (SCD). The purpose of the study was to determine the interaction of the combined haplotypes on the clinical presentations in children with sickle cell disorder. METHODS A cross-sectional study was conducted on 249 children, confirmed for sickle cell disorder. Clinical details and frequencies of clinical episodes in the past one year were noted and a severity index number was allotted to each child and evaluated for their relationship with the combined haplotypes of C677T and A1298C single nucleotide polymorphisms genotyped by real-time PCR. RESULTS The frequency for 677T / 1298A haplotype was 46.4 % and that of 677C / 1298C was 12.4 %. The three variant combined haplotypes had higher plasma homocysteine values than the wild 677C / 1298A haplotypes (P < 0.001). Clinical events like vasoocclusive crisis (VOC), homocysteinemia, hospitalization frequency and SI were found significantly related among the children in sickle cell trait (SCT) group (P < 0.001) but not so in SCD group. Chances for anemia was 1.93 times more in presence of dual variant alleles (95 %CI: 0.95 to 3.92, P = 0.07) in SCT. The 677T / 1298C haplotype accounted for higher SI was 7.85 times more than the wild haplotypic children even in SCT children and 1.67 times in SCD children. CONCLUSIONS Presence of the variant haplotypes had significant implication on crisis events in children with sickle cell trait and make them more prone for the clinical severity. A preliminary allelic screening might be helpful in them. KEY WORDS Dual Variant Alleles, Heterozygous, Homozygous, MTHFR, Variant Haplotypes
... In some of these studies, the T allele of the rs1801133 polymorphism was reported to be associated with an increased risk of CAD [10][11][12] and elevated levels of TG [13,14], TC [13][14][15] and LDL-C [13][14][15][16], and reduced levels of HDL-C [13,17]. However, the results obtained from other studies did not support these findings [18][19][20][21][22]. Hence, a meta-analysis is required to clarify the relationships of the rs1801133 polymorphism with CAD and lipid levels. ...
Article
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Background: The associations of the 5,10-methylenetetrahydrofolate reductase gene (MTHFR) rs1801133 polymorphism with coronary artery disease (CAD) and plasma lipid levels have been widely investigated, but the results were inconsistent and inconclusive. This meta-analysis aimed to clarify the relationships of the rs1801133 polymorphism with CAD and plasma lipid levels. Methods: By searching in PubMed, Google Scholar, Web of Science, Cochrane Library, Wanfang, VIP and CNKI databases, 123 studies (87,020 subjects) and 65 studies (85,554 subjects) were identified for the CAD association analysis and the lipid association analysis, respectively. Odds ratio (OR) and standardized mean difference (SMD) were used to determine the effects of the rs1801133 polymorphism on CAD risk and lipid levels, respectively. Results: The variant T allele of the rs1801133 polymorphism was associated with increased risk of CAD under allelic model [OR = 1.11, 95% confidence interval (CI) = 1.06-1.17, P < 0.01], additive model (OR = 1.25, 95% CI = 1.14-1.37, P < 0.01), dominant model (OR = 1.11, 95% CI = 1.04-1.17, P < 0.01), and recessive model (OR = 1.22, 95% CI = 1.12-1.32, P < 0.01). The T carriers had higher levels of total cholesterol (TC) (SMD = 0.04, 95% CI = 0.01-0.07, P = 0.02) and low-density lipoprotein cholesterol (LDL-C) (SMD = 0.07, 95% CI = 0.01-0.12, P = 0.01) than the non-carriers. Conclusions: The meta-analysis suggested that the T allele of the rs1801133 polymorphism is a risk factor for CAD, which is possibly and partly mediated by abnormal lipid levels.
... The present study failed to show any association between C677T polymorphism and CAD. This is consistent with other earlier findings (Biselli et al.,2009, Chambers et al., 2000, Eftychiou et al., 2012, Folsom et al., 1998Girelli et al., 1998, Gonzalez-perez et al., 2002, Goracy et al., 1999, Gueant Rodriguez et al., 2005, Gupta et al., 2010, Hanson et al., 2001, Hsu et al., 2001, Ibraheim et al.,2009, Iqbal et al., 2005, Kolling et al.,2004, Lin PT et al., 2008, Liu et al., 2014, Meisel et al. (2001, Pandey et al., 2011, Pezzini et al., 2002, Rahimi et al., 2009, Reinhardt et al., 1998, Saffari et al., 2013, Soriente et al., 1998, Van Bockxmeer et al., 1997,Vasisht et al., 2002, Zee et al., 2007, Zheng et al., 2000. On the other hand some studies reported positive association between MTHFR C677T polymorphism and CAD (Alam et al., 2008, Aleyasin et al., 2006, Bennour et al., 2007, Christensen et al., 1997, Dhar et al., 2010, Frosst et al., 1995, Gardemann et al., 1999, Gulec et al., 2000, Kang et al., 1988a,1991, Kluijtmans et al., 1996, Lakshmi et al., 2010, Matam et al., 2014, Morita et al., 1997, Nasiri et al., 2014, Rassoul F et al.,2000, Tripathi et al., 2010. ...
... A study in an Indian population revealed a significant association of Hcy levels with MTHFR A1298C polymorphism which was more common than MTHFR 677TT genotype [40]. However, other studies were unable to demonstrate a relation between Hcy levels and MTHFR 677TT polymorphism [41]. This may explain the observed association of folate with Hcy in western populations. ...
Article
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There is an increase in awareness about the role of nutritional factors in chronic non-communicable diseases. We therefore conducted this study with an aim to assess the relationship between nutritional factor (vitamin B12 and homocysteine [Hcy]) and its association with insulin resistance and inflammatory markers, and differences in traditional and non-traditional risk factors among diabetics and non-diabetics in known cases of coronary artery disease (CAD). Three hundred consecutive patients with known coronary disease on coronary angiography, who were >25 years old were included in this study. All cases were interviewed using a questionnaire. Blood samples were analyzed for insulin, vitamin B12, Hcy and inflammatory markers (highly sensitive C-reactive protein [hsCRP], interleukin-6 [IL-6], Tumor necrosis factor-alfa [TNF-α]). Insulin resistance was calculated with homeostasis model assessment of insulin resistance (HOMA-IR). Mean age of the patients was 60.95 ± 12.3 years. Body mass index and waist hip ratio were comparable in both groups. Triglyceride, very low-density lipoprotein and HbA1C were significantly higher and high-density lipoprotein (HDL) was significantly lower in patients with diabetes. Patients with diabetes had significantly high levels of IL-6, hsCRP and TNF-α compared with non-diabetic patients. Insulin resistance was twofold higher in diabetic patients. Serum vitamin B12 levels were significantly lower and Hcy was significantly higher in the diabetic group compared with the non-diabetic patients. HbA1C, HOMA-IR and Hcy levels were positively correlated with inflammatory markers in the total study population and in the non-diabetic patients; but, in diabetic patients, HbA1C and Hcy showed this relation. Vitamin B12 deficiency is common in the diabetic population. Hcy levels were higher in diabetics compared with non-diabetics, and were related to glycemic level and insulin resistance in diabetic patients. Patients with diabetes had higher traditional risk factors than patients without diabetes in known patients with CAD. Glycemic status was associated with insulin resistance and inflammatory markers.
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Introduction: The significant causes of mortality among individuals with sickle cell anaemia (SCA) such as acute chest syndrome and cerebrovascular disease are related to vascular occlusion. Polymorphisms of the methylene tetrahydrofolate reductase (MTHFR) gene in persons with sickle cell anaemia have been suggested as a potential risk for vaso-occlusive events, with the C677T and A1298C polymorphisms being the commonest. This study therefore aimed to establish the pattern of MTHFR C677T and A1298C gene mutations among adults with HbSS phenotype attending the Haematology Clinic in Lagos State University Teaching Hospital Lagos, Nigeria. Methods: A cross-sectional study was done among SCA patients attending the Haematology Clinic of the Lagos State University Teaching Hospital (LASUTH), using age and sex matched HbAA controls. DNA extraction and gene analysis were done. The selective amplification of a particular segment of the DNA by polymerase chain reaction (PCR) was done and subsequent digestion of the amplified MTHFR gene into its various fragments. Results: The overall prevalence of the C677T mutation among participants was 19.3% (37 of 192), while the prevalence of A1298C was 15% (29 of 192). Conclusion: The prevalence of MTHFR C677T was higher than A1298C mutations among sickle cell anaemia subjects.
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A microvolume fluorimeter integrated with a rapid thermal cycler allows both amplification and point mutation detection from genomic DNA in approximately 30 min. This homogeneous method combines rapid cycle DNA amplification with allele-specific fluorescent probe melting profiles for product genotyping. The amplification reaction includes a primer internally labeled with Cy5 and a 3′-fluorescein-labeled probe that spans the region of interest. During asymmetric amplification, the probe hybridizes to excess Cy5-labeled strand and is observed as fluorescence resonance energy transfer. Resonance energy transfer increases each cycle as product accumulates during amplification. When fluorescence is monitored as the temperature increases through theTmof the probe/product duplex, a characteristic melting profile for each genotype is obtained. Fluorescence genotyping of the common C677T base substitution in the methylenetetrahydrofolate reductase gene in 110 DNA samples correlated perfectly with genotyping by restriction enzyme digestion and gel electrophoresis. The relatively stable G:T mismatch of this example gave a 3°C difference inTmfrom complete Watson–Crick pairing, suggesting that this homogeneous fluorescence method can be used for all single-base mismatches.
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