Thermolabile methylenetetrahydrofolate reductase C677T polymorphism and homocysteine are risk factors for coronary artery disease in Moroccan population

Association of methylenetetrahydrofolate reductase (MTHFR) variant C677T and risk of carotid atherosclerosis: a cross-sectional analysis of 730 Chinese Han adults in Chongqing

BACKGROUND

Uncertainty still remains on the correlation of methylenetetrahydrofolate reductase (MTHFR) variant C677T with risk of carotid atherosclerosis (CAS), and there is a lack of reports on C677T/MTHFR in the Asian population. The association of C677T/MTHFR polymorphisms with CAS in the Chinese Han population in Chongqing was investigated in the present study.

METHODS

Subjects (n = 730, 214 females and 516 males, Han ethnicity) who provided an informed consent were randomly selected from the general population of Chongqing, China. Polymerase chain reaction-restriction fragment length polymorphism and Sanger sequencing genotyping assays were used to determine the MTHFR genotypes. The atherosclerosis index of the intima-media thickness (IMT) was measured by high-resolution ultrasound to evaluate the CAS. Less than 1.0 mm was considered as normal for IMT, 1.0-1.5 mm was considered as thickening, and ≥ 1.5 mm and a local bulge thickened in the lumen was considered as CAS. According to the carotid ultrasonography results, these subjects were divided into two groups: CAS-group (IMT ≥ 1.0 mm) and control group (IMT < 1.0 mm).

RESULTS

The frequency of C/T heterozygotes, T/T homozygotes genotype was significantly higher in the subjects with CAS (62% vs. 36.9%; 16.2% vs. 9.5%; 47.2% vs. 27.9%, P < 0.05), while the frequency of C/C homozygotes and C allele was significantly lower (21.8% vs. 53.7%; 52.8% vs. 72.1%, P < 0.05), when compared to the control group. The risk of CAS was higher for subjects with C/T heterozygotes and T/T homozygotes (OR = 4.06, 95% CI: 2.76-5.98, P < 0.001 and OR = 3.14, 95% CI: 1.73-5.69, P < 0.001, respectively), when compared to the subjects with the C/C genotype. In the model 1 (CT + TT versus CC), C677T/MTHFR was significantly associated with the prevalence of CAS, and the all adjusted OR values for CAS were 3.87 (95% CI, 2.67 to 5.62) in all, 17.18 (95% CI, 7.27 to 40.49) in women and 2.57 (95% CI, 1.65 to 3.99) in men after adjusting for potential confounding factors.

CONCLUSIONS

The present study suggests that a mutation in the methylenetetrahydrofolate reductase gene is a risk factor of CAS in the Chinese Han population.

Analysis of genetic polymorphism of methylenetetrahydrofolate reductase in a large ethnic Hakka population in southern China

Methylenetetrahydrofolate reductase (MTHFR) catalyzes conversion of methylene tetrahydrofolate to methylte trahydrofolate. MTHFR C677T polymorphism has been regarded as a risk factor for various vascular diseases. Our study aimed to investigate the distribution frequencies of this polymorphism among Hakka population living in southern China. We retrospectively recruited 5102 unrelated Chinese Hakka subjects. MTHFR C677T polymorphism was tested using the polymerase chain reaction (PCR) and DNA sequencing. A total of 2358 males and 2744 females (aged from 10 years to 101 years) were included in this study. In total, 2835 (55.63%) subjects were homozygous for the C allele (CC), 1939 (38.00%) subjects were heterozygous (CT), and 325 (6.37%) subjects were homozygous for the T allele (TT). The allelic frequency of mutant T was 25.37% with 325 individual homozygous for this defective allele resulting in a frequency of about 6.37% for the TT genotype. According to the study results, the overall frequency of MTHFR C677T genotypes did not differ significantly among the gender and age groups. Our study showed the prevalence of MTHFR C677T polymorphism in a large ethnic Hakka population living in southern China. It would be important implications for the primary prevention of various vascular diseases.

Associations of the MTHFR rs1801133 polymorphism with coronary artery disease and lipid levels: a systematic review and updated meta-analysis

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.

Association of methylenetetrahydrofolate reductase gene (C677T) with the risk of hypertension in Morocco

Background

Hypertension is a multifactorial disease caused by the interaction between genetic and environmental factors. Mutations in the methylenetetrahydrofolate reductase gene (MTHFR) have been known to be associated with the risk of cardiovascular disease as well as hypertension. This case–control study was conducted out to measure the association of the polymorphism C677T of MTHFR with the risk of hypertension.

Methods

Polymerase chain reaction followed by restriction fragment analysis length was used to identify MTHFR C677T genotypes in patients 101 patients and 102 age and sex matched healthy controls. Odds ratio with 95 % confidence interval was used to assess the risk of association.

Results

The distribution of demographic and clinical features of patients showed no particular trend (p > 0.05). However, the frequency of homozygous 677T allele was higher in patients with a family history of heart disease (30.4 vs. 9 %, p = 0.031). Interestingly, the mutant 677TT genotype was significantly associated with the susceptibility of hypertension when compared to the wild type 677CC genotype (OR 5.4, CI 1.4–19.8, p = 0.008). In addition, the recessive model 677TT vs. 677CC/CT was found to be associated with the risk of hypertension (OR 5.3, CI 1.5–19.1, p = 0.005). However, the dominant model was not associated with the risk of hypertension in our cohort (OR 1.3, CI 0.7–2.2, p = 0.4).

Conclusions

Based on our findings, the homozygous mutant for 677TT of MTHFR gene is associated with the risk of hypertension in our population. Further studies with larger sample sizes are needed to confirm the results of this study.

The TT Genotype of the MTHFR 677C>T Polymorphism Increases Susceptibility to Premature Coronary Artery Disease in Interaction with Some of the Traditional Risk Factors

Background: The presence of several risk factors (genetic and non-genetic) has greater impact on the risk of premature coronary artery disease (CAD) than single risk factor. Objective: The aim of the study was to establish possible relations between genotypes and alleles of 677C>T polymorphism ofMTHFRgene and some traditional risk factors e.g. elevated levels of lipid parameters and smoking in development of premature CAD. Methods: The groups comprised 152 patients with angiographically documented premature CAD (aged 42.9 ± 5.5) and 121 age-matched blood donors (aged 42.3 ± 6.5) were studied. TheMTHFR677C>T polymorphism was genotyped with Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. Results: Patients with TT genotype who simultaneously smoked had increased risk of premature CAD compared to non-smoking cases with CC genotype (OR = 24.62). We also found that individuals with TT genotype and elevated LDL-cholesterol (LDL-chol.) level had significantly higher risk of CAD (OR = 9.92) than individuals with normal LDL-chol. level and CC genotype. Conclusions: The present study shows that simultaneous presence ofMTHFRTT genotype and smoking or elevated levels of LDL-chol. influences the risk of premature CAD. This findings give interesting contribution to gene-environment interaction problem that may have clinical implications in the future.

Association of the APOE, MTHFR and ACE Genes Polymorphisms and Stroke in Zambian Patients

The aim of the present study was to investigate the association of APOE, MTHFR and ACE polymorphisms with stroke in the Zambian population. We analyzed 41 stroke patients and 116 control subjects all of Zambian origin for associations between the genotype of the APOE, MTHFR and ACE polymorphisms and stroke. The APOE ε2ε4 genotype showed increased risk for hemorrhagic stroke (P<0.05) and also a high risk for ischemic stroke (P=0.05). There was complete absence of the APOE ε2ε2 and the MTHFR TT genotypes in the Zambian population. The difference between cases and controls was not significant for the other genetic variants when analyzed for relationship between stroke, stroke subtype and genotype. We show that genetic variation at the APOE locus affects susceptibility to stroke. No detectable association were observed for the MTHFR and ACE genotypes and stroke in the Zambian population.

Analysis of MTHFR and MTRR Gene Polymorphisms in Iranian Ventricular Septal Defect Subjects

Ventricular septal defect (VSD) is one of the most common types of congenital heart defects (CHD). There are vivid multifactorial causes for VSD in which both genetic and environmental risk factors are consequential in the development of CHD. Methionine synthase reductase (MTRR) and methylenetetrahydrofolate reductase (MTHFR) are two of the key regulatory enzymes involved in the metabolic pathway of homocysteine. Genes involved in homocysteine/folate metabolism may play an important role in CHDs. In this study; we determined the association of A66G and C524T polymorphisms of the MTRR gene and C677T polymorphism of the MTHFR gene in Iranian VSD subjects. A total of 123 children with VSDs and 125 healthy children were included in this study. Genomic DNA was extracted from the buccal cells of all the subjects. The restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) method was carried out to amplify the A66G and C524T polymorphism of MTRR and C677T polymorphism of MTHFR genes digested with Hinf1, Xho1 and Nde1 enzymes, respectively. The genotype frequencies of CC, CT and TT of MTRR gene among the studied cases were 43.1%, 40.7% and 16.3%, respectively, compared to 52.8%, 43.2% and 4.0%, respectively among the controls. For the MTRR A66G gene polymorphism, the genotypes frequencies of AA, AG and GG among the cases were 33.3%, 43.9% and 22.8%, respectively, while the frequencies were 49.6%, 42.4% and 8.0%, respectively, among control subjects. The frequencies for CC and CT genotypes of the MTHFR gene were 51.2% and 48.8%, respectively, in VSD patients compared to 56.8% and 43.2% respectively, in control subjects. Apart from MTHFR C677T polymorphism, significant differences were noticed (p < 0.05) in C524T and A66G polymorphisms of the MTRR gene between cases and control subjects.

Methylenehydrofolate reductase (C677T) polymorphism and large artery ischemic stroke subtypes

BACKGROUND

The role for the methylenetetrahydrofolate reductase C677T gene variants in the risk of ischemic stroke is controversial.

METHOD

This first case-control study including 91 cases affected by ischemic stroke and 182 controls matched for age, sex, and same area was conducted in Casablanca, Morocco. Allele and genotype frequency were characterized by using PCR followed by HinfI enzymatic digestion.

RESULTS

We found no statistic association of T allele carriers genetic factors with stroke; odds ratio, 1.1; 95% confidence interval (CI), 0.59-2.04, P = 0.303. The results shown significant association of T allele carriers genetic factors with atherothrombotic subtype stroke (n = 42); odds ratio, 2.1; 95% CI: 1.17-3.8; P = 0.012, and adjusted odds ratio of 6.5; 95% CI: 1.86-23.1, P = 0.003, for TT genotype variant compared with CC wild genotype.

CONCLUSION

We suggested that MTHFR C677T variant may be a determinant of atherothrombotic event of ischemic stroke in Morocco.

Folate and one-carbon metabolism gene polymorphisms and their associations with oral facial clefts

Folate metabolism plays a critical role in embryonic development. Prenatal folate supplementation reduces the risk of neural tube defects and probably oral facial clefts. Previous studies of related metabolic genes have associated polymorphisms in cystathionine-beta-synthase (CBS) and 5,10-methylenetetrahydrofolate reductase (MTHFR) with cleft risk. We explored associations between genes related to one-carbon metabolism and clefts in a Norwegian population-based study that included 362 families with cleft lip with or without cleft palate (CL/P) and 191 families with cleft palate only (CPO). We previously showed a 39% reduction in risk of CL/P with folic acid supplementation in this population. In the present study we genotyped 12 polymorphisms in nine genes related to one-carbon metabolism and looked for associations of clefting risk with fetal polymorphisms, maternal polymorphisms, as well as parent-of-origin effects, using combined likelihood-ratio tests (LRT). We also stratified by maternal periconceptional intake of folic acid (>400 microg) to explore gene-exposure interactions. We found a reduced risk of CL/P with mothers who carried the CBS C699T variant (rs234706); relative risk was 0.94 with one copy of the T allele (95% CI 0.63-1.4) and 0.50 (95% CI 0.26-0.96) with two copies (P = 0.008). We found no evidence of interaction of this variant with folate status. We saw no evidence of risk from the MTHFR C677T variant (rs1801133) either overall or after stratifying by maternal folate intake. No associations were found between any of the polymorphisms and CPO. Genetic variations in the nine metabolic genes examined here do not confer a substantial degree of risk for clefts.

Homocysteine and methylenetetrahydrofolate reductase C677T and A1298C polymorphisms in Tunisian patients with severe coronary artery disease

Elevation in homocysteine and methylenetetrahydrofolate reductase (MTHFR) gene variants, C677T and A1298C, have been linked with atherothrombosis. However their exact contribution to coronary artery disease (CAD) remains controversial. Moreover, data from Tunisian patients are scarse. We examined the association of MTHFR C677T and A1298C, and changes in plasma homocysteine in 352 Tunisian patients with angiographically-demonstrated CAD, and 390 age and gender-matched healthy subjects. Significantly higher frequency of 677T allele and homozygous 677T/T genotype were seen in patients vs. control subjects; the distribution of A1298C alleles and genotypes being comparable in the two groups. Specific MTHFR haplotypes comprising 677C/1298A (P < 0.001) and 677T/1298A (P < 0.001) were negatively and positively associated with CAD, respectively. Plasma homocysteine concentration was significantly higher in 677T/T genotype with respect to 677C/C and 677C/T genotypes in patients and controls, but homocysteine levels were generally comparable between both groups. Univariate analysis identified 677T/1298A (P = 0.033) haplotype to be positively associated with CAD, which remained significant by multivariate analysis after adjusting for a number of covariates (P = 0.038). MTHFR C677T, but not A1298C SNPs, is associated with CAD and with elevated homocysteine levels in a Tunisian population. The negative and positive association of the 1298A allele with CAD being indicative of a neutral (absent) effect of the A1298C SNP on disease pathogenesis.