Is there additional effect of MTHFR C677T mutation on lipid abnormalities in renal allograft recipients?

Association of MTHFR (C677T, A1298C) and MTRR A66G polymorphisms with fatty acids profile and risk of neural tube defects

OBJECTIVE

This study aims to determine if 5,10-methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) and methionine synthase reductase (MTRR A66G) gene polymorphisms were associated with fatty acid (FA) levels in mothers of fetuses with neural tube defects (NTDs) and whether these associations were modified by environmental factors.

METHODS

Plasma FA composition was assessed using capillary gas chromatography. Concentrations of studied FA were compared between 42 mothers of NTDs fetuses and 30 controls as a function of each polymorphism by the Kruskal-Wallis nonparametric test.

RESULTS

In MTHFR gene C677T polymorphism, cases with (CT + TT) genotype had lower monounsaturated FAs (MUFA) and omega-3 polyunsaturated FA (n-3 PUFA) levels, but higher omega-6 polyunsaturated FAs (n-6 PUFA) and omega-6 polyunsaturated FAs: omega-3 polyunsaturated FAs (n-6:n-3) ratio levels. In MTRR gene A66G polymorphism, cases with (AG + GG) genotype had lower MUFA levels, but higher PUFA and n-6 PUFA levels. Controls with (AG + GG) genotype had lower n-6 PUFA levels. In MTHFR gene C677T polymorphism, cases with smoking spouses and (CT + TT) genotype had lower MUFA and n-3 PUFA levels, but higher PUFA, n-6 PUFA, and n-6:n-3 ratio levels. Cases with (CT + TT) genotype and who used sauna during pregnancy had lower n-3 PUFA levels. In MTRR gene A66G polymorphism, cases with (AG + GG) genotype and who used sauna during pregnancy had higher PUFA and n-6 PUFA levels.

CONCLUSIONS

Further research is required to clarify the association of FA metabolism and (MTHFR, MTRR) polymorphisms with NTDs.

Association analysis of MTHFR (rs1801133 and rs1801131) and MTRR (rs1801394) gene polymorphisms towards the development of hypertension in the Bai population from Yunnan, China

OBJECTIVE

Hypertension is one of the leading causes of human death and disability. MTHFR and MTRR regulate folate metabolism and are closely linked to hypertension, although the relationship is inconsistent among different ethnic groups. The present study aims to investigate the effects of MTHFR C677T (rs1801133), MTHFR A1298C (rs1801131), and MTRR A66G (rs1801394) polymorphisms on hypertension susceptibility in the Bai nationality of the Yunnan Province, China.

METHODS

This case-control study included 373 hypertensive patients and 240 healthy controls from the Chinese Bai population. The genotyping of MTHFR and MTRR gene polymorphisms was carried out by using the KASP method. The effects of genetic variations of MTHFR and MTRR genes on hypertension risk were evaluated with odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

The present study revealed that the CT and TT genotypes and T allele of MTHFR C677T locus were considerably associated with an increased risk of hypertension. In addition, MTHFR A1298C locus CC genotype could significantly increase the hypertension risk. The T-A and C-C haplotypes of MTHFR C677T and MTHFR A1298C could increase the risk of hypertension. Further stratified analysis by risk rank of folate metabolism indicated that people with poor utilization of folic acid were more prone to develop hypertension. In the hypertension group, the MTHFR C677T polymorphism was significantly associated with fasting blood glucose, fructosamine, apolipoprotein A1, homocysteine, superoxide dismutase, and malondialdehyde levels.

CONCLUSION

Our study suggested that genetic variations of MTHFR C677T and MTHFR A1298C were significantly associated with susceptibility to hypertension in the Bai population from Yunnan, China.

Associations of MTHFR gene polymorphism with lipid metabolism and risk of cerebral infarction in the Northwest Han Chinese population

Objective

Genetic variation in the methylenetetrahydrofolate reductase (MTHFR) gene may contribute to the development of cerebral infarction (CI); however, results have been inconsistent across studies with different populations, including studies of the Chinese population. The aim of this study was to analyze the effect of MTHFR gene polymorphism on serum lipid and homocysteine levels among patients with CI in the Northwest Chinese Han population.

Patients and methods

A total of 521 CI patients and 524 non-CI controls were enrolled in the study. Polymerase chain reaction and hybridization were utilized to identify MTHFR gene polymorphisms. Multivariate logistic regression analysis was used to assess the associations of MTHFR gene polymorphism with risk of CI.

Results

Frequencies of the TT genotype and the T allele were markedly higher among CI patients than among controls. After stratifying our data by sex and age, we determined that these differences in frequency of the TT genotype and the T allele were statistically significant among participants of two different age brackets and among men, but not among women (i.e., there were no statistically significant differences between female patients and female controls). CI patients and control participants with the CT or TT genotype had significantly higher homocysteine (Hcy) levels than those with the CC genotype. Among CI patients, CT/TT carriers showed significantly lower high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (ApoA-I) levels as compared with CC carriers, but there was no significant difference for control participants. Multivariable logistic regression analysis showed that drinking; smoking; diabetes mellitus; levels of Hcy, direct bilirubin (DB), indirect bilirubin (IB), ApoA-I, and total protein (TP); and TT genotype were significant independent risk factors for CI.

Conclusions

The results suggested that the TT genotype of the MTHFR C677T gene polymorphism, which is associated with hyperhomocysteinemia (HHcy), might be of great clinical significance in the identification of new biomarkers for CI and in the development of individualized preventive and therapeutic strategies.

Individual and Joint Associations of Methylenetetrahydrofolate Reductase C677T Genotype and Plasma Homocysteine With Dyslipidemia in a Chinese Population With Hypertension

We aimed to examine the cross-sectional associations of plasma total homocysteine (tHcy) concentrations and methylenetetrahydrofolate reductase ( MTHFR) C677T genotype with dyslipidemia. A total of 231 patients with mild-to-moderate essential hypertension were enrolled from the Huoqiu and Yuexi communities in Anhui Province, China. Plasma tHcy levels were measured by high-performance liquid chromatography. Genotyping was performed by TaqMan allelic discrimination technique. Compared with MTHFR 677 CC + CT genotype carriers, TT genotype carriers had higher odds of hypercholesterolemia (adjusted odds ratio [OR] [95% confidence interval (CI)]: 2.7 [1.4-5.2]; P = .004) and higher odds of abnormal low-density lipoprotein cholesterol (adjusted OR [95% CI]: 2.3 [1.1-4.8]; P = .030). The individuals with the TT genotype had higher concentrations of log(tHcy) than those with the 677 CC + CT genotype (adjusted β [standard error]: .2 [0.03]; P < .001). Patients with tHcy ≥ 10 μmol/L had significantly higher odds of hypercholesterolemia (adjusted OR [95% CI]: 2.4 [1.2-4.7]; P = .010). Furthermore, patients with both the TT genotype and the tHcy ≥ 10 μmol/L had the highest odds of hypercholesterolemia (adjusted OR [95% CI]: 4.1 [1.8-9.4]; P = .001) and low-density lipoprotein cholesterol (adjusted OR [95% CI]: 2.4 [1.0-6.0]; P = .064). This study suggests that both tHcy and the MTHFR C677T gene polymorphism may be important determinants of the incidence of dyslipidemia in Chinese patients with essential hypertension. Further studies are needed to confirm the role of tHcy and the MTHFR C677T mutation in the development of dyslipidemia in a larger sample.

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.

Joint associations of folate, homocysteine and MTHFR, MTR and MTRR gene polymorphisms with dyslipidemia in a Chinese hypertensive population: a cross-sectional study

BACKGROUND

Dyslipidemia is a well-established risk factor for cardiovascular disease. Serum lipids were affected by several gene polymorphisms, folate, homocysteine and other metabolite levels. We aim to investigate the effects of homocysteine metabolism enzyme polymorphisms (MTHTR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) and their interactions with folate, homocysteine on serum lipid levels in Chinese patients with hypertension.

METHODS

Participants were 480 hypertensive adults that enrolled in September to December 2005 from six different Chinese hospitals (Harbin, Shanghai, Shenyang, Beijing, Xi'an, and Nanjing). Known MTHFR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G genotypes were determined by PCR-RFLP methods. Serum folate was measured by chemiluminescent immunoassay, homocysteine was measured by high-performance liquid chromatography, serum lipids parameters were determined by an automatic biochemistry analyzer, low-density lipoprotein was calculated by Friedewald's equation. Unitary linear regression model was used to assess the associations of gene polymorphisms, folate and homocysteine on serum lipid profiles. Unconditional logistic regression model was applied to test the interactions of folate, homocysteine and gene polymorphisms on dyslipidemia.

RESULTS

No correlations between gene polymorphisms and homocysteine on serum lipid profiles. Compared with normal folate patients, patients with low folate showed higher odds of hypertriglyceridemia (OR = 2.02, 95 % CI: 1.25-3.25, P = 0.004) and low levels of high-density lipoprotein cholesterol (OR = 1.88, 95 % CI: 1.07-3.28, P = 0.027). Each of four gene polymorphisms (MTHTR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) combined with low folate showed higher odds of hypertriglyceridemia (P for trend: 0.049, 0.004, 0.007 and 0.005, respectively). MTHFR C677T and A1298C with low folate showed higher odds of low levels of high-density lipoprotein cholesterol (P for trend: 0.008 and 0.031).

CONCLUSIONS

Low folate status and homocysteine metabolism gene polymorphisms (MTHTR C677T, MTHFR A1298C, MTR A2756G and MTRR A66G) may have a synergistic effect increased the incidence of dyslipidemia in Chinese hypertensive population.

Associations of MTHFR and MTRR polymorphisms with serum lipid levels in Chinese hypertensive patients

OBJECTIVE

To examine the effects of the methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) gene polymorphisms and their interactions with environmental factors on serum lipid levels.

METHODS

We investigated totally 340 patients with essential hypertension, from Dongzhi community, Anhui, China. High-throughput TaqMan allelic discrimination assay was used for the genotyping of MTHFR C677T (Ala222Val), MTHFR A1298C (Glu429Ala), MTRR A66G (Ile22Met), and MTRR His595Tyr.

RESULTS

Compared with the MTRR 66AA genotype carriers, the GG genotype carriers had lower serum total cholesterol (TC) levels (adjusted β ± standard error [SE]: -0.5 ± 0.2 mmol/L; P = .003) and low-density lipoprotein cholesterol (LDL-C) levels (adjusted β ± SE: -0.4 ± 0.2 mmol/L; P = .005). Their false discovery rate (FDR)-adjusted P values were 0.056 and 0.056, respectively. We further found that there was a statistically significant interaction between 677TT genotype and sex in their associations with LDL levels (P interaction = .020), and significant interaction between 677TT genotype and smoking on LDL levels (P interaction = .036). A similar pattern of interaction was found between 66GG and drinking on levels of TC (P interaction = .034) and LDL (P interaction = .020). However, there were no significant interactions observed after FDR adjustment.

CONCLUSION

Both MTHFR and MTRR gene polymorphisms could be important genetic determinants of serum lipid levels in Chinese patients with hypertension. These findings need to be replicated in a larger sample.

MTHFR C677T polymorphism modifies the effect of HRT on metabolic parameters in postmenopausal women

OBJECTIVE

To assess the interaction of the MTHFR C677T polymorphism with changes in lipid and glucose metabolism effected by oral hormone replacement therapy (HRT) in postmenopausal women.

METHODS

In this open-label, prospective, interventional study, parameters of lipid and glucose metabolism, as well as homocysteine, were assessed in 97 postmenopausal women at baseline and 1 year after the initiation of HRT. Participants were stratified into three subgroups, according to the MTHFR C677T polymorphism (wild-type: CC genotype; heterozygous: CT genotype; homozygous for the mutant variable: TT genotype).

RESULTS

The TT genotype was associated with an elevation of total and low density lipoprotein (LDL) cholesterol, while CT and CC genotypes were associated with a reduction of total cholesterol and LDL cholesterol after 1 year of HRT (p = 0.032 for total cholesterol and p = 0.002 for LDL cholesterol). Women with the TT genotype had higher glucose levels in contrast to women with the CC genotype who had lower glucose levels after 1 year of HRT (p = 0.011). Additionally, CC carriers under HRT had a significant elevation of apolipoprotein A1 levels (p = 0.018), contrarily to CT and TT genotypes.

CONCLUSION

While HRT was associated with favorable changes in lipid and metabolic parameters in carriers of the CC genotype, this effect was not evident in carriers of the T allele. The MTHFR C677T polymorphism may modify the effect of HRT on lipid and metabolic parameters in postmenopausal women.

Association of methylenetetrahydrofolate reductase C677T polymorphism and serum lipid levels in the Guangxi Bai Ku Yao and Han populations

Background

The association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphism and serum lipid profiles is still controversial in diverse ethnics. Bai Ku Yao is an isolated subgroup of the Yao minority in China. The aim of the present study was to eveluate the association of MTHFR C677T polymorphism and several environmental factors with serum lipid levels in the Guangxi Bai Ku Yao and Han populations.

Methods

A total of 780 subjects of Bai Ku Yao and 686 participants of Han Chinese were randomly selected from our previous stratified randomized cluster samples. Genotyping of the MTHFR C677T was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing.

Results

The levels of serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein (Apo) AI and ApoB were lower in Bai Ku Yao than in Han (P < 0.05-0.001). The frequency of C and T alleles was 77.4% and 22.6% in Bai Ku Yao, and 60.9% and 39.1% in Han (P < 0.001); respectively. The frequency of CC, CT and TT genotypes was 58.7%, 37.3% and 4.0% in Bai Ku Yao, and 32.6%, 56.4% and 11.0% in Han (P < 0.001); respectively. The levels of TC and LDL-C in both ethnic groups were significant differences among the three genotypes (P < 0.05-0.01). The T allele carriers had higher serum TC and LDL-C levels than the T allele noncarriers. The levels of ApoB in Han were significant differences among the three genotypes (P < 0.05). The T allele carriers had higher serum ApoB levels as compared with the T allele noncarriers. The levels of TC, TG and LDL-C in Bai Ku Yao were correlated with genotypes (P < 0.05-0.001), whereas the levels of LDL-C in Han were associated with genotypes (P < 0.001). Serum lipid parameters were also correlated with sex, age, body mass index, alcohol consumption, cigarette smoking, and blood pressure in the both ethnic groups.

Conclusions

The differences in serum TC, TG, LDL-C and ApoB levels between the two ethnic groups might partly result from different genotypic and allelic frequencies of the MTHFR C677T or different MTHFR gene-enviromental interactions.

Plasma homocysteine and gene polymorphisms associated with the risk of hyperlipidemia in northern Chinese subjects

OBJECTIVE

To examine the relationship between occurrence of hyperlipidemia, plasma homocysteine and polymorphisms of methylenetetra hydrofolate reductase (MTHFR) gene and methionine synthase (MS) gene.

METHODS

A total of 192 hyperlipidemia patients were selected and divided into hypercholesterolemia group, hypertriglyceridemia group, and combined hyperlipidemia group. Another 208 normal individuals were selected as control. Total plasma homocysteine (tHcy) concentration was measured by high-performance liquid chromatography (HPLC). Lipid profiles were measured for all subjects. The polymorphisms of MTHFR gene C677T and MS gene A2756G were analyzed by PCR-RFLP.

RESULTS

The tHcy concentration in the combined hyperlipidemia patients was significantly higher than that in the control (15.95 micromol/L vs 13.43 micromol/L, P < 0.05). The prevalence of hyperhomocysteinemia (HHcy) in the combined hyperlipidemia group was significantly higher than that in the control (42.2% vs. 23.0%, P = 0.015), with the odds ratio (OR) of 3.339 (95% CI: 1.260-8.849). The hyperlipidemia patients with HHcy had a higher concentration of total cholesterol (TC) than that in the normal tHcy patients (5.67 +/- 0.95 mmol/L vs. 5.47 +/- 0.92 mmol/L, P=0.034). There was no significant difference in genotype or allele frequencies of MTHFR C677T between the hyperlipidemic and control groups. The hyperlipidemia patients with MTHFR CT/TT genotype had a higher concentration of triglyceride (TG) than those with CC genotype (2.24 +/- 1.75 mmol/L vs 1.87 +/- 0.95 mmol/L, P < 0.05). Individuals with CT/TT genotype had a higher concentration of tHcy than those with 677CC genotype both in the hyperlipidemia group (12.61 +/- 1.24 micromol/L vs. 11.20 +/- 1.37 micromol/L, P < 0.05) and in the control group (14.04 +/- 1.48 micromol/L vs. 12.61 +/- 1.24 micromol/L, P < 0.05). The percentage of MS 2756 GG/AG genotype in the combined hyperlipidemia group was significantly higher than that in the control (26.7% vs. 13.0%, P = 0.012), with the OR of 3.121 (95% CI: 1.288-7.651). The hyperlipidemia patients with MS 2756AG/GG genotype had a higher concentration of TC (5.87 +/- 0.89 mmol/L vs. 5.46 +/- 0.93 mmol/L, P < 0.05) and LDL-C (3.29 +/- 0.81 mmol/L vs. 2.94 +/- 0.85 mmol/L, P < 0.05) than those with AA genotype. However, individuals with 2756AG/GG genotype showed no significant difference in tHcy among those with AA genotype.

CONCLUSION

HHcy and MS A2756G mutation may be the risk factors for combined hyperlipidemia. Further study is needed to confirm the role of HHcy and MS A2756G mutation in the development of hyperlipidemia.

Interaction between Mediterranean diet and methylenetetrahydrofolate reductase C677T mutation on oxidized low density lipoprotein concentrations: the ATTICA study

BACKGROUND

The oxidative modification of low-density lipoprotein (LDL) has been suggested to be a key element in atherogenesis, while methylenetetrahydrofolate reductase (MTHFR) C677T mutation has been associated with the development of coronary heart disease. We evaluated whether adoption of a Mediterranean type of diet is associated with oxidized LDL levels, as well as the role of MTHFR C677T mutation in this relationship.

METHODS

We studied demographics, lifestyle, clinical, biochemical and genetic data from 322 men (46+/-13 years) and 252 women (45+/-14 years), without any clinical evidence of cardiovascular disease, from the Attica region, Greece (i.e. the ATTICA study). Among the other parameters we also measured oxidized (ox)-LDL levels, and the distribution of MTHFR. Adherence to the Mediterranean diet was evaluated by a special diet score.

RESULTS

The distribution of MTHFR genotypes was: 41% for homozygous normal (CC) genotype, 48% for heterozygous (CT) and 11% for homozygous mutant (TT) genotype. Ox-LDL levels were higher in TT as compared to CC and CT (70.8+/-26 vs. 51.0+/-26 vs. 63.7+/-24 mg/dl, p<0.001). Greater adherence to the Mediterranean diet was inversely associated with ox-LDL levels (standardized beta=-0.34, p<0.001), after controlling for several confounding variables; however, stratified analysis revealed that adherence to the Mediterranean diet was associated with lower ox-LDL levels in TT and CT individuals (standardized beta=-0.67, p=0.001 and standardized beta=-0.66, p=0.025, respectively), but not in CC (standardized beta=-0.18, p=0.10), after controlling for several potential confounders.

CONCLUSION

The observed gene-to-diet interaction on ox-LDL concentrations may provide a pathophysiological explanation by which a Mediterranean type of diet could influence coronary risk in people with increased oxidative stress.