Methionine Synthase Reductase A66G Polymorphisms Research Articles

Association between Methionine Synthase Reductase A66G Polymorphism and Male Infertility: A Meta-Analysis

The aim of this meta-analysis was to assess the methionine synthase reductase (MTRR) gene 66A>G polymorphism and male infertility susceptibility. Studies were identified in PubMed and Embase databases. An odds ratio (OR) was used to assess the relationship between MTRR 66A>G polymorphism and male infertility risk. A total of seven case-control studies containing 1438 patients and 1363 controls were enrolled in the meta-analysis. Our results showed that no association exists between the MTRR 66A>G polymorphism and male infertility risk in the total population (GG vs. AA: OR = 1.29, 95% confidence interval [CI] = 1.00-1.66; GA vs. AA: OR = 1.09, 95% CI = 0.92-1.30; dominant model: OR = 1.13, 95% CI = 0.96-1.34; recessive model: OR = 0.83, 95% CI = 0.67-1.03). In a subgroup analysis by nationality, the 66A>G polymorphism was not associated with male infertility in both Asians and Caucasians. In a subgroup analysis stratified by male infertility type, significant association was found with oligoasthenozoospermia (OAT) (GG vs. AA: OR = 1.83, 95% CI = 1.24-269; GA vs. AA: OR = 1.36, 95% CI = 0.88-2.11; dominant model: OR = 1.51, 95% CI = 1.13-2.01; recessive model: OR = 0.62, 95% CI = 0.46-0.85). In summary, the present meta-analysis suggests that MTRR 66A>G polymorphism may be associated with OAT risk.

Association between methionine synthase reductase A66G polymorphism and primary infertility in Chinese males.

We examined the association between the methionine synthase reductase (MTRR A66G), methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), and methionine synthase (MS A2756G) genotypes and non-obstructive male infertility in a Chinese population. This case-control study included 162 infertile Chinese patients with azoospermia (N = 100) or oligoasthenozoospermia (N = 62) and 120 fertile men as controls. The polymorphisms MTRR A66G, MTHFR C677T, A1298C, and MS A2756G were identified by direct DNA sequencing and the results were statistically analyzed. We found no association between the incidence of any of these variants in azoospermia patients and control populations. The frequency of the MTRR66 polymorphic genotypes (AG, AG+GG) was significantly higher in the oligoasthenozoospermia group compared to the controls (P = 0.013, 0.012). Our findings revealed an association between the single-nucleotide polymorphism A66G in the MTRR gene and male infertility, particularly in oligoasthenozoospermia males, suggesting that this polymorphism is a genetic risk factor for male infertility in Chinese men.

Association Between Methionine Synthase Reductase A66G Polymorphism and the Risk of Congenital Heart Defects: Evidence From Eight Case–Control Studies

Methionine synthase reductase (MTRR) plays a major role in hyperhomocysteinemia, a risk factor related to the occurrence of congenital heart defects (CHDs). However, the associations between MTRR polymorphism and CHDs have been inconclusive. Thus, a metaanalysis of eight case-control studies was conducted to investigate 3,592 cases and 3,638 control subjects for MTRR A66G polymorphism to identify the association. Odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were used to assess the strength of the association. The results showed that MTRR A66G polymorphism was associated with a higher CHD risk in the allele comparison (G vs A: OR 1.163; 95 % CI 1.016-1.330; P heterogeneity = 0.004), the homozygote comparison (GG vs AA: OR 1.332; 95 % CI 1.020-1.740; P heterogeneity = 0.035), and the dominant model (GG/AG vs AA: OR 1.218; 95 % CI 1.001-1.482; P heterogeneity = 0.001). In the subgroup analysis, this polymorphism was associated with CHDs in Asians in the homozygote comparison (GG vs AA: OR 1.427; 95 % CI 1.017-2.001; P heterogeneity = 0.019) and the allele comparison (G vs A: OR 1.203; 95 % CI 1.018-1.422; P heterogeneity = 0.002). In summary, the metaanalysis demonstrated that MTRR A66G polymorphism is a risk factor for CHDs. Further studies should be performed to investigate the association of plasma homocysteine levels, enzyme activity, parental genotypes, and vitamin complex intakes with the risk of CHDs.

Methionine Synthase Reductase A66G Polymorphism is not Associated with Breast Cancer Susceptibility - a Meta-analysis

Several studies have investigated the association between methionine synthase reductase (MTRR) A66G polymorphism and breast cancer risk, but controversial results were yielded. Therefore, we performed a meta-analysis to provide a more robust estimate of the effect of this polymorphism on susceptibility to breast cancer. Case-control studies investigating the relationship between MTRR A66G polymorphism and breast cancer risk were included by searching PubMed, EMBASE, China National Knowledge Infrastructure and Wanfang Database. Either fixed-effects or random-effects models were applied to calculate odds ratios(ORs) and 95% confidence intervals (CIs) by RevMan5.2 software. A total of 9 studies bearing 7,097 cases and 7,710 controls were included in the meta-analysis. The results were that the combined ORs and 95%CIs of MTRR 66AG, GG, (AG+GG) genotypes were 0.98(0.91-1.05), 1.06(0.97-1.16) and 1.02(0.94-1.10), respectively with p=0.52, 0.19 and 0.65. We also performed subgroup analysis by specific ethnicity. The results of the combined analysis of MTRR 66AG, GG, (AG+GG) genotypes and breast cancer in Asian descent were Z=0.50, 0.53 and 0.21, with p all>0.05; for breast cancer in Caucasian descent, the results were Z=1.14, 1.65 and 0.43, with p all>0.05. Our findings suggested that MTRR A66G polymorphism was not associated with breast cancer susceptibility.

Methionine synthase reductase A66G polymorphism and leukemia risk: evidence from published studies

Methionine synthase reductase (MTRR) is required for the reductive methylation of cobalamin, which is the functional cofactorial form of methionine synthase (MS) in the remethylation of homocysteine to methionine. The MTRR A66G (rs1801394) polymorphism is found to be associated with decreased enzyme affinity for MTR, the gene that encodes MS, and has been widely investigated for cancer risk, including leukemia. However, the conclusions of epidemiological studies have always been contradictory. To further clarify the association of MTRR A66G polymorphism with the risk of leukemia, this meta-analysis was performed for 2913 cases and 4764 controls. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Pooled ORs were determined for the co-dominant model (GG vs. AA, AG vs. AA), dominant model (GG + AG vs. AA) and recessive model (GG vs. AA+ AG), respectively. No significant associations were found for all comparisons in the overall pooled analysis. However, the results of stratified analyses revealed that MTRR A66G GG genotype was associated with decreased leukemia risk in the Caucasian population, in children and for acute lymphoblastic leukemia (ALL). In contrast, increased risk was observed in the Asian population and for acute myeloid leukemia (AML). This meta-analysis suggests that MTRR A66G GG is associated with decreased risk of leukemia in a Caucasian population and in children, especially for ALL.

Methionine synthase reductase A66G polymorphism contributes to tumor susceptibility: evidence from 35 case–control studies

Methionine synthase reductase (MTRR) gene is involved in tumorigenesis by regulating DNA methylation through activation of methionine synthase (MTR). MTRR is polymorphic at nucleotide 66 (A-to-G) and the resulting variant enzyme has a lower affinity for MTR. The reported associations of MTRR A66G polymorphism with cancer risk are contradictory. Therefore, we performed a meta-analysis to better assess the associations, including 18,661 cases and 27,678 controls from 35 studies. Crude ORs with 95% CIs were used to assess the strength of association between the MTRR A66G polymorphism and cancer risk. The pooled ORs were performed for homozygote model (GG vs. AA), heterozygote model (GG vs. GA), recessive genetic model (GG vs. GA + AA), and dominant genetic model (GG + GA vs. AA), respectively. Overall, results indicated that the G allele and GG variant genotypes were associated with a significantly increased cancer risk (G vs. A: OR, 1.039; 95% CI, 1.009-1.078; homozygote model: OR, 1.094; 95% CI, 1.006-1.191). In subgroup analysis by ethnicity, significant increased risks were found among Asians with G allele (G vs. A: OR, 1.063; 95% CI, 1.011-1.119; homozygote model: OR, 1.189; 95% CI, 1.055-1.341; recessive model: OR, 1.197; 95% CI, 1.068-1.341). For stratification analysis, the cancer types with fewer than three studies were categorized into "other cancers", and the results indicated that there was a significant elevated cancer risk in "other cancers" in all genetic models, not in colorectal cancer, lymphoid leukemia or breast cancer. In summary, our study suggests that the MTRR A66G polymorphism is a potential biomarker for cancer risk.

Uttar Pradesh Methionine Synthase Reductase A66g Polymorphism in Rural Population of Uttar Pradesh (India)

Uttar Pradesh Methionine Synthase Reductase A66g Polymorphism in Rural Population of Uttar Pradesh (India)

Polymorphism C776G in the transcobalamin II gene and homocysteine, folate and vitamin B 12 concentrations. Association with MTHFR C677T and A1298C and MTRR A66G polymorphisms in healthy children

One of the etiologies of hyperhomocysteinemia is decreased vitamin B 12. Genetic variation in the transcobalamin II gene, the transporter of vitamin B 12 to the cells, may produce altered homocysteine levels. We determined transcobalamin II C776G polymorphism, homocysteine, folate and vitamin B 12 levels and analyzed the interactive effect with the methylenetetrahydrofolate reductase C677T and A1298C and methionine synthase reductase A66G polymorphisms in 207 healthy Brazilian children. The prevalence of GG genotype of transcobalamin II C776G polymorphism in this Brazilian population, a highly miscigeneous population was 12.5% and the statistical analysis showed that this population is in Hardy–Weinberg equilibrium, it could be considered representative of the general population. We observed a significant increase in homocysteine in the 776GG vs. 776CC genotype, corroborating the influence of age as a determinant of homocysteine in relation to this polymorphism. When we analyzed vitamin B 12 and its relationship with the C776G polymorphism, we found no significant differences. Only 776CG/66AA or 776GG/66AG genotypes presented a significant increase in homocysteine when compared with other groups. In the multivariate analysis, transcobalamin II C776G (CC/CG vs. GG), methylenetetrahydrofolate reductase C677T (CC/CT vs. TT), folate, gender and age presented statistical significance in relation to the homocysteine. These can be considered independent risk factors for hyperhomocysteinemia in this children group. Our results, if confirmed in other populations, highlight the necessity for investigation of the transcobalamin II C776G polymorphism in the research for hyperhomocysteinemia risk factors.

Effects of Methionine Synthase (MS) A2756G and Methionine Synthase Reductase (MSR) A66G Polymorphisms on Methionine Metabolism in Brazilian Pregnant Women and Their Neonates.

Methionine synthase (MS) is a cobalamin dependent enzyme that catalyses the remethylation of homocysteine to methionine. The methionine synthase reductase (MSR) maintains adequate levels of methylcob(III)alamin, the activated cofactor for MS. The aim of this study was to investigate the effect of MS A2756G and MSR A66G polymorphisms on total homocysteine (tHcy), S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH) levels in 390 pregnant women and their 292 newborns, from Sorocaba city, Brazil. Genotypes of two polymorphisms were determined by PCR-RFLP. Pregnant women with MS 2756AA genotype have higher tHcy and lower Cbl levels than those with 2756G alleles. The MMA values were increased in neonates with MS 2756AA genotypes (Table 1). There are no difference between the maternal values of Cbl, serum folate, tHcy, MMA and SAM according to MSR A66G genotypes.The values of SAM were lower in neonates with MSR 66G alleles than those with AA genotypes (Table 2). We conclude that MS 2756AA genotypes are associated with higher tHcy levels in pregnant women and higher MMA levels in neonates. The MSR 66GG genotypes is associated with lower SAM levels in neonates.Table 1- Distribution of geometric means and confidence intervals 95% (CI 95%) and numbers of subjects for maternal and neonatal values of cobalamin (Cbl), serum folate, total homocysteine (tHcy), methymalonic acid (MMA) and S- adenosylmethionine (SAM) according to genotypes for the polymorphism MS A2756G.VariablesGenotypes for MS A2756GStudent t TestAAAG + GGPregnant WomenCbl (pmol/L)139 (133 – 144) 235156 (146 – 166) 129P= 0.001SF (nmol/L)14.3 (13.6 – 15.0) 23414.5 (13.6 – 15.5) 129P= 0.667tHcy( μmol/L)6.8 (6.5 – 7.1) 2356.2 (5.9 – 6.6) 128P= 0.036MMA(nmol/L)234 (219 – 245) 194241 (219 – 265) 106P= 0.610SAM(nmol/L)81.8 (77.9 – 86,0) 22983.1 (79.1 – 87.4) 124P= 0.663NeonatesCbl (pmol/L)227 (212 – 244) 188234 (213 – 257) 101P= 0.646SF (nmol/L)32.0 (31.0 – 33.0) 18632.0 (30.8 – 33.2) 99P= 0.967tHcy μmol/L)5.8 (5.5 – 6.1) 1855.5 (5.1 – 5.9) 100P= 0.229MMA(nmol/L)383 (364 – 402) 183342 (317 – 369) 100P= 0.011SAM(nmol/L)188 (181 – 196) 178182 (168 – 197) 98P= 0.491Table 2 - Distribution of geometric means and confidence intervals 95% (CI (%%) and number of subjects for neonatal values of cobalamin (Cbl), serum folate, total homocysteine (tHcy), methylmalonic acid (MMA) and S- adenosylmethionine (SAM) according to genotypes for the polymorphism MSR A66G.VariablesGenotypes MSR A66GStudent t TestAAAGGGNeonatesCbl (pmol/L)225 (202 – 249) 86229 (214 – 246) 166247 (205 – 298) 35P= 0.602SF (nmol/L)33.0 (31.6 – 34.4) 8431.7 (30.7 – 32.7) 16631.8 (29.7 – 34.2) 33P= 0.352tHcy μmol/L) (5.7 (5.3 – 6.2) 845.6 (5.3 – 5.9) 1655.9 (5.3 – 6.6) 34P= 0.618MMA (nmol/L)360 (334 – 389) 84378 (357 – 400) 163339 (299 – 384) 34P= 0.230SAM (nmol/L)200 (186 – 215)a 82184 (176 – 192)a 159170 (149 – 195)b 33P= 0.032Groups not sharing a common superscript letter are significantly different at P<0.05 based on Tukey's test