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1.
Methylenetetrahydrofolate reductase (MTHFR) enzyme plays an important role in folate metabolism and MTHFR polymorphisms have been suggested to be associated with risk of various cancers. MTHFR C677T polymorphism is a common genetic alteration and may affect the host susceptibility to ovarian cancer. The aim of this study was to investigate the association between MTHFR C677T polymorphism and ovarian cancer risk by performing a meta-analysis. Pubmed, Embase, Web of Science and Chinese Biomedical Database (CBM) databases were searched for case–control studies investigating the association between MTHFR C677T polymorphism and ovarian cancer. Odds ratio (OR) and its 95 % confidence interval (95 % CI) was used to assess this possible association. 13 individual case–control studies from 10 publications with a total of 18, 628 subjects (5, 932 cases and 12, 696 controls) were included into this meta-analysis. Meta-analyses showed there was no association between MTHFR C677T polymorphism and ovarian cancer risk in Caucasians under all five genetic models (All P values for the pooled ORs were more than 0.05), whereas there was an obvious association between MTHFR C677T polymorphism and ovarian cancer risk in Asians under four genetic models (for T vs C, OR (95 % CI) = 1.38(1.19–1.61); for TT vs CC, OR (95 % CI) = 2.32(1.63–3.29); for TT vs TC+CC, OR (95 % CI) = 2.04(1.47–2.85); for TT+TC vs CC, OR (95 % CI) = 1.36(1.12–1.65)). Subgroup analyses suggested ethnicity was the major source of heterogeneity. This meta-analysis supports an association between MTHFR C677T polymorphism and ovarian cancer risk, and there might be a race-specific effect in this association. Further studies with large sample size and careful design are needed to identify this association more comprehensively.  相似文献   

2.
Epidemiological studies have evaluated the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and primary open-angle glaucoma (POAG) risk. However, the results remain conflicting. The aim of this study was to investigate the association between MTHFRC677T polymorphism and POAG risk. All genetic association studies on MTHFR C677T polymorphism and POAG were systematically searched by the electronic databases PubMed, Embase and Web of Science. Study selection, data abstraction and study quality evaluation were conducted in duplicate independently. The strength of association between MTHFR C677T polymorphism and POAG was measured by odds ratios (ORs) and 95% confidence intervals (CIs). Publication bias was tested by Begg's funnel plot and Egger's regression test. A total of 10 studies including 1224 cases and 1105 controls were included in our final meta-analysis. There was no evidence of significant association of the overall population (for allelic model: OR = 1.17, 95% CI = 0.94–1.46; for additive model: OR = 1.15, 95% CI = 0.85–1.57; for dominant model: OR = 1.19, 95% CI = 0.92–1.55 and for recessive model: OR = 1.11, 95% CI = 0.83–1.49). Significant associations were found between MTHFR C677T polymorphisms and POAG in allelic model (OR = 1.39, 95% CI = 1.05–1.83) and additive model (OR = 1.88, 95% CI = 1.04–3.43) for population-based (PB) subgroup. This meta-analysis suggested that there were significant associations between MTHFR C677T polymorphism and POAG in allelic model and additive model for PB subgroup which indicated that the T allele or TT genotype might increase the risk of POAG, whereas no evidence of significant association was shown of the overall studied population. However, this conclusion should be interpreted cautiously. More large sample-size and multi-ethnicity studies with well-defined POAG patients and well-study design are needed in the future study.  相似文献   

3.
The results of studies on association between the C677T polymorphism of the 5,10-methylene-tetrahydrofolate reductase (MTHFR) gene and osteonecrosis of the femoral head (ONFH) are controversial. To derive a more precise estimation of the relationship between the MTHFR C677T polymorphism and ONFH, a meta-analysis was performed. Eight studies on MTHFR C677T association with ONFH were searched up to April 2011, and the genotype frequencies in control group were consistent with Hardy–Weinberg equilibrium. The effect summary odds ratio (OR) and 95% confidence intervals were obtained. Publication bias was tested by funnel plot, Egger’s regression test, and heterogeneity was assessed. Eight studies containing 778 cases and 1,162 controls were included. Heterogeneity was observed (χ 2 = 18.58, P = 0.01). Under the random effects model, the common OR was 1.38 (95% CI: 0.92–2.08; P = 0.12). In the subgroup meta-analysis, there was an association between MTHFR C677T polymorphism and ONFH in non-Asian population for CT + TT vs. CC (OR = 1.72; 95% CI: 1.21–2.43; P = 0.002; I 2  = 37.9%, P = 0.17), but not for Asian population (OR = 0.88; 95% CI: 0.66–1.66; P = 0.35; I 2  = 45.4%, P = 0.16). There was heterogeneity between studies and no clear evidence of an association on a worldwide population. When stratifying for the race, this meta-analysis did not provide an evidence of confirming association between MTHFR C677T polymorphism and ONFH. The large sample and well-designed study based on different ethnic groups should be considered in future associated studies to clarify the association of MTHFR C677T polymorphism with ONFH susceptibility.  相似文献   

4.
Numerous studies have reported a relationship between folate status, the methylenetetrahydrofolate reductase (MTHFR) 677C-->T variant and disease risk. Although folate and choline metabolism are inter-related, only limited data are available on the relationship between choline and folate status in humans. This study sought to examine the influences of folate intake and the MTHFR 677C-->T variant on choline status. Mexican-American women (n=43; 14 CC, 12 CT and 17 TT) consumed 135 microg/day as dietary folate equivalents (DFE) for 7 weeks followed by randomization to 400 or 800 microg DFE/day for 7 weeks. Throughout the study, total choline intake remained unchanged at approximately 350 mg/day. Plasma concentrations of betaine, choline, glycerophosphocholine, phosphatidylcholine and sphingomyelin were measured via LC-MS/MS for Weeks 0, 7 and 14. Phosphatidylcholine and sphingomyelin declined (P=.001, P=.009, respectively) in response to folate restriction and increased (P=.08, P=.029, respectively) in response to folate treatment. The increase in phosphatidylcholine occurred in response to 800 (P=.03) not 400 (P=.85) microg DFE/day (week x folate interaction, P=.017). The response of phosphatidylcholine to folate intake appeared to be influenced by MTHFR C677T genotype. The decline in phosphatidylcholine during folate restriction occurred primarily in women with the CC or CT genotype and not in the TT genotype (week x genotype interaction, P=.089). Moreover, when examined independent of folate status, phosphatidylcholine was higher (P<.05) in the TT genotype relative to the CT genotype. These data suggest that folate intake and the MTHFR C677T genotype influence choline status in humans.  相似文献   

5.
MTHFR C677T polymorphism and osteoporotic fractures.   总被引:1,自引:0,他引:1  
The C677T (rs1801133) polymorphism of MTHFR (methylenetetrahydrofolate reductase) has been associated with the risk of cardiovascular events, and also with osteoporosis in some studies. However, the results are controversial. Our objective was to determine the relationship of the polymorphism with osteoporotic fractures by means of a case-control study. C677T was analyzed in 823 subjects (365 controls, 136 with vertebral fractures and 322 with hip fracture) by using a Taqman assay. The distribution of MTHFR genotypes was similar in patients and controls. In comparison with TC/CC genotypes, the age-adjusted OR for hip fractures of the TT genotype was 1.0 (95% confidence interval 0.6-1.7) in women and 0.7 (0.3-1.8) in men. The OR for vertebral fractures was 0.8 (0.4-1.7) in women and 1.7 (0.4-6.7) in men. A meta-analysis combining these data with previous reports confirmed the lack of association between MTHFR and fractures, with an OR of 1.1 (0.7-1.9, p=0.65) for vertebral fractures and 1.2 (0.7-2.0; p=0.45) for peripheral fractures, but there was significant heterogeneity among the results of individual studies, particularly about peripheral fractures. In conclusion, the C677T polymorphism of the MTHFR gene does not appear to be associated with the overall risk of osteoporotic fractures. However, given the heterogeneity of the results of published studies, further investigations are needed to evaluate its influence in specific population subgroups.  相似文献   

6.
BACKGROUND: We investigated whether infants with homozygous genotype TT of the MTHFR gene were at increased risk of severe mental retardation. METHODS: One hundred children with severe mental retardation (cases) were investigated from a large geographic-based study of infants born in California in 1992-1993. Cases were compared to 743 randomly selected nonmalformed control infants born in California during 1987-1991. DNA was extracted from newborn screening filter papers. Cases and controls were genotyped TT if homozygous for the MTHFR C677T allele, CT if heterozygous for the C677T allele, and CC if homozygous for the C677 (wild type) allele. RESULTS: Overall, case and control infants had similar percentages of TT and CT genotypes. Percentages between cases and controls differed somewhat across race/ethnic groups. Elevated ORs of 1.9 (95% CI: 0.7-5.0) and 2.6 (95% CI: 1.1-5.8) were observed for the TT and CT genotypes, respectively, among Hispanic children. Observed results were not substantially altered for analyses that removed 41 case children who also had structural birth defects. CONCLUSIONS: Folate-related mechanisms are important to investigate for etiologies of birth defects, and such lines of inquiry may be revealing for mental retardation given the relationships between mental retardation and birth defects and potential relationships between folate, DNA methylation, and mental retardation.  相似文献   

7.
The C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase (MTHFR) have been reported to alter the risk of ovarian cancer. However, the results are still inconclusive. For better understanding of the effect of these two polymorphisms on ovarian cancer risk, a meta-analysis was performed. An extensive search was performed to identify all case–control studies investigating such association. The strength of association between these two polymorphisms and ovarian cancer risk was assessed by odds ratio (OR) with the corresponding 95?% confidence interval (95?% CI). 3,496 cases and 3,631 controls for C677T polymorphism and 3,280 cases and 3,346 controls for A1298C polymorphism were included in this meta-analysis. The results suggested that there were no significant associations between C677T and A1298C polymorphisms and ovarian cancer risk in overall comparisons in all genetic models (For C677T: TT vs. CC: OR?=?0.94, 95?% CI?=?0.71–1.24, P?=?0.65; CT vs. CC: OR?=?1.03, 95?% CI?=?0.93–1.14, P?=?0.57; TT/CT vs. CC: OR?=?1.01, 95?% CI?=?0.88–1.16, P?=?0.87; TT vs. CC/CT: OR?=?0.93, 95?% CI?=?0.72–1.20, P?=?0.58. For A1298C: CC vs. AA: OR?=?1.05, 95?% CI?=?0.88–1.25, P?=?0.65; CA vs. AA: OR?=?0.98, 95?% CI?=?0.88–1.08, P?=?0.66; CC/CA vs. AA: OR?=?0.99, 95?% CI?=?0.90–1.09, P?=?0.85; CC vs. AA/CA: OR?=?1.06, 95?% CI?=?0.90–1.26, P?=?0.46). Subgroup analysis based on ethnicities and influence analysis did not perturb the results. In conclusion, the results of this meta-analysis indicate that the MTHFR C677T and A1298C polymorphisms are not associated with ovarian cancer risk, especially in Caucasians.  相似文献   

8.
Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in folate metabolism and is involved in DNA synthesis, DNA repair and DNA methylation. The two common functional polymorphisms of MTHFR, 677 C→T and 1298 A→C, have been shown to impact various diseases, including cancer. The 677 C→T polymorphism has been widely investigated in different cancers and has been implicated as a risk factor for the development of various cancers. We investigated MTHFR C677T genotype frequency in colorectal cancer cases in the Kashmiri population and correlated this information with the known clinicopathological characters of colorectal cancer, in a case-control study. Eighty-six colorectal cancer cases were studied for MTHFR C677T polymorphism, compared to 160 controls taken from the general population, employing the PCR-RFLP technique. We found the frequency of the three different genotypes of MTHFR in our ethnic Kashmir population, i.e., CC, CT and TT, to be 68.6, 20.9 and 10.4% among colorectal cancer cases and 75.6, 16.9 and 7.5% among the general control population, respectively. There was a significant association between the MTHFR TT genotype and colorectal cancer in the higher age group. We conclude that the MTHFR C677T polymorphism slightly increases the risk for colorectal cancer development in our ethnic Kashmir population.  相似文献   

9.
Chronic pancreatitis and pancreatic adenocarcinoma are extensively studied as common and potentially lethal disorders. However, their causes and genetic background in most cases remain unclear. The C677T polymorphism in 5',10'-methylenetetrahydrofolate reductase (MTHFR) gene may modulate the risk of pancreatic disorders. In this study, we tested whether MTHFR C677T polymorphism is associated with chronic pancreatitis and pancreatic adenocarcinoma in the Serbian population. DNA was extracted from blood samples of 51 chronic pancreatitis patients, 21 pancreatic adenocarcinoma patients, and a control group consisting of 50 healthy smokers. The MTHFR C677T polymorphism was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Although, no statistically significant differences were observed in the distribution of MTHFR genotype or allele frequencies between patients and control groups, the results showed an increased frequency of homozygotes for MTHFR C677T polymorphism in chronic pancreatitis patients (14%) and a decreased frequency in pancreatic adenocarcinoma patients (5%) in comparison to the control group (8%). We speculate that the MTHFR C677T polymorphism could act as a possible risk factor for chronic pancreatitis and a possible protective factor in pancreatic adenocarcinoma. This observation needs further investigation in prospective studies on a larger number of patients, in which the effect of other genetic and environmental factors should also be taken into consideration.  相似文献   

10.
Wei B  Xu Z  Ruan J  Zhu M  Jin K  Zhou D  Xu Z  Hu Q  Wang Q  Wang Z 《Molecular biology reports》2012,39(2):1997-2002
Epidemiological studies have evaluated the association between MTHFR 677C>T and 1298A>C polymorphisms and risk of male infertility. However, the results from the published studies on the association between these two MTHFR polymorphisms and male infertility risk are conflicting. To derive a more precise estimation of association between the MTHFR polymorphisms and risk of male infertility, we performed a meta-analysis. A comprehensive search was conducted to identify all case–control studies of MTHFR polymorphisms and male infertility risk. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. Overall, we found that both 677C>T and 1298A>C polymorphisms were not significantly associated with male infertility risk. However, in stratified analysis by ethnicity, we found that the 677C>T polymorphism was significantly associated with the risk of male infertility in Asian population (TT vs. CC: OR = 1.57, 95% CI: 1.05–2.37, P = 0.03; TT vs. TC + CC: OR = 1.40, 95% CI: 1.05–1.86, P = 0.02; TT + TC vs. CC: OR = 1.34, 95% CI: 1.01–1.77, P = 0.04). Although some modest bias could not be eliminated, this meta-analysis suggested that the MTHFR 677T allele might be a low-penetrant risk factor for male infertility, especially in Asian population.  相似文献   

11.
Many studies have investigated the associations between methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms and risk of fractures, but the impact of MTHFR polymorphisms on fractures risk is unclear owing to the obvious inconsistence among those studies. This study aims to quantify the strength of association between MTHFR C677T and A1298C polymorphisms and risk of fractures. We searched the PubMed, Embase and Wanfang databases for articles relating the association between MTHFR C677T and A1298C polymorphisms and risk of fractures in humans. We estimated summary odds ratios (ORs) with their confidence intervals (CIs) to assess the associations. Meta-analyses suggested MTHFR C677T polymorphism was associated with increased risk of any site fractures (for T vs. C, OR = 1.17, 95 % CI 1.03–1.32; for TT vs. CC, OR = 1. 31, 95 % CI 1.11–1.54; for TT vs. CT, OR = 1.22, 95 % CI 1.04–1.43; for TT vs. CT/CC, OR = 1.31, 95 % CI 1.13–1.51). Besides, MTHFR A1298C polymorphism was also associated with increased risk of any site fractures. Subgroup meta-analyses suggested MTHFR C677T polymorphism was associated with increased risk of vertebral fractures under three genetic contrast modes (for TT vs. CC, OR = 1.43, 95 % CI 1.05–1.95; for TT vs. CT, OR = 1.36, 95 % CI 1.01–1.85; for TT vs. CT/CC, OR = 1.50, 95 % CI 1.17–1.91), but there was no association between MTHFR C677T polymorphism and risk of hip fractures and non-vertebral fractures (all P values were more than 0.05). Thus, individuals with homozygote genotype TT of MTHFR C677T have obviously increased risk of vertebral fractures compared those with heterozygote genotype CT or homozygote genotype CC. There is no association between MTHFR C677T polymorphism and risk of hip fractures and non-vertebral fractures.  相似文献   

12.
Combined oral contraceptives (Ocs) are the most commonly used androgen suppressors and the treatment of choice for menstrual dysfunction in women with polycystic ovarian syndrome (PCOs). Although OCs have remained popular due to their convenience and effectiveness, there have been continuing concerns about adverse effects. The OCs have long been known to incur and increased risk of venous thromboembolism especially in carriers of common inherited thromboembolic defects. Factor V Leiden, prothrombin factor G20210A polymorphism, MTHFR (C677T) mutation and 4G/5G polymorphism of the PAI-1 gene account for the majority of thromboembolic events in association with oral contraceptive use. The aim of the article is to present woman with unrecognized inherited thrombophilia who was treated with OCs due to PCOs signs.  相似文献   

13.
14.
Non-syndromic cleft lip with or without cleft palate (nsCL/P) is among the most common major birth defects, with complex inheritance involving multiple genes and environmental factors. Numerous studies of MTHFR, encoding methylenetetrahydrofolate reductase, which catalyzes the rate-limiting step of folic acid biosynthesis, have shown inconsistent association of two common hypomorphic allelic variants, C677T and A1298C, in nsCL/P patients and, in some cases, their mothers. We have studied the MTHFR C677T and A1298C polymorphisms in nsCL/P patients, their mothers, and population-matched controls from northern Venezuela. We found no evidence for contribution of the MTHFR C677T and A1298C variants to the risk of nsCL/P in northern Venezuela. Overall, our findings fail to support a causal role of either the MTHFR C677T or A 1298C variants in the pathogenesis of nsCL/P in northern Venezuela.  相似文献   

15.
16.
5,10-Methlenetetrahydrofolate reductase (MTHFR) is one of the most important enzymes for folate metabolism. This enzyme is mapped on chromosome 1, which is located at the end of the short arm (1p36.3). The C677T and A1298C are MTHFR polymorphisms that decrease in vitro MTHFR enzyme activity. Folate metabolism plays a key role in cell metabolism. These reactions are associated with purine?Cpyrimidine synthesis: DNA, RNA, and protein methylation. Polymorphism is also a factor in biodiversity, and be affected by ethnic heritage and geographic locale. In the case of unknown outcomes, not only should all geographical regions be investigated to ascertain biodiversity, but all populations as well to fully understand the variations in the effect. PUBMED was searched from January 2006 to December 2011 to develop an investigatory pursuit strategy. MTHFR, cancer, C677T, A1298C, and polymorphisms were key words used to focus the search. The literature review included all published relevant cancer types and MTHFR polymorphisms for that 5?years period. All selected polymorphisms data for cancer types was listed in tables for easy access and retrieval.  相似文献   

17.
Cytochrome P450 1A1 (CYP1A1), an important phase I xenobiotic metabolizing enzyme, is responsible for metabolizing numerous carcinogens, particularly polycyclic aromatic hydrocarbons. The genetic polymorphism of CYP1A1 at the site of MspI (CYP1A1 MspI) has been implicated in prostate cancer risk, but the results of individual studies remain conflicting and inconclusive. The aim of this meta-analysis was to investigate the association of CYP1A1 MspI polymorphism with prostate cancer risk more precisely. We performed a comprehensive search of the PubMed, Embase, Web of Science, and China National Knowledge Infrastructure databases from their inception up to September 20, 2012 for relevant publications. The pooled odds ratios with the corresponding 95 % confidence intervals (95 % CIs) were calculated to assess the association of CYP1A1 MspI polymorphism with prostate cancer risk. In addition, stratified analyses by ethnicity and sensitivity analyses were conducted for further estimation. Sixteen eligible publications with 6,411 subjects were finally included into the meta-analysis after checking the retrieved papers. Overall, meta-analysis of total studies suggested that individuals carrying the TC genotype and a combined C genotype (CC + TC) were more susceptible to prostate cancer (ORTC vs. TT = 1.33, 95 % CI 1.10–1.61, P OR = 0.004; ORCC+TC vs. TT = 1.27, 95 % CI 1.05–1.55, P OR = 0.016). Stratified analysis of high quality studies also confirmed the significant association (ORTC vs. TT = 1.32, 95 % CI 1.04–1.67, P OR = 0.024; ORCC+TC vs. TT = 1.30, 95 % CI 1.02–1.66, P OR = 0.035). In subgroup analyses by ethnicity, a significant association between the CYP1A1 MspI polymorphism and risk of prostate cancer was found among Asians (ORTC vs. TT = 1.44, 95 % CI 1.20–1.72, P OR < 0.001; ORCC+TC vs. TT = 1.33, 95 % CI 1.12–1.58, P OR = 0.001), but not in Caucasians or mixed populations. The meta-analysis suggests an important role of the CYP1A1 MspI polymorphism in the risk of developing prostate cancer, especially in Asians.  相似文献   

18.
DNA methylation is mediated by DNA methyltransferases (DNMTs) that add a methyl group to the 5′-carbon of cytosine. The enzyme methylenetetrahydrofolate reductase (MTHFR) catalyzes the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate in the rate-limiting step of the cycle involving the methyl donor S-adenosyl-L-methionine (SAM). The MTHFR C677T polymorphism results in a thermolabile enzyme with reduced activity that is predicted to influence the DNA methylation status. In this study, we investigated the impact of the MTHFR C677T polymorphism on the global DNA methylation of oral epithelial cells obtained from 54 healthy subjects. There were no significant differences in global DNA methylation among the MTHFR CC, CT and TT genotypes (p = 0.75; Kruskal-Wallis test).  相似文献   

19.
The C677T methylenetetrahydrofolate reductase (MTHFR) gene polymorphism results in reduced MTHFR enzymatic activity. This in turn results in increased levels of homocysteine. It has been suggested that increased levels of homocysteine cause vascular disease, which is known to increase the risk of developing pre-eclampsia (PE) during pregnancy. However, recent studies on Japanese, Italian and American populations have failed to reach agreement on an association between the C677T polymorphism and PE. In this study, 156 cases of eclampsia (E)/PE and 79 normal pregnant control cases from an Australian population were genotyped for this mutation. No significant difference could be found in the incidence of the homozygote mutation or in the allele frequency. We conclude from this study that the C677T mutation in our population is not associated with the development of PE/E.  相似文献   

20.
Gallbladder carcinoma (GBC) is a leading cause of cancer deaths in north India. Evidence has highlighted the role of abnormal DNA methylation patterns on inappropriate gene expression in development and progression of various cancers. 5,10-Methylenetetrahydrofolate reductase (MTHFR) plays a major role in provision of methyl groups for DNA methylation. A C/T substitution in MTHFR at nucleotide 677 results in replacement of ala222-to-val in the N-terminal catalytic domain of protein, and causes considerable decrease in enzymatic activity. Thus, MTHFR C677T polymorphism may influence genetic susceptibility to GBC. The present study aimed to examine the role of C677T MTHFR polymorphism in conferring genetic susceptibility to GBC. The present study included 146 proven GBC patients and 210 healthy controls. Genotyping was done by PCR-RFLP method. The MTHFR C677T genotypes in control population were in Hardy-Weinberg equilibrium (p = ns). No statistically significant difference was observed in frequency of variant TT genotype in GBC patients in comparison to healthy controls (4.1% and 2.9%). Stratification of GBC patients on the basis of presence or absence of gallstones showed no significant association with the disease. Further, gender and age of onset of the disease did not show any significant association. In conclusion, the present study indicates that the genetic risk for GBC is not modulated by MTHFR C677T polymorphism.  相似文献   

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