Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.5.7.1 (methylenetetrahydrofolate reductase)
2,116 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Methotrexate (MTX), widely used in the treatment of rheumatoid arthritis (RA), inhibits dihydrofolate reductase (DHFR) and folate-dependent enzymes. Thymidylate synthase (TS) and methylenetetrahydrofolate reductase (MTHFR) are key enzymes in the folate metabolism and both have been shown to be polymorphic affecting the enzyme activity. To clarify the association between these genetic variations and MTX-related toxicity and efficacy in the treatment of RA, a total of 167 Japanese individuals with RA, including 52 and 63 patients treated with low-dose MTX with or without adverse effects, respectively, and 52 patients without MTX administration were analyzed. Among the 93 patients treated with MTX for >2 months, significantly more patients homozygous for the triple-repeat allele of the polymorphism in the promoter region of the TYMS gene required higher dose of MTX compared to those having at least a double-repeat allele (P=0.033). The incidence of > or =50% improvement in the serum CRP level was significantly higher in patients homozygous for the deletion allele of the polymorphism in the 3'-untranslated region (UTR) of the TYMS gene (P=0.0383). The allele frequency of the insertion/deletion polymorphism in the TYMS 3'UTR in Japanese was significantly different from that in Caucasians (P<0.0001), as was the tandem-repeat polymorphism in its promoter region. On the other hand, MTHFR C677T and A1298C polymorphisms showed no association with MTX-related toxicity or efficacy. Our results suggest that the genotyping for the TYMS polymorphisms may become a useful indicator in determining the appropriate dose of MTX in patients with RA.
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PMID:Polymorphisms in the thymidylate synthase and methylenetetrahydrofolate reductase genes and sensitivity to the low-dose methotrexate therapy in patients with rheumatoid arthritis. 1268 95

Methotrexate (MTX) has proven efficient in the treatment of a number of malignancies, as well as non-malignant disorders characterized by a rapid cellular growth. Yet some patients might develop resistance, while others could have toxic side effects. MTX achieves its cytotoxicity through the inhibition of folate-dependent enzymes, suggesting that the genes controlling their activity or the levels of folate cofactors can modulate drug efficacy and, thus, the sensitivity of a patient to MTX. Indeed, several studies, conducted mostly in leukemia and rheumatoid arthritis patients, have addressed the potential for tailoring MTX therapy based on a patient's genetics. Several genetic variants have been shown to have a predictive role, among which the most frequently studied are those of methylenetetrahydrofolate reductase and thymidylate synthase genes. The other candidates, as well as gene-gene interactions, which may be even more important for the prediction of disease outcomes than the individual gene effects, are also briefly discussed.
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PMID:Pharmacogenetics of methotrexate. 1546 5

The authors investigated whether high-dose methotrexate-induced toxicity differed according to the presence of methylenetetrahydrofolate reductase (MTHFR) or reduced folate carrier 1 (RFC1) genetic polymorphism. The authors studied 15 children with acute lymphoblastic leukemia or lymphoblastic lymphoma who were treated using protocols that included high-dose methotrexate (3.0 g/m), for an overall total of 43 courses. Methotrexate-induced toxicities and the plasma methotrexate concentrations were evaluated retrospectively. Hematologic toxicity was the most frequently observed toxicity, appearing in 87% of the patients. In a subset of patients (47%), elevation of liver transaminase levels showed a repeated tendency to develop. High plasma methotrexate concentrations at 48 hours after the methotrexate infusion were not significantly related to methotrexate-induced toxicities except for mucositis. A generalized estimating equation analysis revealed that vomiting during the high-dose methotrexate treatment was more pronounced in patients who had a larger number of G alleles at the RFC1 80G>A polymorphism. No significant differences in the development of other toxicities or in the plasma methotrexate concentrations were observed for the different MTHFR 677C>T or RFC1 80G>A polymorphisms. This study suggests but does not prove that the RFC1 80G>A polymorphism may contribute to interindividual variability in responses to high-dose methotrexate.
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PMID:Effects of methylenetetrahydrofolate reductase and reduced folate carrier 1 polymorphisms on high-dose methotrexate-induced toxicities in children with acute lymphoblastic leukemia or lymphoma. 1646 75

Methotrexate (MTX), used as a graft-versus-host disease (GvHD) prophylactic agent in hematopoietic stem cell transplantation (HSCT), exerts its effect via folate cycle inhibition. A critical enzyme involved in folate metabolism is 5,10-methylenetetrahydrofolate reductase (MTHFR). We examined the association of a single nucleotide polymorphism (SNP) at position 677 in the MTHFR gene on GvHD outcomes in allogeneic HSCT patients administered MTX. MTHFR genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on 193 HSCT patients and donors. A total of 140 patients were transplanted with an HLA-matched related donor and 53 with an unrelated donor. GvHD outcomes were compared between genotypes by univariate and multivariate analysis. The combined donor 677CT and TT genotypes were associated with a decreased incidence of GvHD (acute and chronic combined) in HSCT recipients with an HLA-matched related donor (75% at 1 year in the CT and TT group compared with 91% in the wild type CC group, P=0.01), increased time to onset of first GvHD (P=0.001) and time to first GvHD treated with systemic therapy (P=0.022). Unrelated donor MTHFR genotype was not associated with outcome parameters and no associations of recipient genotype in either related or unrelated donor cohorts were observed.
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PMID:Donor methylenetetrahydrofolate reductase genotype is associated with graft-versus-host disease in hematopoietic stem cell transplant patients treated with methotrexate. 1651 29

Methotrexate is administered in high doses to treat childhood acute lymphoblastic leukemia and malignant lymphoma. Hepatotoxicity and bone marrow suppression often limit its use, however. The objective of this study was to determine the genetic polymorphisms associated with the hepatotoxicity and elimination of methotrexate. Genetic polymorphisms of glutathione S-transferase (GST) genes including GSTT1 positive/null, GSTM1 positive/null, and GSTP1 A313G, and genes for reduced folate carrier 1 G80A (RFC1 G80A), methylenetetrahydrofolate reductase C677T (MTHFR C677T), and breast cancer resistant protein C421A (BCRP C421A) were determined for 26 patients by the polymerase chain reaction (PCR) method or by direct sequencing. A high frequency of hepatotoxicity (P = 0.035) was observed for patients with GSTM1 positive and RFC1 AA(80), and serum concentrations of methotrexate 48 h after the start of infusion were higher for patients with the TT(677) genotype of MTHFR (P = 0.028). In conclusion, GSTM1 positive/null and RFC1 G80A polymorphisms could be predictors for hepatotoxicity, and the MTHFR C677T polymorphism is associated with elimination of methotrexate.
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PMID:Genetic polymorphisms associated with adverse events and elimination of methotrexate in childhood acute lymphoblastic leukemia and malignant lymphoma. 1718 May 79

Methotrexate (MTX) is an important anticancer drug and the most efficient chemotherapy component in primary CNS lymphoma (PCNSL). A typical side effect of intravenous high-dose MTX is the occurrence of confluent CNS white matter changes (WMC). Because MTX directly interferes with methionine metabolism, we analyzed the impact of genetic variants of methionine metabolism on the occurrence of WMC as a model of MTX toxicity. In a retrospective analysis of 68 PCNSL patients treated with MTX-based polychemotherapy with (n = 42) or without (n = 26) intraventricular treatment, 10 genetic variants influencing methionine metabolism were analyzed. Pearson's chi(2) test and multinominal regression analysis were used to define the relevance of these genetic variants for the occurrence of WMC. In this patient sample, the occurrence of WMC was significantly predicted by the TT genotype of methylenetetrahydrofolate reductase c.677C>T (chi(2) = 8.67; p = 0.013; df = 2), the AA genotype of methylenetetrahydrofolate reductase c.1298A>C (chi(2) = 13.5; p = 0.001; df = 2), and the GG genotype of transcobalamin 2 c.776C>G (chi(2) = 19.73; p < 0.001), in addition to male gender (chi(2) = 11.95; p = 0.001). These data strengthen the hypothesis that MTX effects are influenced by methionine metabolism, which may offer new strategies to improve MTX-based therapies.
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PMID:Association of genetic variants of methionine metabolism with methotrexate-induced CNS white matter changes in patients with primary CNS lymphoma. 1880 28

To identify the major factors predicting the response to Methotrexate (MTX) therapy in rheumatoid arthritis (RA) patients, we evaluated the relationship between the response to MTX and factors such as the concentration of MTX-polyglutamates (MTX-PGs) in erythrocytes (RBCs), genotypes of thymidylate synthase (TYMS) 5'-UTR (2R/3R) and 3'-UTR (-6/+6), 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, and other patient-related factors. Thirty-six Japanese RA patients were enrolled in this cohort study. The concentrations of MTX-PGs in RBCs were measured, and polymorphisms were determined using PCR-RFLP method. As an indicator of the accumulated capacity of MTX-PGs in the RBCs of each patient, the MTX dose/MTX-PGs (AC-MPG, l/week) was calculated. The response to MTX therapy was assessed using the MTX dose for a>or=50% decrease in CRP level (MTX dose for 50%CRP, mg/week), and the relationships between MTX dose for 50%CRP and various other factors were evaluated using multiple linear regression analysis. The MTX dose was 6.9+/-0.3 mg/week and the MTX-PGs concentration in RBCs was 97.3+/-8.1 nmol/l (n=36, blood samples=95, mean+/-S.D.). The range of MTX dose for 50%CRP was 2.0-13.0 mg/week. Most individual AC-MPG levels showed no change during the evaluation period (coefficient of variation=5.9%). Based on the results of multiple linear regression analysis, AC-MPG, TYMS 3'-UTR (-6/+6), and ESR at the start of MTX therapy were associated with the MTX dose for 50%CRP. AC-MPG, TYMS 3'-UTR (-6/+6), and ESR might be the major predictive factors for the response to MTX therapy in Japanese RA patients.
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PMID:Preliminary study to identify the predictive factors for the response to methotrexate therapy in patients with rheumatoid arthritis. 1957 19

Methotrexate is still a mainstay of rheumatoid arthritis treatment, but a significant variability in drug response is observed among patients. It has been proposed that C677T and A1298C polymorphisms of methylenetetrahydrofolate reductase (MTHFR), an enzyme involved in the folate pathway, could be related to its efficacy and toxicity. Many studies have investigated the predictive value of such polymorphisms for Methotrexate outcome, though with discordant results. Our experience on 79 patients did not find any significant association between genotype and drug response and the review of the literature did not provide sufficient evidences to support the use of MTHFR genetic screening in clinical practice.
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PMID:[Methylenetetrahydrofolate reductase polymorphisms in methotrexate treatment of rheumatoid arthritis patients. Review of the literature and personal experience]. 1963 96

Methotrexate (MTX)-associated myelopathy is a rare but serious subacute complication of MTX-based chemotherapy. We report the case of a woman with breast cancer and meningeal carcinomatosis who developed severe progressive myelopathy after four cycles of intrathecal MTX administration. We substituted high doses of the key metabolites of the methyl-transfer pathway: S-adenosylmethionine (SAM), 200 mg three times daily i.v.; folinate, 20 mg four times daily i.v.; cyanocobalamin, 100 microg once daily i.v.; and methionine, 5 g daily p.o. The patient's paraparesis improved rapidly thereafter, and magnetic resonance (MR) imaging showed resolution of the intramedullary lesions. Genetic analyses revealed homozygosity for the A allele of methylenetetrahydrofolate reductase (MTHFR) c.1298A>C (p.E429A), whereas other genetic variants of folate/methionine metabolism associated with MTX neurotoxicity were not present. Substitution with multiple folate metabolites may be a promising strategy for the treatment of MTX-induced neurotoxicity.
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PMID:Methotrexate-induced myelopathy responsive to substitution of multiple folate metabolites. 1982 Oct 69

Rheumatoid arthritis (RA) is the prototype of the rheumatic diseases worldwide. Methotrexate (MTX) is the drug of first choice in the treatment of this disease due to its immunosuppressant effect. However, side events are present in 30% of the patients. The C677T and A1298C polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene are involved in the metabolism of MTX. Earlier studies reported an association between these polymorphisms and elevation of hepatic enzymes. We analyzed the frequencies of both polymorphisms and the presence of transaminasemia in 70 Mexican patients with rheumatic arthritis treated with MTX. The 19% (13/70) of patients had an increase in the serum level of transaminases. The A1298C polymorphism was associated with elevation of transaminases (P=0.024). The identification of MTHFR genotypes for C677T and A1298C polymorphisms could lead clinicians to identify patients in risk of elevation of transaminases, and give them an individualized treatment, as is a goal of pharmacogenetics.
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PMID:Polymorphisms C677T and A1298C in the MTHFR gene in Mexican patients with rheumatoid arthritis treated with methotrexate: implication with elevation of transaminases. 2051 79


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