Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.5.7.1 (methylenetetrahydrofolate reductase)
 2,116 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Osteoporosis is partly genetically determined. The genetics of osteoporosis is polygenic in nature with multiple common polymorphic alleles interacting with each other and environmental factors to determine bone mass. A number of studies have attempted to dissect the genetic factors responsible for the pathogenesis of osteoporosis using genome-wide scanning and the candidate gene approach. However, the results of such studies among different populations have been mostly inconsistent, suggesting genetic heterogeneity of osteoporosis. It is likely that the cohort of genes indicating predisposition to the risk of osteoporosis may be different among populations with different ethnic backgrounds. The successful identification of susceptibility genes for osteoporosis should prove to be helpful in targeting preventive and therapeutic measures to individuals at higher risk and to render the effort more cost-effective. Information with regard to genetic variations is also likely to be useful in targeting preventive or therapeutic measures to subjects genetically determined to have better responsiveness. Intestinal calcium absorption is dependent on vitamin D receptor gene polymorphisms. Skeletal responsiveness to estrogen, particularly at lower doses, is related to polymorphisms in the estrogen receptor-alpha gene. Recently, circulating homocysteine levels have been shown to be associated with fracture risk. Folate and vitamin B supplements for reducing serum homocysteine and fractures in postmenopausal women have not been fully investigated. However, there is an interaction between folate status and methylenetetrahydrofolate reductase gene polymorphism on bone phenotypes. Due to recent technological advances, whole-genome association study is becoming more feasible. Genomic information with regard to the susceptibility to osteoporosis and the responsiveness to preventive or therapeutic modalities should supplement rather than replace conventional clinical information. Clinical decision should also take into account the social, health and economic perspectives in order to balance the benefit of novel clinical strategies against the associated risks and available resources.
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PMID:Osteoporosis: the role of genetics and the environment. 1768 12

Aberrant promoter methylation is recognized as an important feature of breast carcinogenesis. We hypothesized that genetic variation of genes for methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR), two critical enzymes in the one-carbon metabolism, may alter DNA methylation levels and thus influence DNA methylation in breast cancer. We evaluated case-control association of MTHFR C677T, A1298C, and MTR A2756G polymorphisms for cases strata-defined by promoter methylation status for each of three genes, E-cadherin, p16, and RAR-beta2 in breast cancer; in addition, we evaluated case-case comparisons of the likelihood of promoter methylation in relation to genotypes using a population-based case-control study conducted in Western New York State. Methylation was evaluated with real-time methylation-specific PCRs for 803 paraffin-embedded breast tumor tissues from women with primary, incident breast cancer. We applied unordered polytomous regression and unconditional logistic regression to derive adjusted odds ratios and 95% confidence intervals. We did not find any association of MTHFR and MTR polymorphisms with breast cancer risk stratified by methylation status nor between polymorphisms and likelihood of promoter methylation of any of the genes. There was no evidence of difference within strata defined by menopausal status, estrogen receptor status, folate intake, and lifetime alcohol consumption. Overall, we found no evidence that these common polymorphisms of the MTHFR and MTR genes are associated with promoter methylation of E-cadherin, p16, and RAR-beta2 genes in breast cancer.
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PMID:DNA promoter methylation in breast tumors: no association with genetic polymorphisms in MTHFR and MTR. 1924 Feb 36