title: The MTHFR C677T polymorphism contributes to increased risk of Alzheimer's disease: evidence based on 40 case-control studies.
abstract: The association between methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and Alzheimer's Disease (AD) risk has been widely reported with inconsistent results. We performed an updated meta-analysis of all available studies to clarify this situation. We conducted a comprehensive literature search in PubMed Alzgene, Embase, and Chinese Biomedical Literature database (CBM) for the period up to June 2014. Finally, a total of 40 case-control studies with 4503 AD cases and 5767 controls were included. Overall, significant increased AD risk was found, when all studies were pooled into the meta-analysis. In subgroup analyses stratified by ethnicity, age of onset, and APOE ϵ4 status, significant increased AD risk was found in Asians, late-onset AD, and APOE ϵ4 carriers, but not in Caucasians, early-onset AD, and non-APOE ϵ4 carriers. The present meta-analysis suggested that the MTHFR is a candidate gene for AD susceptibility. The MTHFR C677T polymorphism may be a risk factor for AD in Asians, APOE ϵ4 carriers, and late-onset AD. Further, investigations taking the potential gene-gene and gene-environmental interactions into consideration for the MTHFR C677T polymorphism should be conducted.
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Qiliu
authors.initials: Q
authors.lastname: Peng
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Xianjun
authors.initials: X
authors.lastname: Lao
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Xiuli
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Qin
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Geriatrics, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China. Electronic address: zengzhiyu888@126.com.
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Zeng
mesh_terms: D000544:Alzheimer Disease / Q000201:enzymology / Q000208:ethnology / Q000235:genetics*; D053327:Apolipoprotein E4 / Q000235:genetics; D016022:Case-Control Studies; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D011110:Polymorphism, Genetic
chemical_list: D053327:Apolipoprotein E4; D042965:Methylenetetrahydrofolate Reductase (NADPH2)
keywords: Alzheimer’s disease; C677T; MTHFR; Meta-analysis; Polymorphism