Methylenetetrahydrofolate reductase (MTHFR) C677T/A1298C polymorphisms and susceptibility to Parkinson's disease: A meta-analysis

Background: The association between the methylenetetrahydrofolate reductase (MTHFR) C677T/A1298C polymorphisms and susceptibility to Parkinson's disease (PD) was controversial in previous studies. The present study was therefore designed to investigate a more reliable estimate. Methods: 15 studies were identified by a search of PubMed, EBMBASE, PDGENE, Elsevier, Springer Link, CBM (Chinese Biomedical Database), CNKI (Chinese National Knowledge Infrastructure), VIP (Chinese), and Wanfang (Chinese) databases, up to April 2013. Odds ratios (ORs) with corresponding 95% confidence interval (Cl) were calculated using fixed effects model or random effects model. The subgroup analyses were made on the ethnicity. Results: MTHFR C677T polymorphism had a significant association with susceptibility to PD in all genetic models (for T vs. C: OR = 1.24, 95% CI = 1.11-1.38; for TT + CT vs. CC: OR = 127, 95% Cl = 1.10-1.46; for TT vs. CC: OR = 1.56,95% CI = 1.22-1.98; for TT vs. CT + CC: OR = 1.43, 95% CI = 1.14-1.79). Subgroup analyses by ethnicity revealed that the association between the MTHFR C677T polymorphism and PD existed in Caucasian population and Asian population. However, no association was detected between the MTHFR A1298C polymorphism and PD. Conclusions: Results from this meta-analysis supported that the MTHFR C677T polymorphism was associated with an increased risk of PD. The MTHFRA1298C polymorphism may not increase the susceptibility to PD. Further studies are required to confirm our findings: (C) 2013 Elsevier B.V. All rights reserved.