Association of COMT Val158Met polymorphism with wearing-off susceptibility in Parkinson's disease.

In previous study, we have found the catechol-O-methyltransferase (COMT) Val158Met polymorphism may be associated with the risk of Parkinson's disease (PD) in Asians, especially Japanese population. In this study, we further evaluated the associations of PD wearing-off susceptibility with COMT polymorphisms. We carried out a retrieval of studies and included the relevant studies which met the criteria. After the data were extracted, the Stata software 11.0 was used to analyse the genotype frequencies. A total of five studies were included. The pooled result indicated that genotype AA was significantly associated with the wearing-off risk of PD (AA vs. others: OR = 2.52, 95 % CI 1.21-5.26, P = 0.013; AA vs. GA: OR = 2.51, 95 % CI 1.18-5.34, P = 0.017; AA vs. GG: OR = 2.17, 95 % CI 1.09-4.33, P = 0.027). The results also showed allele A was correlated with PD wearing-off risk (A vs. G: OR = 1.95, 95 % CI 1.18-3.22, P = 0.009). In conclusion, this study suggested that Val158Met polymorphisms in COMT may increase the risk of wearing-off. Further studies with larger sample sizes are needed to confirm our results.