The COMT Val158Met polymorphism as an associated risk factor for Parkinson's disease in Asian rather than Caucasian populations

Background: Catechol-O-methyltransferase (COMT) gene has been reported to be associated with the risk of Parkinson's disease (PD). Aims: To evaluate the associations of PD risk with COMT polymorphisms. Materials and Methods: A retrieval of studies that investigated associations between COMT polymorphisms and PD was carried out. Studies were included if they met the eligibility criteria. Statistical Analysis: Data were analyzed using Stata version 12.0. Results: A total of 18 studies including 2926 PD cases and 3151 controls were included. The results showed no significant association with all genotypes and alleles in Caucasians. However in Asians, the homozygote A/A (Odds ratio [OR] = 1.51, 95% confidence interval [CI] = 1.16-1.98, P = 0.002) tends to increase risk of PD, however, the homozygote G/A (OR = 0.85, 95% CI = 0.74-0.98, P = 0.03) may be a slightly protective effect against PD. Conclusions: This study showed that the COMT polymorphisms may be associated with PD in Asians rather than Caucasians. But further studies are needed to confirm our results.