COMT Val158Met polymorphism and Parkinson's disease risk: a pooled analysis in different populations.

OBJECTIVE: Many studies have analyzed the association between the catechol-O-methyltransferase (COMT) Val158Met polymorphism and Parkinson's disease (PD), which yield inconsistent results. This meta-analysis was designed to determine the possible association between the COMT Val158Met polymorphism and the risk of PD in different populations.

METHODS: The PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure and Chinese Biology Medicine databases were used for literature searching up to May 2018. The association between the COMT Val158Met polymorphism and the risk of PD was evaluated by calculating the pooled odds ratio (OR) and 95% confidence intervals (CIs).

RESULTS: A total of 27 studies including 10,239 PD patients and 15,538 controls were screened out. In the overall population, COMT Val158Met polymorphism was not significantly associated with the risk of PD. In the subgroup analysis stratified by ethnicity, a significant association between COMT Val158Met polymorphism and PD risk was detected in Japan (LL vs. HH: OR = 1.48, 95% CI = 1.04-2.11; LL vs. HH+HL: OR = 1.54, 95% CI = 1.10-2.15) and India (LL+HL vs. HH: OR = 1.48, 95% CI = 1.14-1.91).

CONCLUSION: This study indicated a significantly closer association between COMT Val158Met polymorphism and PD in the Japanese and Indian populations compared with other ethnicities. Ethnicity seems to play an important role in the genetic association of PD.