UCH-L1 S18Y variant and risk of Parkinson's disease in Asian populations: an updated meta-analysis.

The ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) gene has been implicated in the etiology of Parkinson's disease (PD). Several studies have evaluated the association between the UCH-L1 S18Y variant and the risk of PD. However, conflicting results have been reported. Therefore, we performed a meta-analysis to explore whether the UCH-L1 S18Y variant is associated with susceptibility to PD in Asians. A database search in Web of Science, MEDLINE, Embase and PubMed up to March 2014 identified 10 studies comprising 4,897 PD patients and 4,446 controls in total, which were included in this meta-analysis. In an updated meta-analysis, no significant associations between the S18Y polymorphism and PD in Asians were observed in recessive [p = 0.28, odds ratio (OR) = 1.47, 95% confidence interval (CI): 0.86-1.04] or dominant models (p = 0.46, OR = 0.96, 95% CI: 0.88-1.06). In the subgroup analysis by ethnicity, still no significant association was detected in dominant (for Chinese, OR = 0.97, 95% CI: 0.85-1.10; for Japanese, OR = 0.96, 95% CI: 0.83-1.11) and recessive models (for Chinese, OR = 0.99, 95% CI: 0.88-1.11; for Japanese, OR = 0.89, 95% CI: 0.76-1.04). The results of this meta-analysis suggested that the UCHL-1 S18Y polymorphism was not associated with the risk of PD in Asians. To our knowledge, this is the latest and largest meta-analysis assessing the association of the UCHL-1 S18Y variant with the risk of PD in Asian ancestry. © 2014 S. Karger AG, Basel.