“…Furthermore, we reviewed the reference lists from retrieved articles to search for more studies. Following criteria were used to identify relevant studies for the meta-analysis: (1) Clinical diagnosis of PD Gopalai et al, 2013;Heckman et al, 2013;Jasinska-Myga et al, 2010;Li et al, 2012;Nuytemans et al, 2009;Ross et al, 2011;Tan et al, 2010;Wu et al, 2012;Wu-Chou et al, 2013). We extracted the following data from each publication: the first author's name, the publication year, population studied, the frequency of the LRRK2 A419V variant among PD patients, and the controls group (Table 1).…”