Accordingly, genes including SCNA [12], Parkin [13], leucine-rich repeat kinase 2 (LRRK2) [14], phosphatase and tensin homolog deleted on chromosome 10-induced putative kinase 1 (PINK1) [15], glucocerebrosidase (GBA) [16], vacuolar protein sorting 35 (VPS35) [17], and DJ-1 [18] are linked to genetic variants that directly contribute to PD. This evidence concerns the gene LRRK2 and Parkinson disease.