SNCA and Parkinson disease: Mutations of SNCA, Leucine-rich repeat kinase 2 (LRRK2), Parkin, PTEN-induced putative kinase 1 (PINK1), and DJ-1 genes have been associated with monogenic forms of PD and linked to specific clinical characteristics slightly different from those observed in non-mutated patients (Koros et al., 2017).