one of several specific genes. [ 21 ] Mutations in specific genes have been conclusively shown to cause PD. These genes code for alpha-synuclein (SNCA), parkin (PRKN), leucine-rich repeat kinase 2 ( LRRK2 or dardarin), PTEN-induced putative kinase 1 ( PINK1 ), DJ-1 and ATP13A2 . [ 4 ] [ 21