The majority of PD cases have no known monogenetic etiology, but a subset of cases is associated with mutations in alpha-synuclein, LRRK2, Parkin, PINK1, DJ-1 [14,15] or glucocerebrosidase (GBA) and other lysosomal enzymes [16,17,18,19,20]. Here, SNCA is linked to Parkinson disease.