GBA1 and Parkinson disease: Aside from SNCA, coding for a-syn, several other genes encoding parkin (PRKN), PTEN-induced putative kinase I (PINK1), DJ-1 protein (DJ-1), leucine-rich repeat serine/threonine-protein kinase 2 (LRRK2) and glucocerebrosidase (GBA) have been linked to PD.