LRRK2 and Parkinson disease: Familial PD is commonly caused by alterations in six genes: membrane interaction gene (alpha-synuclein [SNCA]); mitochondrial quality control genes (parkin [PRKN], PTEN-induced kinase 1 [PINK1], and leucine-rich repeat kinase 2 [LRRK2]); oxidative damage control gene (Parkinson disease protein 7 [PARK7]); and lysosomal enzyme gene (glucocerebrosidase [GBA1]) [9, 10].