In rare familial cases of PD, causal mutations in a number of coding genes have been identified and include PTEN-induced putative kinase 1 (PINK1), parkin (PRKN), α-synuclein (SNCA), leucine-rich repeat kinase 2 (LRRK2), ATPase 13A2 (ATP13A2), VPS35 (PARK17), and Parkinsonism-associated deglycase (PARK7)/DJ-1 (4). The gene discussed is LRRK2; the disease is Parkinson disease.