In recent years, some PD-associated genes have been identified, including α-synuclein (SNCA), PTEN-induced putative kinase 1 (PINK1), parkin, DJ-1 (PARK7), and leucine rich repeat kinase 2 (LRRK2), mutations of which lead to the familial forms of PD (early-onset) [3]. Here, SNCA is linked to Parkinson disease.