Though most PD cases are sporadic, duplications, triplications, and mutations (A30P, E46K, H50Q, G51D, A53T) of the α-synuclein gene (SNCA) further implicate α-synuclein in disease pathogenesis (Polymeropoulos et al., 1997; Athanassiadou et al., 1999; Singleton et al., 2003; Zarranz et al., 2004; Flagmeier et al., 2016; Guella et al., 2016). This evidence concerns the gene SNCA and Parkinson disease.