SNCA and Parkinson disease: The identification of A53T point mutation in 1996 in familial cases of PD first linked α-synuclein to PD (Polymeropoulos et al., 1997), a finding that was further validated by a later discovery that duplication and triplication of the synuclein-alpha (SNCA) gene is sufficient to cause PD, with an earlier onset of the disease and its severity correlating with higher genetic copies of α-synuclein (Singleton et al., 2003; Chartier-Harlin et al., 2004; Ibáñez et al., 2004).