The overexpression of α-syn due to duplication or triplication of the SNCA gene causes rare familial forms of parkinsonism, and single nucleotide polymorphisms in the SNCA gene (Ala53Thr, Ala30Pro, and Glu46Lys) are linked to sporadic PD (Angot et al., 2012). The gene discussed is SNCA; the disease is Parkinson disease.