After the 1997 discovery of the gene that codes for α-synuclein (SNCA) and subsequent identification of α-synuclein as the major component in Lewy bodies (the hallmark pathologic finding in PD), basic and clinical research shifted focus on this protein as one of the important factors in understanding the pathogenesis of neurodegeneration in PD2,7,8. This evidence concerns the gene SNCA and Parkinson disease.