SNCA and Parkinson disease: While our approach of targeted α-syn overexpression may relate more closely to familial forms of synucleinopathies, such as duplications and triplications of the encoding SNCA locus,73 the observed data resemble key features of the onset and progression of Parkinson’s disease, PDD and DLB, and demonstrate that accumulating α-syn can cause synaptopathy and progressive neurodegeneration.