These different diseases are either based on gene duplications of the SNCA gene, in the case of inherited forms of Parkinson’s disease, or missense mutations within the first ~55 residues of the SNCA gene in multiple systems atrophy (MSA) and dementia with Lewy bodies (DLB) [5,6,7,8,9,10,11,12,13,14,15]. This evidence concerns the gene SNCA and Lewy body dementia.