In 1997 and 1998, it was reported that α-synuclein (α-syn) is a major component of Lewy bodies (LBs) observed in the brains of patients with Parkinson's disease (PD), dementia with Lewy bodies (DLB) and glial cytoplasmic inclusions (GCIs) observed in multiple system atrophy (MSA) [26, 276, 302]. This evidence concerns the gene SNCA and Lewy body dementia.