Aggregation of the protein α-synuclein (α-syn) is a histological hallmark of multiple neurodegenerative diseases collectively known as synucleinopathies, including Parkinson’s disease (PD), PD with dementia (PDD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA)4,10,11. This evidence concerns the gene SNCA and multiple system atrophy.