SNCA and Parkinson disease: Several neurodegenerative diseases, including Parkinson’s disease (PD), PD dementia (PDD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), are described as synucleinopathies, which are characterized by the progressive accumulation of fibrillized α-synuclein (α-syn) in the affected regions [1,2].