SNCA and Parkinson disease: Several neurodegenerative diseases, including PD, multiple system atrophy (MSA), and dementia with Lewy bodies (DLB), show abnormal folding and aggregation of the alpha-synuclein protein correlating with death of neuronal cells (Barnham et al., 2004; Barnham and Bush, 2008; Wong and Krainc, 2017).