SNCA and Parkinson disease: Parkinson’s disease (PD) is pathologically characterized by the presence of α-synuclein (α-syn)-containing deposits in neuronal perikarya (Lewy bodies, LBs) and neuronal processes (Lewy neurites, LNs) and the loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) [1].