SNCA and Parkinson disease: Neuropathologically, PD is characterized by the loss of dopaminergic neurons (DaNs) in the substantia nigra pars compacta (SN), as well as the accumulation of α-synuclein (α-Syn) containing inclusions, termed Lewy bodies and Lewy neurites (collectively: Lewy pathology) in surviving neurons [6–8].