SNCA and Parkinson disease: The most characteristic neuropathologic change in PD is the formation of proteinaceous inclusions, known as Lewy bodies (LBs) and Lewy neurites (LNs), which are mainly composed of aggregated alpha-synuclein (α-syn) (Spillantini et al., 1998), a small soluble protein normally enriched in pre-synaptic terminals (Cheng et al., 2011).