SNCA and Parkinson disease: Classic neuropathological PD hallmarks are the progressive degeneration of dopaminergic neurons of the substantia nigra in the midbrain that cause reduced levels of striatal dopamine levels, accumulation of improperly folded cytoplasmatic α-synuclein (α-syn)—an intraneuronal protein present in Lewy bodies (LBs), and Lewy neuritis (LNs) [2].