SNCA and Parkinson disease: Parkinson's disease is a chronic progressive disorder characterized pathologically by the loss of dopaminergic neurons located in the substantia nigra pars compacta, and, to a lesser extent, in putamen, caudate, and globus pallidus and by the formation of intracellular protein inclusions of mainly alpha-synuclein (named as Lewy bodies) in the remaining neurons [8, 9].