The neuropathological hallmark of Parkinson's disease is the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta of the brain in addition to astrocytic gliosis and the presence of numerous other neuronal systems, associated with widespread occurrence of intracytoplasmatic alpha-synuclein positive inclusions known as the Lewy bodies and the Lewy neuritis of neuronal cells [54]. Here, SNCA is linked to Parkinson disease.