Histologically, PD is characterized by the prominent death of dopaminergic neurons, especially in the substantia nigra pars compacta (SNpc) area of the brain, and by the presence of Lewy bodies and Lewy neurites, which are inclusions of abnormal aggregates of α-synuclein (α-syn) in neuronal cell bodies and neuronal cell processes, respectively [3]. The gene discussed is SNCA; the disease is Parkinson disease.