Parkinson’s disease (PD) is an age-related debilitating neurodegenerative disorder characterized pathologically by selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) accompanied by a decrease in dopamine (DA) level, and intracytoplasmic Lewy bodies aggregated by α-synuclein (α-Syn)1. The gene discussed is SYN1; the disease is Parkinson disease.