PD is the second most common neurodegenerative disease and is characterized by misfolding and aggregation of α-synuclein in the cytoplasm of the neurons (Lewy bodies), leading to progressive loss of dopaminergic (DA) neurons in the pars compacta of the substantia nigra (SNpc) (Balestrino and Schapira, 2020). The gene discussed is SNCA; the disease is Parkinson disease.