There are three fundamentally different types of PD models: (i) genetic models based on the impaired metabolism of endogenous proteins, leading to their conversion into neurotoxins, such as α-synuclein; (ii) neurotoxic models based on the entry of exogenous neurotoxins—pesticides, heavy metals, etc.—into the brain; and (iii) combined models [10,14,28,29,30,31]. Here, SNCA is linked to Parkinson disease.