Upon the identification that alpha-synuclein is the main component of Lewy bodies in idiopathic cases of PD and DLB (Spillantini et al., 1997), the field of PD modeling in NHPs quickly moved to approaches based on the use of either AAVs coding for different forms of the SNCA gene or preformed, synthetic alpha-synuclein fibrils (reviewed in Koprich et al., 2017; Marmion and Kordower, 2018). The gene discussed is SNCA; the disease is Parkinson disease.