Wild‐type mice exhibited α‐synuclein inclusions with phosphorylation at serine‐129, a hallmark of PD, 30 days after α‐synuclein PFF administration and significant dopaminergic neuronal loss by 180 days, while Snca−/− mice injected with PFFs did not show any signs of PD pathology or neuronal loss (Luk et al., 2012). This evidence concerns the gene SNCA and Parkinson disease.