SNCA and Parkinson disease: We observed no difference in expression level of alpha-synuclein (p = 0.67) and the interactors of alpha-synuclein between Braak alpha-synuclein 1–2 compared to controls, but significant changes were observed for alpha-synuclein (p = 0.001) and most of the interactors in PD compared to controls (Table 2).