SNCA and Alzheimer disease: The levels of plasma p-tau181 (FC = 2.5, β = 10.6, p < 0.001), p-tau217 (FC = 1.9, β = 3.4, p < 0.001), p-tau231 (FC = 3.8, β = 23.9, p < 0.001), NfL (FC = 1.8, β = 63.0, p < 0.001), GFAP (FC = 2.1, β = 29.6, p < 0.001), and α-synuclein (FC = 2.0, β = 4053.3, p < 0.001) were significantly higher in the aMCI/AD group compared to the HC group.