CHIT1 and Alzheimer disease: Beyond these established markers, we also identified several targets with marked changes in asymptomatic AD, including upregulation of GAP43, FABP3, CALM1, UCHL1, MAPT, CHIT1, and the decrease of histones (HIST1H2BK, HIST3H3, HIST1H2AB, HIST1H4A), and immunoglobulin proteins (IGHV1–2 and IGKV3–15) (PFDR<0.05).