MAPT and Alzheimer disease: Both CSF and plasma p-tau markers (e.g., p-tau181, p-tau217, and p-tau231) show great value in the diagnosis of prodromal AD and differentiating AD from non-AD primary tauopathies (e.g., PSP or CBD), as well as other non-AD neurodegenerative disorders (e.g., DLB or behavioral variant frontotemporal dementia) [5, 58, 277, 278].