MAPT and Alzheimer disease: In particular, despite the definitive confirmation of the diagnosis of AD being possible today only at brain autopsy, specific CSF peptides and proteins (i.e., β-amyloid 1–42 [Aβ1–42], total tau, and hyperphosphorylated tau [P-tau]) linked to the main hallmarks of AD pathology, such as amyloid plaques and neurofibrillary tangles, can complement clinical examination for the diagnosis of AD [6, 7].