MAPT and Alzheimer disease: These biomarkers, including the ratio of amyloid-beta 42 (Aβ1–42) and amyloid-beta 40 (Aβ1–40), phosphorylated tau 181 (pTau181), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) [9–12], facilitate the assessment of (comorbid) neurodegenerative processes associated with AD.