Recognized biomarkers for AD diagnosis are currently divided into three main categories according to the ATN (amyloid, tau, and neurodegeneration) staging system6; amyloid markers (reduced amyloid beta [Aβ]42 or Aβ42/Aβ40 ratio in the cerebrospinal fluid [CSF], or positive amyloid positron emission tomography [PET]), tau (increased phosphorylated tau [p‐tau]181 in the CSF or positive tau PET), and neurodegeneration (atrophy on magnetic resonance imaging [MRI], positive 18F‐fluorodeoxyglucose [FDG] PET, and increased total tau [t‐tau] in the CSF). Here, MAPT is linked to Alzheimer disease.