MAPT and Alzheimer disease: Progression from MCI due to AD to AD dementia is also linked with biomarkers of AD pathology such as cerebrospinal fluid (CSF) markers of phosphorylated tau (pTau) and total tau (tTau)/Aβ(1–42) ratio, with brain atrophy (hippocampal, medial temporal lobe, entorhinal) and parieto-temporal hypometabolism on [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) [22, 27].