MAPT and early-onset autosomal dominant Alzheimer disease: The brain disease pathology of Alzheimer’s disease (AD) is characterized by amyloid plaques, axonal degeneration and intra-neuronal tangles, which can be monitored using the core cerebrospinal fluid (CSF) biomarkers amyloid beta peptides 1–40 (Aβ40), amyloid-beta 1–42 (Aβ42), total tau (t-tau) and phosphorylated tau (p-tau) proteins as well as Aβ positron emission tomography (PET) imaging [1].