MAPT and early-onset autosomal dominant Alzheimer disease: Alzheimer’s disease is characterized by two pathological hallmarks, namely, the extracellular accumulation of amyloid β (Aβ) peptides, generated by the cleavage of amyloid precursor proteins (APPs), and the intracellular accumulation of hyperphosphorylated tau, manifested as neurofibrillary tangles (NFTs) [7].