MAPT and early-onset autosomal dominant Alzheimer disease: The aberrant accumulation of aggregated amyloid-β (Aβ) peptides and abnormally phosphorylated tau protein as extracellular plaques and intraneuronal neurofibrillary tangles (NFTs), respectively, are the fundamental hallmarks of Alzheimer’s disease (AD) neuropathology and remain to be the conclusive confirmation of the disease—thus a definitive diagnosis cannot be attributed until post-mortem.