MAPT and early-onset autosomal dominant Alzheimer disease: Alzheimer's disease is the most common age-related and chronic neurodegenerative disorder characterized histopathologically by the accumulation of insoluble forms of amyloid-β (Aβ) in plaques and the aggregation of hyperphosphorylated forms of the microtubule-associated protein-tau into neurofibrillary tangles (NFT) in neurons 1,2.