MAPT and early-onset autosomal dominant Alzheimer disease: Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by the presence of extracellular deposits of β-amyloid peptide (Aβ) in the form of Aβ plaques (also known as senile, neuritic, and amyloid plaques) with different morphologies [1] and an intracellular aggregation of neurofibrillary tangles composed of hyperphosphorylated tau protein [2].