MAPT and early-onset autosomal dominant Alzheimer disease: Alzheimer’s disease (AD) is a neurodegenerative disease characterized by histopathologic lesions of amyloid plaques and neurofibrillary tangles composed of the β-amyloid (Aβ) protein and paired helical filaments of hyperphosphorylated tau protein, respectively (Hyman and Trojanowski, 1997).