MAPT and early-onset autosomal dominant Alzheimer disease: Postischemic brain neurodegeneration, such as that seen in Alzheimer’s disease, is a progressive neurodegenerative disease with two progressive pathological changes, i.e., extracellular amyloid plaques composed of β-amyloid peptide and intracellular neurofibrillary tangles composed of hyperphosphorylated tau protein.