APP and early-onset autosomal dominant Alzheimer disease: The aggregation proteins in the form of neurofibrillary tangles contribute to neurotoxicity in Alzheimer’s disease (AD), which are composed of extracellular senile plaques and hyperphosphorylated tau 1,2 deposited in small peptides of amyloid-β (Aβ) derived from sequential proteolytic cleavages of the amyloid precursor protein (APP) 3.