APP and early-onset autosomal dominant Alzheimer disease: Alzheimer’s disease (AD) is characterized by the deposition of intracellular neurofibrillary tangles (NFTs), composed of a highly phosphorylated form of the tau protein, and extracellular senile plaques, composed of insoluble aggregates of the amyloid-β (Aβ) peptide cleaved from the amyloid precursor protein (APP) by β- and γ-secretases [7,8,9,10].