APP and early-onset autosomal dominant Alzheimer disease: The hallmark pathologies of Alzheimer's disease are the existence of extracellular plaques composed of amyloid-beta (Aβ) peptide resulting from abnormal proteolytic cleavage of amyloid precursor protein (APP) and intracellular neurofibrillary tangles (NFT), which result from hyper phosphorylation of the microtubule-associated tau proteins (Hoogmartens et al., 2021[54]; Mattson, 2004[92]).