APP and Alzheimer disease: The amyloid cascade hypothesis, the most studied and prominent one, portrays the mismetabolism of amyloid β precursor protein (APP), a transmembrane protein primarily found in synapses, and subsequent Aβ deposition in the brain as the primary events in the pathological cascade of AD, to which it succeeds the development of NFTs, depletion of transmitters, neuronal loss, and dementia [26,27].