APP and Alzheimer disease: The pathogenesis of sporadic Alzheimer's disease (AD) is complex, but Amyloid Cascade Hypothesis has occupied the centre stage for several decades in this regard; the mainstay of this hypothesis is the multitude of toxic actions of amyloid beta 42 derived from the amyloid precursor protein (APP) leading to neuronal degenerations in several parts of the brain concerned with cognition and memory [1].