Aβ production occurs through the action of β-secretase, also known as β-site amyloid precursor protein cleaving enzyme-1 (BACE-1), generating AD-associated toxicity and neurodegeneration, while neurofibrillary tangles, formed from tau hyperphosphorylation, prevent the stabilization of neuronal microtubules and disrupt the pathway for intracellular transport. Here, MAPT is linked to Alzheimer disease.