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. The gene discussed is BACE1; the disease is Alzheimer disease.