APP and Alzheimer disease: Deposition of amyloid‐β (Aβ) is a key sign of Alzheimer's disease (AD).[1] In the brain of AD patients, Aβ monomers are released from amyloid precursor protein by abnormal enzymatic cleavages and aggregate into neurotoxic soluble oligomers and insoluble plaques, which are the pathological processes leading to neurodegeneration.