APP and neurodegenerative disease: Alzheimer’sdisease (AD)is a neurodegenerative disease, whose major pathological feature isthe progressive loss of neuronal functions.1 β-amyloid (Aβ) is a proteolytic product of amyloid precursorprotein (APP), which is a causative factor during AD pathology.2 Aβ includes many subtypes; the most commonsubtypes of Aβ in the human body are Aβ1–40 and Aβ1–42.