APP and early-onset autosomal dominant Alzheimer disease: In terms of the regulation of iron in the pathogenesis of Alzheimer’s disease, most scholars believe that the homeostasis of zinc, copper, and iron is related to the misfolding process of amyloid (Aβ), amyloid precursor protein (APP), and hyperphosphorylated tau, which finally leads to neuronal oxidative stress [92] (Figure 3).