IAPP and early-onset autosomal dominant Alzheimer disease: Cytotoxicity is an unequivocal hallmark of at least two amyloid-related disorders, Alzheimer’s disease and type 2 diabetes, where intracellular and extracellular oligomeric species of the Aβ and islet amyloid polypeptide (IAPP) peptides cause death of neurons and pancreatic islet β-cells, respectively [15–18].