IAPP and proteostasis deficiencies: Amyloid disorders are a group of protein-misfolding diseases in which the different proteins—amylin or islet amyloid polypeptide (IAPP), beta peptide (Aβ), prion protein, and synuclein—share the characteristic of aggregating into soluble oligomers, which evolve toward insoluble aggregates, ultimately leading to the formation of mature fibrils.