Examples of the former are fibrils found within light-chain synthesizing plasma cells in multiple myeloma (Ishihara et al., 1991), phosphorylated tau fibrils found in neurons containing neurofibrillary tangles (Ruben et al., 1992; Snow et al., 1992), islet amyloid polypeptide (IAPP) in β-cells of the islets of Langerhans (de Koning et al., 1994b; Westermark et al., 2011) and amyloid-like fibrils seen in various species of yeast (Wickner et al., 2013). The gene discussed is IAPP; the disease is plasma cell myeloma.