Although fibril structures of WT and S20G IAPP have yet to be solved ex vivo, four structures have been observed by seeding monomeric WT hIAPP in vitro with material extracted from the Islets of Langerhans of a donor with T2D.30 Interestingly, the subunit fold of 2PFP resembles the subunits within the ex vivo seeded WT hIAPP amyloid with polymorphs TW1 and TW3, described by Cao et al.30 (Figure S13). Here, IAPP is linked to type 2 diabetes mellitus.