Examination of pancreases from subjects with T2D indicated that islets with large amyloid deposits often have fewer β cells.85 When human IAPP, which can form amyloid unlike rodent IAPP, is overexpressed in β cells of mice or rats, the result is worsening of diabetes associated with more amyloid deposition.86–88 It now appears that the toxicity is exerted not by the extracellular deposits but by small fibrils or toxic oligomers that can damage cell membranes.89,90 There is increasing evidence that these can cause damage while inside the β cell; they may when outside as well. This evidence concerns the gene IAPP and diabetes mellitus.