Amyloid deposition within the pancreatic islets of MetS and T2DM (islet amyloidosis) occurs primarily in humans, feline species and non-human primates but does not appear in rodents due to the lack of amyloidogenic rodent amylin because of a proline substitution at positions 25, 28, and 29 of the 37 amino acid amylin. This evidence concerns the gene IAPP and metabolic syndrome.