Examples of hybrid peptide fusions to InsB are particularly interesting because they suggest a mechanism whereby InsB9-23 may be cleaved at amino acid 21 to allow formation of a fusion protein that would essentially accomplish a R22E or R22D amino acid substitution required for InsB9-23 to favorably bind to diabetes-susceptibility MHC molecules in register 3 (82). This evidence concerns the gene HLA-C and diabetes mellitus.