The course of the disease development in these animals can be divided into four phases: Phase A, normoinsulinemia and normoglycemia; phase B, hyperinsulinemia and normoglycemia; phase C, overt diabetes, characterized by hyperinsulinemia and hyperglycemia; and phase D, hypoinsulinemia and severe hyperglycemia as a result of β-cell degranulation, and markedly reduced pancreatic insulin content [21]. This evidence concerns the gene INS and hyperinsulinism.