According to several kinds of literature most DM cases fall into three main categories: (i) Type 1 diabetes (insulin-dependent DM, due to β-cell destruction, usually leading to absolute insulin deficiency); (ii) Type 2 diabetes (non-insulin-dependent DM, due to insulin resistance in peripheral organs) and (iii) Gestational diabetes mellitus (GDM) (diabetes diagnosed in the 2nd or 3rd trimester of pregnancy). The gene discussed is INS; the disease is diabetes mellitus.