INS and obesity due to melanocortin 4 receptor deficiency: More than 90% of diabetes patients are diagnosed with type 2 diabetes mellitus (T2DM) (Laakso et al., 2022), which is a chronic metabolic disease characterized by hyperglycemia, intestinal flora disorder, insulin resistance, and obesity due to insufficient insulin secretion and an ineffective insulin response, and has become disease that has caused a high public burden worldwide (Ahmad et al., 2022; Magliano et al., 2022).