Patients with diabetes mellitus can develop a variety of skin lesions, including: (1) skin infections: bacterial, fungal, or viral infections; (2) skin diseases directly related to diabetes mellitus: diabetic maculopapular, acanthosis nigricans, etc.; (3) the skin manifestations of chronic complications of diabetes mellitus: skin ulcers or even gangrene caused by diabetic foot; (4) the skin changes due to diabetes mellitus treatment: for example, subcutaneous fat proliferation, subcutaneous fat reduction, etc., caused by the injection of insulin. The gene discussed is INS; the disease is diabetes mellitus.