Type 1 diabetes mellitus, or insulin-dependent diabetes, is most common in children and adolescents, affecting millions of people worldwide.[1] Owing to insufficient insulin production, patients have to use multiple daily injections (MDIs) of insulin or continuous subcutaneous insulin injection (CSII); otherwise, blood glucose cannot be well controlled.[2] The incidence of T1DM is much lower than that of T2DM, but T1DM is more dangerous. The gene discussed is INS; the disease is type 1 diabetes mellitus.