INS and type 2 diabetes mellitus: Diabetes is primarily classified into four types: Type 1 diabetes results from an absolute absence of insulin secretion; Type 2 diabetes, which is significantly more prevalent, is caused by a combination of insufficient insulin secretory response and resistance to insulin action; and Type 1.5 diabetes, also known as latent autoimmune diabetes in adults (LADA), presents characteristics of both Type 1 and Type 2 diabetes, typically developing in adulthood with a slower progression to insulin dependency.