Atypical Diabetes- Neonatal and Monogenic Forms of Diabetes Mellitus

Monogenic forms of diabetes are part of the group of atypical diabetes. People with atypical forms of diabetes have symptoms and signs that are different from those of type 1 or type 2 diabetes. Monogenic diabetes is a rare condition resulting from mutations (changes) in a single gene. In contrast, the most common types of diabetes—type 1 and type 2—are caused by multiple genes (and in type 2 diabetes, lifestyle factors such as obesity). The majority of monogenic diabetes cases are inherited from a parent who has the condition. It is responsible for 2–5% of all cases of diabetes mellitus. Monogenic diabetes comes in a variety of types and mostly affects young adults, primarily those under 25. Most disease types are characterized by a decrease in the body's ability to produce insulin, a hormone that helps the body use glucose (sugar) for energy. Rarely, the issue is significant insulin resistance, which occurs when the body is unable to adequately use insulin. This chapter covers the specific form of monogenic diabetes may be called also MODY (formerly, maturity-onset diabetes of the young) or neonatal diabetes, depending on when it develops. One subset of Atypical Diabetes is Latent Autoimmune Diabetes in Adults (LADA) which is also covered extensively in this chapter.