Approach to Monogenic Diabetes

Stefan S Fajans has described the diabetes mellitus and well-controlled metabolic syndrome with the help of sulfonylurea in non-obese children and adolescents with the mild symptoms for the first time in 1960. In spite of the unapparent difference between type 1 diabetes mellitus (T1DM), all of the clinical findings of this newly described DM would have clarified after 15 years and it has been identified as ‘Maturity Onset of Diabetes of the Young’ (MODY). After the last classification done by American Diabetes Association and World Health Organization, MODY has been put in the ‘beta cell genetic dysfunction’ group. They constitute 2-5% of all diabetes. In recent studies, the prevalence is 45/1 000 000 in children and 100/1 000 000 in adults. 80% of the cases have been shown to take either T1DM or T2DM diagnoses mistakenly. The description of genetic subgroups is vitally important for the response achieved after the treatment. Monogenic diabetes is the diabetes resulted after either one or more mutations at a single gene. Mutation could have either occurred de novo or could have been inherited dominantly or recessively. There are more than 40 genetic subtypes of MODY. The diagnosis could be made with molecular testing with 1-2% rate. In childhood, almost all of the monogenic diabetes would occur with the gene mutations controlling beta cell functions and very seldom with the mutations resulting in insulin resistance. Most important approach is to think monogenic diabetes as a diagnosis. Because it is an autosomal dominant disease, a detailed anamnesis is vitally important. Monogenic diabetes should always be in mind for the cases having a diagnosis inconsistent with their current clinical situations: 1) Whatever the age of the diabetic patient, all of the diabetic patients having a diagnosis within 6 months, 2) Unprogressive, moderate fake bad scale elevations, 3) Patients with clinical findings inconsistent with T1DM; a) diagnosis.