Background: Diabetes is classified as Type 1 diabetes, Type 2 diabetes, gestational diabetes and other types. Our goal was to provide an overview of new genetic knowledge of monogenic and type 2 diabetes.
Material and method: The article is based on literature identified through a non-systematic search in PubMed and own experience concerning research in diabetes genetics and treatment of patients with monogenic diabetes.
Results: 18 genes have been found for which one single mutation may cause diabetes. The most common causes for such monogenic diabetes are mutations in the genes KCNJ11, ABCC8 and INS when the condition is diagnosed at the age 0 - 6 months, and in the genes HNF1A, GCK, HNF4A and HNF1B when the diagnosis is made later than six months of age. Genetic testing is appropriate in assessment of monogenic diabetes, because antidiabetic tablets rather that insulin injections can be used to treat patients with mutations in certain genes; i.e. KCNJ11, ABCC8, HNF1A and HNF4A. Genome-wide association studies have recently identified about 20 genetic variants that increase the risk of Type 2 diabetes, but which have a low predictive value for development of disease. How these genetic variants can cause Type 2 diabetes has not been assessed and clinical relevance remains to be shown.
Interpretation: So far, genetic findings only affect diagnosis and treatment of monogenic diabetes.