Maturity onset diabetes of the young (MODY ) is a clinically heterogenous group of disorders characterized by an autosomal dominant mode of inheritance and onset usually before age 25. It is a primary defect in the function of the beta cells of the pancreas. Mutations in any one of six different genes may result in MODY.
These genes are expressed in beta cells, and mutation of any of them leads to beta cell dysfunction and diabetes mellitus. Fortunately individuals with MODY do not usually develop ketotic diabetes mellitus, which occurs frequently in type 1 diabetes.