Maturity-onset Diabetes of the Young (MODY) refers to a rare form of diabetes characterized by early-onset (usually before the age of 25), a strong family history, and a monogenic inheritance pattern. MODY is caused by mutations in specific genes involved in regulating pancreatic beta-cell function and insulin production. Different subtypes of MODY are associated with mutations in various genes, including HNF1A, HNF4A, HNF1B, and others.