Maturity-onset diabetes of the young (MODY) is an autosomal dominant mode of inheritance and a monogenic form of diabetes, characterized by an early age at onset (usually at ≤25 years of age) and impaired insulin secretion with minimal or no defects in insulin action (in the absence of coexisting obesity) (1, 2). Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.