Insulin-resistant diabetes mellitus with acanthosis nigricans (IRAN) is an unusual cause of diabetes that result from metabolic abnormalities associated with mutations of the insulin receptor (INSR) gene, characterized by phenotypic description of extreme insulin resistance, acanthosis nigricans, and hyperandrogenism. Other phenotype of IRAN form includes hirsutism and polycystic ovarian disease in a patient who is usually not obese. There is no distinctive serum marker. Leprechaunism [DS:H00719] and the Rabson-Mendenhall syndrome [DS:H00942] also have mutations in INSR with subsequent alterations in insulin receptor function and extreme insulin resistance.
