INS and Crouzon syndrome-acanthosis nigricans syndrome: Dysglycaemia and metabolic derangements are the key precipitating factors in the development of CAN; however, the pathophysiological process differs between type 1 diabetes, which predominantly involves hyperglycaemia-related cellular mechanisms, and type 2 diabetes, in which insulin resistance and metabolic syndrome constituents have a complex relationship with developing CAN [2].