CCN2 and obesity due to melanocortin 4 receptor deficiency: Numerous studies described differential expression of CCN2/CTGF gene in response to hyperglycemia and suggested a potentially important role of CCN2/CTGF in the pathogenesis of diabetes, from the initial metabolic insult(s) (e.g., hyperglycemia, obesity, insulin resistance and deficiency), to end-organ complications/failure [131,132].