INS and obesity due to melanocortin 4 receptor deficiency: Interestingly, emerging evidence has indicated that in hypertrophic obesity, the number of preadipocytes in the subcutaneous adipose tissue capable of undergoing adipogenic differentiation to mature adipocytes is paradoxically reduced, and it is anticipated that restoring the impaired preadipocyte differentiation in the subcutaneous adipose tissue may be a new approach to prevention of ectopic lipid accumulation and resultant insulin resistance [2].