LEP and obesity due to melanocortin 4 receptor deficiency: Leptin is a hormone secreted by adipose tissue that regulates energy balance and appetite by suppressing hunger and promoting energy expenditure.[5] It has been reported that serum leptin levels are elevated in individuals with obesity and T2DM.[6,7] Furthermore, several studies have suggested that hyperleptinemia is associated with impaired lipid metabolism and renal dysfunction in T2DM.[8,9] However, the exact mechanism underlying the relationship between serum leptin levels and these comorbidities remains unclear.