Leptin inhibits appetite and food intake, stimulates energy expenditure, and also has pro-inflammatory effects contributing to the low-grade chronic inflammation by enhancing the TNF-α and IL-6 production [33] and vice versa TNF-α stimulated leptin secretion from adipocytes [34] that induces obesity [35,36]. This evidence concerns the gene IL6 and obesity due to melanocortin 4 receptor deficiency.