Leptin is an adipokine highly produced by adipose tissue in obese children [116, 117] and, despite the ‘leptin resistance’ occurring in obesity, some of its effects are retained: specifically, leptin stimulates the production of IL-6 and TNF-α, contributing to the low-grade-inflammation, as well as activating the sympathetic nervous system leading to hypertension [15, 17, 28, 35, 116–119]. The gene discussed is TNF; the disease is obesity due to melanocortin 4 receptor deficiency.