The cytokines TNF and IL-6 are increased in patients with obesity and metabolic syndrome, and in hyperglycemic states, tissues exposed to inflammatory cytokines, such as IL-1, IL-6 and TNF, produce reactive oxygen species (ROS) that directly affects the differentiation and survival of osteoclasts, osteoblasts and osteocytes (16). The gene discussed is TNF; the disease is obesity due to melanocortin 4 receptor deficiency.