Recent reports indicate that adipose tissue functions as an endocrine organ in which adipocytes and recruited macrophages produce cytokines such as tumor necrosis factor (TNF), interleukin 6 (IL-6) and adipokines such as adiponectin, leptin, and resistin, which are thought to be associated with obesity, insulin resistance, and other inflammatory disorders [73]. This evidence concerns the gene RETN and obesity due to melanocortin 4 receptor deficiency.