Initial studies reported the accumulation of macrophages within adipose tissue and the subsequent liberation of proinflammatory cytokines such as interleukin-1 (IL-1), IL-6, and tumor necrosis factor alpha (TNF-α), which contribute to obesity-associated insulin resistance (Weisberg et al., 2003; Xu et al., 2003). This evidence concerns the gene TNF and obesity due to melanocortin 4 receptor deficiency.