RETN and obesity due to melanocortin 4 receptor deficiency: Obesity is associated with low-grade chronic inflammation attributed to the dysregulated production and release of cytokines and adipokines, including tumor necrosis factor (TNF), interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, leptin, resistin and adiponectin in macrophage-infiltrated abdominal adipose tissue [1].