In the state of obesity, macrophages are polarised into pro-inflammatory M1, nitric oxide synthase 2 (NOS2) is activated, and reactive oxygen species such as NO, CD11c are produced, as well as tumor necrosis factor alpha (TNF-α), IL-6, IL-1β, IL-12, and monocyte chemotactic protein are secreted [26,30]. The gene discussed is NOS2; the disease is obesity due to melanocortin 4 receptor deficiency.