Among those, some chemokines such as monocyte chemoattractant protein-1 (MCP-1/CCL2), stromal cell-derived factor (SDF-1/CXCL12), and fractalkine/CX3CL1 and their receptors have been shown to be expressed in the hypothalamus (Banisadr et al., 2005), and their association with obesity-induced inflammatory responses and metabolic complications have been reported (Morari et al., 2014; Poon et al., 2016). The gene discussed is CXCL12; the disease is obesity due to melanocortin 4 receptor deficiency.