CXCL5 and obesity due to melanocortin 4 receptor deficiency: Metabolic network 4, with albumin as the top metabolite, was also associated with variants 10 Kb upstream of EREG and independent variants 8 Kb upstream of CXCL5. EREG encodes epiregulin, part of a family of epidermal growth factors for which there is evidence that osmotic pressure has a role in signal transduction [48], and CXCL5 encodes a cytokine that has previously been linked with obesity and insulin resistance [49].