Ten biochemical parameters related to diabetes and obesity were measured by a multiplex kit: c-peptide, ghrelin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), glucagon, insulin, leptin, plasminogen activator inhibitor-1 (PAI-1), resistin and visfatin. The gene discussed is RETN; the disease is obesity due to melanocortin 4 receptor deficiency.