In our recent study, we indicated a negative correlation between the levels of irisin and IL-6, a pro-inflammatory cytokine involved in metabolic and cardiovascular disorders, in the serum of patients suffering from T2DM under the addition of treatment with glucagon-like peptide 1 (GLP-1) receptor agonists (GLP-1 RA) to any hypoglycemic therapy [49]. The gene discussed is FNDC5; the disease is type 2 diabetes mellitus.