Denosumab is a fully human monoclonal antibody that targets receptor activator of nuclear factor kappa B ligand (RANKL),4,5 blocking its interaction with its receptor RANK on osteoclast precursor cells, thus inhibiting osteoclastogenesis.1 Denosumab is currently widely used for the treatment of osteoporosis and rheumatoid arthritis as well as the prevention of skeletal-related events in patients with solid tumors. The gene discussed is TNFSF11; the disease is osteoporosis.