Prospective trials have demonstrated safe, efficacious use of burosumab in the FGF23 excess disorders X-linked hypophosphatemia (XLH) and tumor-induced osteomalacia (TIO), leading to improved serum phosphate levels and skeletal outcomes without adverse gastrointestinal or renal side effects [10–15]. Here, FGF23 is linked to X-linked hypophosphatemia.