This includes various conditions such as tumor-induced osteomalacia caused by the overproduction of FGF23 due to phosphaturic mesenchymal tumors, hypophosphatemia associated with the intravenous administration of iron preparations, and genetic disorders, such as ADHR, XLH, ARHR1, ARHR2, and RNS (4). The gene discussed is FGF23; the disease is hypophosphatemia.