However, in rare cases, the intravenous administration of saccharated ferric oxide, ferric polymaltose and carboxymaltose was reported from our laboratory and others to cause FGF23-related hypophosphatemia (Schouten et al., 2009; Shimizu et al., 2009; Wolf et al., 2013). The gene discussed is FGF23; the disease is hypophosphatemia.