FGF23 and hypophosphatemia: Our cases were, in some ways, similar to iron infusion-induced FGF23-related hypophosphatemia, which was reported by our laboratory and others approximately a decade ago, indicating that an exogenous factor led to FGF23-related hypophosphatemia (Schouten et al., 2009; Shimizu et al., 2009; Wolf et al., 2013).