Increased renal excretion can be subdivided into FGF23‐mediated and non‐FGF23‐mediated renal phosphate wasting.(1, 6) Increased FGF23 concentrations can be caused by monogenetic disorders such as X‐linked hypophosphatemia or by a FGF23‐producing tumor in the setting of TIO.(1, 5). The gene discussed is FGF23; the disease is neoplasm.