FGF23 also inhibits 1α‐hydroxylase, thereby decreasing the synthesis of 1.25(OH)2D.(2) The differential diagnosis of hypophosphatemia can be divided into three major groups: hypophosphatemia from increased renal excretion, from decreased intestinal absorption, or due to intracellular shift of phosphate. Here, FGF23 is linked to hypophosphatemia.