FGF23 and hypophosphatemia: For individuals with XLH and Hyp mice, the typical result of abnormally elevated FGF23 levels is an increase in renal phosphate excretion and subsequent hypophosphatemia due to the reduced expression of sodium‐dependent phosphate transporters in the proximal tubule 2A and 2C (NaPi2A/2C), as well as a decrease in 1,25D levels through the suppression of renal 1‐α hydroxylase (encoded by Cyp27b1) and the activation of the catabolic 24‐hydroxylase (encoded by Cyp24a1) [13].