Since phosphate is indispensable for skeletal mineralization, chronic hypophosphatemia causes rickets and osteomalacia. Fibroblast growth factor 23 (FGF23), which mainly produced by osteocytes in bone, functions as the central regulator of metabolism increasing renal excretion suppressing production 1,25-dihydroxyvitamin D. The excessive action FGF23 results hypophosphatemic diseases, include a...