FGF23 and hypoparathyroidism: Previous studies showed that mean serum PO4 levels in hypoparathyroid patients remained above the normal range, even in the presence of high serum FGF-23 level [53].Yamashita et al. showed that in transient hypoparathyroidism high serum level of FGF23 and hyperphosphatemia will be normalized only after parathyroid recovery [54].