Finally, regarding therapy for hyperparathyroidism in the setting of FGF23 excess, it has been reported in two cases of TIO that cinacalcet countered the effect of FGF23 on renal phosphate wasting by lowering PTH; however, it has never been tested in a clinical trial and there is concern about hypercalciuria and acute kidney injury.(10). Here, PTH is linked to hyperparathyroidism.