Erratum.

The article incorrectly stated: "Elevations of both fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH) lead to hyperphosphatemia and hypocalcemia because of decreased urinary excretion of phosphorus." In fact, FGF23 normally acts to lower blood phosphate levels. Furthermore, an elevated phosphorus level causes an increase in serum calcium levels and not hypocalcemia. This information has been corrected in the online version of the article. [ABSTRACT FROM AUTHOR]