FGF-23 in fibrous dysplasia of bone and its relationship to renal phosphate wasting

J Clin Invest. 2003 Sep;112(5):683-92. doi: 10.1172/JCI18399.

Abstract

FGF-23, a novel member of the FGF family, is the product of the gene mutated in autosomal dominant hypophosphatemic rickets (ADHR). FGF-23 has been proposed as a circulating factor causing renal phosphate wasting not only in ADHR (as a result of inadequate degradation), but also in tumor-induced osteomalacia (as a result of excess synthesis by tumor cells). Renal phosphate wasting occurs in approximately 50% of patients with McCune-Albright syndrome (MAS) and fibrous dysplasia of bone (FD), which result from postzygotic mutations of the GNAS1 gene. We found that FGF-23 is produced by normal and FD osteoprogenitors and bone-forming cells in vivo and in vitro. In situ hybridization analysis of FGF-23 mRNA expression identified "fibrous" cells, osteogenic cells, and cells associated with microvascular walls as specific cellular sources of FGF-23 in FD. Serum levels of FGF-23 were increased in FD/MAS patients compared with normal age-matched controls and significantly higher in FD/MAS patients with renal phosphate wasting compared with those without, and correlated with disease burden bone turnover markers commonly used to assess disease activity. Production of FGF-23 by FD tissue may play an important role in the renal phosphate-wasting syndrome associated with FD/MAS.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Bone and Bones / metabolism
  • Child
  • Child, Preschool
  • Fibroblast Growth Factors / blood
  • Fibroblast Growth Factors / genetics
  • Fibroblast Growth Factors / physiology*
  • Fibrous Dysplasia of Bone / metabolism*
  • Humans
  • Kidney / metabolism*
  • Middle Aged
  • Phosphates / metabolism*
  • RNA, Messenger / analysis

Substances

  • Phosphates
  • RNA, Messenger
  • Fibroblast Growth Factors
  • fibroblast growth factor 23