Rapid Communication: A Novel Mutation in Fibroblast Growth Factor 23 Gene as a Cause of Tumoral Calcinosis
CONTEXT:Tumoral calcinosis is a disease characterized by ectopic calcification and hyperphosphatemia due to enhanced renal tubular phosphate reabsorption. Fibroblast growth factor (FGF)23 was identified as a responsible factor in hypophosphatemic diseases caused by renal phosphate leak. OBJECTIVE:Th...
Gespeichert in:
Veröffentlicht in: | The journal of clinical endocrinology and metabolism 2005-10, Vol.90 (10), p.5523-5527 |
---|---|
Hauptverfasser: | , , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | CONTEXT:Tumoral calcinosis is a disease characterized by ectopic calcification and hyperphosphatemia due to enhanced renal tubular phosphate reabsorption. Fibroblast growth factor (FGF)23 was identified as a responsible factor in hypophosphatemic diseases caused by renal phosphate leak.
OBJECTIVE:The objective of the study was to analyze the involvement of FGF23 in the development of tumoral calcinosis.
DESIGN:Serum FGF23 level was evaluated in a patient with tumoral calcinosis by two kinds of ELISAfull-length assay that detects only full-length FGF23 with phosphate-lowering activity and C-terminal assay that measures full-length as well as C-terminal fragment of FGF23. FGF23 gene was analyzed by direct sequencing of PCR products, and mutant FGF23 was analyzed by Western blotting after expression in mammalian cells.
PATIENTS:A family of tumoral calcinosis patients were studied.
RESULTS:Serum FGF23 was extremely high when measured by C-terminal assay. In contrast, it was low normal by full-length assay. Analysis of FGF23 gene detected a serine to phenylalanine mutation in codon 129. No wild-type allele of this codon was found in the patient. The brother of the proband showed the same base change. When this mutant FGF23 was expressed in vitro, full-length and N-terminal fragments were barely detectable by Western blotting, whereas C-terminal fragment with the same molecular weight as that from wild-type FGF23 could be detected.
CONCLUSION:The production and serum level of C-terminal fragment of FGF23 are increased in this patient with tumoral calcinosis. Together with the recent similar report of FGF23 mutation, impaired action of full-length FGF23 seems to result in tumoral calcinosis. |
---|---|
ISSN: | 0021-972X 1945-7197 |