Fibroblast growth factor (FGF23) polypeptides
The present invention relates to a kit for diagnosing a disorder comprising a reagent that detects FGF23 polypeptides and mutant FGF23 polypeptides.
1. An isolated polypeptide comprising the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4.
2. A composition comprising the isolated polypeptide of claim 1 and a pharmaceutically-acceptable carrier.
3. An isolated polypeptide comprising the amino acid sequence of SEQ ID NO:2, wherein said polypeptide comprises a mutation selected from the group consisting of an arginine-to-glutamine mutation at amino acid 176 (R176Q) relative to SEQ ID NO:2, an arginine-to-glutamine mutation at amino acid 179 (R179Q) relative to SEQ ID NO:2, and an arginine-to-tryptophan mutation at amino acid 179 (R179W) relative to SEQ ID NO:2.
4. A composition comprising the isolated polypeptide of claim 3 and a pharmaceutically-acceptable carrier.