Fibroblast growth factor receptor (FGFR) (specifically the receptor(s) for fibroblast growth factor 23, i.e., FGFR1c, FGFR3c, FGFR4) (FGFR (subtype context-dependent; commonly FGFR1c, FGFR3c, FGFR4))

The fibroblast growth factor 23 receptor is not a single unique molecular entity, but refers to a group of fibroblast growth factor receptors (FGFRs)—most notably FGFR1c, FGFR3c, and FGFR4—which form a functional receptor complex only in the presence of the co-receptor α-Klotho[3][4][7]. These complexes bind the endocrine hormone fibroblast growth factor 23 (FGF23), which is secreted by osteocytes and osteoblasts. Upon FGF23 binding, the FGFR–α-Klotho complex transduces signals that suppress phosphate reabsorption and vitamin D activation in the kidney, thereby regulating mineral metabolism[1][3][4][10]. Dysfunction in this signaling pathway is implicated in disorders of phosphate homeostasis, such as X-linked hypophosphatemic rickets and tumor-induced osteomalacia, and is a biomarker and therapeutic target in chronic kidney disease and certain rare metabolic bone disorders[6][5][3]. Targeted therapies like burosumab block FGF23, indirectly modulating FGFR–Klotho signaling to treat hypophosphatemic disorders; direct selective modulators of the FGFR-Klotho complex are under investigation[5][4]. **Note:** - The term "Fibroblast growth factor 23 receptor" is not itself a canonical or accurate molecular name—it refers to any FGFR isoform (primarily FGFR1c, FGFR3c, FGFR4) with α-Klotho as an obligate co-receptor for FGF23 signaling[4][7][3]. The precise specification of "Fibroblast growth factor 23 receptor" is incomplete, and thus **is_incorrect** is marked as true. - The correct way to refer to the biological target is "Fibroblast growth factor receptor 1c–Klotho complex", "Fibroblast growth factor receptor 3c–Klotho complex", or "Fibroblast growth factor receptor 4–Klotho complex," depending on the tissue and context[3][4][7].

Other names

FGF23 receptorFGFR-Klotho complexFGF receptor 1cFGF receptor 3cFGF receptor 4FGFR1c-Klotho complexFGFR3c-Klotho complexFGFR4-Klotho complex

Inhibition of FGF23 binding (e.g., burosumab blocks FGF23 so it cannot activate FGFR-Klotho receptors, normalizing phosphate reabsorption and vitamin D synthesis)