FGF23 (Fibroblast Growth Factor 23)

The current literature on FGF23 transmitted tumors in the cervical spine includes six cases treated with definitive local therapy. This case suggests an alternative option for unresectable FGF23 transmitted tumor in the vertebrae, causing spinal myelopathy.

P=N/A, N=85, Recruiting, Aarhus University Hospital

Recognition of AIO should be particularly considered in patients with acquired FGF23-related hypophosphatemia who have undetectable PMTs, relatively mild disease activity, and concurrent autoimmune diseases.

Compared with similar reports, our case highlights the utility of combined positron emission tomography and magnetic resonance imaging in localizing PMTs and the dramatic clinical improvement following resection. This case underscores the importance of recognizing TIO early to enable effective treatment and avoid prolonged morbidity.

Treatment options to reduce blood phosphate levels have only been studied in case reports and small cohorts, with positive effects from phosphate binders, acetazolamide, anti-inflammatory drugs, probenecid, nicotinamide, and sodium thiosulfate. In this report, we present the case of a 50-year-old woman with a large (at least 5,600 base pair) deletion in the gene encoding for GalNAc-T3 (GALNT3) who experienced bone pain during childhood and calcifications of her lower limbs at least since her mid-thirties. Intragenic GALNT3 copy number variants have, to our knowledge, not yet been described as a cause of HTC.

Male sex was associated with a higher risk of kidney failure and mortality, despite adjustment for demographic, clinical, and treatment factors. Males had higher levels of inflammatory and extracellular matrix deposition biomarkers. In contrast, females showed higher levels of matrix turnover and degradation markers. After adjustment for these biomarker differences, the elevated risk associated with male sex was eliminated, suggesting a biological basis for the observed sex difference in outcomes.

The rapid progression of imaging findings, discordant metabolic abnormalities and markedly elevated FGF-23 levels poses a diagnostic challenge. As such, fibrous dysplasia-like lesions of the extremities in the setting of hypophosphataemic rickets should prompt consideration of PMT.

P=N/A, N=400, Not yet recruiting, Tongde Hospital of Zhejiang Province; Tongde Hospital of Zhejiang Province

A high bone turnover state resembling hungry bone syndrome may occur after PMT resection. Awareness of these postoperative biochemical changes and the effects of burosumab on FGF23 assays is essential for monitoring TIO recovery.

P=N/A, N=60, Recruiting, University of Texas Southwestern Medical Center

Tumor-induced osteomalacia should be considered in patients with persistent hypophosphatemia and phosphate wasting. Early recognition is essential, as complete surgical resection remains the only curative option. In advanced or unresectable disease, management is challenging and may be limited by tumor burden and access to targeted therapies, including anti-FGF23 agents, which offer biochemical and symptomatic benefit in selected cases.

This current case illustrates successful correction of renal phosphate wasting with burosumab in a patient with CKD and non-localizable FGF-23. This suggests that targeted anti-FGF-23 therapy can be considered for intolerable or ineffective conventional therapy even in moderate CKD.