The Role of Fibroblast Growth Factor 23 in the Pathogenesis of Mineral and Bone Disorder in Chronic Kidney Disease: A Review of Foundational Discoveries

Abstract

Introduction: Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) is a systemic complication of declining renal function involving abnormalities in mineral metabolism and bone pathology. The traditional understanding of its pathogenesis was profoundly revised following the characterisation of the hormone Fibroblast Growth Factor 23 (FGF23).

Literature Review: A review of pivotal scientific literature reveals that FGF23 was identified as a potent, bone-derived hormone that regulates phosphate homeostasis. Seminal studies demonstrated that in response to declining renal function, FGF23 levels rise early and progressively. This rise is initially an adaptive mechanism to promote urinary phosphate excretion and maintain normal serum phosphate levels. However, this compensation comes at a cost: high FGF23 levels suppress the production of active vitamin D and are a primary stimulus for the development of secondary hyperparathyroidism. Foundational observational studies established a strong and independent association between elevated FGF23 concentrations and adverse outcomes, including cardiovascular disease and mortality, in patients with CKD. The discovery of Klotho as an essential co-receptor for FGF23 function further illuminated this complex signaling axis.

Conclusion: The body of evidence reviewed establishes FGF23 as a central pathogenic factor in CKD-MBD. Its role extends beyond that of a simple biomarker, identifying it as a key mediator that links disordered mineral metabolism with the high rates of cardiovascular morbidity and mortality characteristic of chronic kidney disease.