iFGF23 Plasma Levels in Transfusion-Dependent β-Thalassemia: Insights into Bone and Iron Metabolism

Background: FGF23 is a phosphate homeostasis regulator; the literature suggests a link between FGF23, iron homeostasis and erythropoiesis. Little is known about the FGF23 level variations in β-thalassemia (βT), which is characterized by ineffective erythropoiesis and iron overload. Our cross-sectional study aims to evaluate the iFGF23 level variations in a large cohort of βT patients considering their bone mineral densities (BMDs) and iron loads. Methods: Clinical, biochemical and radiological data were collected from 213 transfusion-dependent βT (TDT) adults referring to the Regional HUB Centre for Thalassaemia and Haemoglobinopathies in Ferrara, Italy. The iFGF23 levels in the TDT patients were compared to the general population’s reference range. The BMDs and hearth and liver iron deposits were assessed with DEXA scans and MRI, respectively. Results: The iFGF23 distribution in the TDT subjects is significantly different from that of the general population. The iFGF23 levels are positively correlated with the age at transfusion initiation and calcium and phosphate levels and are negatively correlated with the osteocalcin plasma levels. Patients treated with deferasirox had lower iFGF23 levels than those treated with other chelators. The iFGF23 levels are not correlated with the BMD or iron status. Conclusions: These findings provide insights into the relationship between the iFGF23 and bone and iron metabolism in TDT patients. Further studies are needed to explore its potential clinical relevance.