Clinical significance of increased serum levels of FGF-23 in fibrous dysplasia.

INTRODUCTION AND

OBJECTIVE

Fibrous dysplasia (FD) can be associated with the development of hypophosphatemic osteomalacia, caused by the production of FGF-23 by dysplastic bone tissue. This study analysed FGF-23 levels in patients with FD, and their association with disease activity and serum phosphate values.

PATIENTS AND

METHODS

Twelve adult patients with FD were included in the study. Clinical history, disease extension and activity and treatments received were reviewed, and the relationship of those values with FGF-23 and serum P levels was analysed.

RESULTS

FGF-23 was elevated in 6/12 patients (50%). Patients with high FGF-23 levels had similar age and disease activity and extension than those who did not. No differences were observed in serum phosphate values between both groups (increased FGF-23: 3.9±0.9 mg/dl vs. decreased FGF-23: 3.5±0.6 mg/dl). In fact, none of the patients with increased FGF-23 had low serum phosphate values.

CONCLUSION

Adult FD patients frequently present elevated FGF-23 values with no serum phosphate level repercussion, suggesting an alteration in the processing of this protein in the dysplastic bone tissue for this pathology.