Autosomal dominant hypophosphatemic rickets: a case report of two sisters with a novel FGF-23 mutation.

Autosomal dominant hypophosphatemic rickets (ADHR) is an exceptionally rare condition with fewer than 50 cases reported in the literature Int J Environ Res Public Health 18(16):8771, 2021. We present the cases of two sisters who experienced late-onset ADHR with severe clinical manifestations. Genetic analysis revealed a previously unreported mutation in the FGF-23 gene (chr12:4.370.559 G > T), likely responsible for their condition. These cases highlight the diagnostic challenges, emphasizing the critical need for genetic analysis in all patients suspected of having Tumor-Induced Osteomalacia (TIO) when the tumor remains unidentified, particularly in the presence of iron deficiency anemia.