Postnatal soluble FGFR3 therapy rescues achondroplasia symptoms and restores bone growth in mice.

[achondroplasia]

Achondroplasia is a rare genetic disease characterized by abnormal bone development , resulting in short stature . It is caused by a single point mutation in the gene coding for fibroblast growth factor receptor 3 (FGFR 3 ), which leads to prolonged activation upon ligand binding . To prevent excessive intracellular signaling and rescue the symptoms of achondroplasia , we have developed a recombinant protein therapeutic approach using a soluble form of human FGFR 3 (sFGFR 3 ), which acts as a decoy receptor and prevents FGF from binding to mutant FGFR 3 . sFGFR 3 was injected subcutaneously to newborn Fgfr 3 (ach /+) mice-the mouse model of achondroplasia -twice per week throughout the growth period during 3 weeks . Effective maturation of growth plate chondrocytes was restored in bones of treated mice , with a dose-dependent enhancement of skeletal growth in Fgfr 3 (ach /+) mice . This resulted in normal stature and a significant decrease in mortality and associated complications , without any evidence of toxicity . These results describe a new approach for restoring bone growth and suggest that sFGFR 3 could be a potential therapy for children with achondroplasia and related disorders .