New Phenotypic Features in FGFR1-Related Osteoglophonic Dysplasia

Osteoglophonic dysplasia (OGD) is a rare skeletal disorder caused by certain variants in FGFR1. The FGFR1 gene encodes a receptor vital for osteogenesis in the axial and craniofacial skeleton. Key OGD features include craniosynostosis, craniofacial dysmorphism, impacted teeth, rhizomelic shortening, and nonossifying fibromas. Patients may have hypophosphatemia due to high FGF23 levels. We report two OGD patients with the c.1141T > C FGFR1 variant [p.(Cys381Arg)], initially diagnosed with Pfeiffer syndrome. Both showed classic symptoms as well as signs not previously reported, including elevated frontal temperature and overlapping toes. This report emphasizes distinguishing OGD from similar disorders and expanding the clinical phenotype.