Osteoglophonic dysplasia (MIM 166250) is caused by heterozygous gain-of-function mutations in FGFR1 (MIM 136350), a rare autosomal dominant disorder characterized by craniosynostosis, rhizomelic short stature, maxillary hypoplasia, depressed nasal bridge, mandibular pragmatism, dental anomalies, tower-shaped skull, vertebral anomalies and bone mineralization defects (metaphyseal radiolucent changes) (89). The gene discussed is FGFR1; the disease is osteoglophonic dysplasia.