This is an autosomal dominant condition caused by a single recurring mutation (Pro252Arg) of the FGFR1 gene and several mutations involving FGFR2. Patients have craniosynostosis, enlarged thumbs and great toes, and a hypoplastic mid face. The hypoplastic mid face gives the forehead an enlarged appearance. The nose is small. Exorbitism may be present, but it is never as prominent as in persons with Crouzon or Apert syndrome. The condition has been classified into 3 types. Patients with type I have the best long-term prognosis, whereas those with types II and III have neurologic compromise and die young