Background: Crouzon syndrome is an autosomal dominant disorder causing premature fusion of the cranial suture. Mutations have been reported in exon IIIa or IIIc of the fibroblast growth factor receptor 2 (FGFR2) gene. Methods: In the present study, nine unrelated Crouzon syndrome patients were screened for mutations in the two exons of FGFR2 by polymerase chain reaction and direct sequencing. Results: Mutations were detected in 67% (6/9) of all cases. More than half the studied Crouzon patients carried a mutation resulting in either the loss or gain of a cysteine residue. A novel mutation, Tyr281Cys substitution, was discovered at exon IIIa. Conclusions: The mechanisms by which the same genotypes cause different phenotypes for each type of craniosynostosis syndrome in still uncertain. However, the molecular identification of the FGFR gene has made a great impact on the clinical classification of craniosynostosis syndromes; a new classification based on genotypes seems to be unavoidable.
