Object: It has been reported that due to premature synostosis of the lambdoid suture in the first 24 months of life, more than 70% of patients with Crouzon syndrome concurrently suffer from chronic tonsillar herniation (Chiari Type I malformation) and some (20%) associated syringomyelia. The goal of the present study was to examine mutations in the fibroblast growth factor receptor (FGFR) genes in Crouzon syndrome and its related conditions.
Methods: Five patients were studied: three with Crouzon syndrome (one sporadic and two familial), one with sporadic Chiari I with syringomyelia, and one with unilateral lambdoid synostosis. Deoxyribonucleic acid was screened for FGFR1-3 mutations by using single-strand conformational polymorphism and subsequent direct sequencing. Two types of missense mutations were detected in the FGFR2 gene, Cys342Trp (1205, TGC --> TGG) in a patient with sporadic Crouzon syndrome and Tyr281Cys (1021, TAC --> TGC) in two siblings (brother and sister) with familial Crouzon syndrome, respectively. The former has been reported only in sporadic cases but the latter has not previously been identified. A polymorphism in the FGFR3 gene, Asn294Asn (882, AAT --> AAC), was also detected in three patients. No mutation was found in the patient with sporadic Chiari I with syringomyelia.
Conclusions: The FGFR2 missense mutation was detected in Crouzon syndrome but not in sporadic Chiari I with syringomyelia or lambdoid synostosis. A novel FGFR2 mutation, Tyr281Cys, was found in familial Crouzon syndrome with Chiari I and syringomyelia. It may be informative to look for this in patients with Crouzon syndrome and associated syringomyelia.