A novel fibroblast growth factor receptor 2 mutation in Crouzon syndrome associated with Chiari type I malformation and syringomyelia.

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.