Crouzon's disease correlates with low fibroblastic growth factor receptor activity in stenosed cranial sutures

Reports have demonstrated that Crouzon's disease is associated with a gene on chromosome 10 coding for the fibroblastic growth factor (FGF) receptor 2. The purpose of this investigation was to evaluate the FGF receptor 2 levels in cranial sutures of children with Crouzon's disease and nonsyndromic, isolated craniosynostosis. Twelve children between the ages of 6 and 24 months were studied. Four patients had Crouzon's disease with coronal suture stenosis. The 8 remaining had a nonsyndromic, isolated coronal stenosis. Stenosed and adjacent nonstenosed cranial sutures were removed at cranioplasty and promptly fixed, decalcified, and embedded in paraffin. Immunohistochemical analysis of cranial sutures was performed with labeled, specific anti-FGF receptor 2 antibodies. In children with Crouzon's disease, we found significantly lower levels of FGF receptor 2 staining in stenosed sutures compared with nonstenosed sutures. In addition, sutures from children with Crouzon's disease demonstrated lower levels of FGF receptor 2 activity in both stenosed and nonstenosed sutures compared with children with a nonsyndromic, isolated coronal stenosis. However, there were no significant differences in FGF receptor 2 staining between stenosed and nonstenosed sutures in children with a nonsyndromic, isolated coronal stenosis. These findings suggest that low FGF receptor 2 activity in cranial sutures correlates with Crouzon's disease. This work supports genetic studies and yet shows that patients with Crouzon's disease have low FGF receptor 2 activity in cranial sutures. The findings also suggest that there may be etiological differences between syndrome- and nonsyndrome-associated craniosynostoses in children.