Crouzon syndrome is caused by changes called mutations in one of the four FGFR genes. Usually it affects the FGFR2 gene, and less often the FGFR3 gene.
Genes carry the instructions for making the proteins that direct the body’s functions. Mutations can affect whatever functions a specific protein has.
FGFR2 codes for a protein called fibroblast growth factor receptor 2. As a baby develops in the womb, this protein signals bone cells to form. Mutations to this gene amp up the signal, increasing bone development and causing the baby’s skull to fuse too soon.
A baby only needs to inherit one copy of the gene mutation from a parent to get Crouzon syndrome. If you have this condition, each of your children has a fifty-fifty chance of inheriting it. This inheritance pattern is called autosomal dominant.
In about 25 to 50 percent of people with Crouzon syndrome, the gene mutation happens spontaneously. In these cases, babies don’t need to have a parent with Crouzon syndrome to get the disorder.