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Craniofacial Program

Genetics of Craniosynostosis

Why Do Patients with Craniosynostosis See a Geneticist and a Genetic Counsellor?

Children born with craniosynostosis often see a geneticist and a genetic counsellor to determine if the craniosynostosis is non-syndromic or part of a genetic syndrome. The majority of children born with craniosynostosis have non-syndromic craniosynostosis. However, identifying a syndrome is important as it can impact the medical management of a child. The genetic assessment also enables the genetics team to inform the family of the likelihood of future children having craniosynostosis.

What are Genes?

Humans have approximately 30 000 pairs of genes, one half of each pair is inherited from each parent. Genes provide instruction on how to build and maintain a human body. The majority of the time, the exact cause of non-syndromic craniosynostosis is unknown, however some individuals have a mutation (change) in the fibroblast growth factor receptor 3 gene (FGFR3). The function of this gene is to produce a protein (a receptor on a cell), which receives signals for the development of bone and cartilage in the skull bones. When one member of the FGFR3 gene pair is not working, the bones of the skull do not develop as they normally would. It is estimated that up to 20% of children with non-syndromic craniosynostosis will have a mutation in their FGFR3 gene.

Is There a Genetic Test for Non-Syndromic Craniosynostosis?

Yes. By taking a blood sample from an individual with non-syndromic craniosynostosis the FGFR3 gene can be analyzed for a mutation. If a mutation is detected, the cause of the craniosynostosis is determined. If no mutation is detected then the exact cause of the craniosynostosis remains undetermined.

In the future, genetic research may identify additional genes that cause non-syndromic craniosynostosis. The Division of Clinical and Metabolic Genetics encourages families to keep in contact to find out about new genetic discoveries.

What is the Chance for a Couple that Has One Child with Non-Syndromic Craniosynostosis to Have Another Child with the Same Condition?

The recurrence risk for craniosynostosis can only be determined after a full genetic assessment has been performed. This involves a review of a child’s medical history, family history, a physical exam, and possibly blood work for genetic testing. Recurrence risks can range from as low as 2% to as high as 50%.

Children followed by the Craniofacial Program at the Hospital for Sick Children are routinely referred for a genetic assessment. If a family has not been seen, they can request an appointment through their family physician, or through a member of the Craniofacial Program.

Please Note:

Genetic counselling is the process of providing individuals and families with information on the nature, inheritance, and implications of genetic conditions to help them make informed medical and personal decisions. This pamphlet is not meant to address all personal or cultural issues that individuals might face or to substitute for consultation with a genetics professional.

For more information, please contact:

Division of Clinical and Metabolic Genetics Clinical and Metabolic Genetics
The Hospital for Sick Children
555 University Avenue
Toronto, ON
M5G 1X8
Phone: 416-813-6390