Crouzon syndrome is a rare genetic disorder estimated to occur in 1.6 per 100,000 people, characterized by craniosynostosis (premature fusion of certain skull bones). This early fusion prevents the skull from growing normally and affects the shape of the head and face. Babies with Crouzon syndrome are born with unusual features. As they grow, the shape of the head may distort further causing various problems, such as: partial hearing loss, dry eyes, strabismus and underdevelopment of the upper jaw with facial deformities and malocclusion. These facial deformities greatly affect the social and emotional development of the affected child.

Crouzon syndrome cannot be cured; long-term supportive treatments such as speech therapy, psychological and educational help, and genetic counseling for the family are important to help the child. Surgery early in life to unlock and move the bones of the skull may be vital to prevent or treat increased pressure on the growing brain. It may also be used to reconstruct the appearance of the face and relieve protrusion of the eyes.

Crouzon syndrome is an autosomal dominant disorder, caused by a mutation in fibroblast growth factor receptor 2 (FGFR2) gene located on chromosome 10q26.13. FGFR2 is involved in the formation of bones, skin, and connective tissues. Mutations in the FGFR2 gene cause upregulation of the signalling pathway involved in bone maturation during embryonic development, which causes the bones of the skull to fuse prematurely.

Few mutations have been identified in the FGFR2 gene linked to Crouzon syndrome; the p.ser347cys mutation of the third cysteine in the immunoglobulin domain which cause perturbation of the normal secondary loop structure that is created by the normal disulphide bond, the T/C transition mutation at nucleotide 1036 predicted to result in a p.C342R, and G/A transition mutation at nucleotide 1044.