Summary

Apert syndrome is a malformation disorder characterised by the association of faciocraniosynostosis and osseous and membranous syndactyly of the four extremities. The incidence has been estimated at 1 in 50 000 births. The craniosynostosis is bicoronal and is evident at birth. The longitudinal system (sagittal and metopic sutures) is abnormally broad, even in the first few months of life. The superior maxilla is severely hypoplastic, resulting in malocclusion and a protruding lower jaw. The face is usually broad with a beaked nose. Ocular abnormalities include hypertelorism and sometimes severe exophthalmos. Syndactyly of the fingers and toes may be total (mitten hands and sock feet) or partial affecting the second, third, and fourth digits. Intellectual deficit is frequent and often severe, usually being associated with cerebral malformations. Nearly 50% of patients have increased intracranial pressure. The majority of patients (more than 98%) carry a mutation (Ser252Trp or Pro253Arg) in the gene encoding fibroblast growth factor receptor type 2 (FGFR2). Alu-element insertion mutations in or near exon 9 of FGFR2 are responsible for the remaining cases. Early intervention for craniosynostosis (before the age of six months) may improve the mental prognosis: a significant number of patients who underwent early surgical intervention later showed normal intellectual performance. Correction of the maxillary hypoplasia and hypertelorism should not be carried out until the patient is at least four years old (except in severe cases).

Expert reviewer(s)

• Dr E LAJEUNIE
• Dr Martine LE MERRER