What are the symptoms? The skull is made up of flat plate-like bones (cranial bones) connected by seam-like joints (sutures). These joints allow neighbouring cranial bones to be mobile, so that they can slide over each other during birth and allow the growth of the brain during childhood. In Crouzon syndrome, during pregnancy or within the first year of life the cranial (or facial) sutures begin to fuse early (craniosynostosis). This alters the normal pattern of skull growth and therefore the shape of the skull. Features include: altered shape of the top of the headraised intracranial pressure (the pressure inside the skull)underdevelopment of mid-faceshallow eye sockets with prominent eyesabnormal arrangement of teethnormal appearance of the hands and feet. Although affected children may have a range of clinical problems, the head shape is usually the most striking initial feature. At the outset the major concerns are the ease of breathing, potential feeding problems, eye protection and remedying raised intracranial pressure. What are the causes? Crouzon syndrome is usually caused by alteration (mutation) in the FGFR2 gene. Rarely, a change in the FGFR3 gene may occur, which also causes people to develop a skin condition called acanthosis nigricans during childhood. How is it diagnosed? The diagnosis is usually suspected clinically, based on the facial appearance, normal hands and feet and presence of craniosynostosis on skull X-rays or scans. The diagnosis is confirmed by testing of DNA, usually from a blood sample. How is it treated? A child may require surgery to relieve raised intracranial pressure and to reshape the skull and midface. A child with Crouzon syndrome usually enters a coordinated programme of care involving many different clinical specialities integrating their diverse expertise, from birth to later teenage years. In the UK a number of specialist craniofacial centres are funded to provide coordinated care for children with Crouzon syndrome. However, provided that the potential complications are treated and the child is regularly monitored, the majority of individuals with Crouzon syndrome have normal development and intelligence. Inheritance patterns and prenatal diagnosis Inheritance patternsMany cases of Crouzon syndrome occur due to new mutations in a family (sporadic) and increased age of the father can be a related factor. People affected with Crouzon syndrome transmit the condition to their children in an autosomal dominant manner. Prenatal diagnosisThe skull changes of Crouzon syndrome cannot reliably be detected by ultrasound scanning in pregnancy. Where the genetic mutation in the FGFR2 or FGFR3 gene is known, prenatal diagnosis for pregnancies at high (50%) risk can be carried out by chorionic villus sampling or amniocentesis; preimplantation diagnosis would also be feasible. In some cases non-invasive prenatal diagnosis (NIPD) may be available by means of a maternal blood sample after 9 weeks of pregnancy. Is there support? As Crouzon syndrome is a craniofacial condition, support and advice is available from Headlines (see entry Craniofacial conditions).