Craniosynostosis

Premature fusion of the cranial sutures (the fibrous joints between the bones of the skull) in an infant, preventing normal growth of the baby's head. Craniosynostosis involving some but not all of the sutures causes an abnormally shaped skull. Premature closure of all of the sutures results in microcephaly (an abnormally small head) which arrests the normal growth and development of the baby's brain and may result in developmental delay and mental retardation. Early detection of the condition is therefore of great importance. Treatment is surgery designed to keep the sutures open. Craniosynostosis can occur as an isolated abnormality or as part of a syndrome. A number of craniosynostosis syndromes are now known to be due to mutations in the FGFR genes (FGFR = fibroblast growth factor receptor). The FGFR-related craniosynostosis syndromes include established entities (the Apert, Crouzon, and Pfeiffer syndromes) and several newer entities (the Beare-Stevenson, Muenke, and Jackson-Weiss syndromes). All are inherited in an autosomal dominant manner. Affected individuals have a 50% chance of passing the mutant gene to each child. Prenatal testing is available.

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Premature ossification of the skull and obliteration of the sutures. The particular sutures involved determine the resultant shape of the malformed head. SYN: craniostosis.

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cra·nio·syn·os·to·sis -.sin-.äs-'tō-səs n, pl -to·ses -.sēz or -to·sis·es premature fusion of the sutures of the skull

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n.

premature fusion of some of the cranial bones, usually before birth, so that the skull is unable to expand in certain directions to assume its normal shape under the influence of the growing brain. Depending on which cranial suture fuse early, the skull may become elongated from front to back, broad and short, peaked (oxycephaly or turricephaly), or asymmetrical. Compare craniostenosis.

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cra·nio·syn·os·to·sis (kra″ne-o-sin″os-toґsis) [cranio- + syn- + ostosis] premature closing of the sutures of the skull of an infant, causing deformities such as oxycephaly and scaphocephaly. Called also craniostosis.