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Craniosynostosis consists of premature fusion of one or more cranial sutures, resulting in an abnormal head shape. It can be divided in several subgroups; the major different types are primary vs secondary craniosynostosis and isolated vs syndromic craniosynostosis. The overall incidence for all forms of craniosynostosis is 1/2,000-1/2,500 live-born children. Most cases are evident during the neonatal period. Occasionally, it may be detected prenatally by ultrasound examination or not noted until late in infancy. A primary defect in the mesenchymal layer ossification in the cranial bones is accepted to play a role in the etiology of primary craniosynostosis. Many of the syndromic forms (Apert, Carpenter, Crouzon, Muenke types) are related to mutations in one of the FGFR genes. Mutations in the TWIST gene have been identified in Saethre-Chotzen syndrome. Mutations in MSX2 are causative in Boston-type craniosynostosis. Autosomal dominant inheritance has been identified in by far the most syndromic forms of craniosynostoses. The percentage of patients showing a spontaneous new mutations is high. Germ line mosaicism is also known to occur and should be discussed with the family. Usually no mendelian pattern of inheritance can be identified in nonsyndromic forms. Craniosynostoses are very heterogeneous traits. All are characterized by skull deformities, with face and often limb involvement in the syndromic forms. Children with syndromic forms (eg, Apert syndrome) can be affected by a variable degree of developmental delay. No medical treatment exists to stop an early ossification of a cranial suture. Infants with a craniosynostosis may require a series of surgical procedures. |