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PubMed · 15131704

[Complex craniofacial synostoses].

Abstract

BACKGROUND: Complex craniofacial synostosis is a group of rare genetic disorders characterized by premature closure of the sutures in the craniofacial skeleton and which to varying degrees affects the extremities. MATERIAL AND METHODS: On the basis of relevant literature, we present a review of syndromal craniofacial synostosis. RESULTS: Phenotypically, the complex craniofacial syndromes have many similarities. Synostosis of the sutures of the cranial vault can result in a variety of skull deformations, depending on the sutures involved, the sequence of premature closure, and the time of closure. Synostosis of the sutures in the skull base and facial skeleton leads to shallow orbits, exophthalmus, hypertelorism, midface retrusion, and prognathia. INTERPRETATION: Precise diagnosis of complex craniofacial syndromes may be difficult solely on the basis of a clinical examination. However, several of the most common syndromes are caused by mutations in genes that code for fibroblast growth-factor receptors. Children with a suspected complex craniofacial syndrome should be referred to genetic testing.

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BibTeXRIS

Torstein R Meling, Karen Helene Ørstavik, Arvid Heiberg. 2004-05-06. [Complex craniofacial synostoses].. https://pubmed.ncbi.nlm.nih.gov/15131704/

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A soluble form of fibroblast growth factor receptor 2 (FGFR2) with S252W mutation acts as an efficient inhibitor for the enhanced osteoblastic differentiation caused by FGFR2 activation in Apert syndrome.

Apert syndrome is an autosomal dominant disease characterized by craniosynostosis and bony syndactyly associated with point mutations (S252W and P253R) in the fibroblast growth factor receptor (FGFR) 2 that cause FGFR2 activation. Here we investigated the role of the S252W mutation of FGFR2 on osteoblastic differentiation. Osteoblastic cells derived from digital bone in two Apert patients with the S252W mutation showed more prominent alkaline phosphatase activity, osteocalcin and osteopontin mRNA expression, and mineralized nodule formation compared with the control osteoblastic cells derived from two independent non-syndromic polydactyly patients. Stable clones of the human MG63 osteosarcoma cells (MG63-Ap and MG63-IIIc) overexpressing a splice variant form of FGFR2 with or without the S252W mutation (FGFR2IIIcS252W and FGFR2IIIc) showed a higher RUNX2 mRNA expression than parental MG63 cells. Furthermore MG63-Ap exhibited a higher osteopontin mRNA expression than did MG63-IIIc. The enhanced osteoblastic marker gene expression and mineralized nodule formation of the MG63-Ap was inhibited by the conditioned medium from the COS-1 cells overexpressing the soluble FGFR2IIIcS252W. Furthermore the FGF2-induced osteogenic response in the mouse calvarial organ culture system was blocked by the soluble FGFR2IIIcS252W. These results show that the S252W mutation in the FGFR2 gene enhances the osteoblast phenotype in human osteoblasts and that a soluble FGFR2 with the S252W mutation controls osteoblast differentiation induced by the S252W mutation through a dominant negative effect on FGFR2 signaling in Apert syndrome.

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Computed tomography assessment of Apert syndrome.

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