Fibroblast growth factor receptor 2 (FGFR2) <sup>C342Y/+</sup> mutation is a known cause of Crouzon syndrome that is characterised by craniosynostosis and midfacial hypoplasia.
Pfeiffer syndrome is a classic form of craniosynostosis that is caused by a proline-->arginine substitution at amino acid 252 (Pro252Arg) in fibroblast growth factor receptor 1 (FGFR1).
Pfeiffer syndrome (PS) is one of the classical craniosynostosis syndromes correlated with specific mutations in the human fibroblast growth factor receptor (FGFR) genes, FGFR1 and FGFR2.
Several of the defects observed in the Fgfr2 (W290R) homozygous mouse mutant are attributable to a loss-of-function mechanism in contrast to the frequently reported gain-of-function receptor function associated with mutated FGF receptors in craniosynostosis.
fibroblast growth factor receptor (FGFR) -related craniosynostosis syndromes are caused by many different mutations within FGFR-1, 2, 3, and certain FGFR mutations are associated with more than one clinical syndrome.
In addition, we describe findings from a sequence analysis of all coding exons and exon/intron boundaries of FGFR2 performed on 124 patients with syndromic craniosynostosis.
We propose that this particular FGFR2 mutation only confers a predisposition to craniosynostosis and that an additional environmental insult (in this case foetal head constraint associated with breech position) is necessary for craniosynostosis to occur.
Heterozygous mutations in the human FGFR2 gene cause various craniosynostosis syndromes including Crouzon and Pfeiffer, but testicular defects were not reported.
We establish here that loss-of-function mutations in FGFR1 underlie KAL2 whereas a gain-of-function mutation in FGFR1 has been shown to cause a form of craniosynostosis.
Identical proline-->arginine gain-of-function mutations in fibroblast growth factor receptor (FGFR) 1 (Pro252Arg), FGFR2 (Pro253Arg) and FGFR3 (Pro250Arg), result in type I Pfeiffer, Apert and Muenke craniosynostosis syndromes, respectively.
Fgfr2+/Y394C mice exhibited epidermal hyperplasia and premature closure of cranial sutures (craniosynostosis) due to abnormal cell proliferation and differentiation.
The data implies that second-site mutations in FGFR2 itself (outside of exon IIIc) or in other genes may determine specific aspects of the phenotypes of craniosynostosis syndromes.
FGFR2 encodes a fibroblast growth factor receptor whose mutations are responsible for the Crouzon syndrome, involving craniosynostosis and facial dysostosis with shallow orbits.
Of note, tracheal cartilaginous sleeves have been reported in other FGFR2-related craniosynostosis syndromes, and are associated with 90% risk of death by two years of age without tracheostomy.
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.