Crouzon syndrome (CS), which results from fibroblast growth factor receptor 2 mutations, is associated with craniosynostosis, exophthalmos, and other symptoms.
The most common craniosynostosis syndromes include Apert (FGFR2), Crouzon (FGFR2), Muenke (FGFR3), Pfeiffer (FGFR1 and FGFR2), and Saethre-Chotzen (TWIST).
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.
FGFR2 encodes a fibroblast growth factor receptor whose mutations are responsible for the Crouzon syndrome, involving craniosynostosis and facial dysostosis with shallow orbits.
A 20-gene panel was designed based on the genes' association with craniosynostosis, and clinically validated through retrospective testing of an Australian and New Zealand cohort of 233 individuals with craniosynostosis in whom previous testing had not identified a causative variant within FGFR1-3 hot-spot regions or the TWIST1 gene.
<b>Background:</b> Apert syndrome is considered as one of the most common craniosynostosis syndromes with a prevalence of 1 in 65,000 individuals, and has a close relationship with point mutations in FGFR2 gene.
The genes related to the pathogenesis of the craniosynostoses itself are those encoding transcription factors, e.g., TWIST1, MSX2, EN1, and ZIC1, and proteins involved in osteogenic proliferation, differentiation, and homeostasis, such as FGFR1, FGFR2, RUNX2, POR, and many others.
The genes related to the pathogenesis of the craniosynostoses itself are those encoding transcription factors, e.g., TWIST1, MSX2, EN1, and ZIC1, and proteins involved in osteogenic proliferation, differentiation, and homeostasis, such as FGFR1, FGFR2, RUNX2, POR, and many others.
Although FGFR2 gene mutations and polymorphisms have been studied in various ethnic groups, we report a mutation of FGFR2 in two different Chinese patients with two different types of syndromic craniosynostosis.
These findings, together with previous data, imply that the same FGFR2 mutations can be associated with a wide range of phenotypes including clinically different forms of syndromic craniosynostosis and apparently normal phenotype, depending on other (epi)genetic and environmental factors.
FGFR1 mutations have also been identified in more severe craniosynostosis syndromes, and a subset of craniosynostosis syndromes-associated FGFR1 mutations show dominant negative effect.
Here we examine integration of brain and skull in two mouse models for craniosynostosis: one carrying the FGFR2c C342Y mutation associated with Pfeiffer and Crouzon syndromes and a mouse model carrying the FGFR2S252W mutation, one of two mutations responsible for two-thirds of Apert syndrome cases.
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.
Heterozygous mutations in the human FGFR2 gene cause various craniosynostosis syndromes including Crouzon and Pfeiffer, but testicular defects were not reported.
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.
Since our patient shows typical radiological findings of Pfeiffer syndrome in hands and feet but at the same time lacks several characteristic features such as clinical signs of craniosynostosis and prominent eyes we suggest introducing the term "FGFR2 associated phenotypes" for similar cases.