Molecular Analysis of Twist1 and FGF Receptors in a Rabbit Model of Craniosynostosis: Likely Exclusion as the Loci of Origin

Abstract

Craniosynostosis is the premature fusion of the cranial vault sutures. We have previously described a colony of rabbits with a heritable pattern of nonsyndromic, coronal suture synostosis; however, the underlying genetic defect remains unknown. We now report a molecular analysis to determine if four genes implicated in human craniosynostosis, TWIST1 and fibroblast growth factor receptors 1–3 (FGFR1–3), could be the loci of the causative mutation in this unique rabbit model. Single nucleotide polymorphisms (SNPs) were identified within the Twist1, FGFR1, and FGFR2 genes, and the allelic patterns of these silent mutations were examined in 22 craniosynostotic rabbits. SNP analysis of the Twist1, FGFR1, and FGFR2 genes indicated that none were the locus of origin of the craniosynostotic phenotype. In addition, no structural mutations were identified by direct sequence analysis of Twist1 and FGFR3 cDNAs. These data indicate that the causative locus for heritable craniosynostosis in this rabbit model is not within the Twist1, FGFR1, and FGFR2 genes. Although a locus in intronic or flanking sequences of FGFR3 remains possible, no direct structural mutation was identified for FGFR3.

Novel mutation detection of fibroblast growth factor receptor 1 (FGFR1) gene, FGFR2IIIa, FGFR2IIIb, FGFR2IIIc, FGFR3, FGFR4 gene for craniosynostosis: A prospective study in Asian Indian patient

“…The therapeutics directed at inhibiting the FGF/FGFR interaction is a promising subject for clinical trials. [ 13 ] Five genes implicated in human CS, TWIST1 and FGFRs 1–3 (FGFR1–3) and its isomers, could be the loci of the causative mutation in this unique human model. [ 3 4 ] Single nucleotide polymorphisms (SNPs) were identified within the TWIST1, FGFR1, and FGFR2 genes.…”

“…In this study, we have evaluated FGFR1 (P250R/+) and Fgfr2 (S252W/+) mouse models of these human conditions to study the pathogenesis of midfacial hypoplasia. [ 13 ] Our histologic and micro-CT evaluation revealed premature synostosis of the premaxillary-maxillary, nasal-frontal, and maxillary-palatine sutures of the face and dysplasia of the premaxilla, maxilla, and palatine bones. These midfacial abnormalities were detected in the absence of premature ossification of the cranial base at postnatal day 0.…”

Molecular Analysis of Gli3, Ihh, Rab23, and Jag1 in a Rabbit Model of Craniosynostosis

“…Sequencing of known candidate genes is unfortunately necessary because of the lack of commercial tools designed for genetic characterization of the rabbit. To date, we have excluded FGFR1-3, Twist1, EFNA4, and EFNB1 as the likely causal loci for synostosis within the CS rabbit colony (Gallo et al, 2013(Gallo et al, , 2014. We examined Gli3, Ihh, Rab23, and Jag1 in this study because previous work in our laboratory has implicated Hedgehog signaling members in the CS rabbit.…”

Molecular Analyses in a Rabbit Model of Craniosynostosis: Likely Exclusion of Known Candidate Genes as the Loci of Origin

“…We have bred this individual and her offspring and have developed a breeding colony of rabbits with familial, primary coronal suture synostosis (Mooney et al, 1994a; Mooney et al, 1994b). The genetic basis for CS in this naturally occurring animal model remains uncertain although we have excluded a panel of likely candidates including Fgfr1 , Fgfr2 , Fgfr3 , Tgfbr1 , Tgfbr2 , Twist1 , Efna4 , Efnb1 , Gli3 , Ihh , Jag1 , and Rab23 (Gallo et al, 2013; Gallo et al, 2014; Gilbert et al, 2018; Taylor et al, 2018). Other candidates who are recurrently linked to fusion of the coronal suture in patients include a panel of developmentally regulated transcription factors ( Erf , Msx2 , Tcf12 , Zeb2 ), rare mutations affecting genes involved in development and metabolism ( Cyp26b1 , Il11ra , Por , Ski ), and genes associated with tissue mineralization ( Alpl , Ostm1 ; Table 1; Heuzé et al, 2014).…”