Craniofacial anomalies in a murine model of heterozygous fibroblast growth factor 10 gene mutation.

OBJECTIVE: Dysregulation of Fibroblast Growth Factor 10 (FGF10), a member of the family of Fibroblast Growth Factor (FGF) proteins, has been implicated in craniofacial and dental anomalies, including craniosynostosis, cleft palate, and Lacrimo-Auriculo-Dento-Digital Syndrome. The aim of this murine study was to assess the craniofacial and dental phenotypes associated with a heterozygous FGF10 gene (FGF10+/- ) mutation at skeletal maturity. METHODS: Skulls of 40 skeletally mature mice, comprising two genotypes (heterozygous FGF10+/- mutation, n = 22; wildtype, n = 18) and two sexes (male, n = 23; female, n = 17), were subjected to micro-computed tomography. Landmark-based linear dimensions were measured for the cranial vault, maxilla, mandible, and first molar teeth. Multivariate analysis of variance was performed to assess whether there were significant differences in the craniofacial and dental structures between genotypes and sexes. RESULTS: The craniomaxillary skeleton and the first molar teeth were smaller in the FGF10+/- mice (P < .05), but the mandible was unaffected. Sex did not have a significant effect on these structures (P > .05). Cranial sutural defects were noted in 5/22 (22.7%) mutant versus 2/18 (11.1%) wildtype mice, and cleft palate in only one (4.5%) mutant mouse. None of the mice displayed craniosynostosis, expansive bony lesions, bifid condyles, or impacted teeth. CONCLUSION: The FGF10+/- mutation was associated with craniomaxillary skeletal hypoplasia that probably arose from deficient (delayed) intramembranous ossification of the sutured bones. Overall, the skeletal and dental data suggest that the FGF10 gene plays an important role in the aetiology of craniofacial dysmorphology and malocclusion.

The Role of Fibroblast Growth Factor 10 Signaling in Duodenal Atresia.

INTRODUCTION: Duodenal atresia (DA) is a congenital bowel obstruction requiring major surgery in the first week of life. Three morphological phenotypes are described, reflecting increasing degrees of obstruction and discontinuity of the duodenum. The cause of DA is not known. Tandler's original "solid cord" hypothesis conflicts with recent biological evidence, and is unable to account for differing DA types. In humans, a genetic etiology is supported by the association between Trisomy 21 and DA, and reports of familial inheritance patterns. Interruption of FGF10/FGFR2b signaling is the best demonstrated genetic link to DA in mice, with 35-75% of homozygous knockout embryos developing DA. PURPOSE: This review examines the current evidence surrounding the etiology of DA. We focus on research regarding FGF10/FGFR2b signaling and its role in duodenal and other intestinal atresia. Further, we outline planned future research in this area, that we consider necessary to validate and better understand this murine model in order to successfully translate this research into clinical practice. CONCLUSION: Determining the etiology of DA in humans is a clinical and scientific imperative. Fgf10/Fgfr2b murine models represent current science's best key to unlocking this mystery. However, further research is required to understand the complex role of FGF10/FGFR2b signaling in DA development. Such complexity is expected, given the lethality of their associated defects makes ubiquitous interruption of either Fgf10 or Fgfr2b genes an unlikely cause of DA in humans. Rather, local or tissue-specific mutation in Fgf10, Fgfr2b, or their downstream targets, is the hypothesized basis of DA etiology.

Clinical data and Pediatric Quality of Life Inventory (PedsQL™) scores for children with duodenal atresia.

This article presents raw data obtained from a prospectively collected database of children with duodenal atresia at tertiary pediatric surgery hospital. For all potential participants, pertinent demographic, clinical and operative data was obtained from the database. Potential participants were then contacted and invited to complete a Pediatric Quality of Life Inventory (PedsQL™) 4.0 core score and gastrointestinal module questionnaires. Participant's response to each item in the questionnaires is provided, as well as their calculated health related quality of life scores. Data has the potential to be reused in future studies examining quality of life in duodenal atresia, paediatric gastrointestinal conditions, surgical neonatal conditions and children with trisomy 21. Further analysis and discussion is contained in related research article titled "Quality of life outcomes in children born with duodenal atresia" [1].

Quality of life outcomes in children born with duodenal atresia.

PURPOSE: The aim of this study was to determine long term quality of life (QoL) outcome for children who underwent surgery for duodenal atresia (DA). METHODS: Patients were identified from a prospective database of neonatal DA cases managed at a tertiary pediatric surgical centre. The QoL was measured using the validated PedsQL™ 4.0 core score and PedsQL™ gastrointestinal module; higher score equates to better QoL. Participants' scores were compared to published control cohorts, age-matching the core score. Trisomy 21 was identified a priori as a possible confounder, informing subgroup analyses for children with and without trisomy 21. RESULTS: Fifty-five families were invited to participate, with 38 surveys returned (39% male; median age 6.7y, range 2.7-17.3y). Seven participants had trisomy 21. There were no differences in QoL measures between all DA participants and controls. The PedsQL™ core score was significantly lower for DA participants with trisomy 21, but there was no accompanying difference in PedsQL™ gastrointestinal score. CONCLUSIONS: Children undergoing DA surgery in the neonatal period typically grow up to have a QoL comparable to a healthy population. Children with DA and trisomy 21 were more likely to have reduced overall QoL, albeit without an associated difference in gastrointestinal QoL score. LEVEL OF EVIDENCE: Prognosis study - level II (prospective cohort study).

FGF10 and the Mystery of Duodenal Atresia in Humans.

Background: Duodenal atresia (DA) is a congenital obstruction of the duodenum, which affects 1 in 7000 pregnancies and requires major surgery in the 1st days of life. Three morphological DA types are described. In humans, the association between DA and Down syndrome suggests an underlying, albeit elusive, genetic etiology. In mice, interruption of fibroblast growth factor 10 (Fgf10) gene signaling results in DA in 30-50% of embryos, supporting a genetic etiology. This study aims to validate the spectrum of DA in two novel strains of Fgf10 knock-out mice, in preparation for future and translational research. Methods: Two novel CRISPR Fgf10 knock-out mouse strains were derived and embryos generated by heterozygous plug-mating. E15.5-E19.5 embryos were genotyped with respect to Fgf10 and micro-dissected to determine the presence and type of DA. Results: One twenty seven embryos (32 wild-type, 34 heterozygous, 61 null) were analyzed. No wild-type or heterozygous embryos had DA. However, 74% of Fgf10 null embryos had DA (49% type 1, 18% type 2, and 33% type 3). Conclusion: Our CRISPR-derived strains showed higher penetrance of DA due to single-gene deletion of Fgf10 in mice than previously reported. Further, the DA type distribution in these mice more closely reiterated that observed in humans. Future experiments will document RNA and protein expression of FGF10 and its key downstream signaling targets in normal and atretic duodenum. This includes exploitation of modern, high-fidelity developmental tools, e.g., Fgf10 flox/+-tomatoflox/flox mice.