Oro-dental and cranio-facial characteristics of osteogenesis imperfecta type V

Osteogenesis imperfecta (OI) type V is an ultrarare heritable bone disorder caused by the heterozygous c.-14C > T mutation in IFITM5. The oro-dental and craniofacial phenotype has not been described in detail, which we therefore undertook to evaluate in a multicenter study (Brittle Bone Disease Consortium). Fourteen individuals with OI type V (age 3-50 years; 10 females, 4 males) underwent dental and craniofacial assessment. None of the individuals had dentinogenesis imperfecta. Six of the 9 study participants (66%) for whom panoramic radiographs were obtained had at least one missing tooth (range 1-9). Class II molar occlusion was present in 8 (57%) of the 14 study participants. The facial profile was retrusive and lower face height was decreased in 8 (57%) individuals. Cephalometry, performed in three study participants, revealed a severely retrusive maxilla and mandible, and moderately to severly retroclined incisors in a 14-year old girl, a protrusive maxilla and a retrusive mandible in a 14-year old boy. Cone beam computed tomograpy scans were obtained from two study participants and demonstrated intervertebral disc calcification at the C2-C3 level in one individual. Our study observed that OI type V is associated with missing permanent teeth, especially permanent premolar, but not with dentinogenesis imperfecta. The pattern of craniofacial abnormalities in OI type V thus differs from that in other severe OI types, such as OI type III and IV, and could be described as a bimaxillary retrusive malocclusion with reduced lower face height and multiple missing teeth.

Advancements in craniofacial prosthesis fabrication: A narrative review of holistic treatment

The treatment of craniofacial anomalies has been challenging as a result of technological shortcomings that could not provide a consistent protocol to perfectly restore patient-specific anatomy. In the past, wax-up and impression-based maneuvers were implemented to achieve this clinical end. However, with the advent of computer-aided design and computer-aided manufacturing (CAD/CAM) technology, a rapid and cost-effective workflow in prosthetic rehabilitation has taken the place of the outdated procedures. Because the use of implants is so profound in different facets of restorative dentistry, their placement for craniofacial prosthesis retention has also been widely popular and advantageous in a variety of clinical settings. This review aims to effectively describe the well-rounded and interdisciplinary practice of craniofacial prosthesis fabrication and retention by outlining fabrication, osseointegrated implant placement for prosthesis retention, a myriad of clinical examples in the craniofacial complex, and a glimpse of the future of bioengineering principles to restore bioactivity and physiology to the previously defected tissue.

The South Asian facial anthropometric profile: A systematic review

PURPOSE

Craniofacial anatomy, as measured by facial anthropometric data, varies significantly between races. South Asia, comprised of eight countries, represents a large proportion of the global population and is the fastest-growing region of the world. This systematic review presents the facial anthropometric data collected for populations from this region.

MATERIALS AND METHODS

This systematic review was conducted in accordance with PRISMA guidelines. A systematic review of the literature was conducted by an electronic search of the MEDLINE and Cochran databases, returning 1675 articles. Bibliographies of accepted articles were screened to identify further eligible studies.

RESULTS

A total of 12 articles were considered eligible for the systematic review. Two studies were conducted in Bangladesh, 7 in India, and 3 in Nepal. No facial anthropometric data were found for populations from Afghanistan, Bhutan, Maldives, Pakistan, or Sri Lanka. Qualitative and quantitative parameters from the 12 studies were extracted.

CONCLUSION

There is a paucity of facial anthropometric data for South Asian populations. As South Asia has a significant prevalence of craniofacial anomalies and a burgeoning cosmetic facial surgery market, it is in the interest of both the craniofacial surgeon and the South Asian patient to collect baseline facial anthropometric data for this population.

Subclustering in Skeletal Class III Phenotypes of Different Ethnic Origins: A Systematic Review

OBJECTIVE

We aimed to systematically review articles investigating the efficiency of the clustering of skeletal class III malocclusion phenotypic subtypes of different ethnic origins as a diagnostic tool.

METHODS

The review protocol was structured in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and registered in Prospero (CRD42016053865). A survey of articles published up to March 2018 investigating the identification of different subgroups of skeletal class III malocclusion via cluster analysis was performed using 11 electronic databases. Any type of study design that addressed the classification of subclusters of class III malocclusion was considered. The Newcastle-Ottawa scale for cohort and cross-sectional (modified) studies was used for quality assessment.

RESULTS

The final selection included 7 studies that met all the criteria for eligibility (% overall agreement 0.889, free marginal kappa 0.778). All studies identified at least 3 different types of class III clusters (ranging from 3 to 14 clusters; the total variation of the prevalence of each cluster ranged from 0.2% to 36.0%). The main shared variables used to describe the more prevalent clusters in the studies included were vertical measurements (Ar-Go-Me: 117.51°-135.8°); sagittal measurements: maxilla (SNA: 75.3°-82.95°), mandible (SNB: 77.03°-85.0°). With regard to ethnicity, a mean number of 8.5 and 3.5 clusters of class III were retrieved for Asian and Caucasian population, respectively.

CONCLUSIONS

The total number of clusters identified varied from 3 to 14 to explain all the variability in the phenotype class III malocclusions. Although each extreme may be too simple or complex to facilitate an exhaustive but useful classification for clinical use, a classification system including 4 to 7 clusters may prove to be efficient for clinical use in conjunction with complete and meticulous subgrouping.

CLINICAL SIGNIFICANCE

The identification and description of a subclustering classification system may constitute an additional step toward more precise orthodontic/orthopedic diagnosis and treatment of skeletal class III malocclusion.

Prenatal ultrasonography of craniofacial abnormalities

Craniofacial abnormalities are common. It is important to examine the fetal face and skull Epub ahead of print during prenatal ultrasound examinations because abnormalities of these structures may indicate the presence of other, more subtle anomalies, syndromes, chromosomal abnormalities, or even rarer conditions, such as infections or metabolic disorders. The prenatal diagnosis of craniofacial abnormalities remains difficult, especially in the first trimester. A systematic approach to the fetal skull and face can increase the detection rate. When an abnormality is found, it is important to perform a detailed scan to determine its severity and search for additional abnormalities. The use of 3-/4-dimensional ultrasound may be useful in the assessment of cleft palate and craniosynostosis. Fetal magnetic resonance imaging can facilitate the evaluation of the palate, micrognathia, cranial sutures, brain, and other fetal structures. Invasive prenatal diagnostic techniques are indicated to exclude chromosomal abnormalities. Molecular analysis for some syndromes is feasible if the family history is suggestive.

A case of chronic granulomatous craniofacial osteomyelitis

We present the clinical image of a 56-year old male who presented with chronic multiple craniofacial discharging sinuses with lytic, sclerotic destruction of facial bones on radiology causing gross facial deformity. He remained undiagnosed for years. The diagnosis was clinched on histopathology as a chronic granulomatous osteomyelitis showing Actinomyces.

Fox proteins are modular competency factors for facial cartilage and tooth specification

Facial form depends on the precise positioning of cartilage, bone, and tooth fields in the embryonic pharyngeal arches. How complex signaling information is integrated to specify these cell types remains a mystery. We find that modular expression of Forkhead domain transcription factors (Fox proteins) in the zebrafish face arises through integration of Hh, Fgf, Bmp, Edn1 and Jagged-Notch pathways. Whereas loss of C-class Fox proteins results in reduced upper facial cartilages, loss of F-class Fox proteins results in distal jaw truncations and absent midline cartilages and teeth. We show that Fox proteins are required for Sox9a to promote chondrogenic gene expression. Fox proteins are sufficient in neural crest-derived cells for cartilage development, and neural crest-specific misexpression of Fox proteins expands the cartilage domain but inhibits bone. These results support a modular role for Fox proteins in establishing the competency of progenitors to form cartilage and teeth in the face.

The impact of dietary consistency on structural craniofacial components: Temporomandibular joint/condyle, condylar cartilage, alveolar bone and periodontal ligament. A systematic review and meta-analysis in experimental in vivo research

OBJECTIVE

The aim of this systematic review was to provide a comprehensive synthesis of available evidence evaluating the effect of dietary loading on temporomandibular joint/condyle, condylar cartilage, alveolar bone of the mandible and the periodontal ligament in healthy mice and rats.

DESIGN

Medline via PubMed, EMBASE and Open Grey databases were searched for published and unpublished literature. Search terms included "mandiblular condyle", "alveolar bone", "temporomandibular joint", "condylar cartilage", "periodontal ligament", "rat", "mice". After data extraction, risk of bias (SYRCLE) and reporting quality (ARRIVE) were assessed. Random effects meta-analyses were performed for the outcomes of interest where applicable.

RESULTS

A total of 33 relevant articles were considered in the systematic review, while only 6 studies were included in the quantitative synthesis. Risk of Bias in all studies was judged to be unclear to high overall, while reporting quality was suboptimal. Comparing soft to hard diet animals, significantly reduced anteroposterior condylar length (4 studies, weighted mean difference: -0.40 mm; 95% CI: -0.47, -0.32; p < 0.001) and width (4 studies, weighted mean difference: -0.043 mm; 95% CI: -0.51, -0.36; p < 0.001) were found in rats. Decreased anteroposterior condylar dimensions were detected for mice as well (2 studies, weighted mean difference: -0.049; 95% CI: -0.56, -0.43; p < 0.001).

CONCLUSIONS

Overall, there was strong evidence to suggest a significant effect of soft diet on reduced condylar dimensions in rodents; however, there is need for further high quality experimental studies to inform current knowledge on condylar cartilage, alveolar bone and periodontal ligament related outcomes.

Factors affecting subjective appearance evaluations among patients with congenital craniofacial conditions: An application of Cash's cognitive-behavioural model of body image development

Satisfaction with appearance is of central importance for psychological well-being and health. For individuals with an unusual appearance, such as congenital craniofacial anomalies (CFA), appearance evaluations could be especially important. However, few, if any papers have presented a comprehensive synthesis of the factors found to affect subjective satisfaction with appearance among children, adolescents, and adults born with a CFA. Further, only a handful of craniofacial studies have applied psychological theories or models to their findings, resulting in an overall lack of guidance for researchers in the field. This paper summarises the literature pertaining to satisfaction with appearance among those affected by CFAs, and examines the extent to which Cash's cognitive-behavioural model of body image development (2012) fits with this literature. Given the overlap between factors of interest in the field of CFAs, and in the area of body image more broadly, a closer collaboration between the two research fields is suggested.

Developmental constraint through negative pleiotropy in the zygomatic arch

BACKGROUND

Previous analysis suggested that the relative contribution of individual bones to regional skull lengths differ between inbred mouse strains. If the negative correlation of adjacent bone lengths is associated with genetic variation in a heterogeneous population, it would be an example of negative pleiotropy, which occurs when a genetic factor leads to opposite effects in two phenotypes. Confirming negative pleiotropy and determining its basis may reveal important information about the maintenance of overall skull integration and developmental constraint on skull morphology.

RESULTS

We identified negative correlations between the lengths of the frontal and parietal bones in the midline cranial vault as well as the zygomatic bone and zygomatic process of the maxilla, which contribute to the zygomatic arch. Through gene association mapping of a large heterogeneous population of Diversity Outbred (DO) mice, we identified a quantitative trait locus on chromosome 17 driving the antagonistic contribution of these two zygomatic arch bones to total zygomatic arch length. Candidate genes in this region were identified and real-time PCR of the maxillary processes of DO founder strain embryos indicated differences in the RNA expression levels for two of the candidate genes, Camkmt and Six2.

CONCLUSIONS

A genomic region underlying negative pleiotropy of two zygomatic arch bones was identified, which provides a mechanism for antagonism in component bone lengths while constraining overall zygomatic arch length. This type of mechanism may have led to variation in the contribution of individual bones to the zygomatic arch noted across mammals. Given that similar genetic and developmental mechanisms may underlie negative correlations in other parts of the skull, these results provide an important step toward understanding the developmental basis of evolutionary variation and constraint in skull morphology.

Use of computer-assisted design and manufacturing to localize dural venous sinuses during reconstructive surgery for craniosynostosis

OBJECTIVE

Cranial vault remodeling surgery for craniosynostosis carries the potential risk of dural venous sinus injury given the extensive bony exposure. Identification of the dural venous sinuses can be challenging in patients with craniosynostosis given the lack of accurate surface-localizing landmarks. Computer-aided design and manufacturing (CAD/CAM) has allowed surgeons to pre-operatively plan these complex procedures in an effort to increase reconstructive efficiency. An added benefit of this technology is the ability to intraoperatively map the dural venous sinuses based on pre-operative imaging. We utilized CAD/CAM technology to intraoperatively map the dural venous sinuses for patients undergoing reconstructive surgery for craniosynostosis in an effort to prevent sinus injury, increase operative efficiency, and enhance patient safety. Here, we describe our experience utilizing this intraoperative technology in pediatric patients with craniosynostosis.

METHODS

We retrospectively reviewed the charts of children undergoing reconstructive surgery for craniosynostosis using CAD/CAM surgical planning guides at our institution between 2012 and 2016. Data collected included the following: age, gender, type of craniosynostosis, estimated blood loss, sagittal sinus deviation from the sagittal suture, peri-operative outcomes, and hospital length of stay.

RESULTS

Thirty-two patients underwent reconstructive cranial surgery for craniosynostosis, with a median age of 11 months (range, 7-160). Types of synostosis included metopic (6), unicoronal (6), sagittal (15), lambdoid (1), and multiple suture (4). Sagittal sinus deviation from the sagittal suture was maximal in unicoronal synostosis patients (10.2 ± 0.9 mm). All patients tolerated surgery well, and there were no occurrences of sagittal sinus, transverse sinus, or torcular injury.

CONCLUSIONS

The use of CAD/CAM technology allows for accurate intraoperative dural venous sinus localization during reconstructive surgery for craniosynostosis and enhances operative efficiency and surgeon confidence while minimizing the risk of patient morbidity.

Calcium-containing scaffolds induce bone regeneration by regulating mesenchymal stem cell differentiation and migration

Background

Osteoinduction and subsequent bone formation rely on efficient mesenchymal stem cell (MSC) recruitment. It is also known that migration is induced by gradients of growth factors and cytokines. Degradation of Ca²⁺-containing biomaterials mimics the bone remodeling compartment producing a localized calcium-rich osteoinductive microenvironment. The aim of our study was to determine the effect of calcium sulfate (CaSO₄) on MSC migration. In addition, to evaluate the influence of CaSO₄ on MSC differentiation and the potential molecular mechanisms involved.

Methods

A circular calvarial bone defect (5 mm diameter) was created in the parietal bone of 35 Balb-C mice. We prepared and implanted a cell-free agarose/gelatin scaffold alone or in combination with different CaSO₄ concentrations into the bone defects. After 7 weeks, we determined the new bone regenerated by micro-CT and histological analysis. In vitro, we evaluated the CaSO₄ effects on MSC migration by both wound healing and agarose spot assays. Osteoblastic gene expression after BMP-2 and CaSO₄ treatment was also evaluated by qPCR.

Results

CaSO₄ increased MSC migration and bone formation in a concentration-dependent manner. Micro-CT analysis showed that the addition of CaSO₄ significantly enhanced bone regeneration compared to the scaffold alone. The histological evaluation confirmed an increased number of endogenous cells recruited into the cell-free CaSO₄-containing scaffolds. Furthermore, MSC migration in vitro and active AKT levels were attenuated when CaSO₄ and BMP-2 were in combination. Addition of LY294002 and Wortmannin abrogated the CaSO₄ effects on MSC migration.

Conclusions

Specific CaSO₄ concentrations induce bone regeneration of calvarial defects in part by acting on the host’s undifferentiated MSCs and promoting their migration. Progenitor cell recruitment is followed by a gradual increment in osteoblast gene expression. Moreover, CaSO₄ regulates BMP-2-induced MSC migration by differentially activating the PI3K/AKT pathway. Altogether, these results suggest that CaSO₄ scaffolds could have potential applications for bone regeneration.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0713-0) contains supplementary material, which is available to authorized users.

Novel functions of LHX2 and PAX6 in the developing telencephalon revealed upon combined loss of both genes

Patterning of the telencephalic neuroepithelium is a tightly regulated process controlled by transcription factors and signalling molecules. The cortical primordium is flanked by two signalling centres, the hem medially, and the antihem laterally. The hem induces the formation of the hippocampus in adjacent neuroepithelium. Therefore, the position of the hem defines the position of the hippocampus in the brain. The antihem is positioned at the boundary between the dorsal and ventral telencephalon and proposed to provide patterning cues during development.

LIM-homeodomain (LIM-HD) transcription factor LHX2 suppresses both hem and antihem fate in the cortical neuroepithelium. Upon loss of Lhx2, medial cortical neuroepithelium is transformed into hem, whereas lateral cortical neuroepithelium is transformed into antihem. Here, we show that transcription factor PAX6, known to regulate patterning of the lateral telencephalon, restricts this tissue from transforming into hem upon loss of Lhx2. When Lhx2 and Pax6 are both deleted, the cortical hem expands to occupy almost the complete extent of the cortical primordium, indicating that both factors act to suppress hem fate in the lateral telencephalon. Furthermore, the shift in the pallial-subpallial boundary and absence of the antihem, observed in the Pax6 mutant, are both restored in the Lhx2; Pax6 double mutant.

Together, these results not only reveal a novel function for LHX2 in regulating dorsoventral patterning in the telencephalon, but also identify PAX6 as a fundamental regulator of where the hem can form, and therefore implicate this molecule as a determinant of hippocampal positioning.

Differences in maxillomandibular morphology among patients with mucopolysaccharidoses I, II, III, IV and VI: a retrospective MRI study

OBJECTIVE

The aims of this study were to analyze the maxillomandibular morphology of patients with mucopolysaccharidosis (MPS) type I, II, III, IVa and VI and to evaluate the craniofacial effect of hematopoietic stem cell transplantation (HCST) in MPS I.

MATERIALS AND METHODS

One hundred head magnetic resonance images were retrospectively analyzed from 41 MPS and 27 control individuals. The width, height and length of the maxilla and mandible were plotted against age and the means of controls, MPS I, MPS II and MPS III were statistically compared. To determine the effect of HSCT in MPS I, jaw morphology was compared between MPS I patients with full donor chimerism versus patients with mixed/no donor chimerism.

RESULTS

Maxillary dimensions were not statistically different between the MPS types. The height and length of the mandible were clearly smaller in MPS I as compared to those in controls, MPS II and MPS III. This was associated with progressive resorption of the mandibular condyles in MPS I, which was also observed in MPS II and VI, but not in MPS III or IVa. Whereas the success of HCST did not affect these changes, mandibular width was significantly smaller in MPS I individuals with full donor chimerism.

CONCLUSION

MPS I individuals have a smaller mandible as compared to control, MPS II and MPS III individuals due to progressive condylar degeneration. These abnormalities are also evident following successful HSCT.

CLINICAL RELEVANCE

Clinicians should be aware of specific differences in mandibular morphology and condylar involvement among the MPS subtypes.

Robinow Syndrome and Fusion of Primary Teeth

Managing patients with rare genetic disorders is a challenge that dentists face often. Robinow syndrome (RS) is one such rare genetic disorder with <200 cases reported worldwide. RS demonstrates multiple craniofacial abnormalities and orodental disorders, which need to be taken into consideration by a dental practitioner while rendering dental care.

Genetic analysis of IRF6, a gene involved in craniofacial midline formation, in relation to pituitary and facial morphology of patients with idiopathic growth hormone deficiency

INTRODUCTION

Growth hormone is secreted by the pituitary gland, which forms part of the craniofacial midline. IRF6 encodes a transcription factor involved in the development of the craniofacial midline and mutations in IRF6 are known to disturb craniofacial development. Craniofacial and pituitary development are closely related. After whole exome sequencing revealed a new mutation in IRF6 in a family with Idiopathic Growth Hormone Deficiency (IGHD), we screened the remainder of our IGHD cohort for mutations in this gene and related their genotypes to pituitary and craniofacial morphology.

MATERIALS AND METHODS

We sequenced all coding exons and exon-intron boundaries of IRF6 in 81 patients with IGHD. We performed a multiplex ligation-dependent probe amplification (MLPA) in order to exclude copy number variations in IRF6. We analyzed facial measurements taken from standardized digital pictures of 48 patients.

RESULTS

We found two new variants and eleven polymorphisms. Apart from the new mutation found in the index family (p.Arg233Cys), we found one other new heterozygous missense mutation in IRF6 (Pro456Ser). p.Arg233Cys was reported as extremely rare in exome databases (1 allele out of 120.852 alleles sequenced), strictly conserved among species and was predicted deleterious by all variant predictor programs. Pro456Ser was predicted to be benign. MLPA did not reveal any exon deletions or duplications in any of the patients.

CONCLUSION

This is the first report of IRF6 analysis in an IGHD cohort. We found one new mutation which, based on in silico analysis, could be of functional relevance. However, we did not find any mutations in the other patients. Therefore, we conclude that IRF6 defects are rare in IGHD patients and further research should focus on new candidate genes.

Natural history of cranial fibrous dysplasia revealed during long-term follow-up: Case report and literature review

BACKGROUND

Fibrous dysplasia (FD) is a rare developmental disease characterized by the replacement of bone marrow with proliferating fibro-osseous tissue. There exist three forms of FD-monostotic, polyostotic, and that associated with McCune-Albright syndrome. The disease can present in different locations and with a variety of symptoms. One of the more common locations of FD occurrence is the craniofacial region. Treatment of asymptomatic FD often involves conservative management with serial imaging. Medical management with bisphosphonates is an option, though long-term efficacy data are lacking. Surgical resection is usually reserved for very large or symptomatic lesions.

CASE DESCRIPTION

We discuss the most unusual case of a 52-year-old male found to have a left pterional mass while being worked up for sinus headaches. The patient elected to follow this lesion conservatively, and imaging several years later showed obvious growth which accelerated in the last 4 years during an 18-year observational period. He ultimately underwent successful resection of an extradural and intradural FD.

CONCLUSIONS

The significant growth potential of these lesions was revealed in this patient, in whom conservative management had been adopted. Despite optimal surgical resection and outcome in this case, the importance of surveillance imaging and perhaps earlier intervention cannot be underestimated when managing cranial FD.

Validation of a new three-dimensional imaging system using comparative craniofacial anthropometry

Background

The aim of this study is to validate a new three-dimensional craniofacial stereophotogrammetry imaging system (3dMDface) through comparison with manual facial surface anthropometry. The null hypothesis was that there is no difference between craniofacial measurements using anthropometry vs. the 3dMDface system.

Methods

Facial images using the new 3dMDface system were taken from six randomly selected subjects, sitting in natural head position, on six separate occasions each 1 week apart, repeated twice at each sitting. Exclusion criteria were excess facial hair, facial piercings and undergoing current dentofacial treatment. 3dMDvultus software allowed facial landmarks to be marked and measurements recorded. The same measurements were taken using manual anthropometry, using soluble eyeliner to pinpoint landmarks, and sliding and spreading callipers and measuring tape to measure distances. The setting for the investigation was a dental teaching hospital and regional (secondary and tertiary care) cleft centre. The main outcome measure was comparison of the craniofacial measurements using the two aforementioned techniques.

Results

The results showed good agreement between craniofacial measurements using the 3dMDface system compared with manual anthropometry. For all measurements, except chin height and labial fissure width, there was a greater variability with the manual method compared to 3D assessment. Overall, there was a significantly greater variability in manual compared with 3D assessments (p < 0.02).

Conclusions

The 3dMDface system is validated for craniofacial measurements.

Genome-wide analysis of facial skeletal regionalization in zebrafish

Patterning of the facial skeleton involves the precise deployment of thousands of genes in distinct regions of the pharyngeal arches. Despite the significance for craniofacial development, how genetic programs drive this regionalization remains incompletely understood. Here we use combinatorial labeling of zebrafish cranial neural crest-derived cells (CNCCs) to define global gene expression along the dorsoventral axis of the developing arches. Intersection of region-specific transcriptomes with expression changes in response to signaling perturbations demonstrates complex roles for Endothelin 1 (Edn1) signaling in the intermediate joint-forming region, yet a surprisingly minor role in ventralmost regions. Analysis of co-variance across multiple sequencing experiments further reveals clusters of co-regulated genes, with in situ hybridization confirming the domain-specific expression of novel genes. We then created loss-of-function alleles for 12 genes and uncovered antagonistic functions of two new Edn1 targets, follistatin a (fsta) and emx2, in regulating cartilaginous joints in the hyoid arch. Our unbiased discovery and functional analysis of genes with regional expression in zebrafish arch CNCCs reveals complex regulation by Edn1 and points to novel candidates for craniofacial disorders.

Percutaneous sclerotherapy of pediatric lymphatic malformations: experience and outcomes according to the agent used

OBJECTIVE

Analyze statistically the success, number of sessions required and complete duration of treatment of agents used in pediatric percutaneous sclerotherapy of lymphatic malformations, to determine the most suitable.

MATERIAL AND METHODS

Retrospective study based on outcomes from percutaneous sclerotherapy performed on lymphatic malformations of 56 patients conducted by pediatric interventional radiologist for 14 years. As first approach, the procedure consists of ultrasound-guided introduction of sclerosing agent. Sessions were repeated until clinical resolution. Success, number of sessions and the duration of treatment were recorded and statistical treatment of the data was performed to obtain further conclusions.

RESULTS

Lost patients in follow up and other minority agents used were excluded from the data. Eventually, 52 patients treated with OK432 (n=29), Ethibloc (n=5) and combination therapy (n=18) were included. The average number of sessions and duration in months of treatment was respectively 2.38 and 8.6 for OK432, 1.4 and 5.6 for Ethibloc, and 1.83 and 2.30 for dual therapy. The results were statistically significant for the difference in duration between OK432 and dual therapy. Also, 60-80% of patients reached proper results related to success, but the difference was no significant among the agents. Other demographic and anatomical variables were analyzed, not showing any difference, which supports the homogeneity of the sample.

CONCLUSIONS

Despite of no significant difference in success and number of sessions among agents, longer duration of treatment with OK432 than dual therapy could mean greater health costs and probably greater disturb for patient and family.

The Cyprinodon variegatus genome reveals gene expression changes underlying differences in skull morphology among closely related species

BACKGROUND

Understanding the genetic and developmental origins of phenotypic novelty is central to the study of biological diversity. In this study we identify modifications to the expression of genes at four developmental stages that may underlie jaw morphological differences among three closely related species of pupfish (genus Cyprinodon) from San Salvador Island, Bahamas. Pupfishes on San Salvador Island are trophically differentiated and include two endemic species that have evolved jaw morphologies unlike that of any other species in the genus Cyprinodon.

RESULTS

We find that gene expression differs significantly across recently diverged species of pupfish. Genes such as Bmp4 and calmodulin, previously implicated in jaw diversification in African cichlid fishes and Galapagos finches, were not found to be differentially expressed among species of pupfish. Instead we find multiple growth factors and cytokine/chemokine genes to be differentially expressed among these pupfish taxa. These include both genes and pathways known to affect craniofacial development, such as Wnt signaling, as well as novel genes and pathways not previously implicated in craniofacial development. These data highlight both shared and potentially unique sources of jaw diversity in pupfish and those identified in other evolutionary model systems such as Galapagos finches and African cichlids.

CONCLUSIONS

We identify modifications to the expression of genes involved in Wnt signaling, Igf signaling, and the inflammation response as promising avenues for future research. Our project provides insight into the magnitude of gene expression changes contributing to the evolution of morphological novelties, such as jaw structure, in recently diverged pupfish species.

RUNX2 repeat variation does not drive craniofacial diversity in marsupials

BACKGROUND

Runt-related transcription factor 2 (RUNX2) is a transcription factor essential for skeletal development. Variation within the RUNX2 polyglutamine / polyalanine (QA) repeat is correlated with facial length within orders of placental mammals and is suggested to be a major driver of craniofacial diversity. However, it is not known if this correlation exists outside of the placental mammals.

RESULTS

Here we examined the correlation between the RUNX2 QA repeat ratio and facial length in the naturally evolving sister group to the placental mammals, the marsupials. Marsupials have a diverse range of facial lengths similar to that seen in placental mammals. Despite their diversity there was almost no variation seen in the RUNX2 QA repeat across individuals spanning the entire marsupial infraclass. The extreme conservation of the marsupial RUNX2 QA repeat indicates it is under strong purifying selection. Despite this, we observed an unexpectedly high level of repeat purity.

CONCLUSIONS

Unlike within orders of placental mammals, RUNX2 repeat variation cannot drive craniofacial diversity in marsupials. We propose conservation of the marsupial RUNX2 QA repeat is driven by the constraint of accelerated ossification of the anterior skeleton to facilitate life in the pouch. Thus, marsupials must utilize alternate pathways to placental mammals to drive craniofacial evolution.

Negative regulation of endothelin signaling by SIX1 is required for proper maxillary development

Jaw morphogenesis is a complex event mediated by inductive signals that establish and maintain the distinct developmental domains required for formation of hinged jaws, the defining feature of gnathostomes. The mandibular portion of pharyngeal arch 1 is patterned dorsally by Jagged-Notch signaling and ventrally by endothelin receptor A (EDNRA) signaling. Loss of EDNRA signaling disrupts normal ventral gene expression, the result of which is homeotic transformation of the mandible into a maxilla-like structure. However, loss of Jagged-Notch signaling does not result in significant changes in maxillary development. Here we show in mouse that the transcription factor SIX1 regulates dorsal arch development not only by inducing dorsal Jag1 expression but also by inhibiting endothelin 1 (Edn1) expression in the pharyngeal endoderm of the dorsal arch, thus preventing dorsal EDNRA signaling. In the absence of SIX1, but not JAG1, aberrant EDNRA signaling in the dorsal domain results in partial duplication of the mandible. Together, our results illustrate that SIX1 is the central mediator of dorsal mandibular arch identity, thus ensuring separation of bone development between the upper and lower jaws.

Cilia-dependent GLI processing in neural crest cells is required for tongue development

Ciliopathies are a class of diseases caused by the loss of a ubiquitous, microtubule-based organelle called a primary cilium. Ciliopathies commonly result in defective development of the craniofacial complex, causing midfacial defects, craniosynostosis, micrognathia and aglossia. Herein, we explored how the conditional loss of primary cilia on neural crest cells (Kif3a^f/f;Wnt1-Cre) generated aglossia. On a cellular level, our data revealed that aglossia in Kif3a^f/f;Wnt1-Cre embryos was due to a loss of mesoderm-derived muscle precursors migrating into and surviving in the tongue anlage. To determine the molecular basis for this phenotype, we performed RNA-seq, in situ hybridization, qPCR and Western blot analyses. We found that transduction of the Sonic hedgehog (Shh) pathway, rather than other pathways previously implicated in tongue development, was aberrant in Kif3a^f/f;Wnt1-Cre embryos. Despite increased production of full-length GLI2 and GLI3 isoforms, previously identified GLI targets important for mandibular and glossal development (Foxf1, Foxf2, Foxd1 and Foxd2) were transcriptionally downregulated in Kif3a^f/f;Wnt1-Cre embryos. Genetic removal of GLI activator (GLIA) isoforms in neural crest cells recapitulated the aglossia phenotype and downregulated Fox gene expression. Genetic addition of GLIA isoforms in neural crest cells partially rescued the aglossia phenotype and Fox gene expression in Kif3a^f/f;Wnt1-Cre embryos. Together, our data suggested that glossal development requires primary cilia-dependent GLIA activity in neural crest cells. Furthermore, these data, in conjunction with our previous work, suggested prominence specific roles for GLI isoforms; with development of the frontonasal prominence relying heavily on the repressor isoform and the development of the mandibular prominence/tongue relying heavily on the activator isoform.

Craniofacial characteristics in the sagittal dimension: A cephalometric study in Lebanese young adults

OBJECTIVES

The purpose of this study was to assess the sagittal cephalometric characteristics of young adult Lebanese individuals and assess gender-related differences.

MATERIALS AND METHODS

Conventional lateral cephalograms were obtained from 117 subjects. Eight linear/angular measurements combining sagittal parameters selected form McNamara and Steiner analyses were recorded. Paired t-test was applied to evaluate differences between genders and skeletal classes.

RESULTS

Males showed significantly greater maxillary and mandibular length than females. ANB was larger in females with no significant differences in SNA values indicating that Lebanese females tend to have a more convex profile than their male counterparts. Subjects with skeletal Class III tended to have a retrognathic maxilla rather than a prognathic mandible.

CONCLUSIONS

Sexual dimorphism is evident in young Lebanese adults relative to linear skeletal dimensions regardless of the skeletal class. Skeletal determinants of Class III malocclusions may be different from those of other population groups.