Craniosynostosis update 1987

Crouzon Syndrome Spanning Three Generations: Advances in the Treatment of Syndromic Midface Deficiency

Background

Crouzon syndrome is an autosomal dominant genetic disorder characterized by craniosynostosis, midface retrusion, and exophthalmos. Over the past century, the treatment of craniofacial disorders like Crouzon syndrome has evolved significantly.

Methods

An institutional review board-approved retrospective study was conducted to ascertain the treatment of three individuals with Crouzon syndrome from one family, complemented with a series of literature searches to examine the evolution of craniofacial surgical history.

Results

Dr. David Williams Cheever developed the Le Fort I level to correct malocclusion, maxillomandibular malformations, and midface hypoplasia. Later, Dr. Paul Tessier introduced the Le Fort II and III osteotomies to treat syndromic midface hypoplasia. In 1978, Dr. Fernando Ortiz-Monasterio and Dr. Antonio Fuente del Campo published the first series of monobloc osteotomies, allowing for simultaneous correction of supraorbital and midface malformations, although complicated by blood loss and high infection rates. In 1992, McCarthy et al introduced the concept of gradual distraction to the craniofacial skeleton. In 1995, Polley et al performed the first monobloc advancement using external distraction. Subsequently, in 1997, Polley and Figueroa introduced a rigid external distraction device with multiple vector control to manage severe cleft maxillary hypoplasia. The technique was further refined and applied to treat syndromic midface hypoplasia, reducing complication rates. Currently, either external or internal distraction approaches are used to safely treat this challenging group of patients.

Conclusion

The treatment of syndromic midface deficiency has significantly evolved over the past 50 years, as evidenced by this report of three generations of Crouzon syndrome.

From mesenchymal niches to engineered in vitro model systems: Exploring and exploiting biomechanical regulation of vertebrate hedgehog signalling

Tissue patterning is the result of complex interactions between transcriptional programs and various mechanical cues that modulate cell behaviour and drive morphogenesis. Vertebrate Hedgehog signalling plays key roles in embryogenesis and adult tissue homeostasis, and is central to skeletal development and the osteogenic differentiation of mesenchymal stem cells. The expression of several components of the Hedgehog signalling pathway have been reported to be mechanically regulated in mesodermal tissue patterning and osteogenic differentiation in response to external stimulation. Since a number of bone developmental defects and skeletal diseases, such as osteoporosis, are directly linked to aberrant Hedgehog signalling, a better knowledge of the regulation of Hedgehog signalling in the mechanosensitive bone marrow-residing mesenchymal stromal cells will present novel avenues for modelling these diseases and uncover novel opportunities for extracellular matrix-targeted therapies. In this review, we present a brief overview of the key molecular players involved in Hedgehog signalling and the basic concepts of mechanobiology, with a focus on bone development and regeneration. We also highlight the correlation between the activation of the Hedgehog signalling pathway in response to mechanical cues and osteogenesis in bone marrow-derived mesenchymal stromal cells. Finally, we propose different tissue engineering strategies to apply the expanding knowledge of 3D material-cell interactions in the modulation of Hedgehog signalling in vitro for fundamental and translational research applications.

Craniofacial Malformations as Fundamental Diagnostic Tools in Syndromic Entities

Background: A long list of syndromic entities can be diagnosed immediately through scrutinizing the clinical phenotype of the craniofacial features. The latter should be assisted via proper radiological interpretations. Patients and Methods: Different children aged from 1 month to 12 years were referred to our departments seeking orthopedic advice. Primarily, all received variable false diagnoses in other institutes. Two unrelated boys of one month and 12 months were falsely diagnosed as having positional plagiocephaly associated with contractures of idiopathic origin. Two unrelated boys of 14 months and 2 years were diagnosed with pseudo-hydrocephalus and non-specific syndrome, and were referred to explore their skeletal development. Two unrelated girls of 4 years old and 12 years old presented with multiple contractures were referred because of progressive scoliosis. A 4-year-old girl was referred with a false provisional diagnosis of facial diplegia. All children underwent detailed clinical, radiological and tomographic phenotypic characterizations and genetic testing, respectively. Results: Idaho syndrome (craniosynostosis associated with multiple dislocations) was the final diagnosis in the two unrelated boys with plagiocephaly and multiple contractures. Two children falsely diagnosed with pseudo-hydrocephalus and non-specific syndrome, were diagnosed with Silver–Russell syndrome (RSS). Contractural arachnodactyly Beals (CAB) was confirmed as the definitive diagnosis in the two unrelated girls with progressive scoliosis and multiple contractures. Parry–Romberg syndrome (PRS) associated with congenital lumbar kyphosis was the final diagnosis of the girl with the diagnosis of facial diplegia. Hypomethylation of ICR1 was confirmed in the RSS patients. Whole exome sequencing (WES) revealed a heterozygous mutation in the PRS patients. WES and array-CGH showed that no relevant variants or copy number variations (CNV) were identified in the CAB patients. Conclusions: On the one hand, newborn children can manifest diverse forms of abnormal craniofacial features, which are usually associated with either major or minor dysmorphic stigmata. A cleft lip/ palate is a major craniofacial malformation, and frontal bossing or a disproportionate craniofacial contour can be falsely considered as a transient plagiocephaly, which is spontaneously resolved by time. On the other hand, many physicians fall into the problem of deeming a countless number of diseases, such as contractures, as an idiopathic or non-specific syndrome. The latter stems from limited clinical experience. Therefore, failing to establish between the onset of the deformity and other inexplicit abnormal features that the patient or their immediate families or relatives carry is the final outcome. In this study, we used, for the first time, a reconstruction CT scan to further delineate the congenital disruption of the craniofacial anatomy and the other skeletal malformation complex.

Relating Metopic Craniosynostosis Severity to Intracranial Pressure

PURPOSE

A subset of patients with metopic craniosynostosis are noted to have elevated intracranial pressure (ICP). However, it is not known if the propensity for elevated ICP is influenced by the severity of metopic cranial dysmorphology.

METHODS

Children with nonsyndromic single-suture metopic synostosis were prospectively enrolled and underwent optical coherence tomography to measure optic nerve head morphology. Preoperative head computed tomography scans were assessed for endocranial bifrontal angle as well as scaled metopic synostosis severity score (MSS) and cranial morphology deviation score determined by CranioRate, an automated severity classifier.

RESULTS

Forty-seven subjects were enrolled between 2014 and 2019, at an average age of 8.5 months at preoperative computed tomography and 11.8 months at index procedure. Fourteen patients (29.7%) had elevated optical coherence tomography parameters suggestive of elevated ICP at the time of surgery. Ten patients (21.3%) had been diagnosed with developmental delay, eight of whom demonstrated elevated ICP. There were no significant associations between measures of metopic severity and ICP. Metopic synostosis severity score and endocranial bifrontal angle were inversely correlated, as expected (r=-0.545, P<0.001). A negative correlation was noted between MSS and formally diagnosed developmental delay (r=-0.387, P=0.008). Likewise, negative correlations between age at procedure and both MSS and cranial morphology deviation was observed (r=-0.573, P<0.001 and r=-0.312, P=0.025, respectively).

CONCLUSIONS

Increased metopic severity was not associated with elevated ICP at the time of surgery. Patients who underwent later surgical correction showed milder phenotypic dysmorphology with an increased incidence of developmental delay.

Morphology of the Occipital Bones and Foramen Magnum Resulting From Premature Minor Suture Fusion in Crouzon Syndrome

To identify skull-base growth patterns in Crouzon syndrome, we hypothesized premature minor suture fusion restricts occipital bone development, secondarily limiting foramen magnum expansion.

Skull-base suture closure degree and cephalometric measurements were retrospectively studied using preoperative computed tomography (CT) scans and multiple linear regression analysis.

Evaluation of multi-institutional CT images and 3D reconstructions from Wake Forest's Craniofacial Imaging Database (WFCID).

Sixty preoperative patients with Crouzon syndrome under 12 years-old were selected from WFCID. The control group included 60 age- and sex-matched patients without craniosynostosis or prior craniofacial surgery.

None.

2D and 3D cephalometric measurements.

3D volumetric evaluation of the basioccipital, exo-occipital, and supraoccipital bones revealed decreased growth in Crouzon syndrome, attributed solely to premature minor suture fusion. Spheno-occipital (β = -398.75; P < .05) and petrous-occipital (β = -727.5; P < .001) suture fusion reduced growth of the basioccipital bone; lambdoid suture (β = -14 723.1; P < .001) and occipitomastoid synchondrosis (β = -16 419.3; P < .001) fusion reduced growth of the supraoccipital bone; and petrous-occipital suture (β = -673.3; P < .001), anterior intraoccipital synchondrosis (β = -368.47; P < .05), and posterior intraoccipital synchondrosis (β = -6261.42; P < .01) fusion reduced growth of the exo-occipital bone. Foramen magnum morphology is restricted in Crouzon syndrome but not directly caused by early suture fusion.

Premature minor suture fusion restricts the volume of developing occipital bones providing a plausible mechanism for observed foramen magnum anomalies.

New method for quantification of the relative severity and (a)symmetry of isolated metopic synostosis

Trigonocephaly is the result of premature fusion of the metopic suture and its severity can vary widely. However, there is no gold standard for quantification of the severity. This study was performed to quantify severity using the Utrecht Cranial Shape Quantifier (UCSQ) and to assess forehead symmetry. Nineteen preoperative non-syndromic trigonocephaly patients (age ≤1 year) were included for the analysis of severity and symmetry. Severity according to the UCSQ was based on the following combined variables: forehead width and relative skull elongation. The UCSQ was compared to the most established quantification methods. A high correlation was found between the UCSQ and visual score (r=0.71). Moderate to negligible correlation was found between the UCSQ and frontal angle, binocular distance, inter-ocular distance, and frontal stenosis. Additionally, correlation between the visual score and these established quantification methods was negligible. Assessment of the frontal peak (a)symmetry (ratio of right to left triangle area in the curve) showed a mean right versus left triangle area ratio of 1.4 (range 0.9-2.4). The results suggest that the UCSQ is appropriate for the quantification of severity based on the high correlation with clinical judgement. Furthermore, a larger triangle area right than left was unexpectedly found, indicating forehead asymmetry.

New method for quantification of severity of isolated scaphocephaly linked to intracranial volume

PURPOSE

The aim is to implement Utrecht Cranial Shape Quantificator (UCSQ) for quantification of severity of scaphocephaly and compare UCSQ with the most used quantification method, cranial index (CI). Additionally, severity is linked to intracranial volume (ICV).

METHODS

Sinusoid curves of 21 pre-operative children (age < 2 years) with isolated scaphocephaly were created. Variables of UCSQ (width of skull and maximum occiput and forehead) were combined to determine severity. CI was calculated. Three raters performed visual scoring for clinical severity (rating of 6 items; total score of 12 represents most severe form). Pearson's correlation test was used for correlation between UCSQ and visual score and between both CIs. ICV was calculated using OsiriX. ICV was compared to normative values and correlated to severity.

RESULTS

Mean UCSQ was 22.00 (2.00-42.00). Mean traditional CI was 66.01 (57.36-78.58), and mean visual score was 9.1 (7-12). Correlations between both traditional CI and CI of UCSQ and overall visual scores were moderate and high (r = - 0.59; p = 0.005 vs. r = - 0.81; p < 0.000). Mean ICV was 910 mL (671-1303), and ICV varied from decreased to increased compared to normative values. Negligible correlation was found between ICV and UCSQ (r = 0.26; p > 0.05) and between ICV and CI and visual score (r = - 0.30; p > 0.05 and r = 0.17; p > 0.05, respectively).

CONCLUSION

Our current advice is to use traditional CI in clinical practice; it is easy to use and minimally invasive. However, UCSQ is more precise and objective and captures whole skull shape. Therefore, UCSQ is preferable for research. Additionally, more severe scaphocephaly does not result in more deviant skull volumes.

New diagnostic approach of the different types of isolated craniosynostosis

In this study, we diagnose skull shape deformities by analysing sinusoid curves obtained from standardized computed tomography (CT) slices of the skull for the common craniosynostoses (scaphocephaly, brachycephaly, trigonocephaly, right- and left-sided anterior plagiocephaly). Scaphocephaly has a high forehead peak and low troughs, in contrast to brachycephaly. Anterior plagiocephaly has asymmetry and shifting of the forehead peak. Trigonocephaly has a high and narrow frontal peak. Control patients have a symmetrical skull shape with low troughs and a high and broader frontal peak. Firstly, we included 5 children of every group of the common craniosynostoses and additionally 5 controls for extraction and calculation of characteristics. A diagnostic flowchart was developed. Secondly, we included a total of 51 craniosynostosis patients to validate the flowchart. All patients were correctly classified using the flowchart.Conclusion: Our study proposes and implements a new diagnostic approach of craniosynostosis. We describe a diagnostic flowchart based on specific characteristics for every type of craniosynostosis related to the specific skull deformities and control patients. All variables are expressed in number; therefore, we are able to use these variables in future research to quantify the different types of craniosynostosis. What is Known: • Premature fusion of one or more cranial sutures results in a specific cranial shape. • Clinical diagnosis is relatively simple; however, objective diagnosis based on distinctive values is difficult. What is New: • Using external landmarks and curve analysis, distinctive variables, and values for every type of craniosynostosis related to the specific skull deformities were determined and used to create a diagnostic flowchart for diagnosis. • Validation with an independent data set of 51 patients showed that all patients were correctly classified.

Craniosynostosis: To Study the Spectrum and Outcome of Surgical Intervention at a Tertiary Referral Institute in India

Aims and Objectives:

This study aimed to analyze the spectrum and surgical outcome of cases of craniosynostosis operated at a tertiary referral institute in India

Design:

This was a cross-sectional study.

Materials and Methods:

We retrospectively examined 60 cases of craniosynostosis operated at our institute from 2008 to 2014 (with a minimum follow-up of 2 years). Data was collected including name, age, gender, involved sutures, other medical conditions, whether syndromic craniosynostosis or not, whether symptoms and signs of intracranial hypertension were present or not, associated findings on magnetic resonance imaging of brain and cervico-medullary junction, type of surgery performed, age at which surgery was performed, perioperative complications (if any), and findings on follow-up. To be able to analyze the surgical results, we used the seven category classification system used by Sloan et al.

Results:

Craniosynostosis affected more men than women. The incidence of syndromic craniosynostosis was 11.67%. Mean age at first surgery was 3.85 years. Chiari malformation was present in 80% of the Crouzon’s syndrome cases, 62.5% of the oxycephaly cases, and 4.44% of the non-syndromic, non-oxycephaly cases. Intracranial hypertension was present in 80% of the Crouzon’s syndrome cases, 75% of the oxycephaly cases, and 6.67% of the non-syndromic, non-oxycephaly cases. Perioperative complications were present in 42.86% of the syndromic craniosynostosis cases, 50% of the oxycephaly cases, and 15.56% of the non-syndromic, non-oxycephaly cases. Compromised overall correction was present in 4 of 7 cases of syndromic craniosynostosis, 3 of 8 cases of oxycephaly, and 2 of 45 cases of non-syndromic, non-oxycephaly group.

Conclusion:

The study highlights the importance of educating the masses so that cases of craniosynostosis present early. The incidence of Chiari malformation, intracranial hypertension, and perioperative complications was significantly higher in the syndromic craniosynostosis and oxycephaly groups than in single-suture craniosynostosis. The best surgical outcome and the least perioperative complications were seen in the trigonocephaly group. Compromised overall correction and reoperations were more common in the syndromic and complex craniosynostosis groups than in single-suture craniosynostosis.

Craniofacial Sutural Pattern and Surgical Management in Patients With Different Degrees of Trigonocephaly Severity

The aim of this study was to identify quantitative tools to classify the severity of trigonocephaly to guide surgical management and predict outcome.

METHODS

We reviewed high-resolution computed tomography images of 59 patients with metopic synostosis. We assessed the craniofacial sutural pattern as well as interfrontal and metopic angles, and we related the frontal angulation degree with the sutural pattern, the surgical management, and clinical outcome.

RESULTS

We identified 3 groups according to the severity of trigonocephaly. No difference was found between the sutural pattern of nasion complex and severity, whereas the closure of zygomatic maxillary sutures increased with the severity degree (P < 0.05). The operative management was related to the severity degree (P < 0.001) and to the reduced age (P = 0.009).

CONCLUSIONS

Interfrontal and metopic angles are complementary measurements to evaluate with high accuracy the degree of frontal angulation. In preoperative assessment, they may guide surgery decision in particular when the choice is not straightforward.

Patient with Crouzon Syndrome Treated with Modified Le Fort III Osteotomy without Previous Orthodontic Treatment: Case Report and a Review of the Literature

Crouzon syndrome is the most common type of craniofacial dysostosis anomaly which presents a great challenge for clinicians since birth. Multiple synostoses in the sutures of the cranial base in this syndrome result in the hypoplasia of the midface, shallow orbits, a short nasal dorsum, maxillary hypoplasia, and, in severe cases, obstruction of the upper airways. Apart from esthetic and functional problems, these patients suffer from various psychological problems which mandate correction of midface deformities at younger ages. The aim of this report is to describe the case of a 26-year-old female patient with Crouzon syndrome displaying severe midface hypoplasia and proptosis with no history of orthodontic treatment, who was treated with modified Le Fort III osteotomy with a coronal and intraoral approach without periocular incisions.

Syndromic and Systemic Diagnoses Associated With Isolated Sagittal Synostosis

Reports of systemic associations in patients with Isolated Sagittal Synostosis (ISS) are sparse. Craniofacial surgeons, and other providers, should be aware that a significant proportion of patients with ISS may have syndromic or systemic involvement. This study investigates the incidence of systemic disease and syndromic diagnosis in a cohort of patients presenting with ISS (ie, patients with sagittal synostosis without other sutural involvement).

METHODS

This study consists of a retrospective review of patients diagnosed with ISS between 2007 and 2017 at a single institution. Patients were divided according to onset (early <1 year, late >1 year) of ISS. Patient notes were examined for congenital anomalies, systemic conditions, and molecular testing. Only patients with isolated sagittal fusion-meaning, patients with sagittal synostosis and no other sutural involvement-were included.

RESULTS

Three hundred seventy-seven patients met the inclusion criteria: systemic conditions were identified in 188/377 (50%) of them. One hundred sixty-one patients with early onset (Group A), and 216 patients with late onset ISS (Group B) were identified. Systemic involvement was identified in 38% of Group A and 60% of Group B, which was statistically significant (P < 0.001). Forty-eight of 377 (13%) of patients had a syndromic diagnosis, and 79% of these were confirmed via genetic testing. Thirty-five percent of patients were diagnosed with central nervous system anomalies and 16% had craniofacial anomalies.

CONCLUSIONS

Nearly 50% of the patients initially diagnosed with ISS were found to have some form of systemic involvement. This supports affording full pediatric and genetic evaluation with molecular testing to these children.

Craniosynostosis affects the majority of mucopolysaccharidosis patients and can contribute to increased intracranial pressure

BACKGROUND

The mucopolysaccharidoses are multisystem lysosomal storage diseases characterized by extensive skeletal deformities, including skull abnormalities. The objective of this study was to determine the incidence of craniosynostosis in the different mucopolysaccharidosis (MPS) types and its clinical consequences.

METHODS

In a prospective cohort study spanning 10 years, skull imaging and clinical evaluations were performed in 47 MPS patients (type I, II, VI, and VII). A total of 215 radiographs of the skull were analyzed. The presence and type of craniosynostosis, the sutures involved, progression over time, skull shape, head circumference, fundoscopy, and ventriculoperitoneal shunt (VPS) placement data were evaluated.

RESULTS

Craniosynostosis of at least one suture was present in 77% of all 47 MPS patients (≤ 6 years of age in 40% of all patients). In 32% of all MPS patients, premature closure of all sutures was seen (≤ 6 years of age in 13% of all patients). All patients with early closure had a more severe MPS phenotype, both in the neuronopathic (MPS I, II) and non-neuronopathic (MPS VI) patient groups. Because of symptomatic increased intracranial pressure (ICP), a VPS was placed in six patients, with craniosynostosis as a likely or certain causative factor for the increased pressure in four patients. One patient underwent cranial vault expansion because of severe craniosynostosis.

CONCLUSIONS

Craniosynostosis occurs in the majority of MPS patients. Since the clinical consequences can be severe and surgical intervention is possible, skull growth and signs and symptoms of increased ICP should be monitored in both neuronopathic and non-neuronopathic patients with MPS.

Fibroblast Growth Factor Receptor 2 (FGFR2) Mutation Related Syndromic Craniosynostosis

Craniosynostosis results from the premature fusion of cranial sutures, with an incidence of 1 in 2,100-2,500 live births. The majority of cases are non-syndromic and involve single suture fusion, whereas syndromic cases often involve complex multiple suture fusion. The fibroblast growth factor receptor 2 (FGFR2) gene is perhaps the most extensively studied gene that is mutated in various craniosynostotic syndromes including Crouzon, Apert, Pfeiffer, Antley-Bixler, Beare-Stevenson cutis gyrata, Jackson-Weiss, Bent Bone Dysplasia, and Seathre-Chotzen-like syndromes. The majority of these mutations are missense mutations that result in constitutive activation of the receptor and downstream molecular pathways. Treatment involves a multidisciplinary approach with ultimate surgical fixation of the cranial deformity to prevent further sequelae. Understanding the molecular mechanisms has allowed for the investigation of different therapeutic agents that can potentially be used to prevent the disorders. Further research efforts are need to better understand screening and effective methods of early intervention and prevention. Herein, the authors provide a comprehensive update on FGFR2-related syndromic craniosynostosis.

C278F mutation in FGFR2 gene causes two different types of syndromic craniosynostosis in two Chinese patients

The current study was performed with aim to investigate the fibroblast growth factor receptor 2 (FGFR2) gene in two Chinese families with two different forms of syndromic craniosynostosis, and to characterize their associated clinical features. Two families underwent complete ophthalmic examinations, and two patients from each family were diagnosed with craniosynostosis. Genomic DNA was extracted from leukocytes of peripheral blood collected from these two families and from 200 unrelated subjects within the same population as controls. Exons 8 and 10 of the FGFR2 gene were amplified by polymerase chain reaction and directly sequenced. Ophthalmic examinations of the two patients revealed shallow orbits and ocular proptosis, accompanied by midface hypoplasia and craniosynostosis. Case 1 had retinal detachment, abnormal limbs and hands, while case 2 exhibited normal hands and feet upon clinical examination. A heterozygous FGFR2 missense mutation c.833G>T (C278F) in exon 8 was identified in these two patients, but not in unaffected family members or the normal controls. 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.

Gastrointestinal disorders in Curry-Jones syndrome: Clinical and molecular insights from an affected newborn

Curry-Jones syndrome (CJS) is a pattern of malformation that includes craniosynostosis, pre-axial polysyndactyly, agenesis of the corpus callosum, cutaneous and gastrointestinal abnormalities. A recurrent, mosaic mutation of SMO (c.1234 C>T; p.Leu412Phe) causes CJS. This report describes the gastrointestinal and surgical findings in a baby with CJS who presented with abdominal obstruction and reviews the spectrum of gastrointestinal malformations in this rare disorder. A 41-week, 4,165 g, female presented with craniosynostosis, pre-axial polysyndactyly, and cutaneous findings consistent with a clinical diagnosis of CJS. The infant developed abdominal distension beginning on the second day of life. Surgical exploration revealed an intestinal malrotation for which she underwent a Ladd procedure. Multiple small nodules were found on the surface of the small and large bowel in addition to an apparent intestinal duplication that seemed to originate posterior to the pancreas. Histopathology of serosal nodules revealed bundles of smooth muscle with associated ganglion cells. Molecular analysis demonstrated the SMO c.1234 C>T mutation in varying amounts in affected skin (up to 35%) and intestinal hamartoma (26%). Gastrointestinal features including structural malformations, motility disorders, and upper GI bleeding are major causes of morbidity in CJS. Smooth muscle hamartomas are a recognized feature of children with CJS typically presenting with abdominal obstruction requiring surgical intervention. A somatic mutation in SMO likely accounts for the structural malformations and predisposition to form bowel hamartomas and myofibromas. The mutation burden in the involved tissues likely accounts for the variable manifestations.

Crouzon's Syndrome: A Rare Genetic Disorder

Crouzon's syndrome, also known as brachial arch syndrome, is an autosomal dominant disorder with complete penetrance and variable expressivity. Described by a French neurosurgeon in 1912, it is a rare genetic disorder. Crouzon's syndrome is caused by mutation in the fibroblast growth factor receptor 2 (FGFR2) gene. Normally, the sutures in the human skull fuse after the complete growth of the brain, but if any of these sutures close early, then it may interfere with the growth of the brain. The disease is characterized by craniosynostosis, with associated dentofacial anomalies. This report describes the different clinical features in a 10-year-old male patient, with particular reference to characteristic findings of this syndrome.

HOW TO CITE THIS ARTICLE

Kaushik A, Bhatia H, Sharma N. Crouzon's Syndrome: A Rare Genetic Disorder. Int J Clin Pediatr Dent 2016;9(4):384-387.

Effects of thyroxine exposure on the Twist 1 +/- phenotype: A test of gene-environment interaction modeling for craniosynostosis

BACKGROUND

Craniosynostosis, the premature fusion of one or more of the cranial sutures, is estimated to occur in 1:1800 to 2500 births. Genetic murine models of craniosynostosis exist, but often imperfectly model human patients. Case, cohort, and surveillance studies have identified excess thyroid hormone as an agent that can either cause or exacerbate human cases of craniosynostosis.

METHODS

Here we investigate the influence of in utero and in vitro exogenous thyroid hormone exposure on a murine model of craniosynostosis, Twist 1 +/-.

RESULTS

By 15 days post-natal, there was evidence of coronal suture fusion in the Twist 1 +/- model, regardless of exposure. With the exception of craniofacial width, there were no significant effects of exposure; however, the Twist 1 +/- phenotype was significantly different from the wild-type control. Twist 1 +/- cranial suture cells did not respond to thyroxine treatment as measured by proliferation, osteogenic differentiation, and gene expression of osteogenic markers. However, treatment of these cells did result in modulation of thyroid associated gene expression.

CONCLUSION

Our findings suggest the phenotypic effects of the genetic mutation largely outweighed the effects of thyroxine exposure in the Twist 1 +/- model. These results highlight difficultly in experimentally modeling gene-environment interactions for craniosynostotic phenotypes. Birth Defects Research (Part A) 106:803-813, 2016. © 2016 Wiley Periodicals, Inc.

Primary delayed onset craniosynostosis in a child demonstrated by serial computed tomography imaging

Primary delayed onset craniosynostosis is a rarely reported phenomenon. The unique case of a 2-year-old boy who had computed tomography (CT) scans performed 20 months apart demonstrating the post-gestational development of sagittal suture craniosynostosis is presented. The otherwise healthy male initially presented to the emergency department at age 7 months with soft tissue swelling over his left parietal region secondary to a fall. A CT scan revealed a possible left parietal skull fracture without intracranial pathology and patent cranial sutures with a normocephalic calvarial configuration. Twenty months later, his paediatrician referred the boy to the craniofacial service for evaluation of progressive dolichocephaly. A new CT scan showed complete fusion of the sagittal suture with resultant biparietal narrowing, frontal bossing, and occipital prominence. The patient subsequently underwent uncomplicated frontoparietal craniotomy with calvarial vault reconstruction. Prior reports in the literature of cases of non-syndromic primary delayed onset craniosynostosis all lack 'pre-synostosis' CT imaging that proves post-birth patency of the cranial sutures. This case report documents CT demonstrating true primary delayed onset craniosynostosis.

A Recurrent Mosaic Mutation in SMO, Encoding the Hedgehog Signal Transducer Smoothened, Is the Major Cause of Curry-Jones Syndrome

Curry-Jones syndrome (CJS) is a multisystem disorder characterized by patchy skin lesions, polysyndactyly, diverse cerebral malformations, unicoronal craniosynostosis, iris colobomas, microphthalmia, and intestinal malrotation with myofibromas or hamartomas. Cerebellar medulloblastoma has been described in a single affected individual; in another, biopsy of skin lesions showed features of trichoblastoma. The combination of asymmetric clinical features, patchy skin manifestations, and neoplastic association previously led to the suggestion that this could be a mosaic condition, possibly involving hedgehog (Hh) signaling. Here, we show that CJS is caused by recurrent somatic mosaicism for a nonsynonymous variant in SMO (c.1234C>T [p.Leu412Phe]), encoding smoothened (SMO), a G-protein-coupled receptor that transduces Hh signaling. We identified eight mutation-positive individuals (two of whom had not been reported previously) with highly similar phenotypes and demonstrated varying amounts of the mutant allele in different tissues. We present detailed findings from brain MRI in three mutation-positive individuals. Somatic SMO mutations that result in constitutive activation have been described in several tumors, including medulloblastoma, ameloblastoma, and basal cell carcinoma. Strikingly, the most common of these mutations is the identical nonsynonymous variant encoding p.Leu412Phe. Furthermore, this substitution has been shown to activate SMO in the absence of Hh signaling, providing an explanation for tumor development in CJS. This raises therapeutic possibilities for using recently generated Hh-pathway inhibitors. In summary, our work uncovers the major genetic cause of CJS and illustrates strategies for gene discovery in the context of low-level tissue-specific somatic mosaicism.

Cole-Carpenter syndrome is caused by a heterozygous missense mutation in P4HB

Cole-Carpenter syndrome is a severe bone fragility disorder that is characterized by frequent fractures, craniosynostosis, ocular proptosis, hydrocephalus, and distinctive facial features. To identify the cause of Cole-Carpenter syndrome in the two individuals whose clinical results were presented in the original description of this disorder, we performed whole-exome sequencing of genomic DNA samples from both individuals. The two unrelated individuals had the same heterozygous missense mutation in exon 9 of P4HB (NM_000918.3: c.1178A>G [p.Tyr393Cys]), the gene that encodes protein disulfide isomerase (PDI). In one individual, the P4HB mutation had arisen de novo, whereas in the other the mutation was transmitted from the clinically unaffected father who was a mosaic carrier of the variant. The mutation was located in the C-terminal disulfide isomerase domain of PDI, sterically close to the enzymatic center, and affected disulfide isomerase activity in vitro. Skin fibroblasts showed signs of increased endoplasmic reticulum stress, but despite the reported importance of PDI for collagen type I production, the rate of collagen type I secretion appeared normal. In conclusion, Cole-Carpenter syndrome is caused by a specific de novo mutation in P4HB that impairs the disulfide isomerase activity of PDI.

Fibroblast growth factor (FGF) signaling in development and skeletal diseases

Fibroblast growth factors (FGF) and their receptors serve many functions in both the developing and adult organism. Humans contain 18 FGF ligands and four FGF receptors (FGFR). FGF ligands are polypeptide growth factors that regulate several developmental processes including cellular proliferation, differentiation, and migration, morphogenesis, and patterning. FGF-FGFR signaling is also critical to the developing axial and craniofacial skeleton. In particular, the signaling cascade has been implicated in intramembranous ossification of cranial bones as well as cranial suture homeostasis. In the adult, FGFs and FGFRs are crucial for tissue repair. FGF signaling generally follows one of three transduction pathways: RAS/MAP kinase, PI3/AKT, or PLCγ. Each pathway likely regulates specific cellular behaviors. Inappropriate expression of FGF and improper activation of FGFRs are associated with various pathologic conditions, unregulated cell growth, and tumorigenesis. Additionally, aberrant signaling has been implicated in many skeletal abnormalities including achondroplasia and craniosynostosis. The biology and mechanisms of the FGF family have been the subject of significant research over the past 30 years. Recently, work has focused on the therapeutic targeting and potential of FGF ligands and their associated receptors. The majority of FGF-related therapy is aimed at age-related disorders. Increased understanding of FGF signaling and biology may reveal additional therapeutic roles, both in utero and postnatally. This review discusses the role of FGF signaling in general physiologic and pathologic embryogenesis and further explores it within the context of skeletal development.

Prenatal findings in carpenter syndrome and a novel mutation in RAB23

Carpenter syndrome is caused by mutations of the RAB23 gene. To date, 12 distinct mutations have been identified among 34 patients from 26 unrelated families. We report on the prenatal findings in a fetus with Carpenter syndrome with a novel RAB23 mutation. Cystic hygroma, bowed femora, abnormal skull shape and a complex heart defect were seen on ultrasound scan, and Carpenter syndrome was diagnosed at birth. Craniosynostosis and preaxial hexadactyly of the feet were retrospectively detectable on the fetal CT scan. Sequencing of RAB23 identified a homozygous mutation leading to skipping of exon 6 and premature termination codon (c.481G>C; p.Val161Leufs*16). This observation illustrates the difficulty of prenatal ultrasound diagnosis of Carpenter syndrome. To our knowledge, this diagnosis was suggested on ultrasound scan in only one prior patient, although in five other patients abnormal skull shape and variable findings, mainly limb anomalies including bowed femora in one case, were described during the pregnancy. Heart defect and bowed femora are rare postnatal findings. The diagnosis of Carpenter syndrome should therefore be considered on prenatal imaging in cases of bowed femora and/or cardiac defect associated with abnormal skull shape.

Crouzon syndrome with bony upper airway obstruction: case report and review literature

Crouzon syndrome is a rare genetic disorder. It is inherited as an autosomal dominant pattern. Mutations in the FGFR2 gene are known to cause Crouzon syndrome. Craniofacial abnormalities are common at birth and may progress with time. The severity of these signs and symptoms varies among affected children. A full term, large for date, male baby was delivered to a gravida 2 mother by cesarean section having facial dimorphism suggestive of Crouzon syndrome. Genetic team confirmed the diagnosis. Baby had severe respiratory distress. On work up, upper bony airway narrowing was found (diameter 3 mm). Later on, baby was operated for the same. Baby is asymptomatic now and doing well up to 2 months of follow-up. Management of Crouzon disease is multidisciplinary and early diagnosis has prime importance. Follow-up must ensure late features like hearing problems, vision problems, dental problems, intelligence, cranial synostosis, and upper airway problems.

A Ser252Trp mutation in fibroblast growth factor receptor 2 (FGFR2) mimicking human Apert syndrome reveals an essential role for FGF signaling in the regulation of endochondral bone formation

A S252W mutation of fibroblast growth factor receptor 2 (FGFR2), which is responsible for nearly two-thirds of Apert syndrome (AS) cases, causes retarded development of the skeleton and skull malformation resulting from premature fusion of the craniofacial sutures. We utilized a Fgfr2^+/S252W mouse (a knock-in mouse model mimicking human AS) to demonstrate decreased bone mass due to reduced trabecular bone volume, reduced bone mineral density, and shortened growth plates in the long bones. In vitro bone mesenchymal stem cells (BMSCs) culture studies revealed that the mutant mice showed reduced BMSC proliferation, a reduction in chondrogenic differentiation, and reduced mineralization. Our results suggest that these phenomena are caused by up-regulation of p38 and Erk1/2 phosphorylation. Treatment of cultured mutant bone rudiments with SB203580 or PD98059 resulted in partial rescue of the bone growth retardation. The p38 signaling pathway especially was found to be responsible for the retarded long bone development. Our data indicate that the S252W mutation in FGFR2 directly affects endochondral ossification, resulting in growth retardation of the long bone. We also show that the p38 and Erk1/2 signaling pathways partially mediate the effects of the S252W mutation of FGFR2 on long bone development.

The crouzan syndrome-a case report

The Crouzon syndrome is a genetic disorder which is known as the brachial arch syndrome. It is an autosomal dominant disorder which is one of a rare group of syndromes which is characterized by cranio synostosis or a premature closing of the cranial sutures. The major features are brachiocephaly, occular proptosis, an under developed maxilla, mid face hypoplasia, a rare cleft lip or palate, hypodontia (some teeth missing) and crowding of teeth. Due to the maxillary hypoplasia, the Crouzon syndrome patients generally have a considerable permanent underbite and they subsequently cannot chew by using their incisors. We have presented in this article, a case of the Crouzon syndrome which was seen in a girl who was aged six years, with similar symptoms and the multidisciplinary approach which has to be followed in managing the case.

Crouzon's syndrome: A review of literature and case report

Crouzon's syndrome is an autosomal dominant disorder with complete penetrance and variable expressivity. Described by a French neurosurgeon in 1912, it is a rare genetic disorder. Crouzon's syndrome is caused by mutation in the fibroblast growth factor receptor 2 (FGFR2) gene. Normally, the sutures in the human skull fuse after the complete growth of the brain, but if any of these sutures close early then it may interfere with the growth of the brain. The disease is characterized by premature synostosis of coronal and sagittal sutures which begins in the first year of life. Case report of a 7 year old boy is presented with characteristic features of Crouzon's syndrome with mental retardation. The clinical, radiographic features along with the complete oral rehabilitation done under general anesthesia and preventive procedures done are described.

Craniosynostosis

Craniosynostosis is a complex condition, characterized by the premature fusion of one of more of the cranial sutures. They can be seen individually or as part of multisystem syndromes. This review uses computed tomography (CT) with three-dimensional reconstructions to help describe some of the types and classifications of craniosynostosis, as well as describing some of the associations and the management of craniosynostosis.

About the operative management and post-operative neural development of patients with cloverleaf skull deformity

INTRODUCTION

We present our treatment concept for cloverleaf skull deformity on the basis of two representative cases that had been presented to our multidisciplinary skull deformity board.

METHODS

Perioperatively, we monitored electrophysiologic parameters with median nerve somatosensory-evoked potentials (SSEP), tibial nerve (T) SSEP, brainstem acoustic-evoked potential and flush-elicited visual-evoked potential, as well as intracranial pressure. Both patients underwent decompressive bilateral vault craniectomy, frontal and occipital reshaping at an age of four months.

RESULTS

Secondary fronto-orbital advancement and cranial vault reshaping was performed after maximal vault reossification was reached at an age of 8 and 12 months, respectively. Additionally, one of the patients underwent treatment of a Chiari malformation via suboccipital decompressive craniectomy and tonsillary resection, as well as ventriculoperitoneal shunting for hydrocephalus.

DISCUSSION

The patients showed nearly unrestrained neural and neurophysiological development over a follow-up period of 5 years.

Fontaine-Farriaux syndrome: a recognizable craniosynostosis syndrome with nail, skeletal, abdominal, and central nervous system anomalies

Craniosynostosis is an etiologically heterogeneous malformation, which may present as an isolated finding or in association with other anomalies. The concurrence of craniosynostosis together with specific central nervous system, abdominal, genital, and limb malformations defines the Fontaine-Farriaux syndrome, described so far in only two patients. We report on a stillborn who mainly presented severe intrauterine growth retardation, bilateral coronal synostosis, generalized nail hypo/aplasia more evident on the posterior side, tapered digits, mild cutaneous syndactyly, abdominal muscle hypoplasia, micropenis and bilateral cryptorchidism. Skeletal radiographs revealed universal platyspondyly and necropsy findings comprised intestinal malrotation, abnormal cortical gyral formation, periventricular heterotopia, and cerebellar hypoplasia. Comparison between the present and the two previously described patients demonstrates that our case shows a combination of features strikingly resembling the original description. Conversely, the second reported patient shows a very atypical phenotype and is, most probably, affected by a distinct clinical entity. The triad of craniosynostosis, anonychia, and abdominal muscle hypo/aplasia emerges as the most consistent core phenotype, although skeletal and brain anomalies are relevant ancillary findings. An in-depth differential diagnosis with other partially overlapping conditions is carried out.

Perspectives on craniosynostosis: sutural biology, some well-known syndromes, and some unusual syndromes

Perspectives on craniosynostosis are discussed under the following headings: sutural biology (anatomic and genetic categories of synostosis; sutures, suture systems, and types of craniosynostosis; well-known syndromes (Muenke syndrome and Pfeiffer syndrome); and unusual syndromes (thanatophoric dysplasia, Beare-Stevenson cutis gyrata syndrome, Crouzonodermoskeletal syndrome, Carpenter syndrome, Elejalde syndrome, hypomandibular faciocranial syndrome, and craniorhiny). Five of these syndromes are caused by fibroblast growth factor receptor (FGFR) mutations; one is caused by ras-like in rat brain 23 (RAB23) mutations; and three have Mendelian patterns of inheritance, but the molecular basis remains unknown to date.

Intraocular pressure change in orbital disease

Intraocular pressure change has been found concurrent with many orbital pathologies, particularly those involving proptosis. The objective of this review is to offer an inclusive classification of orbital disease-related intraocular pressure change, not only for oculoplastics and glaucoma specialists, but also for general ophthalmologists. Various orbital conditions associated with increased intraocular pressure and glaucoma are comprehensively summarized, and pathophysiology, clinical manifestations, and treatment options of these diseases are discussed. Graves disease, arterio-venous shunts, trauma, and orbital neoplasia, and other common conditions are discussed in detail; less frequent syndromes such as orbitocraniofacial deformities, phakomatoses, and mucopolysaccharidoses are included for the sake of comprehensiveness, but discussed less extensively.

Early orthodontic management of Crouzon Syndrome: a case report

Crouzon Syndrome is an autosomal dominant disorder with complete penetrance and variable expressivity. Described by a French neurosurgeon in 1912, it is a rare genetic disorder. Crouzon syndrome is caused by mutation in the fibroblast growth factor receptor 2 (FGFR2) gene. The disease is characterized by premature synostosis of coronal and sagittal sutures which begins in the first year of life. Once the sutures become closed, growth potential to those sutures is restricted. However, multiple sutural synostoses frequently extend to premature fusion of skull base causing midfacial hypoplasia, shallow orbit, maxillary hypoplasia and occasional upper airway obstruction.The case of a 7-year-old South African black boy with Crouzon Syndrome is presented. He presented with characteristic triad of cranial deformity, maxillary hypoplasia and exophthalmos. The clinical, cephalometric features and initial orthodontic management of this patient are discussed as part of multidisciplinary management.

Mild case of Curry-Jones syndrome

The main features of the Curry-Jones syndrome are syndactyly, pre-axial polydactyly, craniosynostosis, absent corpus callosum, skin anomalies (characteristic pearly white areas that become scarred and atrophic, with increased hair growth), colobomas or microphthalmia and intestinal obstruction because of multiple benign myofibromata of the large bowel. Developmental delay occurs in half of the reported patients. The patient reported here has a mild form of the condition with polysyndactyly and skin changes but no craniosynostosis, bowel problems or developmental delay.

Sustained platelet-derived growth factor receptor alpha signaling in osteoblasts results in craniosynostosis by overactivating the phospholipase C-gamma pathway

The development and growth of the skull is controlled by cranial sutures, which serve as growth centers for osteogenesis by providing a pool of osteoprogenitors. These osteoprogenitors undergo intramembranous ossification by direct differentiation into osteoblasts, which synthesize the components of the extracellular bone matrix. A dysregulation of osteoblast differentiation can lead to premature fusion of sutures, resulting in an abnormal skull shape, a disease called craniosynostosis. Although several genes could be linked to craniosynostosis, the mechanisms regulating cranial suture development remain largely elusive. We have established transgenic mice conditionally expressing an autoactivated platelet-derived growth factor receptor alpha (PDGFRalpha) in neural crest cells (NCCs) and their derivatives. In these mice, premature fusion of NCC-derived sutures occurred at early postnatal stages. In vivo and in vitro experiments demonstrated enhanced proliferation of osteoprogenitors and accelerated ossification of osteoblasts. Furthermore, in osteoblasts expressing the autoactivated receptor, we detected an upregulation of the phospholipase C-gamma (PLC-gamma) pathway. Treatment of differentiating osteoblasts with a PLC-gamma-specific inhibitor prevented the mineralization of synthesized bone matrix. Thus, we show for the first time that PDGFRalpha signaling stimulates osteogenesis of NCC-derived osteoblasts by activating the PLC-gamma pathway, suggesting an involvement of this pathway in the etiology of human craniosynostosis.

Apert's Syndrome: Report of a New Case and its Management

In this article, an interesting case of Apert syndrome in a 14-year-old boy with characteristic craniosynostosis, acrocephaly, midface hypoplasia, pharyngeal attenuation, ocular manifestations, and syndactyly of the hands and feet is presented. The case is discussed in the light of relevant literature. A precise clinical differentiation must be made since considerable overlap of the features of various other syndromes could give rise to difficulties in diagnosing this condition. Besides detection and timely recognition of the syndrome to allow adequate dental care, screening at periodic intervals is merited to improve the overall quality of life of these patients.

Clinical relevance

This paper highlights the importance of the dentist as well as the specialist in the recognition and oral care of children with this syndrome.

Children with teeth of unusual anatomy present a challenge for conventional dentistry.

It is important for a pedodontist to evaluate and intervene the malrelationship of the jaws to reduce the complexity of further orthodontic treatment.

Objectives statement: The reader should understand the clinical implications of recognition of this syndrome and provision of early treatment, with a purpose to reducing the duration and complexity of further treatment.

Pansynostosis: a review

INTRODUCTION

Although rare, pansynostoses are seen and treated by the craniofacial surgeon. To date, a single source that reviews these more severe forms of craniosynostosis is lacking in the literature.

MATERIALS AND METHODS

The present paper outlines and reviews the associations of both syndromic and nonsyndromic cases, potential mechanisms, and the anatomy involved with such forms of premature fusion of the cranial sutures.

RESULTS

Pansynostosis is seen in a myriad of syndromes but can also be identified in nonsyndromic cases. Raised intracranial pressure is a concern in these patients.

CONCLUSIONS

Early recognition and treatment of patients with pansynostosis of the cranial sutures is important.

Novel two-dimensional morphometric maps and quantitative analysis reveal marked growth and structural recovery of the rat hippocampal regions from early hypothyroid retardation

Effects of postnatal hypothyroidism and recovery from this condition on regional growth of the rat hippocampus (HC) were studied using two-dimensional (2D) foldout, morphometric maps of HC and its constituent CA1-CA4 regions. The maps were derived from unfolding serial coronal sections of the rat forebrain, consisting of the entire rostrocaudal extent of HC pyramidal cell layer in the normal control and hypothyroid weanling (P25, postnatal day 25) and young adult (P90) male rats, as well as animals allowed to recover from hypothyroid-induced growth retardation at weaning. The maps revealed novel views of HC regions for assessment of topological relationships and measurement of surface areas of the HC cortical sheet (pyramidal cell layer). In normal control P90 rats, the unfolded HC on each side extended 4 times more laterally than rostrocaudally; total HC surface area was about 40 mm(2), compared to 30 mm(2) in the weanling, indicating 35% growth from P25 to P90; CA1 took up 52% of the total HC surface area, followed by CA3 (31%) and CA2 and CA4, 8% each. Hypothyroidism resulted in significant (p<0.01) 11% and 20% reductions in the HC surface area in P25 and P90 rats, respectively; CA1 and CA4 regions suffered the most reductions while CA3 and CA2 regions the least. Recovering rats examined at P90 exhibited remarkable growth plasticity and recovery in HC regions, as evident by their near normal HC cortical surface area values, compared to age-matched controls. The 2D maps also revealed growth deficits in all HC regions of the hypothyroid rats; recovery in these parameters occurred across all dimensions, although the anterior-posterior growth was more severely affected than the mediolateral one. These results are confirmed and extended by volumetric analysis of laminar volumes of HC regions presented in a companion paper [Farahvar, A., Darwish, N., Sladek, S., Meisami, E., in press. Marked recovery of functional metabolic activity and laminar volumes in the rat hippocampus and dentate gyrus following postnatal hypothyroid growth retardation: a quantitative cytochrome oxidase study. Exp. Neurol.]. These results imply that HC regions, in contrast to whole brain, possess exceptional growth plasticity, as shown by ability to dramatically recover from early hypothyroid retardation; also 2D morphometric maps are useful tools to visualize complex and convoluted regional sheet of HC cortex and depict quantitative aspects of growth in normal and experimental conditions.

FBN1, TGFBR1, and the Marfan-craniosynostosis/mental retardation disorders revisited

The recent identification of TGFBR2 mutations in Marfan syndrome II (MFSII) [Mizuguchi et al. (2004); Nat Genet 36:855-860] and of TGFBR1 and TGFBR2 mutations in Loeys-Dietz aortic aneurysm syndrome (LDS) [Loeys et al. (2005); Nat Genet 37:275-281] [OMIM 609192] has provided direct evidence of abnormal signaling in transforming growth factors beta (TGF-beta) in the pathogenesis of Marfan syndrome (MFS). In light of this, we describe the phenotypes and genotypes of five individuals. Patient 1 had MFS and abnormal cranial dura. Patient 2 had severe early onset MFS and an abnormal skull. Patients 3 and 4 had probable Furlong syndrome (FS). Patient 5 had marfanoid (MD) features, mental retardation (MR), and a deletion of chromosome 15q21.1q21.3. All patients had a condition within the MFS, MD-craniosynostosis (CS) or MD-MR spectrum. The names of these entities may become redundant, and instead, come to be considered within the spectrum of TGF-beta signaling pathway disorders. Two recurrent heterozygous FBN1 mutations were found in Patients 1 and 2, and an identical novel heterozygous de novo TGFBR1 mutation was found in Patients 3 and 4, in whom altered fibrillin-1 processing was demonstrated previously [Milewicz et al. (2000); Am J Hum Genet 67:279]. A heterozygous FBN1 deletion was found in Patient 5. These findings support the notion that perturbation of extracellular matrix homeostasis and/or remodeling caused by abnormal TGF-beta signaling is the core pathogenetic mechanism in MFS and related entities including the MD-CS syndromes.

Crouzon syndrome

BACKGROUND

Crouzon syndrome is a rare genetic disorder characterized by distinctive malformations of the skull and facial region. Premature cranial suture closure is the most common skull abnormality. Optic disc edema and proptosis are among the most common ocular findings.

CASE REPORT

We present a case of a 5-year-old girl with Crouzon syndrome displaying classic facial abnormalities along with proptosis and papilledema. The child's condition was improved dramatically after a monoblock advancement procedure.

CONCLUSIONS

The differential diagnosis of the condition and treatment options are discussed. The referring optometrist can play an integral role in the multidisciplinary care the patients require.

Noggin Underexpression and Runx-2 Overexpression in a Craniosynostosis Rabbit Model

INTRODUCTION

Normal suture fusion has been shown to be driven by the molecular signals elucidated by the underlying dura. However, the pathogenesis of suture fusion in craniosynostosis is not well described. The purpose of our study was to examine the expression patterns of 2 important molecular signals (Noggin and Runx-2) in a cohort of congenital craniosynostotic rabbits to gain a better understanding of suture behavior in craniosynostosis.

METHODS

Coronal (fusing) and sagittal (patent) rabbit cranial sutures from a colony of congenitally synostosed rabbits and wild-type (control) rabbits were harvested at a neonatal time point. These sections were then grown in organ culture and harvested for histology at 0, 7, or 14 days of culture. Fusion percentage was then assessed and an overall fusion score was calculated. Expression of Noggin and Runx-2 was then localized by immunohistochemistry and quantified by Western blot analysis.

RESULTS

Histology of the wild-type cranial sutures (control) showed suture patency (score of 0%) for all coronal and sagittal sutures at 0 days, 7 days, and 14 days of organ culture. Sagittal sutures of craniosynostotic animals also showed suture patency (score of 0%) at all culture times (0, 7, and 14 days). Of the 18 coronal sutures from the craniosynostotic animals, 8 remained patent and 10 fused. For the coronal sutures that fused, fusion scores of 14%, 41%, and 84% were documented at 0, 7, and 14 days of organ culture, respectively. With immunolocalization, Noggin was found to be expressed in both the dura and suture cells underlying patent sutures, but not in fusing sutures in vitro. Runx-2 was found to be expressed in the dura beneath the suture and suture cells of fusing sutures, not patent sutures. Western blot densitometry confirmed these findings.

CONCLUSIONS

Our results suggest that pathologic rabbit coronal sutures progressed toward complete suture fusion in vitro, and expression patterns of Noggin and Runx-2 paralleled that of a well-studied normal suture fusion model.

Effects of different kinds of cranial deformation on the incidence of wormian bones

Researchers have debated whether the presence and frequency of wormian bones (sutural bones, supernumerary bones, and ossicles) are attributable to genetic factors, environmental factors, or both. This research examines the effects of many different kinds of cranial deformation on the incidence of wormian bones. A sample of 127 deformed and undeformed crania from New World archaeological sites was examined. An undeformed cranial sample (n=35) was compared to the following cranially deformed groups: 1) occipital, 2) lambdoid, 3) annular, 4) fronto-vertico-occipital, 5) parallelo-fronto-occipital, and 6) sagittal synostosis. Three levels of degree of cultural cranial deformation were qualitatively determined. Type and number of wormian bones along each major suture were recorded for each cranium. Group means were analyzed using Kruskal-Wallis one-way ANOVA statistical tests to test the null hypothesis that cranial deformation does not have an effect on wormian bone incidence. Results indicate that all forms of cranial deformation affect the frequency of some types of wormian bones. In particular, all cranially deformed groups exhibited significantly greater frequencies of lambdoid ossicles. Apical, parieto-mastoid, and occipito-mastoid wormian bones also appeared with greater frequency in some groups of culturally deformed crania. Further, varying degrees of cultural deformation all had more lambdoid wormian bones than the undeformed group. These results suggest that wormian bone development in posteriorly placed sutures may be affected more by environmental forces than are their anteriorly placed counterparts.

A Ser252Trp [corrected] substitution in mouse fibroblast growth factor receptor 2 (Fgfr2) results in craniosynostosis

Apert syndrome (AS) is one of the most severe craniosynostoses and is characterized by premature fusion of craniofacial sutures. Mutations of either Ser252Trp or Pro253Arg in fibroblast growth factor receptor 2 (FGFR2) are responsible for nearly all known cases of AS. Here we show that mutant mice carrying the activation mutation, Ser252Trp [corrected] which corresponds to Ser252Trp in human FGFR2, have malformations mimicking the skull abnormalities found in AS patients. Mutant mice (Fgfr2(250/+)) are smaller in body size with brachycephaly and exhibit distorted skulls with widely spaced eyes. Unexpectedly, the premature closure of the coronal suture is accompanied by decreased, rather than increased, bone formation. We demonstrate that the Fgfr2-Ser252Trp [corrected] mutation does not cause obvious alterations in cell proliferation and differentiation; however, it results in increased Bax expression and apoptosis of osteogenic cells in mutant coronal suture. The accelerated cell death possibly reduces the space between osteogenic fronts of flat bones and results in the physical contact of these bones. Thus, our data reveal that dysregulated apoptosis plays an important role in the pathogenesis of AS related phenotypes.