Skeletal changes after midface surgery in patients with craniofacial deformities: a three-dimensional quantification method

To determine the skeletal changes after midface surgery in patients with syndromic craniosynostosis who underwent Le Fort III (LFIII), monobloc (MB), or facial bipartition (FB). This was a retrospective study including 75 patients: 33 treated by LFIII, 29 by MB, and 13 by FB. Twenty-five had a diagnosis of Apert, 39 Crouzon, and 11 craniofrontonasal syndrome. A three-dimensional mesh was created from the preoperative scan and registered to the postoperative scan to visualise the advancement. LFIII at age 7-12 years effectuated a higher mean advancement in the maxillary (15.5 mm) and zygomatic (7.6 mm) regions when compared to ≥13 years (10.2 mm and 5.5 mm). After MB, mean advancement of the fronto-orbital region was higher at <7 years (16.4 mm), and similarly lower at ages 7-12 (13.8 mm) and ≥13 (12.5 mm). The mean preoperative inter-dacryon distance (34.4 ± 4.4 mm) was reduced by 8.7 ± 4.2 mm after FB without distraction (n = 10). More advancement was seen when midface surgery was performed at a younger age, due to more severe cases and a desire for overcorrection. The highest mean advancement was observed in the fronto-orbital region. Antero-inferior rotational movement was seen after all three techniques.

Association of cranial base suture/synchondrosis fusion with severity of increased intracranial pressure in Crouzon syndrome

This study investigated how the fusion states of the cranial base is related to the degree of increased intracranial pressure (ICP) in patients with Crouzon syndrome. This retrospective cohort study enrolled patients who were diagnosed with Crouzon syndrome between May 2007 and April 2022. We categorized the patients into three groups: A, B, and C, according to the severity of increased ICP and the number of cranial vault remodeling procedures for corrective operation. The preoperative fusion states of the cranial base sutures/synchondroses were examined using facial bone computed tomography and compared between groups. Overall, 22 patients were included in Groups A, B, and C, including 8, 7, and 7 patients, respectively. The preoperative average grades of the total cranial base suture/synchondrosis fusion appeared to significantly increase with severity, except for the frontoethmoidal suture, which showed the opposite tendency. In the subgroup analysis, frontosphenoidal, sphenoparietal, sphenosquamosal, parietomastoid, and occipitomastoid suture and petro-occipital synchondrosis were associated with earlier fusion in the more severe group. Premature closure of the cranial base sutures/synchodroses seems to be associated with increased ICP severity in patients with Crouzon syndrome. Precise evaluation of minor sutures/synchondroses at the first visit might help build subsequent operative plans and predict disease prognosis.

Correlation analysis of airway-facial phenotype in Crouzon syndrome by geometric morphometrics: A promising method for non-radiation airway evaluation

AIM

This study aimed to verify the correlation of the airway-facial phenotype and visualize the morphological variation in Crouzon syndrome patients. Additionally, to develop a non-radiation methodology for airway assessments.

METHOD

In this study, 22 patients diagnosed with Crouzon syndrome (Age: 7.80 ± 5.63 years; Gender distribution: 11 females and 11 males) were analysed. The soft tissue surface and airway were three-dimensionally reconstructed, and the entire facial phenotype was topologized and converted into spatial coordinates. Geometric morphometrics was employed to verify the correlation and visualize dynamic phenotypic variation associated with airway volume. A total of 276 linear variables were automatically derived from 24 anatomical landmarks, and principal component analysis (PCA) identified the 20 most significant parameters for airway evaluation. Correlation analyses between parameters and airway volume were performed. Then, patients were classified into three groups based on airway volume, and the differences among the groups were compared for evaluating the differentiating effectiveness of parameters.

RESULTS

The facial phenotype was strongly correlated with the airway (coefficient: 0.758). Morphological variation was characterized by (i) mandibular protrusion and anticlockwise rotation; (ii) midface retrusion; (iii) supraorbital frontward and (iv) lengthening of the facial height. All the anthropometric parameters were strongly associated with the airway, and the differences among the groups were statistically significant.

CONCLUSION

This study confirmed the strong correlation between facial phenotype and airway parameters in Crouzon syndrome patients. Despite the development of the airway, pathological midface retrusion was still aggravated, suggesting that surgical intervention was inevitable. Three-dimensional facial anthropometry has potential as a non-radiation examination for airway evaluation.

A unique presentation of Crouzon-like syndrome: Complex craniosynostosis in the absence of genetic mutations or familial predisposition - A case report

Background

Crouzon syndrome is a rare genetic disorder characterized by premature fusion of skull sutures during skull development, resulting in various craniofacial abnormalities and complex craniosynostosis is a condition in which more than one such sutures of the skull fuse prematurely.

Case Description

Herein, we present a case of a 5-year-old male diagnosed with Crouzon-like syndrome and complex craniosynostosis involving multiple cranial sutures, including metopic, sagittal, coronal (right and left), and lambdoid sutures, and without any identifiable mutations on karyotyping. The patient underwent successful surgical intervention with a satisfactory outcome, highlighting the importance of early diagnosis and intervention to prevent or minimize associated neurological manifestations and craniofacial abnormalities.

Conclusion

Our case report underscores the involvement of multiple cranial sutures in complex craniosynostosis and the absence of identifiable mutations or family history of similar craniofacial abnormalities, providing important insights into the diagnosis and management of this condition.

Progressive myelinated retinal nerve fibers in a 10-year-old boy with Crouzon syndrome after craniofacial surgery

Purpose

We present a case of a 10-year-old boy with Crouzon syndrome that demonstrates progressive myelinated retinal nerve fibers (MRNF).

Observations

A 10-year-old boy was referred for ophthalmic examination due to clusters of opaque white fibers around his optic nerve. Past surgical history includes craniofacial surgery at 3 years of age secondary to the deteriorating vision from increased intracranial pressure and papilledema. Upon examination (now 6.5 years post-craniofacial surgery), the patient denied any ocular complaints. The fundus examination showed progressively enlarged myelination of the retinal nerve fiber layer (right eye > left eye). Although previous cases of MRNF with Crouzon syndrome have been reported, our case is unique given its post-operative status with early onset of MRNF.

Conclusion and importance

This case report documents the photographic progression of bilateral myelinated retinal nerve fibers (MRNF) in a pediatric case of Crouzon syndrome post-craniofacial surgery secondary to increased intracranial pressure and papilledema. Based on our patient, craniofacial decompression surgery may not prevent the development of MRNF. The exact mechanisms of MRNF are still being studied. Further investigations correlating craniofacial surgeries, increased intracranial pressure, and progression of myelinated retinal nerve fibers are needed to understand this process.

Long-term follow-up of a patient diagnosed with Crouzon syndrome who underwent Le Fort I and III distraction osteogenesis using a rigid external distractor system

OBJECTIVE

This case report describes the successful treatment of a patient with Crouzon syndrome with severe midfacial deficiency and malocclusion, including reverse overjet.

MATERIALS AND METHODS

In Phase I treatment, maxillary lateral expansion and protraction were performed. In Phase II treatment, after lateral expansion of the maxilla and leveling of the maxillary and mandibular dentition, an orthognathic approach including simultaneous Le Fort I and III osteotomies with distraction osteogenesis (DO) was used to improve the midfacial deficiency.

RESULTS

After DO, 12.0 mm of the medial maxillary buttress and 9.0 mm of maxillary (point A) advancement were achieved, which resulted in a favorable facial profile and stable occlusion.

CONCLUSION

Even after 8 years of retention, the patient's profile and occlusion were preserved without any significant relapse.

Synchondrosis fusion contributes to the progression of postnatal craniofacial dysmorphology in syndromic craniosynostosis

Syndromic craniosynostosis (CS) patients exhibit early, bony fusion of calvarial sutures and cranial synchondroses, resulting in craniofacial dysmorphology. In this study, we chronologically evaluated skull morphology change after abnormal fusion of the sutures and synchondroses in mouse models of syndromic CS for further understanding of the disease. We found fusion of the inter-sphenoid synchondrosis (ISS) in Apert syndrome model mice (Fgfr2^S252W/+ ) around 3 weeks old as seen in Crouzon syndrome model mice (Fgfr2c^C342Y/+ ). We then examined ontogenic trajectories of CS mouse models after 3 weeks of age using geometric morphometrics analyses. Antero-ventral growth of the face was affected in Fgfr2^S252W/+ and Fgfr2c^C342Y/+ mice, while Saethre-Chotzen syndrome model mice (Twist1^+/- ) did not show the ISS fusion and exhibited a similar growth pattern to that of control littermates. Further analysis revealed that the coronal suture synostosis in the CS mouse models induces only the brachycephalic phenotype as a shared morphological feature. Although previous studies suggest that the fusion of the facial sutures during neonatal period is associated with midface hypoplasia, the present study suggests that the progressive postnatal fusion of the cranial synchondrosis also contributes to craniofacial dysmorphology in mouse models of syndromic CS. These morphological trajectories increase our understanding of the progression of syndromic CS skull growth.

Crouzon syndrome complicated with binocular strabismus and extraocular muscle fibrosis: a case report

BACKGROUND

Crouzon syndrome, a rare genetic disorder characterized by premature closure of coronal sutures, results in skull and facial deformities along with abnormal brain and ocular development.

CASE PRESENTATION

Here, we report a case of a 27-year-old ethnic han male patient who presented with complex binocular strabismus secondary to Crouzon syndrome. At the time of surgery, extraocular muscles were found to be fibrotic and results of the pathological examination revealed degeneration of muscle fibers, which were replaced by adipose tissue. The entire exome sequencing DNA testing indicated that the patient and his father possessed the fibroblast growth factor receptor 2 (FGFR2) gene c.G812T:p.G271V heterozygous mutation. Binocular strabismus corrective surgery was performed in this patient with a satisfactory outcome.

CONCLUSIONS

This case demonstrates that Crouzon syndrome patients can show an FGFR2 gene c.G812T:p.G271V mutation and display clinical symptoms such as extraocular muscle fibrosis, exotropia, exophthalmos, and a pointed head deformity.

Cranial Base Reconstruction and Secondary Frontal Advancement for Meningoencephalocele Following LeFort III Osteotomy in a Patient with Crouzon Syndrome: Case Report

Patients with Crouzon syndrome have increased risks of cerebrospinal fluid rhinorrhea and meningoencephalocele after LeFort III osteotomy. We report a rare case of meningoencephalocele following LeFort III midface advancement in a patient with Crouzon syndrome. Over 10 years since it was incidentally found during transnasal endoscopic orbital decompression, the untreated meningoencephalocele eventually led to intermittent clear nasal discharge, frontal headache, and seizure. Computed tomography and magnetic resonance imaging demonstrated meningoencephalocele in the left frontal-ethmoid-maxillary sinus through a focal defect of the anterior cranial base. Through bifrontal craniotomy, the meningoencephalocele was removed and the anterior cranial base was reconstructed with a pericranial flap and split calvarial bone graft. Secondary frontal advancement was concurrently performed to relieve suspicious increased intracranial pressure, limit visual deterioration, and improve the forehead shape. Surgeons should be aware that patients with Crouzon syndrome have the potential for an unrecognized dural injury during LeFort III osteotomy due to anatomical differences such as inferior displacement and thinning of the anterior cranial base.

Inhalational Induction: A Safe Anaesthetic Management in a Patient with Crouzon Syndrome

Crouzon syndrome is a rare genetic disorder involving craniofacial skeleton development. It's characterized by a triad of cranial deformities: premature craniosynostosis, facial anomalies (mid-facial hypoplasia), and exophthalmia. The anaesthetic management challenges include the presence of a difficult airway, history of obstructive sleep apnea, congenital cardiac disorders, hypothermia, blood loss, and venous air embolism. We present the case of an infant with Crouzon syndrome who was scheduled for a ventriculoperitoneal shunt placement managed with inhalational induction.

Orthognathic Surgery in Patients with Syndromic Craniosynostosis

Patients with syndromic and nonsyndromic synostosis may have end-stage skeletal discrepancies involving the lower midface and mandible, with associated malocclusion. While orthognathic surgical procedures in this population can be reliably executed, the surgeon must be aware of the unique morphologic characteristics that accompany the primary diagnoses as well as the technical challenges associated with performing Le Fort I osteotomies in patients who have undergone prior subcranial midface distraction.

Three-dimensional analysis of the palatal morphology in growing patients with Apert syndrome and Crouzon syndrome

Patients with Apert syndrome or Crouzon syndrome present with severe defects in oral-maxillofacial growth and development. In this study, we conducted a quantitative three-dimensional (3D) analysis of the palatal morphology of patients with Apert syndrome and Crouzon syndrome. Four patients with Apert syndrome (average age, 11.0 ± 0.8 years) and five with Crouzon syndrome (average age, 10.1 ± 1.6 years) were investigated. The participants' maxillary dental casts were scanned and analyzed using 3D imaging. Palatal width, depth, cross-sectional area, and palatal angle (PW, PD, PCA, and PA, respectively) were measured, and standard scores were calculated based on sex- and age-matched Japanese standard values; the actual palatal surface areas (PSA) and palatal volumes (PV) were also measured. Our results show that patients with Apert syndrome and Crouzon syndrome had a very narrow PW (standard score: -3.79 and - 0.47, respectively). 3D analysis revealed that patients with Apert syndrome had a significantly shallower PD (standard score: -1.35) than those with Crouzon syndrome (standard score: 2.47), resulting in a smaller PCA (standard score: -5.13), PSA (5.49 cm² ), and PV (1.11 cm³ ) and larger PA (standard score: -0.12) than those in patients with Crouzon syndrome. This might be due to the former having a narrower and shallower palate caused by the predominant swelling of the palatal mucosa. These findings improve our understanding of the differences in palatal morphology between Apert syndrome and Crouzon syndrome patients.

Crouzon syndrome in a fraternal twin: A case report and review of the literature

BACKGROUND

Crouzon syndrome (CS; OMIM 123500) is an autosomal dominant inherited craniofacial disorder caused by mutations in the fibroblast growth factor receptor 2 (FGFR2) gene. CS is characterized by craniofacial dysostosis, exophthalmos, and facial anomalies with hypoplastic maxilla and relative mandibular prognathism.

CASE SUMMARY

Our report involves a 6-year-old fraternal twin boy with many caries in the oral cavity who presented with characteristic features of CS based on clinical and radiographic examinations along with Sanger sequencing. The fraternal girl did not show any abnormalities indicating CS. Carious teeth and poor oral hygiene were managed promptly through administering appropriate behavior guidance, orthodontic treatment was planned, and preventive procedures were described.

CONCLUSION

CS could occur in a fraternal twin caused by a de novo mutation of the FGFR2 gene. Oral hygiene instruction, preventive programs on oral hygiene, orthodontic treatment, and maxillary osteotomy were required for treatment.

Meckel's Cartilage in Mandibular Development and Dysmorphogenesis

The Fgfr2c^C342Y/+ Crouzon syndrome mouse model carries a cysteine to tyrosine substitution at amino acid position 342 (Cys342Tyr; C342Y) in the fibroblast growth factor receptor 2 (Fgfr2) gene equivalent to a FGFR2 mutation commonly associated with Crouzon and Pfeiffer syndromes in humans. The Fgfr2c C342Y mutation results in constitutive activation of the receptor and is associated with upregulation of osteogenic differentiation. Fgfr2c^C342Y/+ Crouzon syndrome mice show premature closure of the coronal suture and other craniofacial anomalies including malocclusion of teeth, most likely due to abnormal craniofacial form. Malformation of the mandible can precipitate a plethora of complications including disrupting development of the upper jaw and palate, impediment of the airway, and alteration of occlusion necessary for proper mastication. The current paradigm of mandibular development assumes that Meckel’s cartilage (MC) serves as a support or model for mandibular bone formation and as a template for the later forming mandible. If valid, this implies a functional relationship between MC and the forming mandible, so mandibular dysmorphogenesis might be discerned in MC affecting the relationship between MC and mandibular bone. Here we investigate the relationship of MC to mandible development from the early mineralization of the mandible (E13.5) through the initiation of MC degradation at E17.7 using Fgfr2c^C342Y/+ Crouzon syndrome embryos and their unaffected littermates (Fgfr2c^+/+). Differences between genotypes in both MC and mandibular bone are subtle, however MC of Fgfr2c^C342Y/+ embryos is generally longer relative to unaffected littermates at E15.5 with specific aspects remaining relatively large at E17.5. In contrast, mandibular bone is smaller overall in Fgfr2c^C342Y/+ embryos relative to their unaffected littermates at E15.5 with the posterior aspect remaining relatively small at E17.5. At a cellular level, differences are identified between genotypes early (E13.5) followed by reduced proliferation in MC (E15.5) and in the forming mandible (E17.5) in Fgfr2c^C342Y/+ embryos. Activation of the ERK pathways is reduced in the perichondrium of MC in Fgfr2c^C342Y/+ embryos and increased in bone related cells at E15.5. These data reveal that the Fgfr2c C342Y mutation differentially affects cells by type, location, and developmental age indicating a complex set of changes in the cells that make up the lower jaw.

Midface advancement in an adult patient with Crouzon syndrome: Modified LeFort III + LeFort I osteotomy accompanied by genioplasty and nasal dorsum augmentation

Crouzon syndrome is an autosomal dominant trait, leading to midface deficiency, undeveloped orbits, short nasal dorsum, and exophthalmos as the typical clinical features. Early correction of craniofacial problems can improve patients' quality of life, but many of these patients with Crouzon syndrome are seeking treatment in older ages when they are missed for multidisciplinary management and distraction technique in proper timing. Modified LeFort III osteotomy is one of the treatment options that can be used for proper resolution in adult patients. The present case report study aims to describe a patient with midface deficiency due to the Crouzon syndrome who has undergone a combination of modified LeFort III osteotomy with the periocular approach and LeFort I osteotomy, nasal dorsum augmentation accompanied by genioplasty, wholly as a single surgical procedure which has been shown that can result in highly satisfactory outcomes for both patient and surgeon.

Phenotypic variability of syndromic craniosynostosis caused by c.833G > T in FGFR2: Clinical and genetic evaluation of eight patients from a five-generation family

Objective

Craniosynostosis is the result of the early fusion of cranial sutures. Syndromic craniosynostosis includes but not limited by Crouzon syndrome and Pfeiffer syndrome. Considerable phenotypic overlap exists among these syndromes and mutations in FGFR2 may cause different syndromes. This study aims to investigate the explanation of the phenotypic variability via clinical and genetic evaluation for eight patients in a large pedigree.

Methods

For each patient, comprehensive physical examination, cranial plain CT scan with three‐dimensional CT reconstruction (3D‐CT), and eye examinations were conducted. Whole exome sequencing was applied for genetic diagnosis of the proband. Variants were analyzed and interpreted following the ACMG/AMP guidelines. Sanger sequencing was performed to reveal genotypes of all the family members.

Results

A pathogenic variant in the FGFR2 gene, c.833G > T (p.C278F), was identified and proved to be co‐segregate with the disease. Some symptoms of head, hearing, vision, mouth, teeth expressed differently by affected individuals. Nonetheless, all the eight patients manifested core symptoms of Crouzon syndrome without abnormality in the limbs, which could exclude diagnosis of Pfeiffer syndrome.

Conclusion

We have established clinical and genetic diagnosis of Crouzon syndrome for eight patients in a five‐generation Chinese family. Variability of clinical features among these familial patients was slighter than that in previously reported sporadic cases.

Perioperative airway complications in infants and children with Crouzon and Pfeiffer syndromes: A single-center experience

BACKGROUND

Crouzon and Pfeiffer syndromes are rare genetic disorders characterized by craniosynostosis, exorbitism, and maxillary hypoplasia. Patients with these syndromes frequently require general anesthesia for various diagnostic and surgical procedures and may present a challenge to anesthetists with regard to airway management.

AIMS

The primary aim of this study was to determine the incidence, timing, and management of perioperative upper airway obstruction in infants and children with Crouzon and Pfeiffer syndromes. The secondary aim was to determine the degree of difficulty in performing endotracheal intubation.

METHODS

A retrospective review of 812 anesthetic encounters in 67 patients was conducted. The following were recorded: timing and management of episodes of perioperative upper airway obstruction, from induction of anesthesia to discharge from recovery, degree of difficulty with laryngoscopy using the Cormack-Lehane grading system and number of intubation attempts required, patient demographics, respiratory comorbidity, surgical procedure, and anesthetic airway management techniques.

RESULTS

Upper airway obstruction at induction of anesthesia was very common, with an incidence of 31% (167/542 anesthetic encounters affecting 54 patients). In a quarter of these incidents, bag-valve-mask ventilation was challenging, but a laryngeal mask airway was almost always effective. Upper airway obstruction on emergence from anesthesia was less common, with an incidence of 2.7% (14/515 anesthetic encounters affecting 10 patients). Contributing factors included patient comorbidity (obstructive sleep apnea, nasal stenosis) and the nature of surgery (craniofacial or airway procedures). Intubation was rarely difficult in this cohort, with 85% of laryngoscopies rated Cormack-Lehane grade 1 or 2 (n = 373), and 89% of intubations successful on the first attempt (n = 306).

CONCLUSIONS

Upper airway obstruction at induction of anesthesia is common in patients with Crouzon and Pfeiffer syndrome. These patients are likely to present some difficulties with perioperative airway management, especially bag-valve-mask ventilation, but rarely endotracheal intubation.

Algorithm to the treatment of Crouzon syndrome

Clinical reports regarding the entire surgical sequence in Crouzon syndrome from the neonatal period to the adult age are rare. The purpose of this study is to trace an operative algorithm with a long term follow up in a homogenous group of patients affected by Crouzon syndrome. A retrospective review was conducted for all patients affected by Crouzon syndrome who completed the entire surgical sequence. 7 Crouzon patients (4 females, 3 males) completed the entire surgical sequence at different ages: fronto-orbital advancement (0.9 years), LF III distraction osteogenesis (11.5 years) and orthognathic surgery (18 years). The mean age at the last follow up was 19.3 years; normalization of the face was obtained in all cases with improvement of the respiratory problems. After orthognathic surgery, all patients had stable occlusion. A one-year postoperative CBCT scan revealed almost complete ossification of all osteotomy sites. Frontoorbital advancement and modified Le Fort III distraction osteogenesis are reliable surgical procedures. SARME and conventional orthognathic surgery with reductive genioplasty and fat grafting are performed at the end of the surgical sequence to enhance facial aesthetics.

Dura cells in the etiopathogenesis of Crouzon syndrome: the effects of FGFR2 mutations in the dura cells on the proliferation of osteoblasts through the hippo/YAP mediated transcriptional regulation pathway

BACKGROUND

FGFR2 (fibroblast growth factor receptor 2) mutations are implicated in the etiopathogenesis of syndromic craniosynostosis, and C278F- or C342Y-FGFR2 mutations can lead to Crouzon syndrome. The dura mater exerts crucial effects in the regulation of cranial suture development. However, the underlying mechanisms of these biological processes are rarely studied. This research explored and analyzed the biological function of FGFR2 overexpressed by dura cells on cranial osteoblasts.

METHODS

Dura cells and cranial osteoblasts from C57BL/6 mice aged 6 days were obtained and cultured respectively. Lentivirus-FGFR2 constructs were engineered with C278F- and C342Y-FGFR2 mutations. The dura cells were infected with the constructs and co-cultured with osteoblasts in a trans-well system. Four experimental groups were established, namely the Oste group, the Oste+Dura-vector group, the Oste+Dura-C278F group, and the Oste+Dura-C342Y group. FACS, CCK8, and EdU assays were used to evaluate the osteoblast proliferation levels. Western blot and RT-qPCR were used to measure the expressions of the factors related to proliferation, differentiation, and apoptosis. Furthermore, the expression levels of the key factors in the Hippo/YAP-PI3K-AKT proliferation pathway were measured and analyzed. Finally, rescue experiments were performed with an RNA interfering assay.

RESULTS

The proliferation and differentiation levels of the osteoblasts in the Oste+Dura-C278F and Oste+Dura-C342Y groups were significantly up-regulated, but the apoptosis levels in the four groups were not significantly different. The YAP, TEADs1-4, p-PI3K, and p-AKT1 expressions in the mutant FGFR2 groups were higher than the corresponding expressions in the control groups, and the results of the rescue experiments showed a reverse expression tendency, which further confirmed the effects of the FGFR2 mutations in the dura cells on the proliferation of the osteoblasts and the underlying possible mechanisms.

CONCLUSION

Our studies suggest that the Crouzon mutations (C278F- and C342Y-) of FGFR2 in dura cells can enhance osteoblast proliferation and differentiation and might influence the pathogenesis of craniosynostosis by affecting the Hippo/YAP-PI3K-AKT proliferation signaling pathway.

Dental phenotype in Crouzon syndrome: A controlled radiographic study in 22 patients

OBJECTIVE

This retrospective radiographic controlled study investigates the dental phenotype in patients with Crouzon syndrome to determine if differences are observed as suggested by the FGFR2^C342Y/+ Crouzon mouse models, and whether these models could be of interest to study the role of this mutation in tooth development.

DESIGN

We assessed dental phenotype using dedicated linear measurements in 22 children with Crouzon syndrome and compared tooth morphology in both primary and permanent dentitions to an age-matched control group. Descriptive statistics were performed with "Sex" and "Age" as covariates for the permanent tooth models and "Sex" only for the primary tooth models, to take into account potential confounding factors.

RESULTS

We showed that permanent but not primary tooth dimensions were globally reduced in Crouzon syndrome, without microdontia. In permanent dentition, crown height, mesiodistal and faciolingual cervical diameters were reduced by 6.3%, 5.7% and 5.5% respectively (p < 0.05).

CONCLUSION

Our results underline the implication of Fibroblast Growth Factor Receptor 2 (FGFR2) in dental development of humans and contribute to support FGFR2^C342Y/+ Crouzon mouse models as partial replicas of this condition, including in the oral region.

Severe craniolacunae and upper and lower extremity anomalies resulting from Crouzon syndrome, FGFR2 mutation, and Ser347Cys variant

Crouzon syndrome is a rare form of syndromic craniosynostosis (SC) characterized by premature fusion of the cranial and facial sutures, elevated intracranial pressure, varying degrees of ocular exposure due to exorbitism, and airway compromise caused by midface retrusion. Craniolacunae and upper and lower extremity anomalies are not frequently found in Crouzon syndrome. We present a girl with Crouzon syndrome caused by c.1040 C > G, p.Ser347Cys, a pathogenic mutation in the FGFR2 gene with atypical characteristics, including craniolacunae resembling severe Swiss cheese type of bone formation, and upper and lower extremity anomalies which are more commonly associated with Pfeiffer syndrome patients. Distinguishing between severe Crouzon syndrome patients and patients who have mild and/or moderate Pfeiffer syndrome can be challenging even for an experienced craniofacial surgeon. An accurate genotype diagnosis is essential to distinguishing between these syndromes, as it provides predictors for neurosurgical complications and facilitates appropriate family counseling related to long-term outcomes.

Complex Airway Management in Patients with Tracheal Cartilaginous Sleeves

OBJECTIVES/HYPOTHESIS

A tracheal cartilaginous sleeve (TCS) is a rare anomaly characterized by anterior fusion of tracheal cartilages. TCS is associated with syndromic craniosynostoses including Apert, Crouzon and Pfeiffer syndromes and FGFR2, FGFR3, and TWIST1 variants. This study presents a 30-year review of patients with syndromic craniosynostosis and TCS and describes diagnostic methods, genetic variants, surgical interventions, and long-term outcomes.

STUDY DESIGN

Retrospective, single-institution review.

METHODS

This review included patients with syndromic craniosynostosis and TCS treated at Seattle Children's Hospital from 1990 to 2020. Tracheostomy, genetic variants, and additional surgery were primary measures. Fisher's exact test compared need for tracheostomy in patients with proposed high-risk (FGFR2 p.W290 or FGFR2 p.C342) versus low-risk genetic variants.

RESULTS

Thirty patients with TCS were identified. Average age at diagnosis was 12 months (range 2-weeks to 7.9-years; standard deviation 19.8 months). Syndromes included Pfeiffer (37%), Apert (37%), and Crouzon (26%). Severe obstructive sleep apnea was present in 76% of patients. Tracheostomy was performed in 17 patients (57%); five were successfully decannulated. Additional interventions included adenotonsillectomy (57%), nasal (20%), laryngeal (17%), and craniofacial skeletal surgery (87%). All patients with Pfeiffer syndrome and FGFR2 p.W290C variants and 83% of patients with FGFR2 p.C342 variants required tracheostomy, differing from other variants (P = .02, odds ratio 33, 95% confidence interval 1.56-697.96). One patient (3%) died.

CONCLUSION

TCS contributes to multilevel airway obstruction in patients with syndromic craniosynostosis. Genetic testing in patients with FGFR2-related syndromic craniosynostoses may identify those at risk of TCS and facilitate early intervention. A better understanding of this patient population may foster individualized airway management strategies and improve outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Comprehensive management of Crouzon syndrome: A case report with three-year follow-up

Crouzon syndrome is one of the most common craniosynostosis facial syndromes caused by a mutation in the fibroblast growth factor receptor 2 (FGFR2) gene. Less commonly, there is a mutation of the FGFR3 gene which results in Crouzon syndrome syndrome with acanthosis nigricans. It involves the premature fusion of sutures of the cranial vault, base, orbital and maxillary region. The clinical presentation of this congenital deformity depends on the pattern and timing of sutural fusion. The present report describes the features and management of this syndrome in an 18-year-old woman. The patient presented with a hypoplastic maxilla, deficient midface, exorbitism due to shallow orbits, severe crowding and bilateral crossbite. A multidisciplinary approach involving orthodontics and surgical intervention with distraction osteogenesis brought about marked improvement in the facial profile, occlusion and upper airway. The aesthetics and function were greatly enhanced, and the results were found to be stable at the end of three years.

Syndrome-related outcomes following posterior vault distraction osteogenesis

PURPOSE

The most commonly occurring syndromic craniosynostoses are Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, and Saethre-Chotzen syndrome. There is insufficient data regarding postoperative syndrome-related outcomes following the posterior vault distraction osteogenesis (PVDO) procedure, as well as data addressing whether or not additional procedures will be subsequently necessary to comprehensively treat children who undergo PVDO. Thus, the objective of this study is to describe and compare syndrome-related potential complications and outcomes associated with the PVDO procedure.

METHODS

An observational retrospective study was performed on consecutive patients (n=24) with Apert syndrome, Crouzon syndrome, Pfeiffer syndrome, or Saethre-Chotzen syndrome, respectively, who underwent PVDO between 2012 and 2019. Demographic data (patient gender and age when the PVDO procedure was performed), diagnosis, surgery-related data, and outcome data (perioperative and midterm complications and need for additional surgery) were verified.

RESULTS

Total relative blood transfusion volumes per kilogram for the patients were as follows: 22.75 ± 9.30 ml for Apert syndrome, 10.73 ± 2.28 ml for Crouzon syndrome (Apert versus Crouzon, p<0.05), 18.53 ± 8.08 ml for Pfeiffer syndrome, and 19.74 ± 9.12 ml for Saethre-Chotzen syndrome. None of the patients required a secondary procedure to alleviate intracranial pressure except for a Saethre-Chotzen patient.

CONCLUSION

PVDO is an effective technique to address elevated intracranial pressure in SC patients that alleviates the need for secondary procedures at midterm follow-up. Apert syndrome patients presented relatively higher total blood transfusion rates than Crouzon syndrome patients who were operated on at a later age and weighed more.

Treating Syndromic Craniosynostosis with Monobloc Facial Bipartition and Internal Distractor Devices: Destigmatizing the Syndromic Face

Monobloc and facial bipartition combined with distraction osteogenesis (MFBDO) has gained popularity over the past several years as a treatment of syndromic craniosynostosis, in part because this surgical technique effectively removes many stigmatic clinical features associated with the syndromic face. The objective of this study is to detail the surgical planning used to achieve medialization of the orbits and describe the authors' experience using MFBDO to destigmatize the syndromic face. By using MFBDO, hypertelorism, vertical orbital dystopia, and downslanting of the palpebral fissure were surgically corrected in all patients, thereby destigmatizing the syndromic face.

Disappointing results of spring-assisted cranial vault expansion in patients with Crouzon syndrome presenting with sagittal synostosis

The aim of this study was to report on a single center's experience with spring-assisted cranial vault expansion (SAE) in patients with Crouzon syndrome and sagittal suture synostosis. Strip craniotomy with SAE has resulted in successful outcomes with low complication and revision rates in patients with isolated scaphocephaly. However, recent experience suggests that outcomes in patients with Crouzon syndrome and sagittal synostosis (SS) who undergo SAE are less favorable compared with the outcomes of those who undergo frontobiparietal (FBP) expansion. The authors reviewed both operations performed at a single center and noticed an upward expansion of the skull, which may be related to ventriculomegaly, with concurrent intracranial hypertension and poor aesthetic outcome. All patients diagnosed with Crouzon syndrome and SS who were treated with SAE required a revision FBP operation. Based on this outcome, the authors consider Crouzon syndrome a contraindication for correcting SS with springs.

Virtual planning in Le Fort III distraction osteogenesis: A case series

The objective of this study is to determine the value of using 3D planning tools and 3D printed cutting guides in Le Fort III osteotomies with external frame distraction osteogenesis. The process of planning and transfer of the virtual planning to the operating room is illustrated with 5 case. The virtual planning is transferred to the operating room using a 3D-printed supra-orbital reference bar with puzzle connections for the planned osteotomy guides. Different systems are presented to transfer the vector of distraction and the position of the external midface distractor. Three-dimensional planning tools and cutting guides help to design the Le Fort III osteotomy and the distraction vector, to anticipate possible difficulties, and to avoid adverse events.

Characterization of dental pulp stem cells isolated from a patient diagnosed with Crouzon syndrome

Stem cells isolated from patients with rare diseases are important to elucidate their pathogeny and mechanisms to enable regenerative therapy. However, the mechanisms underlying tissue regeneration using patient‐derived dental pulp stem cells (DPSCs) are unclear. In this study, we investigated the levels of mRNA and protein expression related to cellular differentiation of Crouzon syndrome patient‐derived DPSCs (CS‐DPSCs) with a Gly338Arg fibroblast growth factor receptor 2 mutation. Multipotency‐related gene expression levels were equivalent in both healthy donor DPSCs and CS‐DPSCs. CS‐DPSCs showed higher osteocalcin (OCN) expression than healthy donor DPSCs. CS‐DPSCs showed a lower increase in the rate of OCN expression among phorbol 12‐myristate 13‐acetate (PMA)‐treated cells than healthy donor DPSCs compared with untreated control cells. CS‐DPSCs showed a lower phosphorylation rate of p38 and p44/42 in PMA‐treated cells than healthy donor DPSCs compared with untreated control cells. These results demonstrate that CS‐DPSCs have higher OCN expression and lower PMA stimulation‐responsiveness than healthy donor DPSCs.

Growth patterns of the airway in Crouzon syndrome patients with different types of cranial vault suture synostosis

The severity of obstructive respiratory difficulty varies among affected Crouzon syndrome patients. The aim of this study was to investigate the correlation between the restricted airway volume in Crouzon syndrome and the associated type of cranial vault suture synostosis. Computed tomography scans of 68 unoperated Crouzon syndrome patients and 89 control subjects were subgrouped into four types: type I, bilateral coronal synostosis; type II, sagittal synostosis; type III, pansynostosis; type IV, perpendicular combinations of synostoses. Measurements were made using Mimics software. Of type I Crouzon patients, 42% had a restricted nasal airway (P=0.002), while the pharyngeal airway volume was not significantly reduced. Type II Crouzon patients grew normal segmental airway volumes. Crouzon patients of type III developed simultaneously reduced nasal and pharyngeal airway volumes in infancy, by 38% (P=0.034) and 51% (P=0.014), respectively. However, the nasal airway achieved a normal volume by 2 years of age without any intervention, while the pharyngeal airway remained significantly reduced up to 6 years of age, by 42% (P=0.013), compared to controls. Type IV Crouzon patients developed a reduced nasal airway volume (32%, P=0.048) and a non-significant restricted pharyngeal airway (18%, P=0.325). Airway compromise in Crouzon syndrome is variable when associated with different craniosynostosis fusion patterns. Type II (sagittal synostosis) Crouzon patients grew a normal nasopharyngeal airway volume. Those with types I (bicoronal synostosis) and IV (perpendicular synostoses) had significantly restricted nasal airways and a tendency towards a reduced pharyngeal volume. Type III (pansynostosis) Crouzon infants had the worst restriction of both airways, although there was some improvement with age.

Racial disparity in orbital morphology and spatial relations in unoperated Crouzon patients

The altered orbital morphology of patients with Crouzon syndrome could have an impact on the planning of treatment in diverse populations, in spite of the confounding influences of different cranial suture synostosis. This study attempted to explore the differences in orbital characteristics between Asian, Caucasian patients with Crouzon syndrome, associated pansynostosis. Eighty-six preoperative computed tomograms (CT) were included (Asian Crouzon syndrome: n=10; Asian controls: n=24; Caucasian Crouzon syndrome: n=19; Caucasian controls: n=33) and measured using Mimics software (Materialise). Unique cephalometric measurements related to orbital morphology and position were designed. Crouzon syndrome and race both have interactive effects on protrusion of the globe (p=0.009) and medial horizontal angle (p=0.012) in the assessment of orbital morphology. They also interact in the width of the ethmoid sinus (p=0.009) and influence bilateral orbital relations. The anteroposterior orbital roof in Caucasian patients with Crouzon syndrome was shortened by 4.09mm (p=0.002) compared with Caucasian controls. However, in Asian patients this dimension developed normally. The anteroposterior orbital floor was significantly reduced to a similar extent in both Asian and Caucasian Crouzon patients (both p<0.001). The visual axes in Caucasian patients with Crouzon showed more inferior rotation, by 4.38° (p=0.031) than they did in Caucasian controls, but did not achieve a statistically significant difference in other comparisons. The effect of Crouzon syndrome on orbital malformation and placement is influenced by race, especially structures related to the ethmoid sinus. Asian patients need greater infraorbital advancement for better correction of orbital proptosis and aesthetic benefits, but may require less fronto-orbital advancement than Caucasian patients.

Assessment of long-term quality of life in patients with syndromic craniosynostosis

Several studies have analyzed the long-term stability of cranioplasty and midface distraction in patients with craniosynostosis; however, few studies have investigated long-term quality of life (QOL) and complications in adults with syndromic craniosynostosis. This study aimed to investigate the QOL (social, physical, and psychosocial) of patients with adult syndromic craniosynostosis. Patients aged ≥20 years with syndromic craniosynostosis, who were surgically treated at a single craniofacial institution, were included in this study. We investigated everyday inconvenience (using the World Health Organization Disability Assessment Schedule questionnaire), any ongoing treatment, marital status, and number of children. Totally, 18 patients aged 22-48 years (mean: 31.4 ± 9.2 years) answered the questionnaire (Crouzon syndrome, 9; Apert syndrome, 5; Pfeiffer syndrome, 4). Of these, only one Crouzon syndrome patient was married; she was also the only one with a child. Apert syndrome patients were found to have difficulty in understanding, communication, and self-care because of their mental retardation and hand and foot handicaps; however, their participation in society was the most aggressive. In contrast, Crouzon syndrome patients had especially poor participation in society. In all patients, any ongoing hospital treatment was due to ophthalmological conditions. Crouzon syndrome patients have extremely poor QOL; the absence of mental retardation and hand and foot handicaps forces them to live in mainstream society, for which they are emotionally ill-equipped. It is necessary to treat these patients without any residual deformity to provide psychological support and to create an accepting society.

[Advances in research on Crouzon syndrome and related ophthalmic complications]

Crouzon syndrome is an autosomal dominant disorder characterized by acrocephaly, exophthalmos, hypertelorism, strabismus, parrot-beaked nose, and hypoplastic maxilla. It is usually caused by a pathogenic mutation in the fibroblast growth factor receptor 2 gene and premature fusion of the sutures of the cranium and the base of the skull. This article documents the ophthalmic complications in patients with Crouzon syndrome before and after the influence of craniofacial surgery with particular emphasis on the different mechanisms and treatments involved. It is important to perform timely decompressive surgery before the presence of optic atrophy and corneal defects, and make early detection and adequate management of amblyopia, ptosis and strabismus. (Chin J Ophthalmol, 2020, 56: 544-548).

Genotype-Phenotype Correlation of Tracheal Cartilaginous Sleeves and Fgfr2 Mutations in Mice

OBJECTIVES

To characterize tracheal cartilage morphology in mouse models of fibroblast growth factor receptor (Fgfr2)-related craniosynostosis syndromes. To establish relationships between specific Fgfr2 mutations and tracheal cartilaginous sleeve (TCS) phenotypes in these mouse models.

METHODS

Postnatal day 0 knock-in mouse lines with disease-specific genetic variations in the Fgfr2 gene (Fgfr2^C342Y/C342Y , Fgfr2^C342Y/+ , Fgfr2^+/Y394C , Fgfr2^+/S252W , and Fgfr2^+/P253R ) as well as line-specific controls were utilized. Tracheal cartilage morphology as measured by gross analyses, microcomputed tomography (μCT), and histopathology were compared using Chi-squared and single-factor analysis of variance statistical tests.

RESULTS

A greater proportion of rings per trachea were abnormal in Fgfr2^C342Y/+ tracheas (63%) than Fgfr2^+/S252W (17%), Fgfr2^+/P253R (17%), Fgfr2^+/Y394C (12%), and controls (10%) (P < .001 for each vs. Fgfr2^C342Y/+ ). TCS segments were found only in Fgfr2^C342Y/C342Y (100%) and Fgfr2^C342Y/+ (72%) tracheas. Cricoid and first-tracheal ring fusion was noted in all Fgfr2^C342Y/C342Y and 94% of Fgfr2^C342Y/+ samples. The Fgfr2^C342Y/C342Y and Fgfr2^C342Y/+ groups were found to have greater areas and volumes of cartilage than other lines on gross analysis and μCT. Histologic analyses confirmed TCS among the Fgfr2^C342Y/C342Y and Fgfr2^C342Y/+ groups, without appreciable differences in cartilage morphology, cell size, or density; no histologic differences were observed among other Fgfr2 lines compared to controls.

CONCLUSION

This study found TCS phenotypes only in the Fgfr2^C342Y mouse lines. These lines also had increased tracheal cartilage compared to other mutant lines and controls. These data support further study of the Fgfr2 mouse lines and the investigation of other Fgfr2 variants to better understand their role in tracheal development and TCS formation.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:E1349-E1356, 2021.

Successful management of anesthesia complications in a child with Crouzon syndrome

Crouzon syndrome (CS) is a rare autosomal dominant inherited disorder caused by mutations in the fibroblast growth factor receptor 2 (FGFR2) gene. The disease is characterized by premature fusion of the coronal and sagittal sutures of the skull, resulting in clinical manifestations of midfacial hypoplasia, shallow orbit, maxillary dysplasia, and occasional upper respiratory obstruction. This article presents the case of a child aged 2 years and 7 months with CS scheduled for bilateral tonsillectomy and adenoidectomy. The patient had a difficult procedure of extubation and was reintubated and the tracheal intubation was removed 2 days after surgery. The CS is a rare condition with physical characteristics that can result in difficult airway manipulation. It is important for anesthesiologists to recognize and avoid potential airway complications in the management of such patients through detailed preoperative evaluation and careful observation after surgery to reduce perioperative risks.

Racial disparity of Crouzon syndrome in maxilla and mandible

The racial disparity of facial features in craniosynostosis patients is not fully understood. The aim of this study was to explore the difference in maxillary and mandibular morphology and spatial position in Asian and Caucasian Crouzon syndrome patients. Ninety-one computed tomography scans were included (12 Asian Crouzon syndrome patients, 22 Asian controls; 16 Caucasian Crouzon syndrome patients, 41 Caucasian controls) and measured using Materialise software. The maxillary and mandibular volumes of Asian patients were both reduced by 19% (P=0.102 and P=0.187), and those of Caucasian patients were reduced by 15% (P=0.142) and 14% (P=0.211) when compared to the respective race-specific controls. Maxilla length of Asian patients was reduced by 6.36mm (14%, P=0.003), while the reduction in Caucasian patients was 4.88mm (10%, P=0.038). ANS was retracted 11.99mm (P<0.001) in Asian patients and 11.54mm (P<0.001) in Caucasian patients. The ANB angle was narrowed by 13.17° (P<0.001) in Asian patients compared to Asian controls, and by 7.02° (P<0.001) in Caucasian patients compared to Caucasian controls. The retrusive midface profiles of Asian and Caucasian Crouzon syndrome look similar; both result from the combined effect of hypoplastic size and backward displacement. However, the insufficiency was found to be more a failure of the anteroposterior maxillary length in Asian patients, and more due to posterior maxillary positioning in Caucasian patients. Therefore, prognathism in Crouzon syndrome patients is more likely caused by displacement rather than elongation of mandibular length in both races. Crouzon syndrome results in the same extent of overall volume deficiency of the maxilla and mandible in these races.

Anomalous extraocular muscles in Crouzon syndrome with V-pattern exotropia

Strabismus associated with Crouzon syndrome is common and often complex. V-pattern strabismus is most commonly reported in this condition and is mainly thought to be due to an excyclorotation of the orbits and rectus muscle pulleys. We report two cases of children with Crouzon syndrome and V-pattern exotropia who had rectus muscle heterotopy on orbital imaging and were also found intraoperatively to have anomalous extraocular muscles. At the time of surgery, bifid insertion, misdirection, and fibrosis of extraocular muscles were noted. This highlights the various causes of V-pattern strabismus associated with Crouzon syndrome, including dysmorphic orbits and extraocular muscle anomalies.

Crouzon Syndrome in a Ten-week-old Infant: A Case Report

Crouzon syndrome is a rare genetic disorder. We report a rare case of Crouzon syndrome in a very young infant with distinct features of craniofacial malformations. A 10-week-old male child presented with features of craniofacial dysostosis with abnormal shape of the skull, proptosis, hypertelorism, curved nose and frontal bossing. Radiological findings revealed a predominant premature fusion of sagittal sutures. The infant had airway obstruction. Features of hydrocephalus, papilledema and optic atrophy were not evident. We chose to manage the symptoms and prevent complications, and the surgery was deferred for later, depending on the degree of malformation and psychological needs. Diagnosis of this rare condition at an early stage can help in preventing the development of complications. A careful follow-up and appropriate surgical intervention can improve the prognosis of this condition, which carries the risk of respiratory complications, poor vision and, in some cases, mental retardation as the age advances.

An Overview of Craniosynostosis Craniofacial Syndromes for Combined Orthodontic and Surgical Management

This article provides an overview of epidemiology, genetics, and common orofacial features of those with craniosynostosis. Patients with craniosynostosis require several surgical procedures along with continuum of care. The earliest surgical interventions are done during the first few years of life to relieve the fused sutures. Midface advancement, limited phase of orthodontic treatment, and combined orthodontics/orthognathic surgery treatment are usually required during later years. This article presents several examples of cases with outcomes associated with these procedures.

Inherited FGFR2 mutation in a Chinese patient with Crouzon syndrome and luxation of bulbus oculi provoked by trauma: a case report

Background

Crouzon syndrome (CS), which results from fibroblast growth factor receptor 2 mutations, is associated with craniosynostosis, exophthalmos, and other symptoms. Herein, we report the genetic abnormalities detected in a Chinese family with autosomal dominant CS, combined with luxation of the eyeball. This luxation was a consequence of the trauma to the shallow orbits.

Case presentation

The proband was a 4-year-old boy. He accidentally fell, following which luxation of the bulbus oculi occurred immediately. Computed tomography and magnetic resonance imaging clearly revealed ocular proptosis. Upon physical examination, the proband, his father, and grandfather had ocular proptosis, shallow orbits, and mid-face hypoplasia. However, their hands and feet were clinically normal. Genomic DNA was extracted from the peripheral blood through a polymerase chain reaction performed for the target sequence. Genetic assessments revealed a heterozygous missense mutation (c.1012G > C, p.G338R) in exon 10 of the human FGFR2, cosegregated with the disease phenotype in this family. These findings confirmed the diagnosis of CS.

Discussion

CS is usually caused by FGFR2 mutations. While there are a few reports of luxation of the bulbus oculi in Chinese families with CS, the ocular proptosis, shallow orbits, combined with luxation of eyeball after trauma observed in this patient were particularly interesting. Our findings enhance the current knowledge of traumatic luxation concomitant with CS.

An internal distraction device for midface distraction osteogenesis: The NAVID system type Z'gok

Midface advancement with distraction osteogenesis is more routinely used for faciocraniosynostosis. Distraction devices are generally classified into external and internal types. Compared with external distractors, internal distractors are smaller and better tolerated, but their removal is complicated. Here, we introduce a refined internal distraction device and describe its applicability. Unlike the previous anterior fixation plate that utilises screws, the refined internal distraction (type Z'gok) has 3 claws. This anterior point of the distractor is positioned behind the malar eminence, or the lateral orbital wall. Eight patients with syndromic craniosynostosis underwent midface distraction osteogenesis using the type Z'gok between 2016 and 2017 (Z'gok group). Twelve patients were treated using conventional internal distractors (control group). Patient age ranged from 6 to 21 years. Among them, 4 patients underwent Le Fort III distraction osteogenesis, while the others underwent Le Fort IV distraction osteogenesis. The operative time to remove the distractors in the Z'gok group was 65 ± 18 min, shorter than 89 ± 12 min in the control group. The blood loss per kilogram of body weight in the Z'gok and control groups was 3.6 ± 3.3 mL/kg and 4.7 ± 1.7 mL/kg, respectively. In conclusion, the type Z'gok is a reliable and effective internal distractor for midface distraction osteogenesis.

[Crouzon syndrome with secretory otitis media: a case report and literature review]

Summary Clinical data from a case of Crouzon syndrome with secretory otitis media in our department was collected and the related literatures were reviewed. Whole exome sequecing and Sanger sequencing were performed to analyze genetic cause. The 6-year old patient with Crouzon syndrome had snoring and mouth breathing during sleep for 2 years, and was found hearing loss for 2 weeks. The results of endoscopy showed adenoid hypertrophy and secretory otitis media of both ears. And CT scan proved chronic rhinosinusitis. Myringotomy and adenoidectomy were done under general anesthesia. The follow-up at 6 months showed normal sleep and hearing level. A heterozygous fibroblast growth factor receptor 2 missense mutation（c.1061C>G, p.S354C） in exon 8 was identified in this patient.

Extremely severe scoliosis, heterotopic ossification, and osteoarthritis in a three-generation family with Crouzon syndrome carrying a mutant c.799T>C FGFR2

Background

Crouzon syndrome is a rare and complex autosomal dominant craniosynostosis syndrome with a prevalence of approximately 1 in 60,000 births. The typical features are craniosynostosis, proptosis, midfacial hypoplasia, and noncranial manifestations, including deformities in the cervical spine, elbow, and fingers. Crouzon syndrome is usually caused by pathogenic variants in the fibroblast growth factor receptor 2 (FGFR2) gene.

Methods

We reported a three‐generation family with Crouzon syndrome; the proband showed extremely severe limb abnormalities. The clinical features were obtained by physical examination and radiographic examination. Sanger sequencing of all 18 exons of FGFR2 was conducted to identify the disease‐causing mutation.

Results

The proband was a 44‐year‐old man who showed characteristics of Crouzon syndrome, including craniofacial dysostosis, shallow orbits, proptosis, midface hypoplasia, beaked nose, strabismus, short superior lip, short stature, and neck injection. In addition to these typical characteristics, radiographic examination showed severe scoliosis, heterotopic ossification of the elbows, knee osteoarthritis, metacarpophalangeal joint valgus, collapse of the articular surface of the thumb metacarpal, knuckle ossification and fusion. Sanger sequencing identified a heterozygous pathogenic variant c.799T>C, p.(Ser267Pro) in exon 7 of FGFR2 in affected individuals.

Conclusion

Crouzon syndrome in this three‐generation family was caused by c.799T>C FGFR2, and the patient showed a different phenotypic appearance from other Crouzon patients with c.799T>C FGFR2.

Is It Safe To Use Frontofacial Monobloc Advancement and Cutting Guides on Adult Patients with Crouzon Syndrome? Introducing 2 Cases on 41- and 56-Year-Old Patients

BACKGROUND

Patients with Crouzon syndrome are mainly treated in childhood by frontofacial monobloc advancement to avoid ophthalmic, neurologic, and maxillary complications. There is no reported case of surgery on adult patients with Crouzon syndrome in the literature. However, when faced with 2 cases of adult patients showing severe quality of life deterioration, our team decided to make an attempt using monobloc advancement technique.

CASE DESCRIPTION

Two women aged 41 and 56 presented with untreated Crouzon syndrome and suffered from exorbitism, intracranial hypertension with chronic headaches, and hypoplastic maxillary. We decided to perform frontofacial monobloc advancement with internal distraction despite their advanced age using planned surgery and cutting guides. Distraction began 7-10 days after surgery and was of 15 mm. Distractors were taken off at 6 months. Surgical treatment corrected chronic headaches, ocular symptoms due to exorbitism, and hypoplastic maxillary. Patients were satisfied with the functional and aesthetic results. We noticed that this heavy surgery was more difficult to bear by these adults than children.

CONCLUSIONS

Adults with craniofacial malformations have a lower self-esteem, lower quality of life, and less satisfaction with their facial look as compared with individuals without facial malformations. There is also an increased risk of psychosocial problems. Despite postoperative difficulties and minor complications, our 2 patients were satisfied with the functional and aesthetic results. This led to the conclusion that surgically addressing adult patients with Crouzon syndrome via monobloc advancement is appropriate and secure when performed by a trained team.

Mandibular dysmorphology due to abnormal embryonic osteogenesis in FGFR2-related craniosynostosis mice

One diagnostic feature of craniosynostosis syndromes is mandibular dysgenesis. Using three mouse models of Apert, Crouzon and Pfeiffer craniosynostosis syndromes, we investigated how embryonic development of the mandible is affected by fibroblast growth factor receptor 2 (Fgfr2) mutations. Quantitative analysis of skeletal form at birth revealed differences in mandibular morphology between mice carrying Fgfr2 mutations and their littermates that do not carry the mutations. Murine embryos with the mutations associated with Apert syndrome in humans (Fgfr2^+/S252W and Fgfr2^+/P253R) showed an increase in the size of the osteogenic anlagen and Meckel's cartilage (MC). Changes in the microarchitecture and mineralization of the developing mandible were visualized using histological staining. The mechanism for mandibular dysgenesis in the Apert Fgfr2^+/S252W mouse resulting in the most severe phenotypic effects was further analyzed in detail and found to occur to a lesser degree in the other craniosynostosis mouse models. Laser capture microdissection and RNA-seq analysis revealed transcriptomic changes in mandibular bone at embryonic day 16.5 (E16.5), highlighting increased expression of genes related to osteoclast differentiation and dysregulated genes active in bone mineralization. Increased osteoclastic activity was corroborated by TRAP assay and in situ hybridization of Csf1r and Itgb3. Upregulated expression of Enpp1 and Ank was validated in the mandible of Fgfr2^+/S252W embryos, and found to result in elevated inorganic pyrophosphate concentration. Increased proliferation of osteoblasts in the mandible and chondrocytes forming MC was identified in Fgfr2^+/S252W embryos at E12.5. These findings provide evidence that FGFR2 gain-of-function mutations differentially affect cartilage formation and intramembranous ossification of dermal bone, contributing to mandibular dysmorphogenesis in craniosynostosis syndromes.

This article has an associated First Person interview with the joint first authors of the paper.

Summary: FGFR2 gain-of-function mutations differentially affect cartilage formation and intramembranous ossification of dermal bone, resulting in abnormal embryonic osteogenesis of the mandible.

Evolution of the phenotype of craniosynostosis with dental anomalies syndrome and report of IL11RA variant population frequencies in a Crouzon-like autosomal recessive syndrome

In 2011, biallelic loss-of-function variants in the interleukin receptor 11 alpha gene IL11RA were found to be associated with a Crouzon-like craniosynostosis syndrome with associated dental anomalies (CRSDA). Since then, a total of 41 similar patients have been reported with IL11RA variants. We report two adult brothers diagnosed with Crouzon syndrome as children, in which the clinical diagnosis of CRSDA was made on reevaluation. Laboratory testing detected biallelic IL11RA variants, c.916_924dup (p.Thr306_Ser308dup) and c.781C > T (p.Arg261Cys), both of which have now been reported in other families. Protein modeling and conservation analysis show that these two mutation sites cluster together near a WSXWS motif that likely plays a significant role in regulating IL11RA protein function. Population analysis from gnomAD shows that Non-Finnish Europeans (similar to ethnicity of this family), have an allele frequency for p.Thr306_Ser308dup of 0.014% and p.Arg261Cys of 0.008%. We found other ethnicities have functional IL11RA missense variants at higher frequencies. With this report, we provide a summary of the clinical findings including details of middle ear anomalies associated with conductive hearing loss. We also provide data supporting the populations at risk for this condition to increase recognition and diagnosis of this rare autosomal recessive craniosynostosis syndrome.

Detection of G338R FGFR2 mutation in a Vietnamese patient with Crouzon syndrome

Crouzon syndrome is a rare autosomal dominant genetic disorder, which causes the premature fusion of the cranial suture. Fibroblast growth factor receptor 2 (FGFR2) mutations are well-known causatives of Crouzon syndrome. The current study aimed to assess the FGFR2 gene associated with Crouzon syndrome in a Vietnamese family of three generations and to characterize their associated clinical features. The family included in the present study underwent complete clinical examination. A patient was clinically examined and presented with typical features of Crouzon syndrome including craniosynostosis, shallow orbits, ocular proptosis and midface hypoplasia. However the patient had normal hands and feet, a normal hearing ability and normal intelligence. Genomic DNA collected from all family members (except from a 16 week-old-foetus) and 200 unrelated control subjects from the same population was extracted from leukocytes obtained from peripheral blood samples. Genomic DNA was extracted from the 16-week-old foetus via the amniotic fluid of the mother. All coding sequences of FGFR2 were amplified via polymerase chain reaction and directly sequenced. A heterozygous FGFR2 missense mutation (c.1012G>C, p.G338R) in exon 10 was identified in the patient with Crouzon but not in other family members, the 16 week-old-foetus or the controls. This mutation was therefore determined to be the causative agent of Crouzon syndrome. In addition, a novel heterozygous silent mutation (c.1164C>T, p.I388I) in exon 11 of the FGFR2 gene was identified in the patient with Crouzon, his mother and the 16-week-old fetus, but not in other family members. The mutation in exon 10 of FGRF2 was confirmed via restriction-enzyme digestion. The gain of the BsoBI site confirmed the FGFR2 mutation in exon 10 of the patient with Crouzon. This molecular finding may provide useful information to aid clinicians in the diagnosis of Crouzon syndrome and may also aid early prenatal diagnoses.

Correlation between Papilledema and Intracranial Hypertension in Crouzon Syndrome: A Case Report and Review of the Literature

Crouzon syndrome represents the most common syndromic craniosynostosis. Ocular complications are frequent, including papilledema and optic atrophy, often related to increased intracranial pressure (ICP). However, there is a poor correlation between ICP normalization and resolution of papilledema. We describe the case of a 6-month-old infant who presented with typical phenotypic features of Crouzon syndrome. Pre- and postoperative ICP monitoring was used. Papilledema persisted despite ICP improvement after decompressive craniectomy. Possible causes of papilledema in this syndromic craniosynostosis are discussed in light of the existing literature.

Midface and upper airway dysgenesis in FGFR2-related craniosynostosis involves multiple tissue-specific and cell cycle effects

Midface dysgenesis is a feature of more than 200 genetic conditions in which upper airway anomalies frequently cause respiratory distress, but its etiology is poorly understood. Mouse models of Apert and Crouzon craniosynostosis syndromes exhibit midface dysgenesis similar to the human conditions. They carry activating mutations of Fgfr2, which is expressed in multiple craniofacial tissues during development. Magnetic resonance microscopy of three mouse models of Apert and Crouzon syndromes revealed decreased nasal passage volume in all models at birth. Histological analysis suggested overgrowth of the nasal cartilage in the two Apert syndrome mouse models. We used tissue-specific gene expression and transcriptome analysis to further dissect the structural, cellular and molecular alterations underlying midface and upper airway dysgenesis in Apert Fgfr2^+/S252W mutants. Cartilage thickened progressively during embryogenesis because of increased chondrocyte proliferation in the presence of Fgf2 Oral epithelium expression of mutant Fgfr2, which resulted in a distinctive nasal septal fusion defect, and premature facial suture fusion contributed to the overall dysmorphology. Midface dysgenesis in Fgfr2-related craniosynostosis is a complex phenotype arising from the combined effects of aberrant signaling in multiple craniofacial tissues.