A clinical study of the craniofacial features in Apert syndrome

Three-dimensional quantification of soft tissue changes and its relationship to skeletal changes after Le Fort III, monobloc, and facial bipartition in syndromic craniosynostosis

To determine the effect of midface surgery on soft tissue changes and their relationship to hard tissue changes in patients with syndromic craniosynostosis. A retrospective analysis of patients who had undergone Le Fort III (LFIII), monobloc (MB), or facial bipartition (FB) was conducted. A 3D soft tissue mesh was generated from the preoperative scan and registered to the postoperative scan, after which the advancement was visualised. A total of 68 patients were included: 28 had undergone LFIII, 27 MB, and 13 FB. The included diagnoses were Apert (n = 23), Crouzon (n = 34), and craniofrontonasal syndrome (n = 11). After LFIII, most soft tissue advancement was seen around subnasale and pronasale (mean 15.1 ± 5.9 mm and 14.7 ± 5.7 mm, at age 7-12 years). After MB, a greater hard tissue than soft tissue advancement was seen for most landmarks, showing a high positive correlation. In patients undergoing FB without distraction (n = 10), mean preoperative inter-canthal distance was 48.9 mm, this reduced by 6.9 mm postoperatively. This study provides a comprehensive overview of the outcomes after midface surgery using 3D quantification for a better understanding of the soft tissue changes and their relationship to hard tissue changes.

Orbital and Eyelid Characteristics, Strabismus, and Intracranial Pressure Control in Apert Children Treated by Endoscopic Strip Craniectomy versus Fronto-Orbital Advancement

Apert syndrome is characterized by eyelid dysmorphology, V-pattern strabismus, extraocular muscle excyclorotation, and elevated intracranial pressure (ICP). We compare eyelid characteristics, severity of V-pattern strabismus, rectus muscle excyclorotation, and ICP control in Apert syndrome patients initially treated by endoscopic strip craniectomy (ESC) at about 4 months of age versus fronto-orbital advancement (FOA) performed about 1 year of age.

Methods

Twenty-five patients treated at Boston Children's Hospital met inclusion criteria for this retrospective cohort study. Primary outcomes were magnitude of palpebral fissure downslanting at 1, 3, and 5 years of age, severity of V-pattern strabismus, rectus muscle excyclorotation, and interventions to control ICP.

Results

Before craniofacial repair and through 1 year of age, none of the studied parameters differed for FOA versus ESC treated patients. Palpebral fissure downslanting became statistically greater for those treated by FOA by 3 (P < 0.001) and 5 years of age (P = 0.001). Likewise, severity of palpebral fissure downslanting correlated with severity of V-pattern strabismus at 3 (P = 0.004) and 5 (P = 0.002) years of age. Palpebral fissure downslanting and rectus muscle excyclorotation were typically coexistent (P = 0.053). Secondary interventions to control ICP were required in four of 14 patients treated by ESC (primarily FOA) and in two of 11 patients initially treated by FOA (primarily third ventriculostomy) (P = 0.661).

Conclusions

Apert patients initially treated by ESC had less severe palpebral fissure downslanting and V-pattern strabismus, normalizing their appearance. Thirty percent initially treated by ESC required secondary FOA to control ICP.

Three-Dimensional Evaluation of Dental Arches in Individuals with Syndromic Craniosynostosis

Objective

Individuals with syndromic craniosynostosis present alterations in the dental arches due to anomalies caused by the early fusion of the craniomaxillary sutures. This study aimed to compare intradental and interdental dimensions between individuals with Apert and Crouzon syndromes and nonsyndromic controls.

Materials and Methods

Digital models were obtained from the archive of a public tertiary care hospital. The sample consisted of 34 patients (Apert n = 18, Crouzon n = 16) and 34 nonsyndromic controls matched for gender and age. Measurements of perimeter, length, intercanine and intermolar distances (upper and lower), overjet, and molar ratio were performed. Statistical comparisons were performed using ANOVA and Tukey tests (p < 0.05).

Results

Patients with Apert and Crouzon syndromes have severely reduced maxillary transverse dimensions, perimeter, and length of the upper arch compared to the control group (p < 0.001). The lower arch is less impacted. Patients with Apert syndrome had an anterior crossbite (p < 0.001), while patients with Crouzon syndrome had an edge-to-edge bite (p <  0.011). Patients with Apert and Crouzon syndromes do not have serious transverse proportion problems when comparing the upper and lower arches.

Conclusions

In this sample, both the Apert and Crouzon groups have severely compromised upper arches compared to the control group. Mild dentoalveolar expansion in the maxilla should be sufficient for the transverse adaptation of the dental arches before frontofacial advancement.

Cleft Palate in Apert Syndrome

Apert syndrome is a rare genetic disorder characterized by craniosynostosis, midface retrusion, and limb anomalies. Cleft palate occurs in a subset of Apert syndrome patients. Although the genetic causes underlying Apert syndrome have been identified, the downstream signaling pathways and cellular mechanisms responsible for cleft palate are still elusive. To find clues for the pathogenic mechanisms of palatal defects in Apert syndrome, we review the clinical characteristics of the palate in cases of Apert syndrome, the palatal phenotypes in mouse models, and the potential signaling mechanisms involved in palatal defects. In Apert syndrome patients, cleft of the soft palate is more frequent than of the hard palate. The length of the hard palate is decreased. Cleft palate is associated most commonly with the S252W variant of FGFR2. In addition to cleft palate, high-arched palate, lateral palatal swelling, or bifid uvula are common in Apert syndrome patients. Mouse models of Apert syndrome display palatal defects, providing valuable tools to understand the underlying mechanisms. The mutations in FGFR2 causing Apert syndrome may change a signaling network in epithelial–mesenchymal interactions during palatogenesis. Understanding the pathogenic mechanisms of palatal defects in Apert syndrome may shed light on potential novel therapeutic solutions.

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.

Frontofacial Reconstruction Technique Modification with Preservation of Blood Supply to the Monobloc Segment

ABSTRACT

Craniosynostosis syndromes, including Apert Syndrome, Pfeiffer Syndrome, and Crouzon Syndrome, share similar phenotypes, including bicoronal craniosynostosis, midface hypoplasia, hypertelorism, and exorbitism. The standard surgical treatment for these craniofacial abnormalities is monobloc osteotomy with distraction osteogenesis. Complications of this technique include the failure of osteogenesis or resorption of the frontal bone. The authors propose an alternative surgical technique with a frontal arch in continuity with the midface segment to ensure vascularization to anterior and posterior borders of distraction. A case report of an 8-year-old female patient with Apert Syndrome is reported using our technique. Our frontal arch monobloc distraction procedure preserves blood supply to a cranial component of the monobloc segment site that becomes the anterior portion of distraction rather than with the traditional devascularized frontal bone flap. This technique modification should improve osteogenesis outcomes by preventing resorption or failure of bone formation.

Update in Management of Craniosynostosis

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand the craniofacial dysmorphology of craniosynostosis, and the variation of each type. 2. Identify the functional concerns and learn the rationale behind timing of operative intervention. 3. Approach each dysmorphology critically and identify the operative intervention needed to improve form and function 4. Understand and address the specific issues related to syndromic craniosynostosis and be able to delineate management plan.

SUMMARY

Craniosynostosis is a condition in which premature fusion of one or more cranial sutures lead to abnormal head shape and growth restriction of the brain. Nonsyndromic craniosynostosis occurs in isolation, and usually involves a single suture, whereas syndromic craniosynostosis may involve multiple sutures and is associated with extracraniofacial findings. Although surgical management can be similar, the treatment plan must take into consideration issues specific to the syndromes. This article aims to provide a concise overview of the authors' current understanding regarding the presentation, treatment principle, surgical option, and debates in craniosynostosis.

Differential diagnosis of syndromic craniosynostosis: a case series

Purpose

Syndromic craniosynostosis is a rare genetic disease caused by premature fusion of one or multiple cranial sutures combined with malformations of other organs. The aim of this publication is to investigate sonographic signs of different syndromic craniosynostoses and associated malformations to facilitate a precise and early diagnosis.

Methods

We identified in the period of 2000–2019 thirteen cases with a prenatal suspected diagnosis of syndromic craniosynostosis at our department. We analyzed the ultrasound findings, MRI scans, genetic results as well as the mode of delivery, and postnatal procedures.

Results

Eight children were diagnosed with Apert Syndrome, two with Saethre Chotzen syndrome, one with Crouzon syndrome, and one with Greig cephalopolysyndactyly syndrome. One child had a mutation p.(Pro253Leu) in the FGFR2 gene. We identified characteristic changes of the head shape as well as typical associated malformations.

Conclusion

Second trimester diagnosis of syndromic craniosynostosis is feasible based on the identified sonographic signs. In case of a suspected diagnosis a genetic, neonatal as well as surgical counseling is recommended. We also recommend to offer a fetal MRI. The delivery should be planned in a perinatal center.

Craniofacial, oral, and cervical morphological characteristics in Japanese patients with Apert syndrome or Crouzon syndrome

BACKGROUND AND OBJECTIVES

Mutations in the fibroblast growth factor receptor 2 (FGFR2) gene are responsible for both Apert syndrome (AS) and Crouzon syndrome (CS). These diseases share phenotypic characteristics, including midfacial hypoplasia and premature fusion of the calvarial suture(s). Given the extensive range of craniofacial growth and developmental abnormalities, management of these patients requires a multidisciplinary approach. This study aimed to compare craniofacial, oral, and cervical morphological characteristics in Japanese orthodontic patients with AS or CS.

SUBJECTS AND METHODS

Lateral cephalograms, orthopantomograms, dental casts, medical interview records, facial photographs, and intraoral photographs of 7 AS patients and 12 CS patients on initial visits were used in this study. Cephalometric analyses were performed, and standard scores were calculated based on age- and sex-matched Japanese standard values.

RESULTS

Cephalometric analysis revealed that AS patients had significantly more severe maxillary hypoplasia in two dimensions and increased clockwise mandibular rotation. Additionally, cleft of the soft palate, anterior open bite, severe crowding in the maxillary dental arch, and congenitally missing teeth occurred more frequently among AS patients. Multiple fusions between cervical vertebrae C2, C3, C5, and C6 were observed in the AS patients.

LIMITATIONS

Small sample size.

CONCLUSIONS/IMPLICATIONS

Our study shows that AS patients have more severe craniofacial and maxillofacial deformities than CS patients.

Lefort II distraction with zygomatic repositioning versus Lefort III distraction: A comparison of surgical outcomes and complications

The aim of the study was to determine if the additional surgical complexity of Lefort II distraction with zygomatic repositioning (LF2ZR) results in increased complications compared to Lefort III distraction (LF3). A retrospective review was performed of all LF3 and LF2ZR advancements performed by the senior author over 15 years. Demographic, operative, postoperative, and cephalometric data were collected from initial procedure through greater than 1 year postoperatively. Univariate and multivariate analyses were performed to compare procedures. 19 LF2ZR and 39 LF3 in 53 patients met inclusion criteria. Diagnoses differed between procedures, with more Crouzon Syndrome in LF3 and more Apert Syndrome in LF2ZR. Complication rate was 7/19 for LF2ZR and 12/39 for LF3 with no severe morbidity or mortality, and no difference between procedures (p = 0.56). The types of complications encountered differed between procedures. LF2ZR had a significantly longer operative time (506 ± 18 vs. 358 ± 24 min, p<0.001). However, a greater number of LF2ZR patients underwent concomitant procedures (15/19 vs. 13/39, p<0.001). Multivariate analysis revealed that Apert Syndrome and reoperative midface advancement were the most significant predictors of increased blood loss. LF2ZR has an equivalent complication rate to LF3. Therefore, it is our treatment of choice for cases requiring differential sagittal and vertical distraction of the central midface.

Apert syndrome diagnosed by prenatal ultrasound combined with magnetic resonance imaging and whole exome sequencing: A case report

BACKGROUND

Most cases of Apert syndrome (AS) are found after birth. Cases of AS diagnosed by ultrasound combined with magnetic resonance imaging (MRI) and whole exome sequencing (WES) during pregnancy are rare.

CASE SUMMARY

We present the case of a 34-year old female patient (gravida 2, para 1) whose fetus was diagnosed with AS during pregnancy. Fetal ultrasound performed at 30, 2/7 wk of pregnancy showed abnormalities. MRI and three-dimensional ultrasound performed at 31, 1/7 wk of pregnancy showed the possibility of AS. Chromosome examination and core family WES were conducted at 31, 5/7 wk of pregnancy. The results showed that FGFR2 in the fetus had a c.755C>G missense mutation in its nucleotide, and AS was confirmed.

CONCLUSION

This case highlights the importance of imaging examinations. Prenatal ultrasound combined with MRI can identify fetal morphological abnormalities accurately, which can be confirmed by WES.

Apert syndrome: Cranial procedures and brain malformations in a series of patients

Background:

Apert syndrome is one of the most severe craniofacial disorders. This study aims to describe the craniofacial surgeries and central nervous system malformations of a cohort of children with Apert syndrome treated in the past 20 years and to compare these data with previously published data.

Methods:

Retrospective analysis of a series of patients with Apert syndrome treated between 1999 and 2019 in our hospital. Information was analyzed regarding craniofacial procedures, hydrocephalus and presence of shunts, Chiari malformation Type 1, and other brain malformations such as corpus callosum and septum pellucidum anomalies.

Results:

Thirty-seven patients were studied. Ventriculoperitoneal shunt prevalence was 24.3%, and 8.1% of patients required decompressive surgery for Chiari malformation. All of them needed at least one cranial vault remodeling procedure. The median age for this procedure was 8 months. In 69.7% of patients, the first cranial vault intervention was performed in the fronto-orbital region. In 36.4% of patients, a midface advancement had been performed at the time of this review, although this proportion was very dependent on the follow-up period and the age of the patients. The median age for the midface advancement procedure was 5.25 years. Anomalies of the corpus callosum and the septum pellucidum were reported in 43.2% and 59.5% of patients, respectively.

Conclusion:

Apert syndrome is a type of syndromic craniosynostosis, and patients usually require one or more cranial and facial surgeries. In comparison with other syndromic craniosynostosis types, Apert syndrome less frequently requires a VP shunt or treatment for a Chiari malformation.

Morphometry and morphology of rostral cranial fossa in brachycephalic dogs - CT studies

Hydrocephalus occurs more often in brachycephalic individuals of different species. Detailed analysis of rostral cranial fossa–region of cerebrospinal fluid outflow–is necessary to understand causes leading to hydrocephalus in specimens with shortened skull. The objective of the study was to determine morphology and morphometry of rostral cranial fossa in brachycephalic dogs. Skulls of 126 dogs of different breeds and morphotypes were examined using computed tomography. Linear and volumetric measurement in the region of rostral cranial fossa and skull base were made. In brachycephalic dogs there is shortening of rostral cranial fossa which is linked with the volume reduction of this region. There are differences in skull base shape between brachycephalic dogs and other morphotypes. Similarities between brachycephalic dogs and patients with craniosynostoses were noted.

Circummaxillary Sutures in Patients With Apert, Crouzon, and Pfeiffer Syndromes Compared to Nonsyndromic Children: Growth, Orthodontic, and Surgical Implications

OBJECTIVE

To evaluate patency of circummaxillary sutures in children with Apert, Crouzon, and Pfeiffer Syndromes and to compare it to a nonsyndromic matched control group.

DESIGN

Case-control study.

SETTING

Tertiary care public hospital.

MATERIALS AND METHODS

Thirty-eight computed tomography (CT) scans of patients affected by syndromic craniofacial synostosis (13 patients with Apert syndrome, 20 patients with Crouzon syndrome, and 5 patients with Pfeiffer syndrome), average age 5 ± 2.8 years, range 1.9 to 12 years, were compared to age- and sex-matched control CTs of 38 nonsyndromic children. Computed tomography scans of the study group had to be performed prior to any midfacial surgery.

MAIN OUTCOME MEASURES

Midpalatal suture, zygomaticomaxillary sutures, and pterigomaxillary sutures were evaluated and scored.

RESULTS

The syndromic group showed a significant earlier ossification of all sutures compared to the nonsyndromic group. Significant differences were already present in early childhood and continued through adolescence.

CONCLUSIONS

Based on the differences in terms of maxillary sutural ossification identified, midfacial hypoplasia does not seem to be only secondary to premature cranial base ossification, but also to primary synostosis of facial sutures, thus providing new insights into the pathogenesis of midface deficiency in children with craniofacial-synostosis. Care should be taken when planning any maxillary orthopedics, such as expansion or maxillary protraction, given the high frequency of early fusion of circummaxillary sutures.

Unilateral Coronal Craniosynostosis in an Apert-Like Patient

Background and Significance

Apert syndrome is a congenital disorder of patients who typically present with bilateral coronal craniosynostosis and varying degrees of complex syndactyly of the hands and feet, among other features. We describe a unique presentation of a rare Apert-like patient with unilateral coronal craniosynostosis and complex syndactyly of the hands and feet.

Case Report

A 2-year-old male patient presented to the craniofacial clinic with his mother due to a concerning head shape. The patient also had bilateral syndactyly of the hands and feet and underwent prior surgical release of the third web space. Computerized tomography of the head illustrated a small open anterior fontanelle, a left harlequin orbit, complete left coronal craniosynostosis, and a patent right coronal suture. The patient subsequently underwent fronto-orbital advancement for expansion of the cranial vault and correction of the asymmetric forehead and orbit. The procedure resulted in improvement of his deformity.

Conclusion

This case illustrates a unique presentation of an acrocephalosyndactyly (ACS) syndrome with asymmetric, unilateral coronal craniosynostosis and complete complex syndactyly of the hands and feet that is most consistent with Apert syndrome. Although the majority of patients with ACS can be categorized into known syndromes, other more unusual presentations must still be considered. Such unique cases are exceedingly rare and only through additional reporting and review of unique phenotypes can new subtypes of common ACS syndromes be classified.

Spatial and temporal changes of midface in Apert's syndrome

The dysplastic maxilla and retracted zygoma characterize Apert's syndrome. The relationship between the cranial base and facial development is believed to be influential and substantial. The purpose of this study is to explore the temporal relationships of maldevelopment of these structures to identify potential influence patterns. Fifty-four CT scans (unoperated Apert's, n = 18; control, n = 36) were included and divided into three age subgroups (0-6 months, 6 months-2 years, and 2-6 years). All measurements were analyzed by Materialize software. Cephalometrics relating to midface and cranial base were collected. In anteroposterior direction, prior to 6 months, the zygoma was markedly retruded by 12% in Apert's, followed by persistent retrusive shape into adulthood, averaging 17% shorter compared to controls. The maxillary anteroposterior dimension was 22% shorter than normal before 6 months of age, thereafter, it maintained at least an 18% deficiency into adulthood. In the horizontal direction, the transverse width of the zygoma increased 39% between 6 months and 2 years of age, and it was 14% wider on average overall into adulthood. The maxilla had normal growth in transverse and vertical directions. The zygoma is the most severely deformed anatomic facial structure in early infancy, in both positional relation and geometric shape in Apert's syndrome. This may develop as a 'bridge', influencing the structure, transmitting malformation stresses, caused by premature fused coronal and peri-zygomatic sutures, into facial structures and the maxilla.

Choanal Atresia and Craniosynostosis: Development and Disease

A number of textbooks, review articles, and case reports highlight the potential comorbidity of choanal atresia in craniosynostosis patients. However, the lack of a precise definition of choanal atresia within the current craniosynostosis literature and widely varying methods of detection and diagnosis have produced uncertainty regarding the true coincidence of these conditions. The authors review the anatomy and embryologic basis of the human choanae, provide an overview of choanal atresia, and analyze the available literature that links choanal atresia and craniosynostosis. Review of over 50 case reports that describe patients diagnosed with both conditions reveals inconsistent descriptions of choanal atresia and limited use of definitive diagnostic methodologies. The authors further present preliminary analysis of three-dimensional medical head computed tomographic scans of children diagnosed with craniosynostosis syndromes (e.g., Apert, Pfeiffer, Muenke, and Crouzon) and typically developing children and, although finding no evidence of choanal atresia, report the potentially reduced nasal airway volumes in children diagnosed with Apert and Pfeiffer syndromes. A recent study of the Fgfr2c Crouzon/Pfeiffer syndrome mouse model similarly found a significant reduction in nasal airway volumes in littermates carrying this FGFR2 mutation relative to unaffected littermates, without detection of choanal atresia. The significant correlation between specific craniosynostosis syndromes and reduced nasal airway volume in mouse models for craniosynostosis and human pediatric patients indicates comorbidity of choanal and nasopharyngeal dysmorphologies and craniosynostosis conditions. Genetic, developmental, and epidemiologic sources of these interactions are areas particularly worthy of further research.

Dual Segmental Distraction Osteogenesis of the Midface in a Patient with Apert Syndrome

Objective

To present orthodontic treatment combined with dual segmental distraction osteogenesis in a patient with Apert syndrome.

Patient

A 15-year-old boy exhibited severe midfacial hypoplasia with retruded and hypoplastic maxilla and anterior open bite. The patient was treated with a rigid external distraction II system for distraction osteogenesis, a preadjusted edgewise appliance, and a modified maxillary protraction headgear. The concave profile with midfacial hypoplasia was improved. A tight occlusal relationship between maxillary and mandibular teeth was achieved. Postoperative treatment results have been stable for 1 year.

Dental approach for Apert syndrome in children: a systematic review

Background

Apert Syndrome (AS), or type I acrocephalosyndactyly, is a rare, congenital craniosynostosis condition resulting from missense mutations in the gene encoding fibroblast growth factor receptor 2. It is characterized by three specific clinical features: brachycephalic skull; midface hypoplasia, and limb abnormalities (syndactyly of hands and feet). The disorder exhibits variable presentations in bones, brain, skin, internal organs, and in the oral/maxillofacial region. The aim of the present paper was to show the main results from a systematic review of AS.

Material and Methods

A search of the literature was performed from April to June 2016 in five electronic databases. Clinical interventional or observational studies, reviews, and case reports were included. The present systematic review was carried out strictly following PRISMA and Cochrane Collaboration criteria.

Results

A total of 129 potential references were identified. After reviewing titles and abstracts, 77 of these did not meet the desired criteria and were discarded. The full text of the remaining 52 manuscripts was critically screened. Finally, 35 relevant papers were identified for inclusion in the present systematic review and classified according to topic type.

Conclusions

According to the information gathered, dentistry practitioners must be able to supply an early diagnosis through the recognition of AS clinical features and provide correct oral management. Additionally, they should be integrated in a multidisciplinary medical care team in order to improve the quality of life of the affected patients.

Key words:Apert syndrome, acrocephalosyndactyly, craniosynostosis, skeletal dysplasias, systematic review.

Deformed Skull Morphology Is Caused by the Combined Effects of the Maldevelopment of Calvarias, Cranial Base and Brain in FGFR2-P253R Mice Mimicking Human Apert Syndrome

Apert syndrome (AS) is a common genetic syndrome in humans characterized with craniosynostosis. Apert patients and mouse models showed abnormalities in sutures, cranial base and brain, that may all be involved in the pathogenesis of skull malformation of Apert syndrome. To distinguish the differential roles of these components of head in the pathogenesis of the abnormal skull morphology of AS, we generated mouse strains specifically expressing mutant FGFR2 in chondrocytes, osteoblasts, and progenitor cells of central nervous system (CNS) by crossing Fgfr2^+/P253R-Neo mice with Col2a1-Cre, Osteocalcin-Cre (OC-Cre), and Nestin-Cre mice, respectively. We then quantitatively analyzed the skull and brain morphology of these mutant mice by micro-CT and micro-MRI using Euclidean distance matrix analysis (EDMA). Skulls of Col2a1-Fgfr2^+/P253R mice showed Apert syndrome-like dysmorphology, such as shortened skull dimensions along the rostrocaudal axis, shortened nasal bone, and evidently advanced ossification of cranial base synchondroses. The OC-Fgfr2^+/P253R mice showed malformation in face at 8-week stage. Nestin-Fgfr2^+/P253R mice exhibited increased dorsoventral height and rostrocaudal length on the caudal skull and brain at 8 weeks. Our study indicates that the abnormal skull morphology of AS is caused by the combined effects of the maldevelopment in calvarias, cranial base, and brain tissue. These findings further deepen our knowledge about the pathogenesis of the abnormal skull morphology of AS, and provide new clues for the further analyses of skull phenotypes and clinical management of AS.

Apert syndrome with S252W FGFR2 mutation and characterization using Phenomizer: An Indian case report

Human genetic disease needs differential diagnosis to optimize clinical management, enable prenatal detection, and genetic counselling. The current methods of robust DNA sequencing also require next generation phenotyping to match with for better interpretation of genotypic and phenotypic heterogeneity commonly observed. We report use of human ontology based phenotypic characterization with Phenomizer that gives statistical score for possible diagnoses based on which, the gene mutation was studied. A case of craniosynostosis which refers to a group of syndromes characterized by a premature fusion of skull was studied. The phenotypic features viz, dental crowding and dental malocclusion, bulbous nose, downslanted palpebral fissures, radial deviation of thumb, syndactyly of fingers, macrocephaly, and oxycephaly were entered to query the web-based tool Phenomizer which indicated high probability of mutation in FGFR2 gene. The proband, a 13-year-old male born to non-consanguineous parents showed mutation on FGFR2 gene at c.755C>G indicative of Apert syndrome. Apert syndrome is one of the most severe craniosynostosis syndromes with two possible mutations in the exon IIIa of FGFR2 gene reported in majority of the cases. This case study shows the importance of Phenomizer and molecular genetic analysis in differential diagnosis of genetic diseases.

Apert syndrome: Surgical outcomes and perspectives

PURPOSE

Apert syndrome is a rare congenital malformation with severe craniofacial anomalies. The aim of this study was to review the outcomes of craniofacial and neurosurgical interventions in Apert syndrome patients treated at a single institution.

MATERIALS AND METHODS

A retrospective review of all patient records with a diagnosis of Apert syndrome assessed and managed in the Australian Craniofacial Unit (ACFU) from 1985 to 2013 was conducted.

RESULTS

A total of 94 patients were identified, and 130 transcranial procedures were performed. Of the patients, 83 underwent a fronto-orbital advancement (FOA) as their primary procedure, and 18 patients also underwent a posterior vault procedure. Twenty patients underwent a fronto-facial monobloc advancement. Overall, 70% of patients underwent at least 2 transcranial procedures. Shunts were inserted in 2 patients preoperatively and in 5 patients postoperatively for cerebrospinal fluid (CSF) leaks or acute hydrocephalus. Re-do FOAs were performed in 8 patients. Patients who underwent an FOA at the age of more than 18 months had no recurrence of raised intracranial pressure (ICP). Of 18 patients who also underwent a posterior vault procedure, 1 patient had recurrence of raised ICP. Midfacial surgery was performed early if there was evidence of obstructive sleep apnoea (OSA), but delayed midfacial surgery was preferred. Complications were reported in 18% of procedures. The most common complications were CSF leaks and acute hydrocephalus.

CONCLUSION

Shunting is rarely required in Apert syndrome patients, confirming a predominantly nonprogressive ventriculomegaly. FOA appears to be a more stable procedure when performed at an age of more than 18 months. Undergoing a posterior vault procedure may reduce the risk of recurrent raised ICP and lead to fewer transcranial procedures needed in childhood. Midfacial surgery should be delayed until adolescence where there is no evidence of OSA, psychological disturbance, or complications of exorbitism. Complications are rare when these patients are treated by an experienced craniofacial team.

Central nervous system and cervical spine abnormalities in Apert syndrome

PURPOSE

Apert syndrome characterized by acrocephalosyndactyly is a rare autosomal dominant congenital malformation with a prevalence of 1/65,000 births. With an extensive range of phenotypic and developmental manifestations, its management requires a multidisciplinary approach. A variety of craniofacial, central nervous system (CNS), and cervical spine abnormalities have been reported in these patients. This study aimed to determine the incidence of these CNS abnormalities in our case series.

METHODS

Retrospective review of Australian Craniofacial Unit (ACFU) database for Apert patients was performed. Data collected that included demographics, place of origin, age at presentation, imaging performed, and images were reviewed and recorded. Where available, developmental data was also recorded.

RESULTS

Ninety-four patients seen and managed at the ACFU had their CNS and cervical spine abnormalities documented. The main CNS abnormalities were prominent convolutional markings (67 %), ventriculomegaly (48 %), crowded foramen magnum (36 %), deficient septum pellucidum (13 %), and corpus callosum agenesis in 11 %. Major C-spine findings were present in 50.8 % of patients and included fusion of posterior elements of C5/C6 (50 %) and C3/4 (27 %). Multilevel fusion was seen in 20 %. Other abnormalities were C1 spina bifida occulta (7 %) and atlanto-axial subluxation (7 %).

CONCLUSION

Multiple CNS and cervical spine (c-spine) abnormalities are common in Apert syndrome. The significance of these abnormalities remains largely unknown. Further research is needed to better understand the impact of these findings on growth, development, and treatment outcomes.

Atypical presentation of a newborn with Apert syndrome

INTRODUCTION

Apert syndrome is a rare syndrome characterized by a consistent phenotype including bilateral coronal suture synostosis with an enlarged anterior fontanel, midface hypoplasia, and complex symmetric syndactyly of hands and feet.

CASE REPORT

We present a boy with Apert syndrome caused by the pathogenic c.755C > G p.Ser252Trp mutation in the FGFR2 gene with atypical characteristics, including premature fusion of the metopic suture with a small anterior fontanel, hypotelorism, and a massive posterior fontanel. Directly after birth, he showed papilledema, epilepsy, and central apneas.

CONCLUSION

We present a newborn with Apert syndrome with atypical craniofacial presentation.

Orthodontic treatment in combination with Le Fort II bone distraction in patient with Apert syndrome

We report a case of an 11-year-old girl presenting with Apert syndrome characterized by midface concavity, protrusion of the eyeballs, and ocular hypertelorism. She had class III anterior crossbite, narrow upper and lower arches, and marked crowding. Based on cephalometric analysis, anterior crossbite associated with marked midfacial hypoplasia was diagnosed. Orthodontic treatment in combination with Le Fort II maxillary distraction was scheduled. The dentition was laterally extended using a Rapid palatal expander in the upper jaw and a Bihelix in the lower jaw. Multi-bracket appliances were simultaneously applied for leveling. Next, Le Fort II maxillary osteotomy was performed to distract the midface bone 16 mm anteroinferiorly using a rigid external distraction system. Orthodontic treatment was completed at 3.8 years after initiation. Bone distraction moved the upper jaw anteriorly downward, and the lower jaw subsequently rotated posteriorly downward, leading to a marked improvement in facial appearance and occlusion. Elongation of the dorsum of the nose, in particular, allowed esthetic improvement of the saddle nose. These improvements remain stable at 2 years after orthodontic treatment.

Klinik und Genetik syndromaler und nichtsyndromaler Kraniosynostosen

Kraniosynostosen gehören mit einer Inzidenz von 1:2000 bis 1:3000 Geburten zu den häufigsten kraniofazialen Anomalien. Die durch die vorzeitige Verknöcherung einer oder mehrerer Schädelnähte verursachte Wachstumshemmung kann zu schweren Deformitäten des Schädel- und Gesichtsskeletts führen. Dies sorgt nicht nur für eine große ästhetische Beeinträchtigung, sondern hat auch funktionelle Auswirkungen für die Patienten. Hierzu können u. a. gehören: intrakranielle Drucksteigerung, Atrophie des N. opticus, Atem-, Hör- und Entwicklungsstörungen. Trotz großer Anstrengungen konnten bisher nur für einen Teil der autosomal-dominanten syndromalen Kraniosynostosen die ursächlichen Gene, z. B „fibroblast growth factor receptor 1-3“ (FGFR1-3), „twist basic helix-loop-helix transcription factor 1“ (TWIST1) etc., gefunden werden. Die Ätiologie der nichtsyndromalen Kraniosynostosen bleibt weiterhin ungeklärt. Aufgrund der verbreiteten Anwendung neuer Sequenziertechnologien zur Identifizierung neuer kausaler Gene bei Patienten mit Kraniosynostose kann in den nächsten Jahren mit der Entschlüsselung vieler weiterer krankheitsverursachender Gene gerechnet werden. Insbesondere die syndromalen Formen der Kraniosynostose bedürfen aufgrund ihrer klinischen Komplexität einer interdisziplinären Betreuung. Die einzige Therapieoption besteht derzeit in der kraniofazialen Chirurgie, welche aber die genetisch determinierten pathologischen Wachstumsmuster der komplexen syndromalen Kraniosynostosen langfristig oft nicht beheben kann.

The molecular and cellular basis of Apert syndrome

Apert syndrome (AS) is a rare genetic and congenital disease characterized by craniosynostosis and syndactly of hands and feet. AS patients generally require lifelong management, however there are still no effective treatment methods except surgery. In recent years, research has made great progress in the pathogenesis of AS. FGFR2 mediates extracellular signals into cells and the mutations in the FGFR2 gene cause AS occurrence. Activated FGFs/FGFR2 signaling disrupt the balance of cell proliferation, differentiation and apoptosis via its downstream signal pathways. However, how the pathways transform the balance is not well understood and contradictions have occurred in different studies. In this review, we'll focus on these problems to get a better understanding of AS pathogenesis.

Normalizing facial ratios in apert syndrome patients with Le Fort II midface distraction and simultaneous zygomatic repositioning

BACKGROUND

Le Fort III distraction advances the Apert midface but leaves the central concavity and vertical compression untreated. The authors propose that Le Fort II distraction and simultaneous zygomatic repositioning as a combined procedure can move the central midface and lateral orbits in independent vectors in order to improve the facial deformity. The purpose of this study was to determine whether this segmental movement results in more normal facial proportions than Le Fort III distraction.

METHODS

Computed tomographic scan analyses were performed before and after distraction in patients undergoing Le Fort III distraction (n = 5) and Le Fort II distraction with simultaneous zygomatic repositioning (n = 4). The calculated axial facial ratios and vertical facial ratios relative to the skull base were compared to those of unoperated Crouzon (n = 5) and normal (n = 6) controls.

RESULTS

With Le Fort III distraction, facial ratios did not change with surgery and remained lower (p < 0.01; paired t test comparison) than normal and Crouzon controls. Although the face was advanced, its shape remained abnormal. With the Le Fort II segmental movement procedure, the central face advanced and lengthened more than the lateral orbit. This differential movement changed the abnormal facial ratios that were present before surgery into ratios that were not significantly different from normal controls (p > 0.05).

CONCLUSION

Compared with Le Fort III distraction, Le Fort II distraction with simultaneous zygomatic repositioning normalizes the position and the shape of the Apert face.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

From shape to cells: mouse models reveal mechanisms altering palate development in Apert syndrome

Apert syndrome is a congenital disorder characterized by severe skull malformations and caused by one of two missense mutations, S252W and P253R, on fibroblast growth factor receptor 2 (FGFR2). The molecular bases underlying differential Apert syndrome phenotypes are still poorly understood and it is unclear why cleft palate is more frequent in patients carrying the S252W mutation. Taking advantage of Apert syndrome mouse models, we performed a novel combination of morphometric, histological and immunohistochemical analyses to precisely quantify distinct palatal phenotypes in Fgfr2^+/S252W and Fgfr2^+/P253R mice. We localized regions of differentially altered FGF signaling and assessed local cell patterns to establish a baseline for understanding the differential effects of these two Fgfr2 mutations. Palatal suture scoring and comparative 3D shape analysis from high resolution μCT images of 120 newborn mouse skulls showed that Fgfr2^+/S252W mice display relatively more severe palate dysmorphologies, with contracted and more separated palatal shelves, a greater tendency to fuse the maxillary-palatine sutures and aberrant development of the inter-premaxillary suture. These palatal defects are associated with suture-specific patterns of abnormal cellular proliferation, differentiation and apoptosis. The posterior region of the developing palate emerges as a potential target for therapeutic strategies in clinical management of cleft palate in Apert syndrome patients.

Dental and orthodontic management of patients with Apert and Crouzon syndromes

Patients with Crouzon and Apert syndromes exhibit particular orofacial features in combination with the craniofacial skeletal discrepancy that requires reconstructive surgical maneuvers at various stages of development. To maximize positive surgical outcomes and patient satisfaction, an interdisciplinary approach, including pediatric dentistry and orthodontics, within a developmental context is needed. Routine dental care is provided in conjunction with ongoing surgical and orthodontic treatment during all phases of the reconstructive process. The goal of orthodontic treatment in the mixed dentition is to resolve issues related to the aberrant eruption of the permanent teeth and favorably influence the occlusion when early midface advancement is planned. Orthodontic treatment during adolescence always is needed to prepare these patients for orthognathic surgery, which usually involves extraction orthodontics within the maxillary arch. Postsurgical orthodontic management is an important component of the definitive occlusal correction after orthognathic surgical procedures.

Mesodermal expression of Fgfr2S252W is necessary and sufficient to induce craniosynostosis in a mouse model of Apert syndrome

Coordinated growth of the skull and brain are vital to normal human development. Craniosynostosis, the premature fusion of the calvarial bones of the skull, is a relatively common pediatric disease, occurring in 1 in 2500 births, and requires significant surgical management, especially in syndromic cases. Syndromic craniosynostosis is caused by a variety of genetic lesions, most commonly by activating mutations of FGFRs 1-3, and inactivating mutations of TWIST1. In a mouse model of TWIST1 haploinsufficiency, cell mixing between the neural crest-derived frontal bone and mesoderm-derived parietal bone accompanies coronal suture fusion during embryonic development. However, the relevance of lineage mixing in craniosynostosis induced by activating FGFR mutations is unknown. Here, we demonstrate a novel mechanism of suture fusion in the Apert Fgfr2(S252W) mouse model. Using Cre/lox recombination we simultaneously induce expression of Fgfr2(S252W) and β-galactosidase in either the neural crest or mesoderm of the skull. We show that mutation of the mesoderm alone is necessary and sufficient to cause craniosynostosis, while mutation of the neural crest is neither. The lineage border is not disrupted by aberrant cell migration during fusion. Instead, the suture mesenchyme itself remains intact and is induced to undergo osteogenesis. We eliminate postulated roles for dura mater or skull base changes in craniosynostosis. The viability of conditionally mutant mice also allows post-natal assessment of other aspects of Apert syndrome.

Ectonucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1) protein regulates osteoblast differentiation

ENPP1 (ectonucleotide pyrophosphatase/phosphodiesterase-1) is an established regulator of tissue mineralization. Previous studies demonstrated that ENPP1 is expressed in differentiated osteoblasts and that ENPP1 influences matrix mineralization by increasing extracellular levels of inorganic pyrophosphate. ENPP1 is also expressed in osteoblastic precursor cells when stimulated with FGF2, but the role of ENPP1 in preosteoblastic and other precursor cells is unknown. Here we investigate the function of ENPP1 in preosteoblasts. We find that ENPP1 expression is critical for osteoblastic differentiation and that this effect is not mediated by changes in extracellular concentration levels of phosphate or pyrophosphate or ENPP1 catalytic activity. MC3T3E1(C4) preosteoblastic cells, in which ENPP1 expression was suppressed by ENPP1-specific shRNA, and calvarial cells isolated from Enpp1 knock-out mice show defective osteoblastic differentiation upon stimulation with ascorbate, as indicated by a lack of cellular morphological change, a lack of osteoblast marker gene expression, and an inability to mineralize matrix. Additionally, MC3T3E1(C4) cells, in which wild type or catalytic inactive ENPP1 expression was increased, exhibited an increased tendency to differentiate, as evidenced by increased osteoblast marker gene expression and increased mineralization. Notably, treatment of cells with inorganic phosphate or pyrophosphate inhibited, as opposed to enhanced, expression of multiple genes that are expressed in association with osteoblast differentiation, matrix deposition, and mineralization. Our results indicate that ENPP1 plays multiple and distinct roles in the development of mineralized tissues and that the influence of ENPP1 on osteoblast differentiation and gene expression may include a mechanism that is independent of its catalytic activity.

Evaluation and management of nonsyndromic craniosynostosis

Craniosynostosis (craniostenosis) is premature fusion of the sutures of the cranial vault. Several factors can affect the growth of the cranial vault during embryonic life and after birth, leading to different types of craniosynostosis; these can be classified on the basis of the specific sutures that are fused. Prognosis is improved by early diagnosis, and it is important to establish the correct approach to these patients on the basis of clinical and neuroradiological investigation. The first priority is to identify the type of craniosynostosis and to distinguish between the types that require surgical intervention and those that do not. We report on the different forms of nonsyndromic craniosynostosis, their clinical and neuroradiological diagnoses, and surgical strategies.

CONCLUSION

The aim of this review is to provide to paediatricians a correct diagnostic approach and management of children affected from nonsyndromic craniosynostosis, for which a careful physical, ophthalmological and neurological examination is fundamental, whereas brain Computed tomography and magnetic resonance imaging are necessary for patients in which the diagnosis is uncertain or for cases of syndromic craniosynostosis.

Ocular manifestations of Apert and Crouzon syndromes: qualitative and quantitative findings

There are significant differences in the ocular manifestations of Apert and Crouzon syndromes. Here, we present qualitative and quantitative data about the oculo-orbital region to demonstrate these differences. Although ocular protosis and hypertelorism characterize both disorders, the nature of the orbital dystopia differs. In Crouzon syndrome, ocular proptosis is primarily caused by retrusion of the lateral and inferior orbital margins with a very short orbital floor. In Apert syndrome, the eyeglobe actually protrudes in relation to the cranial base and to the orbit, probably resulting from marked protrusion of the lateral orbital wall. The implications account for some of the differences encountered. Asymmetry is associated with Apert syndrome frequently. Exotropia is found in Crouzon syndrome, whereas the V pattern is more characteristic in Apert syndrome with divergent upgaze and esotropic downgaze. Subluxation of the eyeglobe is found in some cases of Crouzon syndrome but is not found in Apert syndrome. Optic atrophy found in approximately 20% of Crouzon syndrome patients is not characteristic of Apert syndrome. Structural alterations of the extraocular muscles have been associated with some cases of Apert syndrome, suggesting that ocular motility disturbances in Apert syndrome may not be caused solely by mechanical factors. Absence of the superior rectus and other extraocular muscles has been recorded. Furthermore, albinoid alterations of the fundus have also been associated with Apert syndrome.