Prevalence and complications of single-gene and chromosomal disorders in craniosynostosis

Towards a radiation free numerical modelling framework to predict spring assisted correction of scaphocephaly

Sagittal Craniosynostosis (SC) is a congenital craniofacial malformation, involving premature sagittal suture ossification; spring-assisted cranioplasty (SAC) - insertion of metallic distractors for skull reshaping - is an established method for treating SC. Surgical outcomes are predictable using numerical modelling, however published methods rely on computed tomography (CT) scans availability, which are not routinely performed. We investigated a simplified method, based on radiation-free 3D stereophotogrammetry scans. Eight SAC patients (age 5.1 ± 0.4 months) with preoperative CT and 3D stereophotogrammetry scans were included. Information on osteotomies, spring model and post-operative spring opening were recorded. For each patient, two preoperative models (PREOP) were created: i) CT model and ii) S model, created by processing patient specific 3D surface scans using population averaged skin and skull thickness and suture locations. Each model was imported into ANSYS Mechanical (Analysis System Inc., Canonsburg, PA) to simulate spring expansion. Spring expansion and cranial index (CI - skull width over length) at times equivalent to immediate postop (POSTOP) and follow up (FU) were extracted and compared with in-vivo measurements. Overall expansion patterns were very similar for the 2 models at both POSTOP and FU. Both models had comparable outcomes when predicting spring expansion. Spring induced CI increase was similar, with a difference of 1.2%±0.8% for POSTOP and 1.6%±0.6% for FU. This work shows that a simplified model created from the head surface shape yields acceptable results in terms of spring expansion prediction. Further modelling refinements will allow the use of this predictive tool during preoperative planning.

ERF-Related Craniosynostosis in a Patient With Hypochondroplasia: A Case Report

We report a case of multiple suture craniosynostosis in a patient with hypochondroplasia. The patient presented with short stature marked by a relatively long trunk and short extremities. The clinical and radiological findings were suggestive of hypochondroplasia. Additionally, craniosynostosis was identified during the evaluation, which is an unusual finding in hypochondroplasia. To further investigate, exome sequencing was performed, revealing previously reported pathogenic heterozygous variants in FGFR3 and ERF genes. Exome sequencing not only enhances the accuracy of diagnosing individual cases of genetic skeletal disorders but also contributes to the collective knowledge base, advancing future research in the field.

Surgical Outcomes in Unicoronal Synostosis-A 23-Year Experience From a Single Supraregional Craniofacial Unit

Unicoronal synostosis is a rare condition leading to anterior plagiocephaly with facial scoliosis and deformation of the anterior cranial fossa. Fronto-orbital advancement and remodelling (FOAR) is the standard of care for management, aiming to normalise the brow shape and position while ameliorating the risk of raised intracranial pressure (ICP) throughout childhood. Published long-term surgical outcome data for unicoronal synostosis is lacking. The authors present our series of 151 cases of FOAR for unicoronal synostosis between January 2000 and January 2023. The average age at surgery was 22.7 months, with an average follow-up of 87 months. Ninety-six patients (66.2%) had no comorbidity. Nineteen (13.1%) had named genetic or chromosomal disorders. There was a 33.1% dural tear rate with no related postoperative CSF leak. Ninety-three patients (67.8%) had a blood transfusion with average donor exposure <1. The total early complication rate was 8.6% most commonly infection and wound dehiscence at 3.4% and 2.8%, respectively. The most common late complication was temporal recession in 30 (20.1%) patients and 3 of these patients required revision surgery. None of our patients required investigation for, or treatment of, raised ICP after the primary surgery. There were no life-threatening complications or mortalities. The authors compare our results to a previous publication on trigonocephaly patients and other available published data. The authors present our recommendations, which include support for a supraregionalized service that encompasses high-volume workload and multidisciplinary care.

A morphometric analysis of the cranial base in trigonocephaly

Trigonocephaly occurs when the metopic suture fuses prematurely. Few studies have documented the morphometry of the entire anterior cranium in trigonocephaly and not on the morphometric changes to the cranial fossae alone. Thus, this study aimed to determine and compare the dimensions of the anterior cranial fossa (ACF) in trigonocephaly and control groups. Additionally, volumetric assessments of the middle and posterior cranial fossae (MCF and PCF) were analysed to determine the amount of compensatory growth in these regions. Anatomical landmarks were used to measure the morphometry of the ACF, and volumes of the MCF and PCF on preoperative two-dimensional computed tomography scans of fifteen non-syndromic, isolated trigonocephaly patients between 2012 and 2023, and eight controls. Comparative assessment of the ACF revealed larger dimensions in younger more severe trigonocephaly patients when compared to the control cohort. Smaller ACF dimensions were recorded in older patients who presented with moderate and severe trigonocephaly compared to the control cohort. The volume of the MCF was found to be significant (p = 0.05), and the volume of the PCF was larger in trigonocephaly patients compared to controls. The PCF showed the largest incidence of compensatory growth (30.4%) in trigonocephaly patients. The frontal angle (FA) (p = 0.004) and endocranial bifrontal angle (EBA) were used to categorise the severity of trigonocephaly. The morphometric data obtained could assist craniofacial surgeons in understanding the changes that occur in the ACF to decide which type of corrective treatment is most suitable.

Craniosynostosis: Epidemiology and Pattern at a Tertiary Referral Institute in Oman 2004 to 2023

OBJECTIVE

To date, there are no published studies From the Sultanate of Oman on the incidence or characteristics of craniosynostosis (CS). This is a population-based epidemiological study of the incidence of CS.

METHODS

The prospective registry of the craniofacial surgery unit in Khoula Hospital was used to retrieve data on all individuals with CS treated between 2004 and 2023. The cohort was divided into four 5-year groups based on year of birth: 2004 to 2008, 2009 to 2013, 2014 to 2018, and 2019 to 2023.

RESULTS

We identified 312 individuals with CS. The incidence increased significantly during the study period and was 2.5 per 10 000 live births in the last 5-year period. There was a male preponderance (male/female ratio 1.5:1). Our study findings reveal a notable diversity in the trend of suture involvement, we observed a higher frequency of complex CS within our study population 35.9%. Half of the study population was nonsyndromic, accounting for 51.6%. The nonsyndromic population exhibits a higher proportion of midline suture involvement.

CONCLUSIONS

The incidence of CS increased during the study period. The majority of cases were identified as nonsyndromic. We found that multiple sutures CS were the most prevalent overall in our population. It is imperative to intensify efforts aimed at raising awareness among the general population regarding these deformities.

Orthoptic findings in trigonocephaly patients after completed visual development

PURPOSE

Trigonocephaly is associated with suboptimal visual outcomes in young children. However, the presence of orthoptic abnormalities after completed visual development remains unknown. The purpose of this study is to assess the prevalence of orthoptic abnormalities in trigonocephaly patients, after completed visual development.

METHODS

A retrospective study among non-syndromic trigonocephaly patients aged 8 years and older was conducted at the Dutch Craniofacial center. Ophthalmologic records were reviewed for refractive errors and a history of strabismus and amblyopia. Refractive errors were classified as follows: myopia: spherical equivalent (SE) ≤ -0.50 diopters (D), emmetropia: SE -0.50 D to + 0.50 D, hyperopia: ≥ + 0.50 D, astigmatism: cylinder error ≥ 1.00 D. The history of strabismus and amblyopia was assessed retrospectively. Prevalence and cumulative incidence of these abnormalities in healthy age-matched populations were retrieved from literature.

RESULTS

We included 78 trigonocephaly patients with a median (interquartile range) age of 10.0 (9.0-12.0) years. Thirty-four (43.6%) of these patients presented with a refractive error after the age of 8 years. Specific findings in these 78 patients versus controls were hyperopia in 35.9% vs 8.4%; myopia in 6.4% vs 11.4%; astigmatism in 20.5% vs 11.9%; strabismus in 14.1% vs 2.65%; amblyopia in 6.4% vs 3.4%.

CONCLUSIONS

Trigonocephaly patients have a two-to-threefold higher risk of hyperopia, astigmatism, amblyopia, and strabismus, as compared to healthy populations. We recommend screening and, in case of abnormalities, regular follow-up before completed visual development. In addition, we recommend long-term surveillance of visual functioning by a pediatric ophthalmologist and/or orthoptist.

Craniosynostosis in Siblings, an Extremely Rare Occurrence: A Case Report

Craniosynostosis (CS) is the premature fusion of skull sutures, with all sutures except the metopic suture typically fusing in adulthood. Premature fusion constrains brain growth, leading to abnormal skull shape and potential neurocognitive or neurological issues, along with syndromic features in some cases. While CS is rare, its occurrence in siblings is exceptionally uncommon and holds significant academic importance. We report a case of CS in siblings: a 13-month-old boy and his five-and-a-half-year-old sister. Neither parent exhibits craniofacial dysmorphism or signs of increased intracranial pressure (ICP). The younger sibling presents with dolichocephaly and normal neurological, cognitive, and motor development, while the elder sibling exhibits proptosis, midface hypoplasia, and normal developmental milestones. Neither sibling displays limb or systemic anomalies. Imaging studies, including multislice plain CT brain with 3D skull reconstruction and MRI, revealed multiple suture closures. The younger sibling has complete sagittal suture closure with partial closure of other sutures, while the elder sibling shows multisutural CS. Ophthalmologic evaluations and developmental assessments excluded increased ICP and systemic issues. Most CS cases follow an autosomal dominant inheritance pattern, making this case particularly significant. CT with 3D skull reconstruction remains the diagnostic gold standard. Management aims to preserve cosmetic appearance and prevent complications from increased ICP. Treatment options range from conservative follow-up to surgical interventions, including endoscopic suturectomy, open craniotomy, and distraction osteogenesis, depending on the presence of neurocognitive issues or elevated ICP. Both siblings currently show normal neurological, cognitive, and motor development without increased ICP, emphasizing the need for ongoing monitoring to identify new developments or recurrence after treatment. Differential diagnoses, such as deformational plagiocephaly, must also be considered in such cases.

The role of pathogenic TCF12 variants in children with coronal craniosynostosis-a systematic review with addition of two novel cases

Craniosynostosis constitutes one of the most common congenital cranial malformations, affecting approximately 6/10,0000 live births. A genetic etiology has long been known for several forms of syndromic craniosynostosis, including pathogenic variants in TWIST1 and FGFR3 in children with Saethre-Chotzen and Muenke syndrome. Over the last decade, reports of genetic aberrations in TCF12 in children with craniosynostosis have emerged, in particular in cases with premature closure of the coronal suture(s). In this study, we, therefore, systematically reviewed the rapidly growing knowledge of TCF12-related coronal craniosynostosis, clearly illustrating its high degree of genotype and phenotype variability. With the two novel cases presented, at least 113 cases of TCF12-related coronal craniosynostosis have currently been reported. By pooling data from several prospectively collected undifferentiated craniosynostosis cohorts (ntotal = 770), we estimate a prevalence of pathogenic TCF12 variants of at least 2%. Overall, pathogenic germline variants in TCF12 are relatively frequent in children with coronal craniosynostosis, accounting for ∼10-20% of TWIST1- and FGFR1/2/3-negative cases, with even higher rates for bicoronal and syndromic cases. Genetic counseling is recommended for all children with craniosynostosis, and involvement of the coronal suture(s) should precipitate TCF12 testing.

New CRISPR/Cas9-based Fgfr2C361Y/+ mouse model of Crouzon syndrome exhibits skull and behavioral abnormalities

Crouzon syndrome (CS), a syndromic craniosynostosis, is a craniofacial developmental deformity caused by mutations in fibroblast growth factor receptor 2 (FGFR2). Previous CS mouse models constructed using traditional gene editing techniques faced issues such as low targeting efficiency, extended lineage cycles, and inconsistent and unstable phenotypes. In this study, a CRISPR/Cas9-mediated strategy was employed to induce a functional augmentation of the Fgfr2 point mutation in mice. Various techniques, including bone staining, micro-CT, histological methods, and behavioral experiments, were employed to systematically examine and corroborate phenotypic disparities between mutant mice (Fgfr2C361Y/+) and their wild-type littermates. Confirmed via PCR-Sanger sequencing, we successfully induced the p.Cys361Tyr missense mutation in the Fgfr2 IIIc isoform of the extracellular domain (corresponding to the p.Cys342Tyr mutation in humans) based on Fgfr2-215 transcript (ENSMUST00000122054.8). Fgfr2C361Y/+ mice exhibited characteristics consistent with the phenotypic features associated with CS, including skull-vault craniosynostosis, skull deformity, shallow orbits accompanied by exophthalmos, midface hypoplasia with malocclusion, and shortened skull base, notably without any apparent limb defects. Furthermore, mutant mice displayed behavioral abnormalities encompassing deficits in learning and memory, social interaction, and motor dysfunction, without anxiety-related disorders. Histopathological examination of the hippocampal region revealed structural abnormalities, suggesting possible brain development impairment secondary to craniosynostosis. In conclusion, we constructed a novel gene-edited Fgfr2C361Y/+ mice strain based on CRISPR/Cas9, which displayed skull and behavioral abnormalities, serving as a new model for studying genetic molecular mechanisms and exploring treatments for CS. KEY MESSAGES: CRISPR/Cas9 crafted a Crouzon model by enhancing Fgfr2-C361Y in mice. Fgfr2C361Y/+ mice replicate CS phenotypes-craniosynostosis and midface anomalies. Mutant mice show diverse behavioral abnormalities, impacting learning and memory. Fgfr2C361Y/+ mice offer a novel model for cranial suture studies and therapeutic exploration.

Genetic Testing in Craniofacial Care: Development of Algorithms for Testing Patients with Orofacial Clefting, Branchial Arch Anomalies, and Craniosynostosis

OBJECTIVE

To develop consensus-based algorithms for genetic testing in patients with common craniofacial conditions.

DESIGN

An online collaborative consisting of online meetings, independent work, and feedback across groups. Setting/Participants: A collaborative of genetics and pediatrics providers from three regional craniofacial centers (four institutions).

METHODS

Collaborative participants agreed upon a shared initial framework, developed algorithms independently, and presented/tested the algorithms with a national audience. Algorithms were modified based on consensus feedback.

RESULTS

The collaborative group developed final algorithms for genetic testing in patients with orofacial cleft, branchial arch conditions, and craniosynostosis.

CONCLUSIONS

Timely and accurate diagnosis of genetic conditions can support medical management recommendations that result in safer surgical interventions. Algorithms can help guide best-practices for testing, particularly in institutions without easy access to genetics providers.

Emphasis on Early Prenatal Diagnosis and Perinatal Outcomes Analysis of Apert Syndrome

Apert syndrome is an inherited condition with autosomal dominant transmission. It is also known as acrocephalosyndactyly type I, being characterized by a syndrome of craniosynostosis with abnormal head shape, facial anomalies (median hypoplasia), and limb deformities (syndactyly, rhizomelic shortening). The association can suspect the prenatal diagnosis of these types of anomalies. The methodology consisted of revising the literature, by searching the PubMed/Medline database in which 27 articles were selected and analyzed, comprising 32 cases regarding the prenatal diagnosis of Apert syndrome. A series of ultrasound parameters, the anatomopathological abnormalities found, the obstetric results, and the genetic tests were followed. The distribution of imaging results (US, MRI) identified in the analyzed cases was as follows: skull-shaped abnormalities were evident in 96.8% of cases, facial abnormalities (hypertelorism 43.7%, midface hypoplasia 25%, proptosis 21.8%), syndactyly in 87.5%, and cardiovascular abnormalities in 9.3%. The anomalies detected by the ultrasound examination of the fetus were confirmed postnatally by clinical or gross evaluation or imaging. The management of these cases requires an early diagnosis, an evaluation of the severity of the cases, and appropriate parental counseling.

Epidemiologic Assessment of Craniosynostosis in Mississippi's Pediatric Population from 2015 to 2020

OBJECTIVES

This study aimed to report geographic and demographic patterns of patients with craniosynostosis (CS) treated at Children's of Mississippi, the state's only American Cleft Palate-Craniofacial Association-approved craniofacial team.

METHODS

Patients with CS were treated at a tertiary pediatric hospital cared for by craniofacial surgeons and neurosurgeons from 2015 to 2020. Demographic, geographic, and CS diagnosis details, including sex, gestational age, race, ethnicity, insurance status, and affected cranial suture type(s), number, and associated syndromic diagnosis were collected, including birth county and total live births from state data. Significant differences between prevalence of CS in four regions of Mississippi were examined using two-tailed t tests (P < 0.05).

RESULTS

Among 222,819 live births in Mississippi between 2015 and 2020, 79 pediatric patients presented to Children's of Mississippi with CS, with an overall incidence of 0.355/1000 live births. Most cases were nonsyndromic CS (82%, n = 65) affecting a single major cranial suture (81%, n = 64). The overall incidence of CS was higher in the coastal and central regions compared with northeast Mississippi, at 0.333 and 0.527 vs 0.132/1000 live births (P = 0.012 and P = 0.004), respectively.

CONCLUSIONS

Results from this study suggest regional patterns of CS in Mississippi, which may reflect actual incidence patterns or proximity to Children's of Mississippi. Further study could reveal regional differences in risk factors underlying CS incidence or access to specialized CS care for different regions in the state. This will lead to opportunities for institutional outreach to decrease the burden of CS care in Mississippi.

Macrocephaly and Finger Changes: A Narrative Review

Macrocephaly, characterized by an abnormally large head circumference, often co-occurs with distinctive finger changes, presenting a diagnostic challenge for clinicians. This review aims to provide a current synthetic overview of the main acquired and genetic etiologies associated with macrocephaly and finger changes. The genetic cause encompasses several categories of diseases, including bone marrow expansion disorders, skeletal dysplasias, ciliopathies, inherited metabolic diseases, RASopathies, and overgrowth syndromes. Furthermore, autoimmune and autoinflammatory diseases are also explored for their potential involvement in macrocephaly and finger changes. The intricate genetic mechanisms involved in the formation of cranial bones and extremities are multifaceted. An excess in growth may stem from disruptions in the intricate interplays among the genetic, epigenetic, and hormonal factors that regulate human growth. Understanding the underlying cellular and molecular mechanisms is important for elucidating the developmental pathways and biological processes that contribute to the observed clinical phenotypes. The review provides a practical approach to delineate causes of macrocephaly and finger changes, facilitate differential diagnosis and guide for the appropriate etiological framework. Early recognition contributes to timely intervention and improved outcomes for affected individuals.

Regulatory elements in SEM1-DLX5-DLX6 (7q21.3) locus contribute to genetic control of coronal nonsyndromic craniosynostosis and bone density-related traits

Purpose

The etiopathogenesis of coronal nonsyndromic craniosynostosis (cNCS), a congenital condition defined by premature fusion of 1 or both coronal sutures, remains largely unknown.

Methods

We conducted the largest genome-wide association study of cNCS followed by replication, fine mapping, and functional validation of the most significant region using zebrafish animal model.

Results

Genome-wide association study identified 6 independent genome-wide-significant risk alleles, 4 on chromosome 7q21.3 SEM1-DLX5-DLX6 locus, and their combination conferred over 7-fold increased risk of cNCS. The top variants were replicated in an independent cohort and showed pleiotropic effects on brain and facial morphology and bone mineral density. Fine mapping of 7q21.3 identified a craniofacial transcriptional enhancer (eDlx36) within the linkage region of the top variant (rs4727341; odds ratio [95% confidence interval], 0.48[0.39-0.59]; P = 1.2E-12) that was located in SEM1 intron and enriched in 4 rare risk variants. In zebrafish, the activity of the transfected human eDlx36 enhancer was observed in the frontonasal prominence and calvaria during skull development and was reduced when the 4 rare risk variants were introduced into the sequence.

Conclusion

Our findings support a polygenic nature of cNCS risk and functional role of craniofacial enhancers in cNCS susceptibility with potential broader implications for bone health.

Construction of a Lentiviral Vector for Fgfr2 Overexpression and its Impact on the Biological Behavior of Cranial Suture Mesenchymal Stem Cells

OBJECTIVE

Suture mesenchymal stem cells (SuSCs), possessing self-renewal and multilineage differentiation abilities, play a crucial role in cranial bone growth. However, the impact of the disease-causing fibroblast growth factor receptor 2 (FGFR2) mutation on SuSCs in Crouzon syndrome has not been explored. This study aims to employ a lentivirus to overexpress Fgfr2 and investigate its role in the pathogenesis of Crouzon syndrome.

METHODS

Starting with the prevalent FGFR2 mutation site in patients with Crouzon syndrome, a lentiviral vector carrying the Fgfr2.C361Y mutation was developed and transfected into SuSCs, with a determined multiplicity of infection values. The experimental group, SuSCs+Fgfr2.C361Y, was compared with the empty vector and normal SuSC groups. Cell proliferation, cycle, apoptosis, and osteogenic functionality were assessed using CCK-8 assays, flow cytometry, ALP activity assays, and real-time quantitative polymerase chain reaction.

RESULTS

The lentiviral vector effectively infected SuSCs, leading to heightened Fgfr2 expression, with optimal multiplicity of infection values of 80. The experimental group demonstrated decreased proliferation activity and a higher apoptosis rate compared with controls (P < 0.05). After osteogenic induction, the experimental group showed significantly higher ALP activity than controls (P < 0.05). Real-time quantitative polymerase chain reaction indicated lower mRNA expression levels of Gli1, Axin2, Pcna, Cdk2, and Bcl-2 in the experimental group than controls, whereas Bax, Runx2, and Bmp-2 showed higher expression (P < 0.05).

CONCLUSION

This study constructed a lentivirus vector to upregulate Fgfr2 expression in SuSCs, suppressing stem cell stemness by inhibiting proliferation, promoting apoptosis, and accelerating premature osteogenic differentiation, resulting in premature suture closure. These findings establish the groundwork for further understanding the pathogenesis of Crouzon syndrome.

Skeletal expansion via craniofacial distraction osteogenesis technique in syndromic craniosynostosis: impact on ophthalmic parameters

BACKGROUND

This study aims to compare the changes in ophthalmic parameters among syndromic craniosynostosis patients who underwent craniofacial skeletal expansion procedures via distraction osteogenesis (DO).

METHOD

A retrospective study was conducted involving syndromic craniosynostosis patients who underwent surgical expansion via the DO technique from the year 2012 to March 2022. Changes in six parameters which consist of visual acuity, refractive error, optic disc health, intraocular pressure, degree of proptosis and orbital volume were measured objectively pre and post-surgery. For categorical parameters, the Chi-square cross-tab test was done. Paired sample T-test was used for normally distributed variables. Wilcoxon signed-rank test was used for non-normally distributed data.

RESULTS

Visual impairment was present in 21.4% of eyes before surgery and increased to 28.5% post-surgery. Three patients had changes of refractive error post-surgery with one developed hypermetropia, another developed anisometropia and the last had improvement to no refractive error. Two patients had optic disc swelling which was resolved post-surgery. Intraocular pressure changes were inconsistent post-surgery. All patients achieved a significant reduction in the degree of proptosis post-surgery. Orbital volume calculation using computed tomography (CT) scans shows a significant increase in volume post-surgery for all patients.

CONCLUSION

Our study shows a significant increase in orbital volume post-surgery with a reduction in the degree of proptosis. Optic disc and nerve health improved after the surgery. Changes in terms of visual acuity, refractive error and IOP were inconsistent after the surgical intervention.

The value of genome-wide analysis in craniosynostosis

Background: This study assessed the diagnostic yield of high-throughput sequencing methods in a cohort of craniosynostosis (CS) patients not presenting causal variants identified through previous targeted analysis. Methods: Whole-genome or whole-exome sequencing (WGS/WES) was performed in a cohort of 59 patients (from 57 families) assessed by retrospective phenotyping as having syndromic or nonsyndromic CS. Results: A syndromic form was identified in 51% of the unrelated cases. A genetic cause was identified in 38% of syndromic cases, with novel variants detected in FGFR2 (a rare Alu insertion), TWIST1, TCF12, KIAA0586, HDAC9, FOXP1, and NSD2. Additionally, we report two patients with rare recurrent variants in KAT6A and YY1 as well as two patients with structural genomic aberrations: one with a 22q13 duplication and one with a complex rearrangement involving chromosome 2 (2p25 duplication including SOX11 and deletion of 2q22). Moreover, we identified potentially relevant variants in 87% of the remaining families with no previously detected causal variants, including novel variants in ADAMTSL4, ASH1L, ATRX, C2CD3, CHD5, ERF, H4C5, IFT122, IFT140, KDM6B, KMT2D, LTBP1, MAP3K7, NOTCH2, NSD1, SOS1, SPRY1, POLR2A, PRRX1, RECQL4, TAB2, TAOK1, TET3, TGFBR1, TCF20, and ZBTB20. Conclusion: These results confirm WGS/WES as a powerful diagnostic tool capable of either targeted in silico or broad genomic analysis depending on phenotypic presentation (e.g., classical or unusual forms of syndromic CS).

Ophthalmic Manifestations of Unilateral Coronal Synostosis

PURPOSE

To summarize the ophthalmic manifestations of unilateral coronal synostosis patients.

METHODS

We performed a literature search in the electronic database of PubMed, CENTRAL, Cochrane, and Ovid Medline guided by Preferred Reporting Items for Systematic Reviews and Meta-Analysis Statement for studies evaluating ophthalmic manifestations of unilateral coronal synostosis.

RESULTS

Unilateral coronal synostosis, also called unicoronal synostosis, may be mistaken for deformational plagiocephaly, an asymmetric skull flattening common in newborns. Characteristic facial features, however, distinguish the two. Ophthalmic manifestations of unilateral coronal synostosis include a "harlequin deformity", anisometropic astigmatism, strabismus, amblyopia, and significant orbital asymmetry. The astigmatism is greater on the side opposite the fused coronal suture. Optic neuropathy is uncommon unless unilateral coronal synostosis accompanies more complex multi-suture craniosynostosis. In many cases, surgical intervention is recommended; without intervention, skull asymmetry and ophthalmic disorders tend to worsen with time. Unilateral coronal synostosis can be managed by early endoscopic stripping of the fused suture and helmeting through a year of age or by fronto-orbital-advancement at approximately 1 year of age. Several studies have demonstrated that anisometropic astigmatism, amblyopia, and severity of strabismus are significantly lower after earlier intervention with endoscopic strip craniectomy and helmeting compared to treatment by fronto-orbital-advancement. It remains unknown whether the earlier timing or the nature of the procedure is responsible for the improved outcomes. As endoscopic strip craniectomy can only be performed in the first few months of life, early recognition of the facial, orbital, eyelid, and ophthalmic characteristics by consultant ophthalmologists enables expeditious referral and optimized ophthalmic outcomes.

CONCLUSION

Timely identification of craniofacial and ophthalmic manifestations of infants with unilateral coronal synostosis is important. Early recognition and prompt endoscopic treatment appears to optimize ocular outcomes.

Genetic diagnostic yield in an 11-year cohort of craniosynostosis patients

Craniosynostosis may present in isolation, 'non-syndromic', or with additional congenital anomalies/neurodevelopmental disorders, 'syndromic'. Clinical focus shifted from confirming classical syndromic cases to offering genetic testing to all craniosynostosis patients. This retrospective study assesses diagnostic yield of molecular testing by investigating prevalences of chromosomal and monogenic (likely) pathogenic variants in an 11-year cohort of 1020 craniosynostosis patients. 502 children underwent genetic testing. Pathogenic variants were identified in 174 patients (35%). Diagnostic yield was significantly higher in syndromic craniosynostosis (62%) than in non-syndromic craniosynostosis (6%). Before whole exome sequencing (WES) emerged, single-gene testing was performed using Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). Diagnostic yield was 11% and was highest for EFNB1, FGFR2, FGFR3, and IL11RA. Diagnostic yield for copy number variant analysis using microarray was 8%. From 2015 onwards, the WES craniosynostosis panel was implemented, with a yield of 10%. In unsolved, mainly syndromic, cases suspected of a genetic cause, additional WES panels (multiple congenital anomalies (MCA)/intellectual disability (ID)) or open exome analysis were performed with an 18% diagnostic yield. To conclude, microarray and the WES craniosynostosis panel are key to identifying pathogenic variants. in craniosynostosis patients. Given the advances in genetic diagnostics, we should look beyond the scope of the WES craniosynostosis panel and consider extensive genetic diagnostics (e.g. open exome sequencing, whole genome sequencing, RNA sequencing and episignature analysis) if no diagnosis is obtained through microarray and/or WES craniosynostosis panel. If parents are uncomfortable with more extensive diagnostics, MCA or ID panels may be considered.

A Novel Phenotype of Calvarial Thickening and Increased Rates of Premature Calvarial Suture Closure in Children With Chronic Lung Disease

PURPOSE

The purpose of this study was to characterize a novel type of calvarial thickening and provide objective measurements of skull thickness and calvarial suture morphology in patients with bronchopulmonary dysplasia.

METHODS

Infants with severe bronchopulmonary dysplasia who also had undergone computed tomography (CT) scans were identified from the neonatal chronic lung disease program database. Thickness analysis was performed using Materialise Mimics.

RESULTS

The chronic lung disease team treated 319 patients during the study interval of which, 58 patients (18.2%) had head CT available. Twenty-eight (48.3%) were found to have calvarial thickening. The rate of premature suture closure in the study population was 36.2% (21 of 58 patients), with 50.0% of affected cohort having evidence of premature suture closure on the first CT scan. Multivariate logistic regression identified 2 risk factors, requiring invasive ventilation at 6 months of age and fraction of inspired oxygen requirement at 6 months of age. Increased head circumference at birth protected against the development of calvarial thickening.

CONCLUSIONS

We have described a novel subset of patients with chronic lung disease of prematurity who have calvarial thickening with remarkably high rates of premature closure of cranial sutures. The exact etiology of the association is unknown. In this patient population with radiographic evidence of premature suture closure, operative decision should be made after considering unequivocal evidence of elevated intracranial pressure or dysmorphology and balanced against the risk of the procedure.

Lineage-specific mutation of Lmx1b provides new insights into distinct regulation of suture development in different areas of the calvaria

The calvaria (top part of the skull) is made of pieces of bone as well as multiple soft tissue joints called sutures. The latter is crucial to the growth and morphogenesis of the skull, and thus a loss of calvarial sutures can lead to severe congenital defects in humans. During embryogenesis, the calvaria develops from the cranial mesenchyme covering the brain, which contains cells originating from the neural crest and the mesoderm. While the mechanism that patterns the cranial mesenchyme into bone and sutures is not well understood, function of Lmx1b, a gene encoding a LIM-domain homeodomain transcription factor, plays a key role in this process. In the current study, we investigated a difference in the function of Lmx1b in different parts of the calvaria using neural crest-specific and mesoderm-specific Lmx1b mutants. We found that Lmx1b was obligatory for development of the interfrontal suture and the anterior fontanel along the dorsal midline of the skull, but not for the posterior fontanel over the midbrain. Also, Lmx1b mutation in the neural crest-derived mesenchyme, but not the mesoderm-derived mesenchyme, had a non-cell autonomous effect on coronal suture development. Furthermore, overexpression of Lmx1b in the neural crest lineage had different effects on the position of the coronal suture on the apical part and the basal part. Other unexpected phenotypes of Lmx1b mutants led to an additional finding that the coronal suture and the sagittal suture are of dual embryonic origin. Together, our data reveal a remarkable level of regional specificity in regulation of calvarial development.

Transcriptomic Signatures of Single-Suture Craniosynostosis Phenotypes

Craniosynostosis is a birth defect where calvarial sutures close prematurely, as part of a genetic syndrome or independently, with unknown cause. This study aimed to identify differences in gene expression in primary calvarial cell lines derived from patients with four phenotypes of single-suture craniosynostosis, compared to controls. Calvarial bone samples (N = 388 cases/85 controls) were collected from clinical sites during reconstructive skull surgery. Primary cell lines were then derived from the tissue and used for RNA sequencing. Linear models were fit to estimate covariate adjusted associations between gene expression and four phenotypes of single-suture craniosynostosis (lambdoid, metopic, sagittal, and coronal), compared to controls. Sex-stratified analysis was also performed for each phenotype. Differentially expressed genes (DEGs) included 72 genes associated with coronal, 90 genes associated with sagittal, 103 genes associated with metopic, and 33 genes associated with lambdoid craniosynostosis. The sex-stratified analysis revealed more DEGs in males (98) than females (4). There were 16 DEGs that were homeobox (HOX) genes. Three TFs (SUZ12, EZH2, AR) significantly regulated expression of DEGs in one or more phenotypes. Pathway analysis identified four KEGG pathways associated with at least one phenotype of craniosynostosis. Together, this work suggests unique molecular mechanisms related to craniosynostosis phenotype and fetal sex.

The current understanding of germline predisposition in non-syndromic sagittal craniosynostosis: a systematic review

PURPOSE

The objective of this literature review was to provide a comprehensive and up-to-date overview of the current understanding of the genetic etiology for non-syndromic sagittal craniosynostosis.

METHODS

Using the PubMed database and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), we systematically reviewed relevant records on germline genetics in children with non-syndromic sagittal craniosynostosis.

RESULTS

Two hundred two records were identified, of which 25 were included following title and abstract screening and subsequent full-text review. The 25 records in combination included 829 children with non-syndromic sagittal craniosynostosis. A likely pathogenic or pathogenic germline variant was reported for 9.8% of the 827 patients for whom germline genetic testing was performed. The reported variants were distributed across 50 different genes, with more than one variant detected in 13 genes.

CONCLUSION

Based on the existing literature, genetic predisposition is likely to play a role in at least 9% of children with non-syndromic sagittal craniosynostosis. Future studies will benefit from international consensus in terms of diagnostic nomenclature and a higher level of standardization across study methodologies and bioinformatic approaches.

Occlusal characteristics and oral health-related quality of life in adults operated due to sagittal synostosis in childhood: a case-control study with 26 years of follow-up

PURPOSE

The aim of this case-control study was to investigate occlusal characteristics, received orthodontic treatment, oral health-related quality of life (OHRQoL), and satisfaction with dental esthetics in adults operated due to sagittal synostosis.

METHODS

The study group consisted of 40 adults (25 males, 15 females, mean age 27.4 years, range 18-41) who were operated due to isolated sagittal synostosis in childhood. The control group comprised 40 age and gender-matched adults. Occlusal characteristics were evaluated clinically during study visits. Information on the previous orthodontic treatment was collected from dental records. OHRQoL was measured using the 14-item Oral Health Impact Profile (OHIP-14), and satisfaction with dental esthetics was evaluated using a visual analogue scale.

RESULTS

No statistically significant differences were found between the patient group and the controls in malocclusion traits (overjet, overbite, molar relationships, crossbite, scissor bite), previous orthodontic treatment, pre-treatment malocclusion diagnoses, OHIP variables, or satisfaction with dental esthetics. However, there was a tendency toward increased overjet and overbite in scaphocephalic patients.

CONCLUSION

It seems that adults with scaphocephaly operated in childhood do not differ from the average population in terms of occlusion, received orthodontic treatment, or oral health-related well-being.

Retroperitoneal liposarcoma and craniosynostosis: possible genomic relationship, case report, and literature review

Based on a case report, this review explores the genomic landscape for patients with liposarcomas and possible relationships with gene mutations related to craniosynostosis. We describe the case of a 40-year-old man, known for a surgical correction of craniosynostosis before the age of 1 year, who underwent a radical resection of a voluminous retroperitoneal liposarcoma; histopathological analysis revealed a low-grade well-differentiated, mostly sclerosing, liposarcoma. A genetic analysis searching for mutations in blood DNA was performed and did not detect any specific mutation. A literature review was also conducted. Several tumors related to syndromic and non-syndromic craniosynostosis are mentioned in the literature; no specific link with retroperitoneal liposarcoma is established but the FGFR3 mutation is detected in dedifferentiated liposarcomas. To date, no case has been reported in the literature demonstrating a genetic relationship between craniosynostosis and low-grade differentiated retroperitoneal liposarcoma. We conclude that further studies for gene complex mutations should be conducted to show a possible genetic relationship between retroperitoneal liposarcoma and craniosynostosis.

Three-Dimensional Printed Polycaprolactone Mesh in Pediatric Cranial Vault Remodeling Surgery

BACKGROUND

The surgical management of craniosynostosis has greatly evolved with improvements in both technology and understanding of the disease process. Some drawbacks remain regarding bone regeneration within the surgical bony gaps. Generally, bony gaps improve in the 12 to 24 months after surgery, but some gaps may remain for longer and cause deformity and/or require additional bony reconstruction. These considerations make tissue-engineered bone very attractive. Novel 3-dimensional printed bioresorbable mesh implants made of Polycaprolactone (PCL) can be used to fill the surgical bony defects.

OBJECTIVES

The authors seek to investigate how the use of a 3-dimensional printed biodegradable PCL mesh applied to bony defects in cranial vault surgery affects bone healing.

METHODS

Case series analysis of 8 pediatric patients who have undergone surgical intervention using PCL mesh implants for reconstruction of bony defects during craniosynostosis correction surgery.

FINDINGS

Radiological evaluation of 3 patients at random time points between 9 and 12 months postoperative revealed persistent bony gaps in areas where PCL mesh was laid. One patient who underwent a subsequent cranial vault surgery at 9 months was found to have less bone regeneration in the defect area where PCL mesh was used when compared with an adjacent area where a particulate bone graft was used.

CONCLUSIONS

Based on our experience, the use of PCL mesh on its own did not augment bone regeneration. It is possible that a greater amount of time or increased vascularization of the scaffold is required, which supports the concept of regenerative matching axial vascularization or the further addition of osteogenic factors to increase the rate of bone formation.

Intrafamilial variability in six family members with ERF-related craniosynostosis syndrome type 4

ERF-related craniosynostosis syndrome type 4 (CRS4, OMIM #600775) is a rare autosomal dominant malformation syndrome, caused by pathogenic variants in the ERF gene and characterized by craniosynostosis, developmental delay, and dysmorphic features such as hypertelorism, exophthalmos, depressed nasal bridge, and retrognathia. So far, there are mostly individual reports and only a few descriptions of families with more than two affected patients, allowing statements about the penetrance of a certain variant and its variability only to a limited extent. In this study, we report an in-depth analysis of the clinical course of six family members from three generations with the novel heterozygous nonsense variant c.286A>T (p.Lys96*) in the ERF gene. At the time of examination, all of the six patients showed mild dysmorphic features and brachydactyly, five were overweight/obese and had delayed speech development, and four were short in stature. Hyperactivity, a short concentration span and a history of learning difficulties were found in half of the affected family members. To this day, none of the patients developed increased intracranial hypertension that would require surgical intervention. This work provides further information on the expressive variability of an ERF variant in six members of one family and focuses on the need for close neuropediatric surveillance.

The Evolving Role of Next Generation Sequencing in Pediatric Neurosurgery: a Call for Action for Research, Clinical Practice, and Optimization of Care

NGS (Next-Generation Sequencing) is one of the most promising technologies that have truly revolutionized many aspects of clinical practice in recent years. It has been and is increasingly applied in many disciplines of medicine; however, it appears that pediatric neurosurgery despite its great potential has not truly embraced this new technology and is hesitant to employ it in its routine practice and guidelines. In this review, we briefly summarized the developments that lead to the establishment of NGS technology, reviewed the current applications and potentials of NGS in the disorders treated by pediatric neurosurgeons, and lastly discuss the steps we need to take to better harness NGS in pediatric neurosurgery.

An additional whole-exome sequencing study in 102 panel-undiagnosed patients: A retrospective study in a Chinese craniosynostosis cohort

Craniosynostosis (CRS) is a disease with prematurely fused cranial sutures. In the last decade, the whole-exome sequencing (WES) was widely used in Caucasian populations. The WES largely contributed in genetic diagnosis and exploration on new genetic mechanisms of CRS. In this study, we enrolled 264 CRS patients in China. After a 17-gene-panel sequencing designed in the previous study, 139 patients were identified with pathogenic/likely pathogenic (P/LP) variants according to the ACMG guideline as positive genetic diagnosis. WES was then performed on 102 patients with negative genetic diagnosis by panel. Ten P/LP variants were additionally identified in ten patients, increasing the genetic diagnostic yield by 3.8% (10/264). The novel variants in ANKH, H1-4, EIF5A, SOX6, and ARID1B expanded the mutation spectra of CRS. Then we designed a compatible research pipeline (RP) for further exploration. The RP could detect all seven P/LP SNVs and InDels identified above, in addition to 15 candidate variants found in 13 patients with worthy of further study. In sum, the 17-gene panel and WES identified positive genetic diagnosis for 56.4% patients (149/264) in 16 genes. At last, in our estimation, the genetic testing strategy of “Panel-first” saves 24.3% of the cost compared with “WES only”, suggesting the “Panel-first” is an economical strategy.

ERN CRANIO patient coverage of craniosynostosis in Europe

Background

Against the backdrop of the European Directive on patients’ rights in cross-border healthcare, 24 European Reference Networks (ERNs) were launched in 2017. ERNs are networks of specialised hospitals working together to support patients with rare and/or complex diseases. ERN CRANIO is the ERN for craniofacial anomalies and ear, nose and throat disorders. The aim of this study was to explore ERN CRANIO’s patient coverage of craniosynostosis.

Methods

ERN CRANIO members and applicants were asked to retrospectively report the number of ‘new craniosynostosis patients’ (isolated and syndromic) seen in 2017. The number of live births per country in 2017 was retrieved from EUROSTAT, the EU’s statistical office. The number of new patients reported per country and the number of live births were used to generate country-specific prevalence figures per 10,000 live births. These figures were compared to expected prevalence ranges for craniosynostosis, and syndromic craniosynostosis specifically, defined by recent European studies. The percentage of syndromic craniosynostosis cases per country was also compared to the expected percentage range.

Results

Based on previous studies, the expected prevalence ranges for craniosynostosis and syndromic craniosynostosis specifically were respectively defined as 4.4–7.2 and 0.9–1.6 patients/10,000 live births. For craniosynostosis (‘total’; isolated + syndromic), 'new patient' data from the UK and Finland generated prevalence figures within the expected range, and those in France, Spain, Italy, Portugal and Germany are lower than expected. However, when including applicant data, the prevalence figures for France, Spain and Italy become in range. Data from the Netherlands and Sweden generated higher prevalence figures than expected. For France, Finland, Italy and Sweden, there is inconsistency between patient coverage of ‘total’ and syndromic patients. For France, Germany, Finland and Italy, the percentage of syndromic craniosynostosis was lower than the expected range.

Conclusion

ERN CRANIO’s coverage of craniosynostosis varies across Europe. Results may be explained by data collection methods, genetic testing policies and/or national healthcare systems. With centre caseload a driving force for quality, additional ERN membership calls may not necessarily ensure sufficient patient coverage for countries with decentralised healthcare systems. Liaison with national health ministries should be encouraged to optimise patient coverage.

Management of Minor Suture Craniosynostosis

Although most reported cases of minor suture involvement include multiple sutures, isolated suture involvement has been reported. Morphologic differences such as scaphocephaly and anterior plagiocephaly have been reported. Management should involve proper identification and multidisciplinary treatment. Surgical treatment should involve the expansion of the cranial vault as well as the correction of the deformity.

Evaluating caregiver stress in craniosynostosis patients

OBJECTIVE

Caregiver stress from a child's diagnosis can impact a caregiver's ability to participate in treatment decisions, comply, and manage long-term illness. The aim of this study was to compare caregiver stress in children with craniosynostosis at diagnosis and postoperatively.

METHODS

This prospective study included caregivers of pediatric patients with craniosynostosis receiving operative intervention. Demographics and Parenting Stress Index, Short Form (PSI-SF) and Pediatric Inventory for Parents (PIP) surveys at baseline (preoperatively) and 3 and 6 months postoperatively were completed. PSI-SF scores between 15 and 80 are considered normal, with > 85 being clinically significant and requiring follow-up. Higher PIP scores represent increased frequency and difficulty of stressful events due to the child's illness. Pairwise comparisons were performed using the Wilcoxon signed-rank test. Multivariate analysis was performed to assess for PSI-SF and PIP predictors.

RESULTS

Of 106 caregivers (84% Caucasian), there were 62 mothers and 40 fathers. There were 68 and 45 responses at 3 and 6 months postoperatively, respectively. Regarding the baseline group, more than 80% were between 20 and 40 years of age and 58% had less than 2 years of college education. The median household income fell in the $45,001-$60,000 bracket. There was no significant difference between median baseline PSI-SF score (65, IQR 51-80) and those at 3 months (p = 0.45) and 6 months (p = 0.82) postoperatively. Both median PIP frequency (89 vs 74, p < 0.01) and difficulty (79 vs 71, p < 0.01) scores were lower at 3 months, although no significant difference was observed at 6 months (frequency: 95 vs 91, p = 0.67; difficulty: 82 vs 80, p = 0.34). Female sex, uninsured status, and open surgery type were all risk factors for higher parental stress.

CONCLUSIONS

Stress levels ranged from normal to clinically significant in the caregivers, with sex, uninsured status, and open repair predicting higher stress. Stress decreased at 3 months postoperatively before increasing at 6 months. Intervention targeting caregiver stress should be explored to maintain lower stress observed at 3 months after surgery.

Mechanical loading of cranial joints minimizes the craniofacial phenotype in Crouzon syndrome

Children with syndromic forms of craniosynostosis undergo a plethora of surgical interventions to resolve the clinical features caused by the premature fusion of cranial sutures. While surgical correction is reliable, the need for repeated rounds of invasive treatment puts a heavy burden on the child and their family. This study explores a non-surgical alternative using mechanical loading of the cranial joints to prevent or delay craniofacial phenotypes associated with Crouzon syndrome. We treated Crouzon syndrome mice before the onset of craniosynostosis by cyclical mechanical loading of cranial joints using a custom designed set-up. Cranial loading applied to the frontal bone partially restores normal skull morphology, significantly reducing the typical brachycephalic appearance. This is underpinned by the delayed closure of the coronal suture and of the intersphenoidal synchondrosis. This study provides a novel treatment alternative for syndromic craniosynostosis which has the potential to be an important step towards replacing, reducing or refining the surgical treatment of all craniosynostosis patients.

Results from Genetic Studies in Patients Affected with Craniosynostosis: Clinical and Molecular Aspects

Background: Craniosynostosis (CS) represents a highly heterogeneous genetic condition whose genetic background has not been yet revealed. The abnormality occurs either in isolated form or syndromic, as an element of hundreds of different inborn syndromes. Consequently, CS may often represent a challenging diagnostic issue.

Methods: We investigated a three-tiered approach (karyotyping, Sanger sequencing, followed by custom gene panel/chromosomal microarray analysis, and exome sequencing), coupled with prioritization of variants based on dysmorphological assessment and description in terms of human phenotype ontology. In addition, we have also performed a statistical analysis of the obtained clinical data using the nonparametric test χ².

Results: We achieved a 43% diagnostic success rate and have demonstrated the complexity of mutations’ type harbored by the patients, which were either chromosomal aberrations, copy number variations, or point mutations. The majority of pathogenic variants were found in the well-known CS genes, however, variants found in genes associated with chromatinopathies or RASopathies are of particular interest.

Conclusion: We have critically summarized and then optimised a cost-effective diagnostic algorithm, which may be helpful in a daily diagnostic routine and future clinical research of various CS types. Moreover, we have pinpointed the possible underestimated co-occurrence of CS and intellectual disability, suggesting it may be overlooked when intellectual disability constitutes a primary clinical complaint. On the other hand, in any case of already detected syndromic CS and intellectual disability, the possible occurrence of clinical features suggestive for chromatinopathies or RASopathies should also be considered.

High risk factors for craniosynostosis during pregnancy: A case-control study

Background

Craniosynostosis is a birth defect involving premature cranial sutures’ fusion with an increasing prevalence and unknown underlying causes in nearly 80% of cases. The current study investigates a series of high-risk factors associated with a non-syndromic craniosynostosis.

Methods

Ninety-seven (97) children were included in the retrospective case-control study, 62 controls and 35 with craniosynostosis. A questionnaire with 143 questions was used in face-to-face interviews. After univariate analyses, stepwise multivariate logistic regression analysis was implemented.

Results

In craniosynostosis group, 3 out of 4 were male subjects and 2 out of 3 born with caesarian section. History for central nervous system abnormalities in their younger siblings, low birth weight, extended use of mobile phone from the parents and medications’ use differed significantly between craniosynostosis and control group. After adjustment for all factors, only maternal medication use (aOR 6,1 [2.1 – 19], CI 95%) and oral progesterone intake (aOR 4 [1.2 – 14], CI 95%) were significantly associated with an increased risk in craniosynostosis group.

Conclusion

The maternal medications’ use and particular oral progesterone intake is associated with an increased risk for non-syndromic craniosynostosis. However, due to the study’s limitations, further research is warranted.

Mechanism of Disease: Recessive ADAMTSL4 Mutations and Craniosynostosis with Ectopia Lentis

Craniosynostosis, the premature fusion of the calvarial bones, has numerous etiologies. Among them, several involve mutations in genes related to the TGFb signaling pathway, a critical molecular mediator of human development. These TGFb pathway-associated craniosynostosis syndromes include Loeys–Dietz syndrome (LDS) and Shprintzen–Goldberg syndrome (SGS). LDS and SGS have many similarities common to fibrillinopathies, specifically Marfan syndrome (MFS), which is caused by mutations in FBN1. Historically discriminating features of MFS from LDS and SGS are (1) the presence of ectopia lentis (the subluxation/dislocation of the ocular lens) and (2) the absence of craniosynostosis. Curiously, several instances of a seemingly novel syndrome involving only craniosynostosis and ectopia lentis have recently been reported to be caused by recessive mutations in ADAMTSL4, a poorly characterized gene as of yet. Here, we report on two new cases of craniosynostosis with ectopia lentis, each harboring recessive mutations in ADAMTSL4. We also discuss a proposed mechanism for the relationship between ADAMTSL4, FBN1, and TGFb pathway-related syndromes.

FGFR3 overactivation in the brain is responsible for memory impairments in Crouzon syndrome mouse model

Crouzon syndrome with acanthosis nigricans (CAN, a rare type of craniosynostosis characterized by premature suture fusion and neurological impairments) has been linked to a gain-of-function mutation (p.Ala391Glu) in fibroblast growth factor receptor 3 (FGFR3). To characterize the CAN mutation's impact on the skull and on brain functions, we developed the first mouse model (Fgfr3A385E/+) of this syndrome. Surprisingly, Fgfr3A385E/+ mice did not exhibit craniosynostosis but did show severe memory impairments, a structurally abnormal hippocampus, low activity-dependent synaptic plasticity, and overactivation of MAPK/ERK and Akt signaling pathways in the hippocampus. Systemic or brain-specific pharmacological inhibition of FGFR3 overactivation by BGJ398 injections rescued the memory impairments observed in Fgfr3A385E/+ mice. The present study is the first to have demonstrated cognitive impairments associated with brain FGFR3 overactivation, independently of skull abnormalities. Our results provide a better understanding of FGFR3's functional role and the impact of its gain-of-function mutation on brain functions. The modulation of FGFR3 signaling might be of value for treating the neurological disorders associated with craniosynostosis.

Epidemiology of Rare Craniofacial Anomalies: Retrospective Western Australian Population Data Linkage Study

OBJECTIVE

To describe birth prevalence of rare craniofacial anomalies and associations with antenatal and perinatal factors.

STUDY DESIGN

All live and stillbirths in Western Australia between 1980 and 2010 were identified from the Western Australian Birth Registrations and the Midwives Notification System (also provides information on antenatal and perinatal factors). Rare craniofacial anomalies (craniosynostosis, craniofacial microsomia, and others [Pierre Robin, Van der Woude, and Treacher Collins syndrome]) were ascertained from the Western Australian Register of Developmental Anomalies and linked to other data sources. Trends in prevalence, adjusted for sex and Indigenous status, were investigated by Poisson regression and presented as annual percent change (APC). Strengths of association of related factors were assessed using multivariable log-binomial regression adjusted for sex, Indigenous status, birth year, socioeconomic disadvantage, and remoteness and reported as risk ratios with 95% CIs.

RESULTS

There was a temporal increase in prevalence of metopic synostosis (APC 5.59 [2.32-8.96]) and craniofacial microsomia (Goldenhar syndrome) (APC 4.43 [1.94-6.98]). Rare craniofacial anomalies were more likely among infants born preterm, as twins or greater-order multiples, with growth restriction, to older parents, to mothers undertaking fertility treatments, and with pre-existing medical conditions, specifically epilepsy, diabetes, or hypothyroidism. Prenatal identification of rare craniofacial anomalies was uncommon (0.6%).

CONCLUSIONS

Our findings indicate a steady increase over time in prevalence of metopic synostosis and craniofacial microsomia (Goldenhar syndrome). Possible associations of fertility treatments and pre-existing maternal medical conditions with rare craniofacial anomalies require further investigation.

Management of Lambdoid Craniosynostosis: A Comprehensive and Systematic Review

BACKGROUND

Craniosynostosis is a condition characterized by the premature fusion of 2 or more skull bones. Craniosynostosis of the lambdoid suture is one of the rarest forms, accounting for 1-4% of all craniosynostoses. Documented cases are separated into simple (single suture), complex (bilateral), and associated with adjacent synostoses ("Mercedes Benz" Pattern) or syndromes (i.e., Crouzon, Sathre-Chotzen, Antley-Bixler). This condition can manifest phenotypic deformities and neurological sequelae that can lead to impaired cognitive function if improperly treated or left undiagnosed. Preferred surgical techniques have varied over time but all maintain the common goals of establishing proper head shape and preventing of complications that could contribute to aforementioned sequelae.

SUMMARY

This comprehensive review highlights demographic distributions, embryological development, pathogenesis, clinical presentation, neurological sequelae, radiologic findings, surgical techniques, surgical outcomes, and postoperative considerations of patients with lambdoid craniosynostosis presentation. In addition, a systematic review was conducted to explore the operative management of lambdoid craniosynostosis using PubMed, Embase, and Scopus databases, with 38 articles included after screening. Key Messages: Due to a low volume of published cases, diagnosis and treatment can vary. Large overlap in presentation can occur in patients that display lambdoid craniosynostosis and posterior plagiocephaly, furthering the need for comprehensive analysis. Possessing the knowledge and tools to properly assess patients with lambdoid craniosynostosis will allow for more precise care and improved outcomes.

Multisuture and syndromic craniosynostoses: Simplifying the complex

Most complex craniosynostoses are managed the same way as syndromic craniosynostoses (SCs), as these patients often experience similar problems regarding cognition and increased intracranial pressure (ICP). The evaluation and treatment plan for craniosynostoses is complex, and this, additionally, is complicated by the age at presentation. In this article, the authors review the complexity of SCs in the presentation and management. An algorithm is necessary for such multifaceted and multidimensional pathology as craniosynostoses. In most algorithms, posterior calvarial distraction is a consistent early option for complex craniosynostoses presenting early with raised ICP. Addressing the airway early is critical when significant airway issues are there. All other surgical interventions are tailored on the basis of presentation and age.

Genetics of craniofacial malformations

The field of craniofacial malformations is comprehensive and does not allow to discuss all craniofacial malformations which have been described as single entities. Many of the syndromes with craniofacial malformations are ultrarare. In this review we have chosen craniofacial malformation syndromes which are of relevance for the pediatrician, especially neonatologist: different types of craniosynostoses, oculo-auriculo-vertebral spectrum, Pierre Robin sequence and Treacher Collins syndrome. These syndromes will be described in detail. Diagnostic and therapeutic options will be discussed.

Smartphone-assisted Augmented Reality in Craniofacial Surgery

Augmented reality (AR), a blending of both the physical and digital worlds, can be a valid tool for surgeons wishing to plan interventions and attain symmetry. The use of technology has enabled physicians to achieve desirable results. In this article, we describe a method that uses smartphone's simple AR utilities for convenient, cost effective, and time saving perioperative planning.

Methods

Images of preoperative computed tomography, along with 3D reconstructed scans were uploaded to a smartphone and used in an affordable application (Camera Lucida) to superimpose the loaded pictures over the smartphone camera. In one case, a 3D computed tomography scan of the skull was mirrored to help guide fronto-orbital advancement, and in another case the loaded 3D reconstructed computed tomography scan was used to prioritize areas of scalp coverage in a complicated case of craniosynostosis with major scalp wound dehiscence.

Discussion

Adaptation of AR to assist in the field of craniofacial surgery has been introduced before in several studies that reported the use of computer-based guidance for cranial reshaping. The majority of these reports used sophisticated modalities, combining advanced image registration and tracking with specialized equipment. The utility of smartphone AR for cranial vault reconstruction provided good accuracy when visualizing fronto-orbital advancement and remodeling, together with in depth prioritization of areas in need of soft tissue reconstruction.

Conclusion

Smartphone AR adaptation proved to be a very convenient tool assisting in the planning of different craniofacial conditions that are time saving and do not incur any additional fees beyond those of the surgery.

Ciliary Signalling and Mechanotransduction in the Pathophysiology of Craniosynostosis

Craniosynostosis (CS) is the second most prevalent inborn craniofacial malformation; it results from the premature fusion of cranial sutures and leads to dimorphisms of variable severity. CS is clinically heterogeneous, as it can be either a sporadic isolated defect, more frequently, or part of a syndromic phenotype with mendelian inheritance. The genetic basis of CS is also extremely heterogeneous, with nearly a hundred genes associated so far, mostly mutated in syndromic forms. Several genes can be categorised within partially overlapping pathways, including those causing defects of the primary cilium. The primary cilium is a cellular antenna serving as a signalling hub implicated in mechanotransduction, housing key molecular signals expressed on the ciliary membrane and in the cilioplasm. This mechanical property mediated by the primary cilium may also represent a cue to understand the pathophysiology of non-syndromic CS. In this review, we aimed to highlight the implication of the primary cilium components and active signalling in CS pathophysiology, dissecting their biological functions in craniofacial development and in suture biomechanics. Through an in-depth revision of the literature and computational annotation of disease-associated genes we categorised 18 ciliary genes involved in CS aetiology. Interestingly, a prevalent implication of midline sutures is observed in CS ciliopathies, possibly explained by the specific neural crest origin of the frontal bone.

Craniosynostosis: Clinical Presentation, Genetics, and Prenatal Diagnosis

Importance

Craniosynostosis is a fetal condition caused by premature closure of the cranial sutures. Through provider awareness, we can raise suspicion in high-risk individuals, increase prenatal detection, optimize genetic testing, perform appropriate antenatal surveillance and delivery planning, and allow for a comprehensive, multidisciplinary approach to treatment.

Objective

The aim of this study was to review what is currently known regarding the genetics, pathophysiology, diagnosis, and treatment of craniosynostosis for the obstetric care provider.

Evidence Acquisition

A comprehensive literature review was performed using the PubMed database with the search term "craniosynostosis." The search was limited to the English language.

Results

A total of 220 articles were identified, and a total of 53 were used in completion of this article. The results highlight the multiple factors involved with abnormal suture formation, including various genetic factors. Although rare at this time, prenatal detection can allow families to prepare and practitioners to provide appropriate clinical treatment. Both 3-dimensional sonography and magnetic resonance imaging have been identified as modalities to aid in detection for high-risk individuals. Early referral allows for less-invasive surgical outcomes with lower complication rates.

Results

Familiarity with craniosynostosis among obstetric providers can improve patient counseling, prenatal detection rates, and appropriate antepartum, intrapartum, and postpartum counseling.

Benefits of clinical criteria and high-throughput sequencing for diagnosing children with syndromic craniosynostosis

An accurate diagnosis of syndromic craniosynostosis (CS) is important for personalized treatment, surveillance, and genetic counselling. We describe detailed clinical criteria for syndromic CS and the distribution of genetic diagnoses within the cohort. The prospective registry of the Norwegian National Unit for Craniofacial Surgery was used to retrieve individuals with syndromic CS born between 1 January 2002 and 30 June 2019. All individuals were assessed by a clinical geneticist and classified using defined clinical criteria. A stepwise approach consisting of single-gene analysis, comparative genomic hybridization (aCGH), and exome-based high-throughput sequencing, first filtering for 72 genes associated with syndromic CS, followed by an extended trio-based panel of 1570 genes were offered to all syndromic CS cases. A total of 381 individuals were registered with CS, of whom 104 (27%) were clinically classified as syndromic CS. Using the single-gene analysis, aCGH, and custom-designed panel, a genetic diagnosis was confirmed in 73% of the individuals (n = 94). The diagnostic yield increased to 84% after adding the results from the extended trio-based panel. Common causes of syndromic CS were found in 53 individuals (56%), whereas 26 (28%) had other genetic syndromes, including 17 individuals with syndromes not commonly associated with CS. Only 15 individuals (16%) had negative genetic analyses. Using the defined combination of clinical criteria, we detected among the highest numbers of syndromic CS cases reported, confirmed by a high genetic diagnostic yield of 84%. The observed genetic heterogeneity encourages a broad genetic approach in diagnosing syndromic CS.

Craniosynostosis Develops in Half of Infants Treated for Hydrocephalus with a Ventriculoperitoneal Shunt

BACKGROUND

Craniosynostosis following placement of a ventriculoperitoneal shunt for hydrocephalus has been sporadically described. The purpose of this investigation was to determine the general risk of developing craniosynostosis in this patient population.

METHODS

The authors retrospectively reviewed records and radiographs of infants who underwent ventriculoperitoneal shunt placement for hydrocephalus from 2006 to 2012. Recorded variables included date of shunt placement, demographics, comorbidities, cause of hydrocephalus, shunt type, and number of shunt revisions. Axial computed tomographic images obtained before and immediately after shunt placement and 2 to 4 years after shunt placement were evaluated by a panel of clinicians for evidence of craniosynostosis. Patients with preshunt craniosynostosis, craniosynostosis syndromes, or poor-quality computed tomographic images were excluded. Data were analyzed using STATA Version 15.1 statistical software.

RESULTS

One hundred twenty-five patients (69 male and 56 female patients) were included. Average age at shunt placement was 2.3 ± 2.58 months. Sixty-one patients (48.8 percent) developed craniosynostosis at a median of 26 months after shunt placement. Of these, 28 patients fused one suture; the majority involved the sagittal suture (n = 25). Thirty-three patients fused multiple sutures; the most common were the coronal (n = 32) and the sagittal (n = 30) sutures. Multivariable logistic regression identified older age at shunt placement and more shunt revisions as independent predictors of craniosynostosis. Shunt valve type was not significant.

CONCLUSIONS

Craniosynostosis developed in nearly half of infants who underwent ventriculoperitoneal shunt placement for hydrocephalus. The sagittal suture was most commonly involved. The effect of suture fusion on subsequent cranial growth, shunt failure, or the development of intracranial pressure is unclear.

CLINICAL QUESITON/LEVEL OF EVIDENCE

Risk, III.

Craniosynostosis: current conceptions and misconceptions

Cranial bones articulate in areas called sutures that must remain patent until skull growth is complete. Craniosynostosis is the condition that results from premature closure of one or more of the cranial vault sutures, generating facial deformities and more importantly, skull growth restrictions with the ability to severely affect brain growth. Typically, craniosynostosis can be expressed as an isolated event, or as part of syndromic phenotypes. Multiple signaling mechanisms interact during developmental stages to ensure proper and timely suture fusion. Clinical outcome is often a product of craniosynostosis subtypes, number of affected sutures and timing of premature suture fusion. The present work aimed to review the different aspects involved in the establishment of craniosynostosis, providing a close view of the cellular, molecular and genetic background of these malformations.

A Pilot Study of Identification Genetic Background of Craniosynostosis Cases

ABSTRACT

The early fusion of the cranial sutures was described as a craniosynostosis. The early diagnosis and management of craniosynostosis is very important. Environmental factors and genetic abnormalities plays a key role during the development of craniosynostosis. Syndromic craniosynostosis cases are related with autosomal dominant disorders but nearly half of the affected cases carry a new mutation. In this study, in order to identify the genetic etiology of craniosynostosis the authors analyzed 20 craniosynostosis patients by using conventional karyotype, aCGH, sanger sequencing, next generation sequencing (NGS) and Multiplex ligation-dependent probe amplification (MLPA) techniques. The authors identified mutations on FGFR2 and FGFR3 genes which were associated with Muenke syndrome, Crouzon syndrome and skeletal dysplasia syndromes. NGS applied all of the cases and 7 clinical variations in 5 different gene were detected in %20 of cases. In addition to these abnormalities; del(11)(q14.1q22.2), del(17)(q21.31), dup(22)(q13.31) and t(2;16)(q37;p13) have been identified in our cohort which are not previously detected in craniosynostosis cases. Our study demonstrates the importance of detailed genetic analysis for the diagnosis, progression and management of the craniosynostosis.

Clinical and Genetic Characterization of Craniosynostosis in Saudi Arabia

Background: Craniosynostosis (CS) is defined as pre-mature fusion of one or more of the cranial sutures. CS is classified surgically as either simple or complex based on the number of cranial sutures involved. CS can also be classified genetically as isolated CS or syndromic CS if the patient has extracranial deformities. Currently, the link between clinical and genetic patterns of CS in the Saudi population is poorly understood. Methodology: We conducted a retrospective cohort study among 28 CS patients, of which 24 were operated and four were not. Clinical and genetic data were collected between February 2015 and February 2019, from consenting patient's families. The electronic chart data were collected and analyzed including patient demographics, craniofacial features, other anomalies and dysmorphic features, operative data, intra cranial pressure (ICP), parent consanguinity and genetic testing results. Results: The most common deformity in our population was trigonocephaly. The most performed procedure was cranial vault reconstruction with fronto-orbital advancement, followed by posterior vault distraction osteogenesis and suturectomy with barrel staving. Genetics analysis revealed pathogenic mutations in FGFR2 (6 cases), TWIST1 (3 cases), ALPL (2 cases), and TCF12 (2 cases), and FREM1 (2 case). Conclusion: Compared to Western countries, our Saudi cohort displays significant differences in the prevalence of CS features, such as the types of sutures and prevalence of inherited CS. The genomic background allows our phenotype-genotype study to reclassify variants of unknown significance. Worldwide, the sagittal suture is the most commonly affected suture in simple CS, but in the Saudi population, the metopic suture fusion was most commonly seen in our clinic. Further studies are needed to investigate the characteristics of CS in our population in a multicenter setting.