Quantifying dysmorphologies of the neurocranium using artificial neural networks.

BACKGROUND: Craniosynostosis, a congenital condition characterized by the premature fusion of cranial sutures, necessitates objective methods for evaluating cranial morphology to enhance patient treatment. Current subjective assessments often lead to inconsistent outcomes. This study introduces a novel, quantitative approach to classify craniosynostosis and measure its severity. METHODS: An artificial neural network was trained to classify normocephalic, trigonocephalic, and scaphocephalic head shapes based on a publicly available dataset of synthetic 3D head models. Each 3D model was converted into a low-dimensional shape representation based on the distribution of normal vectors, which served as the input for the neural network, ensuring complete patient anonymity and invariance to geometric size and orientation. Explainable AI methods were utilized to highlight significant features when making predictions. Additionally, the Feature Prominence (FP) score was introduced, a novel metric that captures the prominence of distinct shape characteristics associated with a given class. Its relationship with clinical severity scores was examined using the Spearman Rank Correlation Coefficient. RESULTS: The final model achieved excellent test accuracy in classifying the different cranial shapes from their low-dimensional representation. Attention maps indicated that the network's attention was predominantly directed toward the parietal and temporal regions, as well as toward the region signifying vertex depression in scaphocephaly. In trigonocephaly, features around the temples were most pronounced. The FP score showed a strong positive monotonic relationship with clinical severity scores in both scaphocephalic (ρ = 0.83, p < 0.001) and trigonocephalic (ρ = 0.64, p < 0.001) models. Visual assessments further confirmed that as FP values rose, phenotypic severity became increasingly evident. CONCLUSION: This study presents an innovative and accessible AI-based method for quantifying cranial shape that mitigates the need for adjustments due to age-specific size variations or differences in the spatial orientation of the 3D images, while ensuring complete patient privacy. The proposed FP score strongly correlates with clinical severity scores and has the potential to aid in clinical decision-making and facilitate multi-center collaborations. Future work will focus on validating the model with larger patient datasets and exploring the potential of the FP score for broader applications. The publicly available source code facilitates easy implementation, aiming to advance craniofacial care and research.

Child-Patient Perspective on Results After Correction of Sagittal Synostosis and the Difference Between Child-Patient and Parent's Perspectives.

OBJECTIVE: This study assesses the level of child-patient satisfaction with the surgical result after scaphocephaly correction and the difference between child-patient and parents' perspectives. METHODS: A questionnaire was sent out to children between 6 and 18 years old with isolated sagittal synostosis, who had undergone either a frontobiparietal remodeling or extended strip craniotomy, and separately to their parents. RESULTS: The questionnaire was completed by 96 patients, 81.2% of the patients considered their head to be similar or slightly different from others. Despite the majority being satisfied with the outcome, 33% would change the shape of their head if they could. Patients who underwent extended strip craniotomy wanted to change the back of their head more often ( P = 0.002), whereas patients who underwent frontobiparietal remodeling wanted to change their forehead ( P = 0.005). The patients' own perspective on head shape was independent of the cephalic index (CI). However, patients with a relatively narrow CI received more remarks from others about their heads ( P = 0.038). Parent and child agreement was 49.7% on average. Differences between child-patients and parents were found in reporting adaptive behavior. CONCLUSION: The majority of patients were satisfied with the outcome of their intervention. The child's perspective seems to be a valuable addition to evaluate sagittal synostosis surgery as it is independent of the CI and differentiates between different surgical techniques. In addition, the patient's perspective is comparable to the parent's perspective, but gives more details on adaptive behavior.

The Development of a European Multidisciplinary Cleft Lip and Palate Registry by the European Reference Network CRANIO: Experiences, Barriers, And Facilitators.

The European Reference Network for Rare Craniofacial Aanomalies and Ear-Nose-Throat disorders aims to improve care for patients with such afflictions, including cleft lip and palate (CL/P) across Europe. Cleft treatment remains varied throughout European centers, inhibiting meaningful comparison of treatment outcomes. To overcome these issues, a European-wide common CL/P dataset and registry was developed, facilitating standardized treatment endpoints and outcome measures for international comparison and benchmarking of CL/P centers. Questionnaires and semi-structured interviews were used to determine the set-up of the registry. Previous CL/P initiatives were analyzed to create an initial dataset, refined through consensus meetings. In total, 87 cleft specialists working in specialized CL/P centers from 16 European nations participated. Consensus on a common dataset was reached. A "Level 1" dataset, with mandatory clinical and patient-reported outcome measures, and "Level 2" dataset with additional outcome measures. Finally, 2 dashboards were developed for data dissemination. The development of the European CL/P common dataset and registry tackled challenges with resource disparities, variations in specialists within CL/P teams, regulatory differences in patient data usage, patient-reported outcome measures availability in European languages, and use of assessment tools. This study described the successful development of the European Reference Network for Rare Craniofacial Aanomalies and Ear-Nose-Throat disorders CL/P common dataset and registry. This achievement will help improve patient care and outcomes for patients with CL/P in Europe. Furthermore, this study provides useful information for initiatives with similar aims.

3D Analysis of the Cranial and Facial Shape in Craniosynostosis Patients: A Systematic Review.

With increasing interest in 3D photogrammetry, diverse methods have been developed for craniofacial shape analysis in craniosynostosis patients. This review provides an overview of these methods and offers recommendations for future studies. A systematic literature search was used to identify publications on 3D photogrammetry analyses in craniosynostosis patients until August 2023. Inclusion criteria were original research reporting on 3D photogrammetry analyses in patients with craniosynostosis and written in English. Sixty-three publications that had reproducible methods for measuring cranial, forehead, or facial shape were included in the systematic review. Cranial shape changes were commonly assessed using heat maps and curvature analyses. Publications assessing the forehead utilized volumetric measurements, angles, ratios, and mirroring techniques. Mirroring techniques were frequently used to determine facial asymmetry. Although 3D photogrammetry shows promise, methods vary widely between standardized and less conventional measurements. A standardized protocol for the selection and documentation of landmarks, planes, and measurements across the cranium, forehead, and face is essential for consistent clinical and research applications.

Pathogenic variants in the paired-related homeobox 1 gene (PRRX1) cause craniosynostosis with incomplete penetrance.

PURPOSE: Studies have previously implicated PRRX1 in craniofacial development, including demonstration of murine Prrx1 expression in the preosteogenic cells of the cranial sutures. We investigated the role of heterozygous missense and loss-of-function (LoF) variants in PRRX1 associated with craniosynostosis. METHODS: Trio-based genome, exome, or targeted sequencing were used to screen PRRX1 in patients with craniosynostosis; immunofluorescence analyses were used to assess nuclear localization of wild-type and mutant proteins. RESULTS: Genome sequencing identified 2 of 9 sporadically affected individuals with syndromic/multisuture craniosynostosis, who were heterozygous for rare/undescribed variants in PRRX1. Exome or targeted sequencing of PRRX1 revealed a further 9 of 1449 patients with craniosynostosis harboring deletions or rare heterozygous variants within the homeodomain. By collaboration, 7 additional individuals (4 families) were identified with putatively pathogenic PRRX1 variants. Immunofluorescence analyses showed that missense variants within the PRRX1 homeodomain cause abnormal nuclear localization. Of patients with variants considered likely pathogenic, bicoronal or other multisuture synostosis was present in 11 of 17 cases (65%). Pathogenic variants were inherited from unaffected relatives in many instances, yielding a 12.5% penetrance estimate for craniosynostosis. CONCLUSION: This work supports a key role for PRRX1 in cranial suture development and shows that haploinsufficiency of PRRX1 is a relatively frequent cause of craniosynostosis.

Early and long-term skull growth after surgical correction for sagittal synostosis in relation to the occurrence of papilledema.

OBJECTIVE: Stagnation of skull growth is correlated with papilledema in craniosynostosis. In this retrospective cohort study, we describe the postoperative skull growth after surgical correction for sagittal synostosis and its relation to the development of papilledema. METHODS: Patients with isolated sagittal synostosis at our center between 2005 and 2012 were included. Occipitofrontal circumference (OFC) was analyzed, at 3 time points (preoperative, 2 years postoperative, and last OFC measurement) and 3 phases (initial postoperative growth, long-term growth, and overall growth), and related to papilledema on fundoscopy. RESULTS: In total, 163 patients were included. The first time interval showed a decline in skull growth, with subsequent stabilization at long term. Papilledema occurred postoperatively in 10 patients. In these patients, the OFC at 2 years and at last follow-up (T3) were significantly smaller than in patients without papilledema. A larger OFC resulted in a decreased odds of developing papilledema at both postoperative time points (at T2 (OR = 0.40, p = 0.01) and at T3 (OR 0.29, p < 0.001)). Sensitivity and specificity analysis indicated that an OFC below 0.25 SD at T2 (sensitivity 90%, specificity 65%) and below 0.49 at T3 (sensitivity 100%, specificity 60%) are related to the occurrence of papilledema. CONCLUSION: A small OFC is correlated with the occurrence of papilledema. A decline in OFC within 2 years postoperatively is common in sagittal synostosis and is acceptable up to a value of 0.25SD. Patients with an OFC at last follow-up of less than 0.5SD are at risk for developing papilledema.

Guideline on Treatment and Management of Craniosynostosis: Patient and Family Version.

The care and treatment of patients with craniosynostosis and the new developments were described for health care professionals involved in this in the guideline "Treatment and Management of Craniosynostosis", which was revised in 2020. A patient version was written based on the professional guideline to make the information accessible to patients and parents too. In this patient version, each chapter consists of several sections. Firstly, an introduction and background information is provided in each chapter. Various questions are then answered based on scientific literature. Finally, the recommendations indicate the importance of the literature for care in practice and how this care should be provided in practice. This patient version is an abbreviated and simplified representation of the professional guideline. The introduction, conclusions, and recommendations sections of each chapter were revised and, where necessary, rewritten. With some surgical techniques, links to animation videos (recognizable by underlined references) have been added in the text for clarification. An attempt was made to stay as close as possible to the original guideline in terms of content, questions, numbering, and classification. The patient version can therefore easily be read side by side with the professional guideline if more information is required about a specific subject. As this patient version is a summary and does not deal with all aspects in detail, no rights can be derived from its content and the professional guideline takes precedence at all times. Originally, this patient version has been written in response to the established Dutch guideline on craniosynostosis for health care professionals.2 This professional guideline has been specifically tailored to the Dutch health care setting and policy. There are however differences between health care systems and national health policies of other countries and the Netherlands. It is important to keep in mind that this may, at some points, result in the management of care in your country and/or hospital different from outlined here.

What We Know About Intracranial Hypertension in Children With Syndromic Craniosynostosis.

OBJECTIVE: A scoping review of literature about mechanisms leading to intracranial hypertension (ICH) in syndromic craniosynostosis (sCS) patients, followed by a narrative synopsis of whether cognitive and behavioral outcome in sCS is more related to genetic origins, rather than the result of ICH. METHODS: The scoping review comprised of a search of keywords in EMBASE, MEDLINE, Web of science, Cochrane Central Register of Trials, and Google scholar databases. Abstracts were read and clinical articles were selected for full-text review and data were extracted using a structured template. A priori, the authors planned to analyze mechanistic questions about ICH in sCS by focusing on 2 key aspects, including (1) the criteria for determining ICH and (2) the role of component factors in the Monro-Kellie hypothesis/doctrine leading to ICH, that is, cerebral blood volume, cerebrospinal fluid (CSF), and the intracranial volume. RESULTS: Of 1893 search results, 90 full-text articles met criteria for further analysis. (1) Invasive intracranial pressure measurements are the gold standard for determining ICH. Of noninvasive alternatives to determine ICH, ophthalmologic ones like fundoscopy and retinal thickness scans are the most researched. (2) The narrative review shows how the findings relate to ICH using the Monro-Kellie doctrine. CONCLUSIONS: Development of ICH is influenced by different aspects of sCS: deflection of skull growth, obstructive sleep apnea, venous hypertension, obstruction of CSF flow, and possibly reduced CSF absorption. Problems in cognition and behavior are more likely because of genetic origin. Cortical thinning and problems in visual function are likely the result of ICH.

Health-related Quality of Life in Children and Adolescents With Sagittal Synostosis.

BACKGROUND: This study evaluated the health-related quality of life (HR-QoL) in patients with sagittal synostosis (SS), and the influence of frequent headaches and surgical techniques on the HR-QoL. METHOD: Patients with SS aged 8 to 18 years were invited to participate between June 2016 and February 2017. The Child Health Questionnaire was used to assess the HR-QoL. A detailed questionnaire was used to assess the severity of headache symptoms. The control group consisted of 353 school children aged 5 to 14 years. RESULTS: In all, 95 parents of patients with SS were invited to participate, of whom 68 (71.6%) parents completed the CHQ-PF50. The mean age of the participating patients was 12.4 years (10.8 to 14.2). The Psychosocial- and Physical summary of the patients with SS was similar to the general population. In the distinct CHQ scales, "Family cohesion" ( P =0.02) was higher, and "Mental health" ( P =0.05) was lower compared with the general population. The type and timing of surgery did not affect the HR-QoL. Thirty-two patients (47.1%) reported having headache complaints at least once a month. The CHQ scores of SS patients with frequent headaches had a significantly lower score of mild to large effect than those without headaches. CONCLUSION: Patients with SS have a slightly lower to similar HR-QoL compared with the general population. In all, 47.1% of SS patients have frequent headaches, resulting in lower average HR-QoL. The type and timing of surgery did not affect the results. Clinicians should be aware of lower HR-QoL in some subgroups of patients with SS.

Non-Surgical Respiratory Management in Relation to Feeding and Growth in Patients with Robin Sequence; a Prospective Longitudinal Study.

OBJECTIVE: To reflect upon our non-surgical respiratory management by evaluating clinical outcomes regarding airway, feeding, and growth during the first year of life in patients with Robin Sequence. DESIGN: Prospective study. SETTING: Sophia Children's Hospital, Rotterdam, the Netherlands. PATIENTS/ PARTICIPANTS: 36 patients with Robin Sequence who were treated between 2011 and 2021. INTERVENTIONS: Positional therapy and respiratory support. MAIN OUTCOME MEASURE(S): Data on respiratory outcomes included polysomnography characteristics and capillary blood gas values. Feeding outcomes were based on the requirement of additional tube feeding. Outcomes on growth were expressed as standard-deviation-scores (SDS) for weight-for-age (WFA) and height-for-age (HFA). RESULTS: Twenty patients were treated with positional therapy (PT), whilst the other 16 patients required respiratory support. Twenty-two patients presented with non-isolated Robin Sequence (RS). During the first year of life, obstructive apnea hypopnea index decreased, oxygen levels enhanced, and capillary blood gas values improved. Eighty-six percent (31/36) experienced feeding difficulties, which completely resolved in 71% (22/31) during their first year of life. From start treatment, to stop treatment, to the age of 1 year, the SDS WFA worsened from -0.40 to -0.33 to -1.03, respectively. CONCLUSIONS: Non-surgical respiratory treatment resulted in an improvement of respiratory outcomes to near normal during the first year of life in patients with RS. These patients often experience feeding difficulties and endure impaired weight gain up to 1 year of age, despite near normalization of breathing. The high prevalence of feeding difficulties and impaired weight for age indicate the urgency for early recognition and adequate treatment to support optimal growth.

De Novo Missense Substitutions in the Gene Encoding CDK8, a Regulator of the Mediator Complex, Cause a Syndromic Developmental Disorder.

The Mediator is an evolutionarily conserved, multi-subunit complex that regulates multiple steps of transcription. Mediator activity is regulated by the reversible association of a four-subunit module comprising CDK8 or CDK19 kinases, together with cyclin C, MED12 or MED12L, and MED13 or MED13L. Mutations in MED12, MED13, and MED13L were previously identified in syndromic developmental disorders with overlapping phenotypes. Here, we report CDK8 mutations (located at 13q12.13) that cause a phenotypically related disorder. Using whole-exome or whole-genome sequencing, and by international collaboration, we identified eight different heterozygous missense CDK8 substitutions, including 10 shown to have arisen de novo, in 12 unrelated subjects; a recurrent mutation, c.185C>T (p.Ser62Leu), was present in five individuals. All predicted substitutions localize to the ATP-binding pocket of the kinase domain. Affected individuals have overlapping phenotypes characterized by hypotonia, mild to moderate intellectual disability, behavioral disorders, and variable facial dysmorphism. Congenital heart disease occurred in six subjects; additional features present in multiple individuals included agenesis of the corpus callosum, ano-rectal malformations, seizures, and hearing or visual impairments. To evaluate the functional impact of the mutations, we measured phosphorylation at STAT1-Ser727, a known CDK8 substrate, in a CDK8 and CDK19 CRISPR double-knockout cell line transfected with wild-type (WT) or mutant CDK8 constructs. These experiments demonstrated a reduction in STAT1 phosphorylation by all mutants, in most cases to a similar extent as in a kinase-dead control. We conclude that missense mutations in CDK8 cause a developmental disorder that has phenotypic similarity to syndromes associated with mutations in other subunits of the Mediator kinase module, indicating probable overlap in pathogenic mechanisms.

Missense variants in ANKRD11 cause KBG syndrome by impairment of stability or transcriptional activity of the encoded protein.

PURPOSE: Although haploinsufficiency of ANKRD11 is among the most common genetic causes of neurodevelopmental disorders, the role of rare ANKRD11 missense variation remains unclear. We characterized clinical, molecular, and functional spectra of ANKRD11 missense variants. METHODS: We collected clinical information of individuals with ANKRD11 missense variants and evaluated phenotypic fit to KBG syndrome. We assessed pathogenicity of variants through in silico analyses and cell-based experiments. RESULTS: We identified 20 unique, mostly de novo, ANKRD11 missense variants in 29 individuals, presenting with syndromic neurodevelopmental disorders similar to KBG syndrome caused by ANKRD11 protein truncating variants or 16q24.3 microdeletions. Missense variants significantly clustered in repression domain 2 at the ANKRD11 C-terminus. Of the 10 functionally studied missense variants, 6 reduced ANKRD11 stability. One variant caused decreased proteasome degradation and loss of ANKRD11 transcriptional activity. CONCLUSION: Our study indicates that pathogenic heterozygous ANKRD11 missense variants cause the clinically recognizable KBG syndrome. Disrupted transrepression capacity and reduced protein stability each independently lead to ANKRD11 loss-of-function, consistent with haploinsufficiency. This highlights the diagnostic relevance of ANKRD11 missense variants, but also poses diagnostic challenges because the KBG-associated phenotype may be mild and inherited pathogenic ANKRD11 (missense) variants are increasingly observed, warranting stringent variant classification and careful phenotyping.

The use of OCT to detect signs of intracranial hypertension in patients with sagittal suture synostosis: Reference values and correlations.

PURPOSE: To obtain pediatric normative reference values and determine whether optical coherence tomography (OCT) corresponds better with clinical signs of intracranial hypertension (ICH) compared to the traditional screening method fundoscopy in a large cohort of one type of single suture craniosynostosis. METHODS: Control subjects without optic nerve diseases and isolated sagittal synostosis patients aged 3-10 years who underwent fundoscopy and OCT were included in this prospective cohort study. Normative reference values were obtained through bootstrap analysis. Main outcome was the association between peripapillary total retinal thickness (TRT) and total retinal volume (TRV) and appearance on fundoscopy. Signs and symptoms suggestive of ICH, including skull growth arrest, fingerprinting, and headache, were scored. RESULTS: Sixty-four healthy controls and 93 isolated sagittal synostosis patients were included. Normative cut-off values for mean TRT are < 256 µm and > 504 µm and for mean TRV < 0.21 mm3 and > 0.39 mm3. TRT was increased in 16 (17%) and TRV in 15 (16%) of 93 patients, compared to only 4 patients with papilledema on fundoscopy (4%). Both parameters were associated with papilledema on fundoscopy (OR = 16.7, p = 0.02, and OR = 18.2, p = 0.01). Skull growth arrest was significantly associated with abnormal OCT parameters (OR = 13.65, p < 0.01). CONCLUSIONS: The established cut-off points can be applied to screen for ICH in pediatrics. The present study detected abnormalities with OCT more frequent than with fundoscopy, which were associated with skull growth arrest. Therefore, a combination of OCT, fundoscopy, and skull growth arrest can improve clinical decision-making in craniosynostosis.

Accuracy of Detecting Obstructive Sleep Apnea Using Ambulatory Sleep Studies in Patients With Syndromic Craniosynostosis.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is seen in up to two-third of the patients with syndromic craniosynostosis. Gold standard to diagnose OSA is the hospital-based polysomnography, although alternatively ambulatory home sleep apnea devices are available. Aim of this study was to assess (1) accuracy of ambulatory sleep studies, (2) clinical decision making following sleep studies, and (3) course of OSA during long-term follow-up. MATERIALS AND METHODS: A retrospective cohort study was performed in children with syndromic craniosynostosis, of whom polysomnographies and home sleep apnea device recordings were collected. Measurements of apnea-hypopnea index, respiratory event index, total sleep/recording time, heart rate, oxygen saturation, and oxygen desaturation index were derived from the sleep studies. Primary clinical care subsequent to the sleep studies was determined using electronic patient files. RESULTS: In total, 123 patients were included, with 149 polysomnographies and 108 ambulatory studies. Performing an ambulatory study was associated with increased age at time of measurement (OR=1.1, 95% CI=1.02 to 1.17, P =0.01). No significant difference was found between the 2 types of sleep studies regarding sleep study parameters. Subsequent to sleep studies, patients with no-mild OSA had expectant care whereas patients with moderate-severe OSA underwent OSA-related treatment. OSA was most prevalent up to the age of 5 years, but also noticeable after the age of 10 years in patients with the Crouzon syndrome. CONCLUSIONS: Ambulatory sleep studies are reliable for diagnosing OSA in older children and can be used to determine clinical decision-making. Hence, we recommend implementing ambulatory sleep studies in a protocolized management.

Prenatal Ultrasound Parameters of Twins With Sagittal Suture Craniosynostosis Question Mechanical Constraint as the Leading Cause.

BACKGROUND: Multiple pregnancy is a known predisposing factor for sagittal suture synostosis, and intrauterine constraint has been suggested as a potential cause. This study evaluates prenatal images of single and multiple pregnancies of children with sagittal suture synostosis to assess the possible pathogenesis. MATERIALS AND METHODS: Prenatal ultrasound data of scaphocephaly twins treated at Erasmus MC was retrieved retrospectively. The head circumference, cephalic index (CI), and biparietal diameter (BPD) were analyzed. Data were compared with the nonaffected sibling, singletons with scaphocephaly, and to general fetal growth reference values. RESULTS: Data of 8 twin pregnancies with 10 cases of scaphocephaly was gathered. For the head circumference no difference was found between affected fetuses and reference values throughout pregnancy. For the BPD a reduced growth was found, compared with control values. The growth curve for the CI of the affected twins is lower from the start and declines over time. When comparing affected fetuses to nonaffected fetuses, the same differences for the BPD and CI were found as compared with controls. No differences in growth parameters were found between the nonaffected siblings and reference values, nor between the affected scaphocephaly twins and singletons with scaphocephaly. CONCLUSIONS: Scaphocephaly in twin pregnancy develops early on in pregnancy, similar to singleton pregnancy, making the theory of constraint as a cause less likely. The development of scaphocephaly in twins is likely to be attributed to the same disturbed developmental processes in suture development as in singletons, and not to mechanical constraint.

Evaluation of dental maturity in Muenke syndrome, Saethre-Chotzen syndrome, and TCF12-related craniosynostosis.

OBJECTIVES: To determine whether dental maturity (dental development) was delayed in patients with Muenke syndrome, Saethre-Chotzen syndrome, and TCF12-related craniosynostosis, compared with a Dutch control group without syndromes. MATERIALS AND METHODS: This study included 60 patients (38 patients with Muenke syndrome, 17 patients with Saethre-Chotzen syndrome, and 5 with TCF12-related craniosynostosis), aged 5.8-16.8 years that were treated at the Department of Oral Maxillofacial Surgery, Special Dental Care, and Orthodontics, in Sophia Children's Hospital, Erasmus University Medical Center, Rotterdam, the Netherlands. Dental age was calculated according to Demirjian's index of dental maturity. The control group included 451 children without a syndrome. RESULTS: Compared with the control group, dental development was delayed by an average of one year in 5- to 8-year-old patients with Muenke syndrome (P = 0.007) and in 8- to 10-year-old patients with Saethre-Chotzen syndrome (P = 0.044), but not in patients with TCF12-related craniosynostosis. CONCLUSIONS: Our results indicated that dental development was delayed by one year, on average, in patients with Muenke syndrome and Saethre-Chotzen syndrome, compared with a Dutch control group without syndromes. IMPLICATIONS: Our findings have improved the understanding of dental development in patients with Muenke and Saethre-Chotzen syndrome. These results can provide guidance on whether the orthodontist needs to consider growth disturbances related to dental development.

A de novo substitution in BCL11B leads to loss of interaction with transcriptional complexes and craniosynostosis.

Craniosynostosis, the premature ossification of cranial sutures, is a developmental disorder of the skull vault, occurring in approximately 1 in 2250 births. The causes are heterogeneous, with a monogenic basis identified in ~25% of patients. Using whole-genome sequencing, we identified a novel, de novo variant in BCL11B, c.7C>A, encoding an R3S substitution (p.R3S), in a male patient with coronal suture synostosis. BCL11B is a transcription factor that interacts directly with the nucleosome remodelling and deacetylation complex (NuRD) and polycomb-related complex 2 (PRC2) through the invariant proteins RBBP4 and RBBP7. The p.R3S substitution occurs within a conserved amino-terminal motif (RRKQxxP) of BCL11B and reduces interaction with both transcriptional complexes. Equilibrium binding studies and molecular dynamics simulations show that the p.R3S substitution disrupts ionic coordination between BCL11B and the RBBP4-MTA1 complex, a subassembly of the NuRD complex, and increases the conformational flexibility of Arg-4, Lys-5 and Gln-6 of BCL11B. These alterations collectively reduce the affinity of BCL11B p.R3S for the RBBP4-MTA1 complex by nearly an order of magnitude. We generated a mouse model of the BCL11B p.R3S substitution using a CRISPR-Cas9-based approach, and we report herein that these mice exhibit craniosynostosis of the coronal suture, as well as other cranial sutures. This finding provides strong evidence that the BCL11B p.R3S substitution is causally associated with craniosynostosis and confirms an important role for BCL11B in the maintenance of cranial suture patency.

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

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

Three-Dimensional Stereophotogrammetry in the Evaluation of Craniosynostosis: Current and Potential Use Cases.

ABSTRACT: Three-dimensional (3D) stereophotogrammetry is a novel imaging technique that has gained popularity in the medical field as a reliable, non-invasive, and radiation-free imaging modality. It uses optical sensors to acquire multiple 2D images from different angles which are reconstructed into a 3D digital model of the subject's surface. The technique proved to be especially useful in craniofacial applications, where it serves as a tool to overcome the limitations imposed by conventional imaging modalities and subjective evaluation methods. The capability to acquire high-dimensional data in a quick and safe manner and archive them for retrospective longitudinal analyses, provides the field with a methodology to increase the understanding of the morphological development of the cranium, its growth patterns and the effect of different treatments over time.This review describes the role of 3D stereophotogrammetry in the evaluation of craniosynostosis, including reliability studies, current and potential clinical use cases, and practical challenges. Finally, developments within the research field are analyzed by means of bibliometric networks, depicting prominent research topics, authors, and institutions, to stimulate new ideas and collaborations in the field of craniofacial 3D stereophotogrammetry.We anticipate that utilization of this modality's full potential requires a global effort in terms of collaborations, data sharing, standardization, and harmonization. Such developments can facilitate larger studies and novel deep learning methods that can aid in reaching an objective consensus regarding the most effective treatments for patients with craniosynostosis and other craniofacial anomalies, and to increase our understanding of these complex dysmorphologies and associated phenotypes.

SMAD6 variants in craniosynostosis: genotype and phenotype evaluation.

PURPOSE: Enrichment of heterozygous missense and truncating SMAD6 variants was previously reported in nonsyndromic sagittal and metopic synostosis, and interaction of SMAD6 variants with a common polymorphism nearBMP2 (rs1884302) was proposed to contribute to inconsistent penetrance. We determined the occurrence of SMAD6 variants in all types of craniosynostosis, evaluated the impact of different missense variants on SMAD6 function, and tested independently whether rs1884302 genotype significantly modifies the phenotype. METHODS: We performed resequencing of SMAD6 in 795 unsolved patients with any type of craniosynostosis and genotyped rs1884302 in SMAD6-positive individuals and relatives. We examined the inhibitory activity and stability of SMAD6 missense variants. RESULTS: We found 18 (2.3%) different rare damaging SMAD6 variants, with the highest prevalence in metopic synostosis (5.8%) and an 18.3-fold enrichment of loss-of-function variants comparedwith gnomAD data (P < 10-7). Combined with eight additional variants, ≥20/26 were transmitted from an unaffected parent but rs1884302 genotype did not predict phenotype. CONCLUSION: Pathogenic SMAD6 variants substantially increase the risk of both nonsyndromic and syndromic presentations of craniosynostosis, especially metopic synostosis. Functional analysis is important to evaluate missense variants. Genotyping of rs1884302 is not clinically useful. Mechanisms to explain the remarkable diversity of phenotypes associated with SMAD6 variants remain obscure.