Saethre–Chotzen syndrome caused by TWIST 1 gene mutations: functional differentiation from Muenke coronal synostosis syndrome

Genetic Heterogeneity, Craniofacial Surgical Burden, and Surgical Techniques in Patients With Saethre-Chotzen Syndrome

OBJECTIVE

While genotype correlates with phenotype in patients with many forms of syndromic craniosynostosis, the relationship between molecular diagnosis and craniofacial surgical history in patients with Saethre-Chotzen syndrome (SCS) is more variable. This manuscript characterizes that relationship and evaluates operative trends in these patients over the past 3 decades.

METHODS

Demographic information, molecular diagnosis, and craniofacial surgical history in patients born with SCS between 1989 and 2023 were compared with appropriate statistics, including t tests and analysis of variance.

RESULTS

Thirty-five patients with SCS were included, and there was no difference in total craniofacial procedures among those with TWIST1 substitutions (2.1 ± 1.6), duplications (3.0 ± 4.2), insertions (3.5 ± 0.7), or deletions (2.4 ± 1.9; P = 0.97). Cranial expansion rates were also similar across all genetic diagnoses (P>0.05), and surgical incidence was similar across patients with unicoronal, bicoronal, and multisuture involvement (P > 0.05). Those with an initial fronto-orbital advancement had a lower incidence of secondary cranial vault procedures compared with those with an initial posterior vault distraction osteogenesis (29% versus 71%, P < 0.05), though this did not control for phenotypic severity. On average, total cranial vault surgical burden (1.35 ± 0.67 versus 1.75 ± 0.46) and cranial expansion surgical burden (1.40 ± 0.68 versus 1.88 ± 0.64) between the fronto-orbital advancement-first and posterior vault distraction osteogenesis-first cohorts were similar (P = 0.11, P = 0.17, respectively).

CONCLUSION

While SCS is molecularly and phenotypically heterogeneous, genetic diagnosis does not appear associated with rates of craniofacial surgery. Additional prospective study of correlations between genotype, severity of craniofacial manifestations, and treatment algorithms is warranted; but, in the end, it may be that this highly variable form of syndromic craniosynostosis warrants tailored, expectant management.

A Twist-Box domain of the C. elegans Twist homolog, HLH-8, plays a complex role in transcriptional regulation

TWIST1 is a basic helix-loop-helix (bHLH) transcription factor in humans that functions in mesoderm differentiation. TWIST1 primarily regulates genes as a transcriptional repressor often through TWIST-Box domain-mediated protein-protein interactions. The TWIST-Box also can function as an activation domain requiring 3 conserved, equidistant amino acids (LXXXFXXXR). Autosomal dominant mutations in TWIST1, including 2 reported in these conserved amino acids (F187L and R191M), lead to craniofacial defects in Saethre-Chotzen syndrome (SCS). Caenorhabditis elegans has a single TWIST1 homolog, HLH-8, that functions in the differentiation of the muscles responsible for egg laying and defecation. Null alleles in hlh-8 lead to severely egg-laying defective and constipated animals due to defects in the corresponding muscles. TWIST1 and HLH-8 share sequence identity in their bHLH regions; however, the domain responsible for the transcriptional activity of HLH-8 is unknown. Sequence alignment suggests that HLH-8 has a TWIST-Box LXXXFXXXR motif; however, its function also is unknown. CRISPR/Cas9 genome editing was utilized to generate a domain deletion and several missense mutations, including those analogous to SCS patients, in the 3 conserved HLH-8 amino acids to investigate their functional role. The TWIST-Box alleles did not phenocopy hlh-8 null mutants. The strongest phenotype detected was a retentive (Ret) phenotype with late-stage embryos in the hermaphrodite uterus. Further, GFP reporters of HLH-8 downstream target genes (arg-1::gfp and egl-15::gfp) revealed tissue-specific, target-specific, and allele-specific defects. Overall, the TWIST-Box in HLH-8 is partially required for the protein's transcriptional activity, and the conserved amino acids contribute unequally to the domain's function.

An "unexpected" role for EMT transcription factors in hematological development and malignancy

The epithelial to mesenchymal transition (EMT) is a fundamental developmental process essential for normal embryonic development. It is also important during various pathogenic processes including fibrosis, wound healing and epithelial cancer cell metastasis and invasion. EMT is regulated by a variety of cell signalling pathways, cell-cell interactions and microenvironmental cues, however the key drivers of EMT are transcription factors of the ZEB, TWIST and SNAIL families. Recently, novel and unexpected roles for these EMT transcription factors (EMT-TFs) during normal blood cell development have emerged, which appear to be largely independent of classical EMT processes. Furthermore, EMT-TFs have also begun to be implicated in the development and pathogenesis of malignant hematological diseases such as leukemia and lymphoma, and now present themselves or the pathways they regulate as possible new therapeutic targets within these malignancies. In this review, we discuss the ZEB, TWIST and SNAIL families of EMT-TFs, focusing on what is known about their normal roles during hematopoiesis as well as the emerging and "unexpected" contribution they play during development and progression of blood cancers.

The Role of E3 Ligase Pirh2 in Disease

The p53-dependent ubiquitin ligase Pirh2 regulates a number of proteins involved in different cancer-associated processes. Targeting the p53 family proteins, Chk2, p27Kip1, Twist1 and others, Pirh2 participates in such cellular processes as proliferation, cell cycle regulation, apoptosis and cellular migration. Thus, it is not surprising that Pirh2 takes part in the initiation and progression of different diseases and pathologies including but not limited to cancer. In this review, we aimed to summarize the available data on Pirh2 regulation, its protein targets and its role in various diseases and pathological processes, thus making the Pirh2 protein a promising therapeutic target.

Quantitative Morphologic Analysis of Cranial Vault in Twist1+/- Mice: Implications in Craniosynostosis

BACKGROUND

The haploinsufficiency in the TWIST1 gene encoding a basic helix-loop-helix transcription factor is a cause of one of the craniosynostosis syndromes, Saethre-Chotzen syndrome. Patients with craniosynostosis usually require operative release of affected sutures, which makes it difficult to observe the long-term consequence of suture fusion on craniofacial growth.

METHODS

In this study, we performed quantitative analysis of morphologic changes of the skull in Twist1 heterozygously-deleted mice (Twist1+/-) with micro-computed tomographic images.

RESULTS

In Twist1+/- mice, fusion of the coronal suture began before postnatal day 14 and progressed until postnatal day 56, during which morphologic changes occurred. The growth of the skull was not achieved by a constant increase in the measured distances in wild type mice; some distances in the top-basal axis were decreased during the observation period. In the Twist1+/- mouse, growth in the top-basal axis was accelerated and that of the frontal cranium was reduced. In the unicoronal suture fusion mouse, the length of the zygomatic arch of affected side was shorter in the Twist1+/- mouse. In one postnatal day 56 Twist1+/- mouse with bilateral coronal suture fusion, asymmetric zygomatic arch length was identified.

CONCLUSION

The authors'results suggest that measuring the length of the left and right zygomatic arches may be useful for early diagnosis of coronal suture fusion and for estimation of the timing of synostosis, and that more detailed study on the growth pattern of the normal and the synostosed skull could provide prediction of the risk of resynostosis.

CLINICAL RELEVANCE STATEMENT

The data from this study can be useful to better understand the cranial growth pattern in patients with craniosynostosis.

Facial Dysmorphology in Saethre-Chotzen Syndrome

PURPOSE

Classic features of Saethre-Chotzen syndrome (SCS) described in the literature include a prominent nasal bridge, eyelid ptosis, telorbitism, maxillary hypoplasia, and mandibular prognathism. The purpose of this study was to evaluate objectively the bony features of SCS.

METHODS

Preoperative computer tomography scans of 15 SCS patients, 23 normal controls, 13 bicoronal nonsyndromic, and 7 unicoronal nonsyndromic craniosynostosis patients were included for analysis. Unaffected controls and nonsyndromic patients were age- and sex-matched to SCS patients. Morphometric cephalometrics were analyzed using three-dimensional computer tomography reconstructions. Mann-Whitney U were used to compare facial measurements between SCS and normal and nonsyndromic craniosynostosis controls.

RESULTS

Telorbitism was present in bicoronal SCS patients only (P = 0.04) but absent in the unicoronal and bicoronal/metopic cohorts. The angle of the nasal bone relative to the sella was not different between SCS and controls (P = 0.536), although the angle of the nasal bone relative to the forehead was decreased in SCS by 15.5° (P < 0.001). Saethre-Chotzen syndrome had a 2.6° maxillary retrusion relative to controls (P = 0.03). In addition, SCS patients aged 4 to 7 months had a wider (39.34 versus 35.04, P = 0.017) and anteroposteriorly foreshortened (32.12 versus 35.06, P = 0.039) maxilla. There was no difference in mandibular prognathism among SCS patients as measured by the sella-nasion-B point angle compared to controls (P = 0.705).

CONCLUSIONS

Despite classic descriptions, on morphometric analysis SCS patients did not demonstrate consistency across all suture subtypes in terms of telorbitism, a broad nasal bridge, or mandibular prognathism. Rather, SCS subtypes of SCS based on suture pathology more closely resemble nonsyndromic patients.

Intracranial Volume Measured and Correlated to Cephalic Index in Syndromic and Nonsyndromic Anterior Brachycephaly

BACKGROUND

Premature fusion of both coronal sutures (anterior brachycephaly) alters skull shape and potentially affects intracranial volume (ICV). Currently little is known about preoperative ICV in anterior brachycephaly. Aim is to measure preoperative ICV and compare this with normative data. Additionally, ICV will be correlated to most used clinical method of quantification: cephalic index (CI).

METHODS

Preoperative patients with anterior brachycephaly (age, ≤12 months) were included and categorized by syndrome (when present). Computed tomography scans were used for ICV measurement by manual segmentation (OsiriX (Fondation OsiriX, Geneva, Switzerland)). Intracranial volume of each subgroup was compared with Lichtenberg normative cranial volume growth curves for controls. Cephalic index was calculated and correlated to ICV using Pearson correlation coefficient.

RESULTS

Thirty-four patients with both syndromic and nonsyndromic anterior brachycephaly were included: 17 with Apert syndrome, 6 with Muenke syndrome, 5 with Saethre Chotzen syndrome, 3 with Crouzon, 1 with craniofrontonasal dysplasia, and 2 nonsyndromal. Mean age at preoperative computed tomography scan was 4 months (1-10 months). Mean ICV was 847.31 cm3 (473.91-1459.22 cm3). Nineteen of 34 patients had skull volumes between ±2 SD curves of Lichtenberg, none of the patients had an ICV smaller than -2 SD and 15 of 34 had an ICV larger than +2 SD. Mean ICV in Apert syndrome was 829.85 cm3 (473.91-1061.53 cm3), in Muenke syndrome 942.06 cm3 (768.02-1136.75 cm3), in Saethre Chotzen syndrome 779.72 cm3 (609.21-1002.95 cm3), in Crouzon syndrome 700.57 cm3 (652.31-784.32 cm3), in craniofrontonasal dysplasia 738.97 cm3, and in the nonsyndromal group 1154.64 cm3 (850.07-1459.22 cm3). Apert had a mean greater than +2SD above the mean, the other subgroups had a mean within normal ranges (±2 SD). Correlation between severity of brachycephaly and overall ICV was low (r = 0.42).

CONCLUSIONS

Mean preoperative ICV in both syndromic and nonsyndromic anterior brachycephaly was 847.31 cm3. Intracranial volume in anterior brachycephaly is in 55.9% between normal ranges (±2 SD). In 44.1% ICV was greater than +2 SD, especially in Apert syndrome (11/16 Apert patients). None of the included patients had a deviant small ICV of less than -2 SD. Additionally, low correlation between ICV and CI (r = 0.42) was found and therefore CI is not suitable for estimating ICV in anterior brachycephaly.

De novo ALX4 variant detected in child with non-syndromic craniosynostosis

Current understanding of the genetic factors contributing to the etiology of non-syndromic craniosynostosis (NSC) remains scarce. The present work investigated the presence of variants in ALX4, EFNA4, and TWIST1 genes in children with NSC to verify if variants within these genes may contribute to the occurrence of these abnormal phenotypes. A total of 101 children (aged 45.07±40.94 months) with NSC participated in this cross-sectional study. Parents and siblings of the probands were invited to participate. Medical and family history of craniosynostosis were documented. Biological samples were collected to obtain genomic DNA. Coding exons of human TWIST1, ALX4, and EFNA4 genes were amplified by polymerase chain reaction and Sanger sequenced. Five missense variants were identified in ALX4 in children with bilateral coronal, sagittal, and metopic synostosis. A de novo ALX4 variant, c.799G>A: p.Ala267Thr, was identified in a proband with sagittal synostosis. Three missense variants were identified in the EFNA4 gene in children with metopic and sagittal synostosis. A TWIST1 variant occurred in a child with unilateral coronal synostosis. Variants were predicted to be among the 0.1% (TWIST1, c.380C>A: p. Ala127Glu) and 1% (ALX4, c.769C>T: p.Arg257Cys, c.799G>A: p.Ala267Thr, c.929G>A: p.Gly310Asp; EFNA4, c.178C>T: p.His60Tyr, C.283A>G: p.Lys95Glu, c.349C>A: Pro117Thr) most deleterious variants in the human genome. With the exception of ALX4, c.799G>A: p.Ala267Thr, all other variants were present in at least one non-affected family member, suggesting incomplete penetrance. Thus, these variants may contribute to the development of craniosynostosis, and should not be discarded as potential candidate genes in the diagnosis of this condition.

Evolution of Cranioorbital Shape in Nonsyndromic, Muenke, and Saethre-Chotzen Bilateral Coronal Synostosis: A Case-Control Study of 2-Year Outcomes

BACKGROUND

The purpose of this study was to quantify change in cranioorbital morphology from presentation, after fronto-orbital advancement, and at 2-year follow-up.

METHODS

Volumetric, linear, and angular analyses were performed on computed tomographic scans of consecutive bilateral coronal synostosis patients. Comparisons were made across three time points, between syndromic and nonsyndromic cases, and against normal controls. Significance was set at p < 0.05.

RESULTS

Twenty-five patients were included: 11 were nonsyndromic, eight had Saethre-Chotzen syndrome, and six had Muenke syndrome. Total cranial volume was comparable to normal, age-matched control subjects before and 2 years after surgery despite an expansion during surgery. Axial and sagittal vector analyses showed advancement and widening of the lower forehead beyond control values with surgery and comparable anterior position, but increased width compared to controls at 2 years. Frontal bossing decreased with a drop in anterior cranial height and advanced lower forehead position. Middle vault height was not normalized and turricephaly persisted at follow-up. Posterior fossa volume remained lower at all three time points compared to control subjects. Supraorbital retrusion relative to anterior corneal position was overcorrected by surgery, with values comparable to those of control subjects at 2 years because of differential growth. There was no difference at 2 years between syndromic and nonsyndromic groups.

CONCLUSIONS

Open fronto-orbital advancement successfully remodels the anterior forehead but requires overcorrection to be comparable to normal at 2 years. Although there are differences in syndromic cases at presentation, they do not result in significant morphometric differences on follow-up. Posterior fossa volume remains lower at all time points.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Craniosynostosis: Neonatal Perspectives

Craniosynostosis is the premature fusion of 1 or more sutures that normally separate the bony plates of an infant's skull and occurs in about 1 in 2,000 to 2,500 live births. Primary or congenital craniosynostoses represent the majority of cases and consist of single-suture and multisuture synostoses. Multisuture synostoses are typically associated with distinct craniofacial syndromes, including Muenke syndrome, Apert syndrome, Crouzon syndrome, and Pfeiffer syndrome, and are thus categorized under syndromic craniosynostoses. Secondary causes of craniosynostoses include metabolic or hematologic disorders that affect bone metabolism and typically present much later than primary synostoses. The severity of the deformity and the presence of increased intracranial pressure dictate the need for early surgical intervention, prompting the importance of early recognition and timely referral. Infants with craniosynostosis are also at increased risk for neurodevelopmental impairment and thus require close follow-up and monitoring. The early recognition and referral of craniosynostosis is imperative for the optimization of management and minimization of potential neurologic impairments that may develop.

Saethre-Chotzen syndrome: long-term outcome of a syndrome-specific management protocol

AIM

To assess the long-term outcomes of our management protocol for Saethre-Chotzen syndrome, which includes one-stage fronto-orbital advancement.

METHOD

All patients born with Saethre-Chotzen syndrome between January 1992 and March 2017 were included. Evaluated parameters included occipital frontal head circumference (OFC), fundoscopy, neuroimaging (ventricular size, tonsillar position, and the presence of collaterals/an abnormal transverse sinus), polysomnography, and ophthalmological outcomes. The relationship between papilledema and its associated risk factors was evaluated with Fisher's exact test.

RESULTS

Thirty-two patients (21 females, 11 males) were included. Median (SD) age at first surgery was 9.6 months (3.1mo) for patients who were primarily referred to our center (range: 3.6-13.0mo), the median (SD) age at last follow-up was 13 years (5y 7mo; range: 3-25y). Seven patients had papilledema preoperatively, which recurred in two. Two patients had papilledema solely after first surgery. Second cranial vault expansion was indicated in 20%. Thirteen patients had an OFC deflection, indicating restricted skull growth, one patient had ventriculomegaly, and none developed hydrocephalus. Eleven patients had emissary veins, while the transverse sinus was aberrant unilaterally in 13 (hypoplastic n=10 and absent n=3). Four patients had mild tonsillar descent, one of which was a Chiari type I malformation. Four patients had obstructive sleep apnoea (two mild, one moderate, and one severe). An aberrant transverse sinus was associated with papilledema (p=0.01).

INTERPRETATION

Single one-stage fronto-orbital advancement was sufficient to prevent intracranial hypertension for 80% of our patients with Saethre-Chotzen syndrome. Follow-up should focus on OFC deflection and venous anomalies.

Transcriptome Analysis Reveals High Similarities between Adult Human Cardiac Stem Cells and Neural Crest-Derived Stem Cells

For the identification of a stem cell population, the comparison of transcriptome data enables the simultaneous analysis of tens of thousands of molecular markers and thus enables the precise distinction of even closely related populations. Here, we utilized global gene expression profiling to compare two adult human stem cell populations, namely neural crest-derived inferior turbinate stem cells (ITSCs) of the nasal cavity and human cardiac stem cells (hCSCs) from the heart auricle. We detected high similarities between the transcriptomes of both stem cell populations, particularly including a range of neural crest-associated genes. However, global gene expression likewise reflected differences between the stem cell populations with regard to their niches of origin. In a broader analysis, we further identified clear similarities between ITSCs, hCSCs and other adherent stem cell populations compared to non-adherent hematopoietic progenitor cells. In summary, our observations reveal high similarities between adult human cardiac stem cells and neural crest-derived stem cells from the nasal cavity, which include a shared relation to the neural crest. The analyses provided here may help to understand underlying molecular regulators determining differences between adult human stem cell populations.

Secondary vault reconstruction after open or minimal invasive correction for unisutural, multisutural or syndromic craniosynostosis: A cohort study on the impact of diagnosis and type of initial surgical technique

BACKGROUND

The aim of this study is to identify if certain types of craniosynostosis and/or surgical procedures are more likely to require a secondary intracranial procedure because of insufficient correction of skull shape or raised ICP after initial surgery.

METHODS

All consecutive cases with craniosynostosis that were operated at our center between January 2010 and January 2019 were included and the number of secondary operations of the vault were determined, as well as diagnosis, the indication and type and timing of initial surgery. Monobloc and facial bipartition procedures were excluded.

RESULTS

Over a nine year period, 790 vault corrections were performed in 780 patients of which 38 procedures were reoperations in 35 patient because of raised intracranial pressure or an insufficient esthetic result of the skull shape. Particularly patients with a multisutural or syndromic craniosynostosis are represented in this group, as well as three surgical procedures: 1. biparietal outfracturing for sagittal synostosis; 2. endoscopic stripcraniectomy with helmet therapy for unicoronal, multisutural or syndromic craniosynostosis; 3. conventional occipital expansion for syndromic craniosynostosis.

CONCLUSIONS

The risk of a second intracranial correction for insufficient outcome of skull shape or for raised ICP is related to type of synostosis and type of initial surgical technique. Particularly multisutural and syndromic craniosynostosis are more likely to require repeat surgery for these indications. Concerning initial technique, biparietal outfracturing does not correct sagittal synostosis sufficiently, stripcraniectomy with helmet therapy appears to undercorrect unicoronal, multisutural and syndromic synostosis, and conventional occipital expansion for multisutural and syndromic synostosis has poorer outcome than occipital expansion with distraction.

Caput membranaceum: A novel clinical presentation of ZIC1 related skull malformation and craniosynostosis

We report clinical and radiological features of a patient born with an isolated skull malformation of caput membranaceum and partial bicoronal craniosynostosis with a novel, de novo heterozygous missense variant in ZIC1 [NM_003412.3:c.1183C>G, p.(Pro395Ala)]. Caput membranaceum, or boneless skull, is a rare manifestation of skull ossification defect. It can result from an isolated, enlarged parietal foramina or it can present as part of skeletal dysplasia syndromes associated with poor mineralization such as hypophosphatasia, osteogenesis imperfecta type II, and Saethre-Chotzen syndrome. Their causative genes are well described. ZIC1, Zinc Finger protein of the cerebellum 1 (OMIM #600470) belongs to ZIC family genes, each encoding a Cys2 His2-type zinc finger domain-containing transcription factors. Recent studies have shown that pathogenic variants in ZIC1 have deleterious effect in developing human central nerves system and skull bone. ZIC1 related clinical conditions are reported and include cerebellum malformation, Dandy-Walker malformation, spinal dysraphism, microcephaly, and craniosynostosis with associated intellectual disability. To-date, there is no report of pathogenic variant in ZIC1 causing isolated caput membranaceum. Our observation adds to the clinical spectrum of ZIC1 related skull malformation.

Twist1: A Double-Edged Sword in Kidney Diseases

Background

Twist1 is a basic helix-loop-helix domain containing transcription factor that regulates cell differentiation, migration, proliferation, survival, and inflammatory responses by transcriptionally regulating a wide range of downstream target genes. Its homologous protein, Twist2, shares many structural and functional similarities with Twist1.

Summary

Accumulating evidence from both preclinical and clinical studies suggests that Twist1 is a pivotal regulator of several forms of renal disease. Twist1 is persistently activated following renal insults, particularly in chronic kidney diseases, and contributes to the renal inflammatory responses, tubular cell transformation programs, and possibly fibroblast activation, all of which are involved in the initiation and progression of kidney diseases.

Key Message

This review will specifically focus on Twist1 and outline our understanding of its functions in kidney disorders along with the introduction of Twist2 where pertinent. The thorough knowledge of Twist1's actions in the pathogenesis of kidney diseases should facilitate the development of novel therapeutics for kidney injury.

Language Development, Hearing Loss, and Intracranial Hypertension in Children With TWIST1-Confirmed Saethre-Chotzen Syndrome

Saethre-Chotzen syndrome (SCS) is an autosomal dominant condition defined by mutations affecting the TWIST1 gene on chromosome 7p21.1. Previous research has identified an elevated prevalence of intracranial hypertension and hearing impairment associated with this syndrome. This study aimed to investigate the influence of hearing history and presence of intracranial hypertension on language development in children with SCS.A retrospective study note analysis was performed for all patients with a confirmed TWIST1 gene abnormality who attended the Oxford Craniofacial Unit and underwent a language assessment over a 22-year period. Intracranial pressure monitoring, hearing status, and language outcomes were examined in detail.Thirty patients with genetically confirmed SCS and language assessment data were identified. Twenty-eight patients underwent surgical intervention; 10 presented with intracranial hypertension (5 prior to, and 5 after primary surgical intervention). Language data coinciding with the presentation of intracranial hypertension were available for 8 children. About 44% of children with intracranial hypertension presented with concurrent receptive and expressive language delay (n = 4/8). For both children (n = 2) with longitudinal language data available, the onset of intracranial hypertension reflected a concurrent decline in language skills. Audiometric data were available for 25 children, 80% (n = 20/25) had a history of hearing loss. About 50% of these had confirmed conductive hearing loss with middle ear effusion and the other 50% had presumed conductive hearing loss with middle ear effusion. About 100% of the children with available hearing data in our study had evidence of middle ear effusion in at least 1 ear. Results also indicated that 43% (n = 13/30) of the children presented with receptive and/or expressive language delay during childhood.Given the importance of hearing for language development and the preliminary findings of a potential decline in language skills in children during periods of intracranial hypertension, regular follow-up of hearing, language, and intracranial hypertension are indicated in children with SCS.

Metabolic reprogram associated with epithelial-mesenchymal transition in tumor progression and metastasis

Epithelial-mesenchymal Transition (EMT) is a de-differentiation program that imparts tumor cells with the phenotypic and cellular plasticity required for drug resistance, metastasis, and recurrence. This dynamic and reversible events is governed by a network of EMT-transcription factors (EMT-TFs) through epigenetic regulation. Many chromatin modifying-enzymes utilize metabolic intermediates as cofactors or substrates; this suggests that EMT is subjected to the metabolic regulation. Conversely, EMT rewires metabolic program to accommodate cellular changes during EMT. Here we summarize the latest findings regarding the epigenetic regulation of EMT, and discuss the mutual interactions among metabolism, epigenetic regulation, and EMT. Finally, we provide perspectives of how this interplay contributes to cellular plasticity, which may result in the clinical manifestation of tumor heterogeneity.

Recent Advances in Craniosynostosis

Craniosynostosis is a pathologic craniofacial disorder and is defined as the premature fusion of one or more cranial (calvarial) sutures. Cranial sutures are fibrous joints consisting of nonossified mesenchymal cells that play an important role in the development of healthy craniofacial skeletons. Early fusion of these sutures results in incomplete brain development that may lead to complications of several severe medical conditions including seizures, brain damage, mental delay, complex deformities, strabismus, and visual and breathing problems. As a congenital disease, craniosynostosis has a heterogeneous origin that can be affected by genetic and epigenetic alterations, teratogens, and environmental factors and make the syndrome highly complex. To date, approximately 200 syndromes have been linked to craniosynostosis. In addition to being part of a syndrome, craniosynostosis can be nonsyndromic, formed without any additional anomalies. More than 50 nuclear genes that relate to craniosynostosis have been identified. Besides genetic factors, epigenetic factors like microRNAs and mechanical forces also play important roles in suture fusion. As craniosynostosis is a multifactorial disorder, evaluating the craniosynostosis syndrome requires and depends on all the information obtained from clinical findings, genetic analysis, epigenetic or environmental factors, or gene modulators. In this review, we will focus on embryologic and genetic studies, as well as epigenetic and environmental studies. We will discuss published studies and correlate the findings with unknown aspects of craniofacial disorders.

Muenke syndrome: long-term outcome of a syndrome-specific treatment protocol

OBJECTIVE

The authors evaluated the long-term outcome of their treatment protocol for Muenke syndrome, which includes a single craniofacial procedure.

METHODS

This was a prospective observational cohort study of Muenke syndrome patients who underwent surgery for craniosynostosis within the first year of life. Symptoms and determinants of intracranial hypertension were evaluated by longitudinal monitoring of the presence of papilledema (fundoscopy), obstructive sleep apnea (OSA; with polysomnography), cerebellar tonsillar herniation (MRI studies), ventricular size (MRI and CT studies), and skull growth (occipital frontal head circumference [OFC]). Other evaluated factors included hearing, speech, and ophthalmological outcomes.

RESULTS

The study included 38 patients; 36 patients underwent fronto-supraorbital advancement. The median age at last follow-up was 13.2 years (range 1.3-24.4 years). Three patients had papilledema, which was related to ophthalmological disorders in 2 patients. Three patients had mild OSA. Three patients had a Chiari I malformation, and tonsillar descent < 5 mm was present in 6 patients. Tonsillar position was unrelated to papilledema, ventricular size, or restricted skull growth. Ten patients had ventriculomegaly, and the OFC growth curve deflected in 3 patients. Twenty-two patients had hearing loss. Refraction anomalies were diagnosed in 14/15 patients measured at ≥ 8 years of age.

CONCLUSIONS

Patients with Muenke syndrome treated with a single fronto-supraorbital advancement in their first year of life rarely develop signs of intracranial hypertension, in accordance with the very low prevalence of its causative factors (OSA, hydrocephalus, and restricted skull growth). This illustrates that there is no need for a routine second craniofacial procedure. Patient follow-up should focus on visual assessment and speech and hearing outcomes.

Identification and Management of Cranial Anomalies in Perinatology

Neonatal skull and head shape anomalies are rare. The most common cranial malformations encountered include craniosynostosis, deformational plagiocephaly, cutis aplasia, and encephalocele. Improved prenatal imaging can diagnose morphologic changes as early as the second trimester. Prenatal identification also provides perinatologists and neonatologists with valuable information that helps to optimize care during and after delivery. Cranial anomalies require a multidisciplinary team approach and occasionally a lifetime of care. Today, care begins with the perinatologist as many cranial anomalies can be identified in utero with recent advances in prenatal testing.

Deviating dental arch morphology in mild coronal craniosynostosis syndromes

Objectives

To determine whether the intramaxillary relationship of patients with Muenke syndrome and Saethre-Chotzen syndrome or TCF12-related craniosynostosis are systematically different than those of a control group.

Material and methods

Forty-eight patients (34 patients with Muenke syndrome, 8 patients with Saethre-Chotzen syndrome, and 6 patients with TCF12-related craniosynostosis) born between 1982 and 2010 (age range 4.84 to 16.83 years) that were treated at the Department of Oral Maxillofacial Surgery, Special Dental Care and Orthodontics, Children’s Hospital Erasmus University Medical Center, Sophia, Rotterdam, the Netherlands, were included. Forty-seven syndromic patients had undergone one craniofacial surgery according to the craniofacial team protocol. The dental arch measurements intercanine width (ICW), intermolar width (IMW), arch depth (AD), and arch length (AL) were calculated. The control group existed of 329 nonsyndromic children.

Results

All dental arch dimensions in Muenke (ICW, IMW, AL, p < 0.001, ADmax, p = 0.008; ADman, p = 0.002), Saethre-Chotzen syndrome, or TCF12-related craniosynostosis patients (ICWmax, p = 0.005; ICWman, IMWmax, AL, p < 0.001) were statistically significantly smaller than those of the control group.

Conclusions

In this study, we showed that the dental arches of the maxilla and the mandible of patients with Muenke syndrome and Saethre-Chotzen syndrome or TCF12-related craniosynostosis are smaller compared to those of a control group.

Clinical relevance

To gain better understanding of the sutural involvement in the midface and support treatment capabilities of medical and dental specialists in these patients, we suggest the concentration of patients with Muenke and Saethre-Chotzen syndromes or TCF12-related craniosynostosis in specialized teams for a multi-disciplinary approach and treatment.

Recessive MYF5 Mutations Cause External Ophthalmoplegia, Rib, and Vertebral Anomalies

MYF5 is member of the Myc-like basic helix-loop-helix transcription factor family and, in cooperation with other myogenic regulatory factors MYOD and MYF5, is a key regulator of early stages of myogenesis. Here, we report three consanguineous families with biallelic homozygous loss-of-function mutations in MYF5 who define a clinical disorder characterized by congenital ophthalmoplegia with scoliosis and vertebral and rib anomalies. The clinical phenotype overlaps strikingly with that reported in several Myf5 knockout mouse models. Affected members of two families share a haploidentical region that contains a homozygous 10 bp frameshift mutation in exon 1 of MYF5 (c.23_32delAGTTCTCACC [p.Gln8Leufs^∗86]) predicted to undergo nonsense-mediated decay. Affected members of the third family harbor a homozygous missense change in exon 1 of MYF5 (c.283C>T [p.Arg95Cys]). Using in vitro assays, we show that this missense mutation acts as a loss-of-function allele by impairing MYF5 DNA binding and nuclear localization. We performed whole-genome sequencing in one affected individual with the frameshift mutation and did not identify additional rare variants in the haploidentical region that might account for differences in severity among the families. These data support the direct role of MYF5 in rib, spine, and extraocular muscle formation in humans.

Craniosynostosis as a clinical and diagnostic problem: molecular pathology and genetic counseling

Craniosynostosis (occurrence: 1/2500 live births) is a result of premature fusion of cranial sutures, leading to alterations of the pattern of cranial growth, resulting in abnormal shape of the head and dysmorphic facial features. In approximately 85% of cases, the disease is isolated and nonsyndromic and mainly involves only one suture. Syndromic craniosynostoses such as Crouzon, Apert, Pfeiffer, Muenke, and Saethre-Chotzen syndromes not only affect multiple sutures, but are also associated with the presence of additional clinical symptoms, including hand and feet malformations, skeletal and cardiac defects, developmental delay, and others. The etiology of craniosynostoses may involve genetic (also somatic mosaicism and regulatory mutations) and epigenetic factors, as well as environmental factors. According to the published data, chromosomal aberrations, mostly submicroscopic ones, account for about 6.7-40% of cases of syndromic craniosynostoses presenting with premature fusion of metopic or sagittal sutures. The best characterized is the deletion or translocation of the 7p21 region containing the TWIST1 gene. The deletions of 9p22 or 11q23-qter (Jacobsen syndrome) are both associated with trigonocephaly. The genes related to the pathogenesis of the craniosynostoses itself are those encoding transcription factors, e.g., TWIST1, MSX2, EN1, and ZIC1, and proteins involved in osteogenic proliferation, differentiation, and homeostasis, such as FGFR1, FGFR2, RUNX2, POR, and many others. In this review, we present the clinical and molecular features of selected craniosynostosis syndromes, genotype-phenotype correlation, family genetic counseling, and propose the most appropriate diagnostic algorithm.

Contiguous gene deletion neighboring TWIST1 identified in a patient with Saethre-Chotzen syndrome associated with neurodevelopmental delay: Possible contribution of HDAC9

Saethre-Chotzen syndrome (SCS) is an autosomal dominant craniosynostotic disorder characterized by coronal synostosis, facial asymmetry, ptosis, and limb abnormalities. Haploinsufficiency of TWIST1, a basic helix-loop-helix transcription factor is responsible for SCS. Here, we report a 15-month-old male patient with typical clinical features of SCS in addition to developmental delay, which is a rare complication in SCS. He showed a de novo 0.9-Mb microdeletion in 7p21, in which TWIST1, NPMIP13, FERD3L, TWISTNB, and HDAC9 were included. In comparison with previously reported patients, HDAC9 was suggested to contribute to developmental delay in SCS patients with 7p21 mirodeletions.

Destabilization of the TWIST1/E12 complex dimerization following the R154P point-mutation of TWIST1: an in silico approach

Background

The bHLH transcription factor TWIST1 plays a key role in the embryonic development and in tumorigenesis. Some loss-of-function mutations of the TWIST1 gene have been shown to cause an autosomal dominant craniosynostosis, known as the Saethre-Chotzen syndrome (SCS). Although the functional impacts of many TWIST1 mutations have been experimentally reported, little is known on the molecular mechanisms underlying their loss-of-function. In a previous study, we highlighted the predictive value of in silico molecular dynamics (MD) simulations in deciphering the molecular function of TWIST1 residues.

Results

Here, since the substitution of the arginine 154 amino acid by a glycine residue (R154G) is responsible for the SCS phenotype and the substitution of arginine 154 by a proline experimentally decreases the dimerizing ability of TWIST1, we investigated the molecular impact of this point mutation using MD approaches. Consistently, MD simulations highlighted a clear decrease in the stability of the α-helix during the dimerization of the mutated R154P TWIST1/E12 dimer compared to the wild-type TE complex, which was further confirmed in vitro using immunoassays.

Conclusions

Our study demonstrates that MD simulations provide a structural explanation for the loss-of-function associated with the SCS TWIST1 mutation and provides a proof of concept of the predictive value of these MD simulations. This in silico methodology could be used to determine reliable pharmacophore sites, leading to the application of docking approaches in order to identify specific inhibitors of TWIST1 complexes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12900-017-0076-x) contains supplementary material, which is available to authorized users.

Genetic advances in craniosynostosis

Craniosynostosis, the premature ossification of one or more skull sutures, is a clinically and genetically heterogeneous congenital anomaly affecting approximately one in 2,500 live births. In most cases, it occurs as an isolated congenital anomaly, that is, nonsyndromic craniosynostosis (NCS), the genetic, and environmental causes of which remain largely unknown. Recent data suggest that, at least some of the midline NCS cases may be explained by two loci inheritance. In approximately 25-30% of patients, craniosynostosis presents as a feature of a genetic syndrome due to chromosomal defects or mutations in genes within interconnected signaling pathways. The aim of this review is to provide a detailed and comprehensive update on the genetic and environmental factors associated with NCS, integrating the scientific findings achieved during the last decade. Focus on the neurodevelopmental, imaging, and treatment aspects of NCS is also provided.

Mutation Screening of Candidate Genes in Patients with Nonsyndromic Sagittal Craniosynostosis

BACKGROUND

Craniosynostosis is a condition that includes the premature fusion of one or multiple cranial sutures. Among various craniosynostosis forms, sagittal nonsyndromic craniosynostosis is the most prevalent. Although different gene mutations have been identified in some craniosynostosis syndromes, the cause of sagittal nonsyndromic craniosynostosis remains largely unknown.

METHODS

To screen for candidate genes for sagittal nonsyndromic craniosynostosis, the authors sequenced DNA of 93 sagittal nonsyndromic craniosynostosis patients from a population-based study conducted in Iowa and New York states. FGFR1-3 mutational hotspots and the entire TWIST1, RAB23, and BMP2 coding regions were screened because of their known roles in human nonsyndromic or syndromic sagittal craniosynostosis, expression patterns, and/or animal model studies.

RESULTS

The authors identified two rare variants in their cohort. A FGFR1 insertion c.730_731insG, which led to a premature stop codon, was predicted to abolish the entire immunoglobulin-like III domain, including the ligand-binding region. A c.439C>G variant was observed in TWIST1 at its highly conserved loop domain in another patient. The patient's mother harbored the same variant and was reported with jaw abnormalities. These two variants were not detected in 116 alleles from unaffected controls or seen in the several databases; however, TWIST1 variant was found in a low frequency of 0.000831 percent in Exome Aggregation Consortium database.

CONCLUSIONS

The low mutation detection rate indicates that these genes account for only a small proportion of sagittal nonsyndromic craniosynostosis patients. The authors' results add to the perception that sagittal nonsyndromic craniosynostosis is a complex developmental defect with considerable genetic heterogeneity.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Inflammation fuels tumor progress and metastasis

Inflammation is a beneficial response that can remove pathogens, repair injured tissue and restore homeostasis to damaged tissues and organs. However, increasing evidence indicate that chronic inflammation plays a pivotal role in tumor development, as well as progression, metastasis, and resistance to chemotherapy. We will review the current knowledge regarding the contribution of inflammation to epithelial mesenchymal transition. We will also provide some perspectives on the relationship between ER-stress signals and metabolism, and the role of these processes in the development of inflammation.

Frontal Bone Insufficiency in Gsk3β Mutant Mice

The development of the mammalian skull is a complex process that requires multiple tissue interactions and a balance of growth and differentiation. Disrupting this balance can lead to changes in the shape and size of skull bones, which can have serious clinical implications. For example, insufficient ossification of the bony elements leads to enlarged anterior fontanelles and reduced mechanical protection of the brain. In this report, we find that loss of Gsk3β leads to a fully penetrant reduction of frontal bone size and subsequent enlarged frontal fontanelle. In the absence of Gsk3β the frontal bone primordium undergoes increased cell death and reduced proliferation with a concomitant increase in Fgfr2-IIIc and Twist1 expression. This leads to a smaller condensation and premature differentiation. This phenotype appears to be Wnt-independent and is not rescued by decreasing the genetic dose of β-catenin/Ctnnb1. Taken together, our work defines a novel role for Gsk3β in skull development.

Twist-BRD4 complex: potential drug target for basal-like breast cancer

As an important basic helix-loop-helix (bHLH) transcription factor, Twist associates with several physiological processes such as mesodermal development, and pathological processes such as Saethre-Chotzen syndrome. During cancer progression, Twist induces epithelial-mesenchymal transition (EMT), potentiating cancer cell invasion and metastasis. Although many studies have revealed its multiple biological roles, it remained unclear how Twist transcriptionally activates targeted genes. Recently we discovered tip60-mediated Twist di-acetylation in the ''histone H4-mimic'' GK-X-GK motif. The di-acetylated Twist recruits BRD4 and related transcriptional components to super-enhancer of its targeted genes during progression of basal-like breast cancer (BLBC). Here, we review this new advance of regulation and functional mechanism of Twist.

Whole-genome resequencing analyses of five pig breeds, including Korean wild and native, and three European origin breeds

Pigs have been one of the most important sources of meat for humans, and their productivity has been substantially improved by recent strong selection. Here, we present whole-genome resequencing analyses of 55 pigs of five breeds representing Korean native pigs, wild boar and three European origin breeds. 1,673.1 Gb of sequence reads were mapped to the Swine reference assembly, covering ∼99.2% of the reference genome, at an average of ∼11.7-fold coverage. We detected 20,123,573 single-nucleotide polymorphisms (SNPs), of which 25.5% were novel. We extracted 35,458 of non-synonymous SNPs in 9,904 genes, which may contribute to traits of interest. The whole SNP sets were further used to access the population structures of the breeds, using multiple methodologies, including phylogenetic, similarity matrix, and population structure analysis. They showed clear population clusters with respect to each breed. Furthermore, we scanned the whole genomes to identify signatures of selection throughout the genome. The result revealed several promising loci that might underlie economically important traits in pigs, such as the CLDN1 and TWIST1 genes. These discoveries provide useful genomic information for further study of the discrete genetic mechanisms associated with economically important traits in pigs.

The occipitofrontal circumference: reliable prediction of the intracranial volume in children with syndromic and complex craniosynostosis

OBJECT

Patients with syndromic and complex craniosynostosis are characterized by the premature fusion of one or more cranial sutures. These patients are at risk for developing elevated intracranial pressure (ICP). There are several factors known to contribute to elevated ICP in these patients, including craniocerebral disproportion, hydrocephalus, venous hypertension, and obstructive sleep apnea. However, the causal mechanism is unknown, and patients develop elevated ICP even after skull surgery. In clinical practice, the occipitofrontal circumference (OFC) is used as an indirect measure for intracranial volume (ICV), to evaluate skull growth. However, it remains unknown whether OFC is a reliable predictor of ICV in patients with a severe skull deformity. Therefore, in this study the authors evaluated the relation between ICV and OFC.

METHODS

Eighty-four CT scans obtained in 69 patients with syndromic and complex craniosynostosis treated at the Erasmus University Medical Center-Sophia Children’s Hospital were included. The ICV was calculated based on CT scans by using autosegmentation with an HU threshold < 150. The OFC was collected from electronic patient files. The CT scans and OFC measurements were matched based on a maximum amount of the time that was allowed between these examinations, which was dependent on age. A Pearson correlation coefficient was calculated to evaluate the correlations between OFC and ICV. The predictive value of OFC, age, and sex on ICV was then further evaluated using a univariate linear mixed model. The significant factors in the univariate analysis were subsequently entered in a multivariate mixed model.

RESULTS

The correlations found between OFC and ICV were r = 0.908 for the total group (p < 0.001), r = 0.981 for Apert (p < 0.001), r = 0.867 for Crouzon-Pfeiffer (p < 0.001), r = 0.989 for Muenke (p < 0.001), r = 0.858 for Saethre- Chotzen syndrome (p = 0.001), and r = 0.917 for complex craniosynostosis (p < 0.001). Age and OFC were significant predictors of ICV in the univariate linear mixed model (p < 0.001 for both factors). The OFC was the only predictor that remained significant in the multivariate analysis (p < 0.001).

CONCLUSIONS

The OFC is a significant predictor of ICV in patients with syndromic and complex craniosynostosis. Therefore, measuring the OFC during clinical practice is very useful in determining which patients are at risk for impaired skull growth.

RNA-based TWIST1 inhibition via dendrimer complex to reduce breast cancer cell metastasis

Breast cancer is the leading cause of cancer-related deaths among women in the United States, and survival rates are lower for patients with metastases and/or triple-negative breast cancer (TNBC; ER, PR, and Her2 negative). Understanding the mechanisms of cancer metastasis is therefore crucial to identify new therapeutic targets and develop novel treatments to improve patient outcomes. A potential target is the TWIST1 transcription factor, which is often overexpressed in aggressive breast cancers and is a master regulator of cellular migration through epithelial-mesenchymal transition (EMT). Here, we demonstrate an siRNA-based TWIST1 silencing approach with delivery using a modified poly(amidoamine) (PAMAM) dendrimer. Our results demonstrate that SUM1315 TNBC cells efficiently take up PAMAM-siRNA complexes, leading to significant knockdown of TWIST1 and EMT-related target genes. Knockdown lasts up to one week after transfection and leads to a reduction in migration and invasion, as determined by wound healing and transwell assays. Furthermore, we demonstrate that PAMAM dendrimers can deliver siRNA to xenograft orthotopic tumors and siRNA remains in the tumor for at least four hours after treatment. These results suggest that further development of dendrimer-based delivery of siRNA for TWIST1 silencing may lead to a valuable adjunctive therapy for patients with TNBC.

Hearing loss in syndromic craniosynostoses: otologic manifestations and clinical findings

OBJECTIVE

This review addresses hearing loss as it occurs and has been reported in Muenke syndrome as well as six additional FGFR related craniosynostosis syndromes (Apert syndrome, Pfeiffer syndrome, Crouzon syndrome, Beare-Stevenson syndrome, Crouzon syndrome with acanthosis nigricans, and Jackson-Weiss syndrome.

DATA SOURCES

Pub-Med, Medline, Cochrane Database, Science Direct, NLM Catalog.

REVIEW METHODS

A Medline search was conducted to find all reported cases of the 7 FGFR related syndromic craniosynostosis. Special attention was paid to literature that reported hearing findings and the audiology literature.

RESULTS

Hearing loss occurs in variable percentage as a component part of all FGFR related craniosynostosis syndromes. Our literature review revealed the following incidences of hearing loss in FGFR craniosynostoses: 61% in Muenke syndrome, 80% in Apert Syndrome, 92% in Pfeiffer syndrome, 74% in Crouzon syndrome, 68% in Jackson Weiss syndrome, 4% in Beare Stevenson syndrome and 14% in Crouzon syndrome with Acanthosis Nigricans. The majority of the hearing loss is a conductive hearing loss, with the exception of Muenke syndrome where the majority of patients have a sensorineural hearing loss and Crouzon syndrome where almost half of patients have a pure or component of sensorineural hearing loss.

CONCLUSION

This manuscript presents a diagnostic and management algorithm for patients with syndromic craniosynostosis. It will aid clinicians in treating these patients and further, the recognition of a possible syndrome in patients with hearing loss who also have syndromic features.

Expanding the mutation spectrum in 182 Spanish probands with craniosynostosis: identification and characterization of novel TCF12 variants

Craniosynostosis, caused by the premature fusion of one or more of the cranial sutures, can be classified into non-syndromic or syndromic and by which sutures are affected. Clinical assignment is a difficult challenge due to the high phenotypic variability observed between syndromes. During routine diagnostics, we screened 182 Spanish craniosynostosis probands, implementing a four-tiered cascade screening of FGFR2, FGFR3, FGFR1, TWIST1 and EFNB1. A total of 43 variants, eight novel, were identified in 113 (62%) patients: 104 (92%) detected in level 1; eight (7%) in level 2 and one (1%) in level 3. We subsequently screened additional genes in the probands with no detected mutation: one duplication of the IHH regulatory region was identified in a patient with craniosynostosis Philadelphia type and five variants, four novel, were identified in the recently described TCF12, in probands with coronal or multisuture affectation. In the 19 Saethre-Chotzen syndrome (SCS) individuals in whom a variant was detected, 15 (79%) carried a TWIST1 variant, whereas four (21%) had a TCF12 variant. Thus, we propose that TCF12 screening should be included for TWIST1 negative SCS patients and in patients where the coronal suture is affected. In summary, a molecular diagnosis was obtained in a total of 119/182 patients (65%), allowing the correct craniosynostosis syndrome classification, aiding genetic counselling and in some cases provided a better planning on how and when surgical intervention should take place and, subsequently the appropriate clinical follow up.

Closing the Gap: Genetic and Genomic Continuum from Syndromic to Nonsyndromic Craniosynostoses

Craniosynostosis, a condition that includes the premature fusion of one or multiple cranial sutures, is a relatively common birth defect in humans and the second most common craniofacial anomaly after orofacial clefts. There is a significant clinical variation among different sutural synostoses as well as significant variation within any given single-suture synostosis. Craniosynostosis can be isolated (i.e., nonsyndromic) or occurs as part of a genetic syndrome (e.g., Crouzon, Pfeiffer, Apert, Muenke, and Saethre-Chotzen syndromes). Approximately 85 % of all cases of craniosynostosis are nonsyndromic. Several recent genomic discoveries are elucidating the genetic basis for nonsyndromic cases and implicate the newly identified genes in signaling pathways previously found in syndromic craniosynostosis. Published epidemiologic and phenotypic studies clearly demonstrate that nonsyndromic craniosynostosis is a complex and heterogeneous condition supporting a strong genetic component accompanied by environmental factors that contribute to the pathogenetic network of this birth defect. Large population, rather than single-clinic or hospital-based studies is required with phenotypically homogeneous subsets of patients to further understand the complex genetic, maternal, environmental, and stochastic factors contributing to nonsyndromic craniosynostosis. Learning about these variables is a key in formulating the basis of multidisciplinary and lifelong care for patients with these conditions.

Intellectual, behavioral, and emotional functioning in children with syndromic craniosynostosis

OBJECTIVES

To examine intellectual, behavioral, and emotional functioning of children who have syndromic craniosynostosis and to explore differences between diagnostic subgroups.

METHODS

A national sample of children who have syndromic craniosynostosis participated in this study. Intellectual, behavioral, and emotional outcomes were assessed by using standardized measures: Wechsler Intelligence Scale for Children, Third Edition, Child Behavior Checklist (CBCL)/6-18, Disruptive Behavior Disorder rating scale (DBD), and the National Institute of Mental Health Diagnostic Interview Schedule for Children.

RESULTS

We included 82 children (39 boys) aged 6 to 13 years who have syndromic craniosynostosis. Mean Full-Scale IQ (FSIQ) was in the normal range (M = 96.6; SD = 21.6). However, children who have syndromic craniosynostosis had a 1.9 times higher risk for developing intellectual disability (FSIQ < 85) compared with the normative population (P < .001) and had more behavioral and emotional problems compared with the normative population, including higher scores on the CBCL/6-18, DBD Total Problems (P < .001), Internalizing (P < .01), social problems (P < .001), attention problems (P < .001), and the DBD Inattention (P < .001). Children who have Apert syndrome had lower FSIQs (M = 76.7; SD = 13.3) and children who have Muenke syndrome had more social problems (P < .01), attention problems (P < .05), and inattention problems (P < .01) than normative population and with other diagnostic subgroups.

CONCLUSIONS

Although children who have syndromic craniosynostosis have FSIQs similar to the normative population, they are at increased risk for developing intellectual disability, internalizing, social, and attention problems. Higher levels of behavioral and emotional problems were related to lower levels of intellectual functioning.

Hearing loss in syndromic craniosynostoses: introduction and consideration of mechanisms

PURPOSE

There are a number of craniosynostosis syndromes with hearing loss-including Muenke, Apert, Pfeiffer, Crouzon, Beare-Stevenson, Crouzon with acanthosis nigricans, and Jackson-Weiss syndromes-that result from mutations in the fibroblast growth factor receptor (FGFR) genes. Studies of FGFRs and their ligands, fibroblast growth factors (FGFs), have revealed clues to the precise contribution of aberrant FGFR signaling to inner ear morphogenesis and the hearing loss encountered in craniosynostoses. The purpose of this article is to review basic studies of FGFRs with emphasis on their function and expression in the inner ear and surrounding structures.

METHOD

A Medline search was performed to find basic science articles regarding FGFR, their ligands, and their expression and relevant mouse models. Additional items searched included clinical descriptions and studies of individuals with FGFR-related craniosynostosis syndromes.

RESULTS

The FGF signaling pathway is essential for the morphogensis and proper function of the inner ear and auditory sensory epithelium.

CONCLUSION

The variable auditory phenotypes seen in individuals with Muenke syndrome may have a genetic basis, likely due to multiple interacting factors in the genetic environment or modifying factors. Further analysis and studies of mouse models of Muenke syndrome, in particular, may provide clues to the specific effects of the defining mutation in FGFR3 in the inner ear not only at birth but also into adulthood. In particular, investigations into these models may give insight into the variable expression and incomplete penetrance of this phenotype.

Clinical spectrum and outcomes in families with coronal synostosis and TCF12 mutations

TCF12 mutations have been reported very recently in coronal synostosis. We report several cases of familial coronal synostosis among four families harbouring novel TCF12 mutations. We observed a broad interfamilial phenotypic spectrum with features overlapping with the Saethre-Chotzen syndrome. TCF12 molecular testing should be considered in patients with unilateral- or bilateral-coronal synostosis associated or not with syndactyly, after having excluded mutations in the TWIST1 gene and the p.Pro250Arg mutation in FGFR3.

Maternal complex chromosomal rearrangement leads to TCF12 microdeletion in a patient presenting with coronal craniosynostosis and intellectual disability

We report on a young child with intellectual disability and unilateral coronal craniosynostosis leading to craniofacial malformations. Standard karyotype showed an apparently balanced translocation between chromosomes 2 and 15 [t(2;15)(q21;q21.3)], inherited from his mother. Interestingly, array-CGH 180K showed a 3.64 Mb de novo deletion on chromosome 15 in the region 15q21.3q22.2, close to the chromosome 15 translocation breakpoints. This deletion leads to haploinsufficiency of TCF12 gene that can explain the coronal craniosynostosis described in the patient. Additional FISH analyses showed a complex balanced maternal chromosomal rearrangement combining the reciprocal translocation t(2;15)(q21;q21.3), and an insertion of the 15q22.1 segment into the telomeric region of the translocated 15q fragment. The genomic imbalance in the patient is likely caused by a crossing-over that occurs in the recombination loop formed during the maternal meiosis resulting in the deletion of the inserted fragment. This original case of a genomic microdeletion of TCF12 exemplifies the importance of array-CGH in the clinical investigation of apparently balanced rearrangements but also the importance of FISH analysis to identify the chromosomal mechanism causing the genomic imbalance.

Klinik und Genetik syndromaler und nichtsyndromaler Kraniosynostosen

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

High TWIST1 mRNA expression is associated with poor prognosis in lymph node-negative and estrogen receptor-positive human breast cancer and is co-expressed with stromal as well as ECM related genes

INTRODUCTION

The TWIST homolog 1 (TWIST1) is a transcription factor that induces epithelial to mesenchymal transition (EMT), a key process in metastasis. The purpose of this study was to investigate whether TWIST1 expression predicts disease progression in a large breast cancer cohort with long-term clinical follow-up, and to reveal the biology related to TWIST1 mediated disease progression.

METHODS

TWIST1 mRNA expression level was analyzed by quantitative real-time reverse polymerase chain reaction (RT-PCR) in 1,427 primary breast cancers. In uni- and multivariate analysis using Cox regression, TWIST1 mRNA expression level was associated with metastasis-free survival (MFS), disease-free survival (DFS) and overall survival (OS). Separate analyses in lymph node-negative patients (LNN, n = 778) who did not receive adjuvant systemic therapy, before and after stratification into estrogen receptor (ER)-positive (n = 552) and ER-negative (n = 226) disease, were also performed. The association of TWIST1 mRNA with survival endpoints was assessed using Kaplan-Meier analysis. Using gene expression arrays, genes showing a significant Spearman rank correlation with TWIST1 were used to identify overrepresented Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG)-annotated biological pathways.

RESULTS

Increased mRNA expression level of TWIST1 analyzed as a continuous variable in both uni- and multivariate analysis was associated with shorter MFS in all patients (hazard ratio (HR): 1.17, 95% confidence interval, (95% CI):1.09 to 1.26; and HR: 1.17, 95% CI: 1.08 to 1.26; respectively), in LNN patients (HR: 1.22, 95% CI: 1.09 to 1.36; and HR: 1.21, 95% CI: 1.07 to 1.36; respectively) and in the ER-positive subgroup of LNN patients (HR: 1.34, 95% CI: 1.17 to 1.53; and HR: 1.32, 95% CI: 1.14 to 1.53; respectively). Similarly, high TWIST1 expression was associated with shorter DFS and OS in all patients and in the LNN/ER-positive subgroup. In contrast, no association of TWIST1 mRNA expression with MFS, DFS or OS was observed in ER-negative patients. Genes highly correlated with TWIST1 were significantly enriched for cell adhesion and ECM-related signaling pathways. Furthermore, TWIST1 mRNA was highly expressed in tumor stroma and positively related to tumor stromal content (P <0.001).

CONCLUSIONS

TWIST1 mRNA expression is an independent prognostic factor for poor prognosis in LNN/ER-positive breast cancer. The biological associations suggest an involvement of the tumor microenvironment in TWIST1's adverse role in breast cancer.