Hearing loss in the Saethre-Chotzen syndrome

Bioinformatics analysis of candidate genes involved in ethanol-induced microtia pathogenesis based on a human genome database: GeneCards

OBJECTIVE

Ethanol used by women during pregnancy increases the risk for microtia in the foetus. Traditionally, laboratory experiments and Mouse Genome Informatics (MGI) have been used to explore microtia pathogenesis. The aim of this study was to screen and verify hub genes involved in ethanol-induced microtia and to explore the potential molecular mechanisms.

METHODS

Overlapping genes related to ethanol and microtia were acquired from the GeneCards database and filtered by confidence score. These genes were further analysed via bioinformatics. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis results were visualized with the clusterProfiler R package. A protein-protein interaction (PPI) network was constructed based on data from the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database.

RESULTS

Overall, 41 genes related to both ethanol and microtia were identified. The genes most relevant to ethanol-induced microtia pathogenesis included FGFR-2, FGFR-3, FGF-8, TP53, IGF1, SHH, CTNNB1, and PAX6, among others. Most genes were strongly enriched for tissue and organ development in GO analysis. Additionally, many genes were enriched in the Ras, FoxO, MAPK, and PI3K-Akt signalling pathways in KEGG analysis.

CONCLUSIONS

Bioinformatics analysis was conducted on genes currently known to be related to ethanol-induced microtia pathogenesis. We propose that mechanisms involving FGF-family genes, TP53, IGF1 and SHH contribute significantly to ethanol-induced microtia and the accompanying malformation of other structures.

Saethre-Chotzen Syndrome: A Report of 7 Patients and Review of the Literature

INTRODUCTION

Saethre-Chotzen syndrome is a genetic condition characterized by craniofacial and limb anomalies, with craniosynostosis (mainly coronal) being the most frequent craniofacial finding. Cranial and facial deformities can be extremely variable requiring individualization of treatment strategies. We present our case series to highlight clinical findings, treatment philosophy, and challenges facing Saethre-Chotzen patients.

METHODS

A retrospective review was performed on records of patients given a diagnosis of Saethre-Chotzen syndrome at the University of California Los Angeles (UCLA) Craniofacial Clinic (n = 7) between 1980 and 2010. Patients with complete records were included in this study, and review of demographic data, clinical findings, surgical interventions and postoperative follow-up, and stability were performed.

RESULTS

Seven patients (1 male and 6 female) were included in this study. The average age at which the patients were first seen was 6.5 years. Suture involvement was bicoronal (n = 6) and unicoronal (n = 1). There was 1 patient having superimposed metopic synostosis, and there was another patient having Kleeblattschädel deformity. Previous procedures performed for patients before establishing care at UCLA were strip craniectomy (n = 2) and fronto-orbital advancement (n = 2). All patients (n = 7) had fronto-orbital advancements at UCLA. Other skeletal operations included the following: redo forehead advancement and contouring (n = 3), monobloc advancement (n = 1), and LeFort III distraction (n = 1). Five patients reached skeletal maturity, and 2 patients received LeFort I advancement for class III malocclusion, one of which also required a bilateral sagittal split osteotomy of the mandible.

CONCLUSION

Clinical presentation and severity of deformity in Saethre-Chotzen syndrome are variable. Our current report reviews our treatment strategies and illustrates the predominance of cranial and upper face deformities and frequent need for redo surgeries to address forehead asymmetry in this group of syndromic craniosynostosis patients.

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.

Audiologic findings in Pfeiffer syndrome

Hearing loss has been described in patients with certain craniosynostotic syndromes but is poorly defined in Pfeiffer syndrome (PS). Our objective was to characterize the otologic and audiologic findings in PS. The records of PS patients evaluated at our craniofacial center over a 30-year period were culled. Only patients with a confirmed diagnosis and formal audiologic examination were included. Diagnostic criteria were characteristic mutations in fibroblast growth factor receptor 1 or 2 (FGFR1, FGFR2) or, in the absence of genetic testing, typical clinical findings of PS as determined by a clinical geneticist or the most senior author. Twenty patients met the inclusion criteria, and all had hearing loss. Twenty patients had traditional audiologic testing: 14 (70%) had pure conductive loss (minor to severe), and 3 (15%) had a mixed conductive/sensorineural loss (minor to severe). Two additional patients had hearing loss by Behavioral Observational Audiometry (sound fields method). One patient with early conductive hearing loss was subsequently determined to have a pure sensorineural deficit. Nine patients (45%) had permanent hearing loss significant enough to require audiologic amplification. All patients with PS demonstrated hearing loss, although the severity and the anatomic basis (ie., neural vs conductive) were variable. Conductive hearing loss, possibly caused by structural abnormalities, was most common. Sensorineural hearing loss was less common and may be related to the effect of FGFR mutations on cranial nerve and/or inner-ear development.

Saethre-Chotzen Syndrome, Pro136His TWIST Mutation, Hearing Loss, and External and Middle Ear Structural Anomalies: Report on a Brazilian Family

Objective

To describe the clinical, speech, hearing, and imaging findings in three members of a Brazilian family with Saethre-Chotzen syndrome (SCS) who presented some unusual characteristics within the spectrum of the syndrome.

Design

Clinical evaluation was performed by a multidisciplinary team. Direct sequencing of the polymerase chain reaction–amplified coding region of the TWIST1 gene, routine and electrophysiological hearing evaluation, speech evaluation, and imaging studies through computed tomography (CT) scan and magnetic resonance imaging (MRI) were performed.

Results

TWIST1 gene analysis revealed a Pro136His mutation in all patients. Hearing evaluation showed peripherial and mixed hearing loss in two of the patients, one of them with severe unilateral microtia. Computed tomography scan showed structural middle ear anomalies, and MRI showed distortion of the skull contour as well as some of the brain structures.

Conclusions

We report a previously undescribed TWIST1 gene mutation in patients with SCS. There is evidence that indicates hearing loss (conductive and mixed) can be related both with middle ear (microtia, high jugular bulb, and enlarged vestibules) as well as with brain stem anomalies. Here we discuss the relationship between the gene mutation and the clinical, imaging, speech, and hearing findings.

[Developmental aspects of oral language in craniosynostosis]

BACKGROUND

Aspects of language development in craniosynostosis. Craniosynostosis (premature fusion of the cranial sutures) has an incidence of 0.4 to 1/1000 newborns. Etiology for this congenital anomaly includes environmental and genetic factors. Regarding the form of presentation, it can occur in its isolated form or associated to other congenital anomalies. For this last group, acrocephalosyndactilies are observed. These are genetically determined conditions which present phenotypic similarity, including the following syndromes: Saethre-Chotzen, Apert, Crouzon e Pfeiffer. As all of these conditions affect the craniofacial development, it is possible to find anatomic and functional interferences which determine language delays and/or deficits.

AIM

To revise the literature concerning aspects related to normal verbal language development and to describe the main characteristics associated to this condition in children who present Apert, Crouzon, Pfeiffer and Saethre-Chotzen syndromes. A systematic review on syndromic craniosynostosis and oral language was performed, consulting Medline, Lilacs and other important references on this theme.

CONCLUSION

Several manifestations related to hearing and language have been detected in individuals with syndromic craniosynostosis. The most important are alterations in the sound conduction system, leading to hearing losses, and consequently interfering in language acquisition and development. For this reason, speech-language diagnosis and early intervention are recommended in order to eliminate or minimize damages in language acquisition and development.

Clinical and Genetic Analysis of Patients with Saethre-Chotzen Syndrome

BACKGROUND

Saethre-Chotzen syndrome is a craniosynostosis syndrome further characterized by distinctive facial and limb abnormalities. It shows complete penetrance and variable expressivity and has been linked to the TWIST gene on chromosome 7p21; more than 80 different intragenic mutations and, recently, large deletions have been detected in Saethre-Chotzen patients. The aim of this study was to genetically and phenotypically characterize patients with a clinical diagnosis of Saethre-Chotzen syndrome.

METHODS

Patients with a clinical diagnosis as well as those with a genetic diagnosis of Saethre-Chotzen syndrome (n = 34) were included in the study.

RESULTS

The study showed that the important features of Saethre-Chotzen syndrome are brachycephaly (occurring in 74 percent of patients), a broad, depressed nasal bridge (65 percent), a high forehead (56 percent), ptosis (53 percent), and prominent auricular crura (56 percent). Furthermore, using different molecular techniques, pathogenic mutations in the TWIST gene were identified in 71 percent of patients.

CONCLUSIONS

Patients with deletions of the TWIST gene did not differ from those with intragenic TWIST mutations in frequency or severity of craniofacial abnormalities. However, they did distinguish themselves by the presence of many additional anomalies and diseases and--most importantly--the high frequency of mental retardation, which was borderline significant. The authors conclude that when using stringent inclusion criteria for studies of Saethre-Chotzen syndrome, patients who have a pathogenic mutation of the TWIST gene should be excluded.

Congenital conductive hearing loss in dyschondrosteosis

Conductive hearing loss was detected in a boy with a previous diagnosis of dyschondrosteosis. Dyschondrosteosis is a rare inherited condition characterized by mesomelic dwarfism and Madelung's deformity. The syndrome can be caused by mutations in the SHOX gene, and in that case, the pattern of inheritance is pseudoautosomal dominant. Indeed, SHOX mutation analysis in our patient revealed a deletion. The combination of dyschondrosteosis and conductive hearing loss has been reported in 2 previous cases. In our patient, exploratory tympanotomy revealed ankylosis of the stapes and a malformed incus. A substantial gain in hearing threshold was obtained by a stapedectomy in combination with a malleovestibulopexy.

A child with Saethre-Chotzen syndrome, sensorineural hearing loss, and a TWIST mutation

OBJECTIVE

Patients with syndromic craniosynostosis may have associated hearing deficits. A review of hearing loss associated with syndromic craniosynostosis as well as implications of cochlear implantation in the craniosynostosis patients is presented. In the literature, patients with Saethre-Chotzen syndrome have been shown to have conductive or mixed hearing losses. This case report describes a patient with Saethre-Chotzen syndrome caused by a mutation in the TWIST gene who exhibits a severe to profound sensorineural hearing loss.