The presence of a widened vestibular aqueduct and progressive sensorineural hearing loss in the branchio-oto-renal syndrome. A family study

Sensorineural Hearing Loss in Patients With Chronic Kidney Disease: A Comprehensive Review

This article aims to ascertain the prevalence of loss of hearing in patients with chronic kidney disease (CKD) and also to examine potential causes of sensorineural hearing loss (SNHL) in patients suffering from CKD. It has been discovered in recent years that there is a relationship between the occurrence of SNHL and CKD. Nowadays many people are suffering from CKD. These patients deal with several otorhinolaryngological issues, such as SNHL, candidiasis, epistaxis, halitosis, dysgeusia, xerostomia, and lip and thyroid malignancies. One of the most frequent otorhinolaryngological complications is audiovestibular system impairment. There are various proposed mechanisms for the appearance of loss of hearing in people suffering from CKD. The kidney and the inner ear have multiple functional and structural similarities, which may be the cause of these problems in CKD patients. In addition, changes in the homeostasis of water and electrolytes can affect the endolymphatic fluid and result in endolymphatic hydrops. Finally, some medications, like aminoglycosides and loop diuretics, are well known for their ototoxicity and are utilized to treat patients with CKD. Only a small number of population-based research have so far been able to show a connection between CKD and audiovestibular system impairment. Some investigation has shown that CKD patients are more likely than healthy people to experience vestibular impairment. The quality of life of a patient can be reduced by hearing loss. People with hearing loss experience communication issues in daily life, which negatively affects their cognitive and psychosocial functioning. Social isolation and a poor quality of life in terms of health can all result from hearing loss. In addition, decreased renal function has also been linked to poor quality of life, hospitalization, and cognitive dysfunction.

Molecular Genetic Etiology and Revisiting the Middle Ear Surgery Outcomes of Branchio-Oto-Renal Syndrome: Experience in a Tertiary Referral Center

OBJECTIVES

To explore the phenotypes and genotypes of patients with branchio-oto-renal (BOR) and branchio-otic (BO) syndrome, and to analyze the middle ear surgery outcomes qualitatively and quantitatively, proposing a factor usefully prognostic of surgical outcomes.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

PATIENTS

Eighteen patients with BOR/BO syndrome in 12 unrelated Korean families.

INTERVENTION

Middle ear surgery, including either stapes surgery or ossicular reconstruction.

MAIN OUTCOME MEASURE

Clinical phenotypes, genotypes, and middle ear surgery outcomes.

RESULTS

Eight probands (66.7%) were confirmed genetically; the condition segregated as a dominant or de novo trait. Six EYA1 heterozygous variants were identified by exome sequencing and multiplex ligation-dependent probe amplification. All variants were pathogenic or likely pathogenic based on the ACMG/AMP guidelines. Two novel EYA1 frameshift variants (p.His373Phefs*4 and p.Gln543Asnfs*90) truncating a highly conserved C-terminal Eya domain were identified, expanding the genotypic spectrum of EYA1 in BOR/BO syndrome. Remarkably, middle ear surgery was individualized to ensure optimal audiological outcomes and afforded significant audiological improvements, especially in BOR/BO patients without enlarged vestibular aqueducts (EVAs). A significant difference in air-bone gap closure after middle ear surgery was noted between the two groups even after adjusting for confounders: -20.5 dB in ears without EVAs (improvement) but 0.8 dB in ears with EVAs (no change or deterioration). Furthermore, the success rate was significantly associated with the absence of EVA.

CONCLUSIONS

The results of this study were against the notion that middle ear surgery is always contraindicated in patients with BOR/BO syndrome, and an EVA could be a negative prognostic indicator of middle ear surgery in BOR/BO patients. This may aid to determine the strategy of audiological rehabilitation in patients with BOR/BO syndrome.

An infant with congenital heart defects and proteinuria: a case report

Background

Branchio-Oto-Renal (BOR) Syndrome is a rare autosomal disorder with a wide variety of clinical manifestations and a high degree of heterogeneity. Typical clinical manifestations of BOR syndrome include deafness, preauricular fistula, abnormal gill slits, and renal malformations. However, atypical phenotypes such as congenital hip dysplasia, congenital heart anomaly or facial nerve paresis are rare in BOR syndrome, and this might be easily misdiagnosed with other congenital disorders.

Case presentation

We report a 5-month-old boy of BOR syndrome with "congenital heart defects and proteinuria" as clinical features. Initially, as this case mainly presented with symptoms of recurrent respiratory infections and was found to be with congenital heart disease and proteinuria at the local hospital, but he only was diagnosed with congenital heart disease combined with pulmonary infection and anti-infective and supportive treatment was given. Subsequently, during the physical examination at our hospital, left side preauricular pit and branchial fistulae on the right neck were found. Subsequent evaluation of auditory brainstem response and distortion product otoacoustic emission were revealed sensorineural hearing impairment. Results of renal ultrasonography showed small kidneys. Genetic analysis revealed a microdeletion at chromosome 8q13.2-q13.3 encompassing EYA1 gene, this patient was finally diagnosed with BOR syndrome. Then, this patient received transcatheter patent ductus arteriosus closure and hearing aid treatment. Proteinuria, renal function and hearing ability are monitoring by nephrologist and otologist. The patient is currently being followed up until 3 months after discharge and his condition is stable.

Conclusion

Careful physical examination, detailed history and the implementation of diagnostic laboratory tests can reduce the incidence of misdiagnosis. Genetic sequencing analysis of patients is a key guide to the differential diagnosis of BOR syndrome.

From clinical to molecular diagnosis: relevance of diagnostic strategy in two cases of branchio-oto-renal syndrome - case report

Background

Branchio-oto-renal syndrome (BOR) is an autosomal dominant disorder characterized by deafness, branchiogenic malformations and renal abnormalities. Pathogenic variants in EYA1, SIX1 and SIX5 genes cause almost half of cases; copy number variants (CNV) and complex genomic rearrangements have been revealed in about 20% of patients, but they are not routinely and commonly included in the diagnostic work-up.

Case presentation

We report two unrelated patients with BOR syndrome clinical features, negative sequencing for BOR genes and the identification of a 2.65 Mb 8q13.2–13.3 microdeletion.

Conclusions

We highlight the value of CNV analyses in high level of suspicion for BOR syndrome but negative sequencing for BOR genes and we propose an innovative diagnostic flow-chart to increase current detection rate. Our report confirms a mechanism of non-allelic homologous recombination as causing this recurrent 8q13.2–13.3 microdeletion. Moreover, considering the role of PRDM14 and NCOA2 genes, both involved in regulation of fertility and deleted in our patients, we suggest the necessity of a longer follow-up to monitor fertility issues or additional clinical findings.

Cholesteatoma Is Associated With Pediatric Progressive Sensorineural Hearing Loss

OBJECTIVES

This study identified an association between cholesteatoma and progressive sensorineural hearing loss using a large pediatric longitudinal audiologic dataset. Cholesteatoma is a potential sequela of chronic otitis media with effusion, a commonly observed auditory pathology that can contribute to hearing loss in children. The purpose of this report is to (i) describe the process of identifying the association between cholesteatoma and progressive sensorineural hearing loss in a large pediatric dataset and (ii) describe the audiologic data acquired over time in patients identified with cholesteatoma-associated progressive sensorineural hearing loss.

DESIGN

Records of patients included in the Audiologic and Genetics Database (n = 175,215 patients) were examined using specified criteria defining progressive hearing loss. A linear regression model examined the log frequency of all diagnostic codes in the electronic health record assigned to patients for a progressive hearing loss cohort compared with a stable hearing loss group. Based on findings from the linear regression analysis, longitudinal audiometric air (AC) and bone conduction (BC) thresholds were extracted for groups of subjects with cholesteatoma-associated progressive (n = 58 subjects) and stable (n = 55 subjects) hearing loss to further analyze changes in hearing over time.

RESULTS

The linear regression analyses identified that diagnostic codes for cholesteatoma were associated with progressive sensorineural hearing loss in children. The longitudinal audiometric data demonstrated within-subject changes in masked BC sensitivity consistent with progressive sensorineural hearing loss in children diagnosed with cholesteatoma. Additional analyses showed that mastoidectomy surgeries did not appear to contribute to the observed progressive hearing loss and that a high number of cholesteatoma patients with progressive hearing loss had normal-hearing thresholds at their first test.

CONCLUSIONS

The statistical analyses demonstrated an association between cholesteatoma and pediatric progressive sensorineural hearing loss. These findings inform clinical management by suggesting that children with cholesteatoma diagnoses may be at increased risk for progressive sensorineural hearing loss and should receive continued monitoring even after a normal masked BC baseline has been established.

Anatomical and audiological considerations in branchiootorenal syndrome: A systematic review

Objective

Establish anatomical considerations, audiological outcomes, and optimal management in patients with branchiootic/branchiootorenal syndrome (BO/BOR).

Methods

Databases reviewed: Medline, Pubmed, Embase, Web of Science, Cochrane Collection, and ClinicalTrials.gov. Clinical or radiological studies of patients with BOR syndrome describing either the audiological profile or anatomical changes were included. Articles in which BOR syndrome was associated with other syndromes, and those that were focused only on general and genetic aspects of BOR syndrome were excluded. Articles were assessed using Oxford Centre for Evidence‐Based Medicine (OCEBM) grading system and the Brazzelli risk of bias tool for nonrandomized studies.

Results

Searches identified 379 articles. Of these, 64 studies met the inclusion criteria, reporting outcomes in 482 patients from at least 95 families. In 308 patients, hearing loss was categorized as sensorineural (29%), conductive (20%), and mixed (51%). Hearing outcomes were variable in terms of onset, pattern, and severity; ranging from mild to profound deafness. One hundred sixty‐nine patients presented with inner ear anomalies, 145 had middle, and 151 had external ear abnormalities. In 44 studies, 58 ear operations were described. Mixed outcomes were reported in patients managed with hearing aids or middle ear surgery; however, successful cochlear implantation was described in all five cases.

Conclusion

The anatomical and audiological profiles of patients with BO/BOR are variable. A range of surgical procedures were described, however lacked objective outcome measures. Given the range of anatomical variants, management decisions should be made on an individual basis including full audiological and radiological assessment.

Level of evidence

NA.

Identification and Characterization of a Cryptic Genomic Deletion-Insertion in EYA1 Associated with Branchio-Otic Syndrome

Branchio-oto-renal spectrum disorder (BORSD) is characterized by hearing loss accompanied by ear malformations, branchial cysts, and fistulae, with (branchio-oto-renal syndrome (BORS)) or without renal abnormalities (BOS (branchio-otic syndrome)). As the most common causative gene for BORSD, dominant mutations in EYA1 are responsible for approximately 40% of the cases. In a sporadic deaf patient diagnosed as BOS, we identified an apparent heterozygous genomic deletion spanning the first four coding exons and one 5′ noncoding exon of EYA1 by targeted next-generation sequencing of 406 known deafness genes. Real-time PCR at multiple regions of EYA1 confirmed the existence of this genomic deletion and extended its 5′ boundary beyond the 5′-UTR. Whole genome sequencing subsequently located the 5′ and 3′ breakpoints to 19268 bp upstream to the ATG initiation codon and 3180 bp downstream to exon 5. PCR amplification across the breakpoints in both the patient and his parents showed that the genomic alteration occurred de novo. Sanger sequencing of this PCR product revealed that it is in fact a GRCh38/hg38:chr8:g.71318554_71374171delinsTGCC genomic deletion-insertion. Our results showed that the genomic variant is responsible for the hearing loss associated with BOS and provided an example for deciphering such cryptic genomic alterations following pipelines of comprehensive exome/genome sequencing and designed verification.

Branchial cleft fistula to branchio-oto-renal syndrome: A case report and literature review

Branchial cleft abnormality is a common congenital neck malformation in children, which is caused by the abnormal development of the gill sac or gill groove. It is mainly manifested as a cyst in the sinus tract and fistula in the neck, as well as branchio-oto-renal syndrome (BORS). As a rare autosomal dominant genetic disease, the typical manifestations of BORS are hearing loss, abnormal branchial cleft development and renal dysplasia. In this paper, a patient was admitted to the hospital for bilateral branchial cleft fistulas combined with bilateral anterior auricular fistulas, auricular appendix, auricle dysplasia, external auditory canal stenosis, and hearing loss. The patient was diagnosed with BORS, and underwent fistulectomy of the neck and anterior ear, external auditory canal formation, and tympanoplasty. The aim of this report is to strengthen clinicians' understanding of BORS and reduce the rate of clinical missed diagnosis through our case report and literature review.

Multimodality depiction of findings in branchio-oto-renal syndrome: two case reports

Branchio-oto-renal syndrome is a rare genetic disorder that affects multiple organ systems. Temporal bone abnormalities include the unwound appearance of the cochlea which is common in this syndrome. This appearance can prompt renal imaging and evaluation. Presented here are two cases of branchio-oto-renal syndrome with dysplastic cochleae. A branchial cleft sinus and renal dysplasia were also present in one of the cases.

Neurocristopathies: New insights 150 years after the neural crest discovery

The neural crest (NC) is a transient, multipotent and migratory cell population that generates an astonishingly diverse array of cell types during vertebrate development. These cells, which originate from the ectoderm in a region lateral to the neural plate in the neural fold, give rise to neurons, glia, melanocytes, chondrocytes, smooth muscle cells, odontoblasts and neuroendocrine cells, among others. Neurocristopathies (NCP) are a class of pathologies occurring in vertebrates, especially in humans that result from the abnormal specification, migration, differentiation or death of neural crest cells during embryonic development. Various pigment, skin, thyroid and hearing disorders, craniofacial and heart abnormalities, malfunctions of the digestive tract and tumors can also be considered as neurocristopathies. In this review we revisit the current classification and propose a new way to classify NCP based on the embryonic origin of the affected tissues, on recent findings regarding the molecular mechanisms that drive NC formation, and on the increased complexity of current molecular embryology techniques.

Novel EYA1 variants causing Branchio-oto-renal syndrome

INTRODUCTION

Branchio-oto-renal (BOR) syndrome is an autosomal dominant genetic disorder characterized by second branchial arch anomalies, hearing impairment, and renal malformations. Pathogenic mutations have been discovered in several genes such as EYA1, SIX5, and SIX1. However, nearly half of those affected reveal no pathogenic variant by traditional genetic testing.

METHODS AND MATERIALS

Whole Exome sequencing and/or Sanger sequencing performed in 10 unrelated families from Turkey, Iran, Ecuador, and USA with BOR syndrome in this study.

RESULTS

We identified causative DNA variants in six families including novel c.525delT, c.979T > C, and c.1768delG and a previously reported c.1779A > T variants in EYA1. Two large heterozygous deletions involving EYA1 were detected in additional two families. Whole exome sequencing did not reveal a causative variant in the remaining four families.

CONCLUSIONS

A variety of DNA changes including large deletions underlie BOR syndrome in different populations, which can be detected with comprehensive genetic testing.

Case report of a novel mutation of the EYA1 gene in a patient with branchio-oto-renal syndrome

Branchio-oto-renal (BOR) syndrome is an autosomal dominant disorder characterized by the coexistence of branchial cysts or fistulae, external ear malformation with pre-auricular pits or tags, hearing impairment and renal malformations. However, the presence of the main features varies in affected families. Here, we present a 16-year-old boy admitted to the Department of Nephrology at the Pediatric Clinic, University Clinical Center of Kosovo, Pristina, Republic of Kosovo because of severe renal insufficiency diagnosed 6 years ago, which progressed to end-stage renal failure. Clinical examination on readmission showed a pale, lethargic and edematous child, with auricular deformity, pre-auricular tags and pits as well as bilateral branchial fistulae. Laboratory tests revealed high blood urea nitrogen (BUN) 15.96 mmol/L and serum creatinine 633.0 µmol/L; low glomerular filtration rate (GFR) 12 mL/min./ 1.73 m² and massive proteinuria 4+. Abdominal ultrasound showed bilateral kidney hypoplasia. A novel mutation of the EYA1 gene was confirmed. Daily hemodialysis is continuing until renal transplantation is done. This case is presented to increase awareness among general practitioners to consider BOR syndrome or other renal abnormalities in patients with branchial fistula and/ or external ear anomalies or similar findings in other family members.

Anatomical Changes and Audiological Profile in Branchio-oto-renal Syndrome: A Literature Review

Introduction Branchio-oto-renal (BOR) syndrome is an autosomal-dominant genetic condition with high penetrance and variable expressivity, with an estimated prevalence of 1 in 40,000. Approximately 40% of the patients with the syndrome have mutations in the gene EYA1, located at chromosomal region 8q13.3, and 5% have mutations in the gene SIX5 in chromosome region 19q13. The phenotype of this syndrome is characterized by preauricular fistulas; structural malformations of the external, middle, and inner ears; branchial fistulas; renal disorders; cleft palate; and variable type and degree of hearing loss.

Aim Hearing loss is part of BOR syndrome phenotype. The aim of this study was to present a literature review on the anatomical aspects and audiological profile of BOR syndrome.

Data Synthesis Thirty-four studies were selected for analysis. Some aspects when specifying the phenotype of BOR syndrome are controversial, especially those issues related to the audiological profile in which there was variability on auditory standard, hearing loss progression, and type and degree of the hearing loss. Mixed loss was the most common type of hearing loss among the studies; however, there was no consensus among studies regarding the degree of the hearing loss.

Diagnostic and surgical challenge: middle ear dermoid cyst in 12 month old with branchio-oto-renal syndrome and multiple middle-ear congenital anomalies

Described is the first case report, to our knowledge, of a middle-ear dermoid in a child with branchio-oto-renal (BOR) syndrome. Radiographic, pathologic, and intraoperative figures are shown. This was a diagnostic and surgical challenge as the presentation was similar to a congenital cholesteatoma and the child had numerous significant temporal bone abnormalities. After the intraoperative findings suggested a non-destructive process, the treatment strategy was altered. This case reiterates the need for a cautious, flexible operative approach in a syndromic child. Included is a relevant review of the literature and a detailed clinical analysis.

Audiovestibular findings in a branchio-oto syndrome patient with a SIX1 mutation

CONCLUSION

A reported mutation in SIX1 was identified in a patient with familial hearing loss (HL), a left preauricular pit, and bilateral enlarged vestibular aqueducts (EVA). Although the characteristic symptoms of EVA including fluctuating HL and repetitive vertigo were not seen in the patient, further studies are needed to clarify the association between EVA and such symptoms.

OBJECTIVES

To study the audiovestibular functions, and to identify the causative gene in a patient with branchio-oto syndrome.

METHODS

We enrolled a 30-year-old female in whom HL was pointed out at the age of 6 years. She visited our department at the age of 21 years, and had not experienced any progression of her HL, tinnitus, or vertigo. Pure-tone audiograms showed bilateral moderate mixed HL with no apparent progression during a 9-year follow-up period. Audiovestibular examinations included distortion product otoacoustic emissions (DPOAEs), electrocochleography (ECochG), and electronystagmography (ENG). Direct sequencing was utilized to screen for SIX1, EYA1, SLC26A4, GJB2, and mitochondrial DNA MTRNR1 including 1555 position.

RESULTS

The findings of DPOAEs, ECochG, and ENG indicated cochlear HL with no vestibular dysfunction. A previously reported mutation of a heterozygous c.386A > G (p.Y129C) in SIX1 was detected. No mutation was identified in EYA1, SLC26A4, GJB2, or MTRNR1.

Evidence of progression and fluctuation of hearing impairment in branchio-oto-renal syndrome

We retrospectively analysed long-term serial audiometry data from patients with branchio-oto-renal (BOR) syndrome to show the features of progression and fluctuation in hearing impairment and relate the findings to age and magnetic resonance imaging (MRI) findings in the petrosal bones. Thirty-two clinically affected BOR patients from six Dutch families (A-F) were included. Audiograms were available in 24 cases, covering followup intervals of between 3 and 30 years, and suitable for individual statistical analysis in 16 cases: 14 cases also had MRI findings. Significant progression in hearing impairment was found in 10 cases, while findings of significant fluctuation were made in seven cases. These findings did not clearly correlate with MRI findings. Substantial fluctuation occurred only in cases followed at a relatively young age. Patients with an enlarged endolymphatic duct and/or sac showed significantly higher sensorineural hearing thresholds than those with either normal MRI findings or cochlear/labyrinthine hypoplasia with or without enlarged duct or sac. We conclude that progressive, fluctuant hearing loss occurred in some BOR patients; however, only young patients showed substantial threshold fluctuation. BOR patients with an enlarged endolymphatic duct and/or sac on MRI seemed to be predisposed to developing more severe hearing impairment.

From a branchial fistula to a branchiootorenal syndrome: a case report and review of the literature

Branchial abnormalities constitute 32% to 45% of all neck pathologies in children. They may be a part of branchiootorenal (BOR) syndrome, which is characterized by branchial arch anomalies, preauricular pits, hearing impairment, and renal malformations. Typically, the management of a branchial fistula does not necessarily require an extensive diagnostic workup. However, in patients with a branchial fistula associated with external ear anomalies on physical examination and/or a history of hearing loss and a similar history and findings in other family members, an additional workup should be performed to eliminate the possibility of BOR syndrome. The aim of this report is to make pediatric surgeons aware of the BOR syndrome in patients presenting with branchial arch anomalies.

[Large endolymphatic duct and sac syndrome (LEDS) : part I: analysis of imaging findings]

OBJECTIVE

Large endolymphatic duct and sac (LEDS) syndrome is the most common radiologically detectable form of inner ear malformation (IEM) associated with sensorineural hearing loss (SNHL). Nevertheless, it is relatively unknown in the German-speaking countries.

METHODS

Among all patients referred from ear, nose, and throat specialists to the radiology department with clinically suspected IEM between 1994 and 2003, we identified the cases of LEDS. The retrospective study included clinical records, high-resolution computed tomography, and magnetic resonance imaging.

RESULTS

Of 169 patients, 17 (median age 12 years; 12 females) showed LEDS. A total of 28 ears were affected. Ten patients (6%; 15 ears) had isolated LEDS, while seven patients showed additional IEM (4%; 13 ears). The most frequent of these was dysplastic vestibule (13/13 ears), followed by Mondini deformity (10/13 ears) and dilated semicircular canals (7/13 ears). Three of 13 ears revealed severe IEM of the cochlea, vestibule, and semicircular canals. No correlation could be demonstrated between the severity of morphological changes and the degree of SNHL.

CONCLUSION

LEDS may be an underestimated cause of SNHL. Imaging is necessary for a confident diagnosis.

Branchio-oto-renal syndrome: detection of EYA1 and SIX1 mutations in five out of six Danish families by combining linkage, MLPA and sequencing analyses

The branchio-oto-renal (BOR) syndrome is an autosomal-dominant disorder characterized by hearing loss, branchial and renal anomalies. BOR is genetically heterogeneous and caused by mutations in EYA1 (8q13.3), SIX1 (14q23.1), SIX5 (19q13.3) and in an unidentified gene on 1q31. We examined six Danish families with BOR syndrome by assessing linkage to BOR loci, by performing EYA1 multiplex ligation-dependent probe amplification (MLPA) analysis for deletions and duplications and by sequencing of EYA1, SIX1 and SIX5. We identified four EYA1 mutations (c.920delG, IVS10-1G>A, IVS12+4A>G and p.Y591X) and one SIX1 mutation (p.W122R), providing a molecular diagnosis in five out of the six families (83%). The present, yet preliminary, observation that renal and temporal bone malformations are less frequent in SIX1-related disease suggests a slightly different clinical profile compared to EYA1-related disease. Unidentified mutations impairing mRNA expression or further genetic heterogeneity may explain the lack of mutation finding in one family despite LOD score indications of EYA1 involvement.

Novel EYA1 mutation in a Korean branchio-oto-renal syndrome family

Branchio-oto-renal (BOR) syndrome is an autosomal dominant disorder that is characterized by branchial cysts or fistulae, external ear malformations and/or preauricular pits, hearing loss and renal anomalies. Recent advances in molecular genetics have shown a human homologue of the Drosophila 'eyes absent' gene (EYA1) on chromosome band 8q13.3 to be the most common cause of BOR syndrome. Several mutations have been identified in the EYA1 gene in patients with BOR syndrome worldwide. Here, we report a second Korean family with BOR syndrome with a novel nonsense EYA1 mutation.

Phenotypic consequences in a Japanese family having branchio-oto-renal syndrome with a novel frameshift mutation in the gene EYA1

Branchio-oto-renal (BOR) syndrome is an autosomal dominant inherited disorder characterized by malformations of the ear associated with hearing impairment, branchial fistulae or cysts, and renal malformations. Mutations in the gene EYA1 have been found to be responsible for BOR syndrome in approximately 40% of the subjects. Here we report a Japanese family with BOR syndrome associated with a frameshift mutation in EYA1. This mutation, 1667-1668insT, has not been previously reported and is also the first frameshift mutation in exon 16 of this gene. We describe the detailed clinical features and medical highlights of the family members, and based on their clinical histories we propose that genetic testing for EYA1 mutations would contribute to the diagnosis of BOR syndrome, facilitate genetic counseling for recurrence, give precautions regarding possible renal disorders later in life, and impact the consideration of surgical intervention for middle ear anomalies.

Large vestibular aqueduct syndrome: a human temporal bone study

OBJECTIVES/HYPOTHESIS

Large vestibular aqueduct syndrome (LVAS) is one of the common causes of hearing loss (HL). All prior studies have reported some anomalies associated with LVAS by imaging techniques. This study was undertaken to determine prevalence of LVAS in our temporal bone (TB) collection and its relationship to other systemic or otologic anomalies.

STUDY DESIGN

Retrospective, TB histopathologic study.

METHODS

Anteroposterior diameters of internal (IA) and external (EA) apertures were measured in 40 normal TBs (40 cases). TBs were considered as large vestibular aqueduct (LVA) if width of apertures was 95% greater than "normals." Systemic and otologic anomalies and histopathology of ears with LVAS were noted.

RESULT

Of 1,608 non-"normal" TBs, 63 had LVA. There was negative correlation between IA and EA in 48 TBs with only enlarged IA. Fifteen TBs with enlarged EA always had enlarged IA and were therefore considered as LVAS. The most common pathologic condition was congenital heart anomaly. The most common syndrome or dysplasia was Mondini's. The most common anomalies of external and middle ears were dehiscent facial nerves, low set auricles, and ossicular deformities. Inner ear anomalies included modiolar deficiencies, hair cell loss, interscalar septum defects, and strial atrophy. There was no record of family history of HL, head injury, or craniofacial, branchial, or thyroidal abnormalities.

CONCLUSION

Because HL associated with LVAS may be attributed to other ear anomalies, it is important to investigate other inner ear problems and system diagnoses that may indicate a syndrome in patients with radiologically diagnosed LVAS.

The large vestibular aqueduct--case report and review of the literature

Patients with a large vestibular aqueduct (LVA) suffer from a loss of hearing in childhood at an early onset. An acute loss of hearing can be precipitated by minor head trauma. Until now there seems to be no sufficient therapy for stopping the progression of a loss of hearing. It has been shown that a cochlear implantation is a worthwhile procedure if the patient is almost deaf. We report the case of a patient with a bilateral LVA. A loss of hearing was confirmed at the age of 16 months. Exposure to loud noise triggered an acute progression of the hearing loss. At the age of 18 years, LVA was confirmed radiologically, revealing an enlarged endolymphatic duct and sac in MRI scans and an enlarged vestibular aqueduct in the CT scan. We successfully performed a cochlear implant (MED-EL, Combi 40+ flex). Proceeding from this case report, the paper reviews the literature on LVA.

Enlarged vestibular aqueduct: looking for genotypic–phenotypic correlations

The aim of this work is to provide a guide for clinical and genetic diagnosis and classification of the enlarged vestibular aqueduct syndrome based on a review of the literature and computerized databases with the words large and enlarged vestibular aqueduct. No more than 40 articles described association between the EVA phenotype and a known genetic alteration. Pendred's syndrome, distal renal tubular acidosis, waardenburg's syndrome, X-linked congenital mixed deafness, branchio-oto-renal syndrome, and oto-facio-cervical syndrome can express their genotypic alteration as enlarged vestibular aqueduct syndrome. We also found articles reporting familiar cases of enlarged vestibular aqueduct with no identified mutations in studied genes.

EYA1 expression in the developing inner ear

OBJECTIVES

We sought to determine the developmental anatomy and EYA1 protein distribution in the inner ear of Xenopus laevis.

METHODS

Xenopus laevis embryos were stained with monoclonal antibodies and imaged with confocal microscopy.

RESULTS

At stage 27, the otocyst fully forms, with strong tubulin staining of early sensory cells at its ventromedial aspect. Neuronal ingrowth follows at stage 33/34. At stage 50, the semicircular canals are complete. EYA1 localizes to the anterior aspect of the otocyst from stages 37 to 44. By stage 50, EYA1 distribution is localized primarily to the sensory maculae and the endolymphatic duct of the developing inner ear.

CONCLUSIONS

Whole mount confocal imaging of the developing Xenopus inner ear delineates the exact timing of otic development, sensory cell differentiation, and innervation. EYA1 protein expression has a distinct distribution pattern at the anterior aspect of the developing otocyst in stages 41 and 44. Later stages have a more localized pattern, in which EYA1 is detected only in the sensory epithelium and endolymphatic duct. This specific pattern of expression indicates a possible role in the determination of the anterior-posterior orientation of the inner ear, as well as a later role in sensory cell differentiation.

Large vestibular aqueduct syndrome: audiological, radiological, clinical, and genetic features

PURPOSE

The aim of this study was to analyze the clinical, audiological, radiological, and genetic features of a group of patients affected with large vestibular aqueduct syndrome.

MATERIALS AND METHODS

Seventeen patients affected with large vestibular aqueduct syndrome (LVAS), diagnosed by means of high-resolution magnetic resonance imaging of the inner ear, with 3-dimensional reconstructions of the labyrinth and by high-resolution spiral computed tomography of the temporal bone, performed only on the oldest patients, have been submitted to a complete audiological evaluation, a thyroid functional and ultrasonographic study, and a molecular study of the PDS gene.

RESULTS

The clinical presentation of LVAS was very variable in our group of patients. The enlarged vestibular aqueduct was bilateral in 15 cases and unilateral in 2; it was the only malformation of the labyrinth in 12 patients, whereas it was associated with other inner ear anomalies in the other 5. The hearing loss was very variable in degree (from mild to profound), age at onset, and progression. Moreover, among the 17 patients, 10 were clinically affected by Pendred's syndrome (PS), 3 by distal renal tubular acidosis associated with large vestibular aqueduct, whereas in 3 patients the large vestibular aqueduct was not syndromal. Finally, we identified mutations in the PDS gene in 5 of 10 patients with PS.

CONCLUSIONS

Our data underscore the frequent role of the large vestibular aqueduct syndrome in the pathogenesis of sensorineural hearing loss and the overall wide variability in its audiological features. It is also highlighted that LVAS is often part of some syndromal diseases, most of which are PS, which is often misdiagnosed because of the varying degree of thyroid symptoms. This study also underscores the possible role of hydro-electrolyte and acid-base endolymphatic fluid disorders in the pathogenesis of enlarged vestibular aqueduct syndrome.

Identification of a novel mutation in the EYA1 gene in a Korean family with branchio-oto-renal (BOR) syndrome

The branchio-oto-renal (BOR) syndrome is an autosomal dominant disorder characterized by the association of branchial cysts or fistulae, external ear malformation and/or preauricular pits, hearing loss, and renal anomalies. Mutations in the EYA1 gene on the chromosome band 8q13.3, the human homologue of the Drosophila eyes absent (eya) gene, have been identified to be the underlying genetic defects of the syndrome. We found a Korean family with BOR syndrome and identified a novel insertion mutation (c.1474_1475insC; R492PfsX40) in the EYA1 gene. To the best of our knowledge, this is the first report of genetically confirmed case of BOR syndrome in Korea.

Syndromic etiology in children at schools for the deaf in Turkey

OBJECTIVE

The aim of this study was to determine the syndromic etiology of bilateral severe sensorineural hearing disorders in children and current etiological causes to reduce the cases in the unknown group.

METHODS

This study was conducted on 550 students of five schools for the deaf in Istanbul and Zonguldak, Turkey. Otologic, audiologic, dysmorphologic, ophthalmologic and dental examinations were performed in all children. Familial and medical histories were obtained.

RESULTS

The etiology of hearing loss was genetic in 346 (62.90%), acquired in 107 (19.45%) and unknown in 97 (%17.63) cases. A total of 619 malformations were defined in 550 children and 99 of them belonged to a syndrome. We identified 33 different syndromes for these 99 syndromic children. Syndromic etiology was found in 18.0% of the total and 28.61% of the subjects with genetic etiology. Most common syndrome was Waardenburg syndrome which occurred in 33 children.

CONCLUSION

The incidence of hereditary hearing impairment is very high in developing countries compared to developed countries. Prevention is essential to reduce the incidence, multidisciplinary approach and genetic counselling are necessary in this regard.