Diagnóstico genético de la hipoacusia neurosensorial infantil / Genetic diagnosis of childhood sensorineural hearing loss

Introducción: La hipoacusia neurosensorial (HNS) congénita o de inicio precoz es una de las enfermedades hereditarias más frecuentes en nuestro medio y es la deficiencia sensorial más frecuente. Es importante realizar un estudio etiológico de la hipoacusia y el estudio genético mediante la secuenciación de nueva generación (NGS) es la prueba con mayor rendimiento diagnóstico. Nuestro estudio muestra los resultados genéticos obtenidos en una serie de pacientes con HNS congénita/de inicio precoz bilateral. Material y método: Se incluyeron 105 niños diagnosticados de HNS bilateral a los que se les realizó un estudio genético entre los años 2019 y 2022. El estudio genético consistió en una secuenciación masiva del exoma completo, filtrando el análisis para los genes incluidos en un panel virtual de hipoacusia con 244 genes. Resultados: Se obtuvo un diagnóstico genético en 48% (50/105) de los pacientes. Se detectaron variantes patogénicas y probablemente patogénicas en 26 genes diferentes, siendo los genes más frecuentemente afectados el gen GJB2, USH2A y STRC. De las variantes detectadas 52% (26/50) se asociaron a una hipoacusia no sindrómica, 40% (20/50) una hipoacusia sindrómica y 8% restante (4/50) se podían asociar tanto a una hipoacusia sindrómica como no sindrómica. Conclusiones: El estudio genético constituye una parte fundamental del diagnóstico etiológico de la HNS bilateral. Nuestra serie muestra que el estudio genético de la hipoacusia mediante NGS tiene un alto rendimiento diagnóstico y nos proporciona información de gran utilidad en la práctica clínica.(AU)

Introduction: Congenital/early-onset sensorineural hearing loss (SNHL) is one of the most common hereditary disorders in our environment. There is increasing awareness of the importance of an etiologic diagnosis, and genetic testing with next-generation sequencing (NGS) has the highest diagnostic yield. Our study shows the genetic results obtained in a cohort of patients with bilateral congenital/early-onset SNHL. Materials and methods: We included 105 children with bilateral SNHL that received genetic testing between 2019 and 2022. Genetic tests were performed with whole exome sequencing, analyzing genes related to hearing loss (virtual panel with 244 genes). Results: 48% (50/105) of patients were genetically diagnosed. We identified pathogenic and likely pathogenic variants in 26 different genes, and the most frequently mutated genes were GJB2, USH2A and STRC. 52% (26/50) of variants identified produced non-syndromic hearing loss, 40% (20/50) produced syndromic hearing loss, and the resting 8% (4/50) could produce both non-syndromic and syndromic hearing loss. Conclusions: Genetic testing plays a vital role in the etiologic diagnosis of bilateral SNHL. Our cohort shows that genetic testing with NGS has a high diagnostic yield and can provide useful information for the clinical workup of patients.(AU)

Case report of a novel mutation in the TNC gene in Chinese patients with nonsyndromic hearing loss.

RATIONALE: Hereditary hearing loss is known to exhibit a significant degree of genetic heterogeneity. Herein, we present a case report of a novel mutation in the tenascin-C (TNC) gene in Chinese patients with nonsyndromic hearing loss (NSHL). PATIENT CONCERNS: This includes a young deaf couple and their 2-year-old baby. DIAGNOSES: Based on the clinical information, hearing test, metagenomic next-generation sequencing (mNGS), Sanger sequencing, protein function and structure analysis, and model prediction, in our case, the study results revealed 2 heterozygous mutations in the TNC gene (c.2852C>T, p.Thr951Ile) and the TBC1 domain family member 24 (TBC1D24) gene (c.1570C>T, p.Arg524Trp). These mutations may be responsible for the hearing loss observed in this family. Notably, the heterozygous mutations in the TNC gene (c.2852C>T, p.Thr951Ile) have not been previously reported in the literature. INTERVENTIONS: Avoid taking drugs that can cause deafness, wearing hearing AIDS, and cochlear implants. OUTCOMES: Regular follow-up of family members is ongoing. LESSONS: The genetic diagnosis of NSHL holds significant importance as it helps in making informed treatment decisions, providing prognostic information, and offering genetic counseling for the patient's family.

Genetically modified pigs: Emerging animal models for hereditary hearing loss.

Hereditary hearing loss (HHL), a genetic disorder that impairs auditory function, significantly affects quality of life and incurs substantial economic losses for society. To investigate the underlying causes of HHL and evaluate therapeutic outcomes, appropriate animal models are necessary. Pigs have been extensively used as valuable large animal models in biomedical research. In this review, we highlight the advantages of pig models in terms of ear anatomy, inner ear morphology, and electrophysiological characteristics, as well as recent advancements in the development of distinct genetically modified porcine models of hearing loss. Additionally, we discuss the prospects, challenges, and recommendations regarding the use pig models in HHL research. Overall, this review provides insights and perspectives for future studies on HHL using porcine models.

Perrault syndrome: The Way Forward After Genetic Counselling?

A female, term neonate, born via vaginal delivery to a G5P1D1A3 hypothyroid mother with a history of an elder sibling being homozygous for HSD17B4 mutation, diagnosed while working up his progressive neurological disorder and succumbing to the same. The family screening revealed that both parents were heterozygous carriers of the same mutation in the gene HSD17B4 After genetic counselling, amniocentesis revealed the fetus to be having homozygosity for the same mutation. In view of precious pregnancy, normal antenatal scans and investigations, the pregnancy was continued, and baby was born with a birth weight of 2.65 kg and had a smooth perinatal transition. Parents were counselled regarding the course of the illness, possible complications and the need for regular follow-up. Ultrasound of the abdomen, pelvis and head was normal in the neonatal period. She was vaccinated as per the national schedule and gaining weight normally.

Causal relationship between psychiatric disorders and sensorineural hearing loss: A bidirectional two-sample mendelian randomization analysis.

OBJECTIVE: This study employed bidirectional two-sample Mendelian randomization (MR) to investigate the causal links between psychiatric disorders and sensorineural hearing loss (SNHL). METHODS: Instrumental variables were chosen from genome-wide association studies of schizophrenia (SCH, N = 127,906), bipolar disorder (BD, N = 51,710), major depressive disorder (MDD, N = 500,199), and SNHL (N = 212,544). In the univariable MR analysis, the inverse-variance weighted method (IVW) was conducted as the primary analysis, complemented by various sensitivity analyses to ensure result robustness. RESULTS: SCH exhibited a decreased the risk of SNHL (OR = 0.949, P = 0.005), whereas BD showed an increased incidence of SNHL (OR = 1.145, P = 0.005). No causal association was found for MDD on SNHL (OR = 1.088, P = 0.246). Multivariable MR validated these results. In the reverse direction, genetically predicted SNHL was linked to a decreased risk of SCH with suggestive significance (OR = 0.912, P = 0.023). No reverse causal relationships were observed for SNHL influencing BD or MDD. These findings remained consistent across various MR methods and sensitivity analyses. CONCLUSION: This study demonstrated that the causal relationships between diverse psychiatric disorders with SNHL were heterogeneous. Specifically, SCH was inversely associated with SNHL susceptibility, and similarly, a reduced risk of SNHL was observed in schizophrenia patients. In contrast, BD exhibited an increased incidence of SNHL, although SNHL did not influence the prevalence of BD. No causal association between MDD and SNHL was found.

Cochleovestibular Phenotype in a Rare Genetic MED13L Mutation.

The gene MED13 participates in transcription. The MED13L gene is a paralog of MED13 that is involved in developmental gene expression. Mutations in the gene have been shown to result in a heterogenous phenotype affecting several physiological systems. Hearing loss has been reported very rarely, and vestibular weakness has never been reported in the condition. In this report, we present a mutation of MED13L in c.1162A > T (p.Arg388Ter), where we detail and describe a cochleovestibular phenotype with objective vestibulometry for the first time. The child showed bilateral sloping sensorineural hearing loss, a bilateral vestibular weakness, and an inner ear vestibular structural abnormality on imaging. Early intervention with hearing aids and vestibular rehabilitation led to a favorable outcome in terms of speech, communication, and balance. We emphasize the importance of comprehensive audiovestibular assessment in children diagnosed with MED13L mutations for effective management of these children.

L-shaped association of triglyceride glucose index and sensorineural hearing loss: results from a cross-sectional study and Mendelian randomization analysis.

Background: The association between the sensorineural hearing loss (SNHL) and triglyceride-glucose (TyG) index remains inadequately understood. This investigation seeks to elucidate the connection between the TyG index and SNHL. Methods: In this cross-sectional study, we utilized datasets sourced from the National Health and Nutrition Examination Survey (NHANES). A comprehensive analysis was conducted on 1,851 participants aged 20 to 69, utilizing complete audiometry data from the NHANES database spanning from 2007 to 2018. All enrolled participants had accessible hearing data, and the average thresholds were measured and calculated as both low-frequency pure-tone average and high-frequency pure-tone average. Sensorineural hearing loss (SNHL) was defined as an average pure tone of 20 dB or higher in at least one better ear. Our analysis involved the application of multivariate linear regression models to examine the linear relationship between the TyG index and SNHL. To delineate any non-linear associations, we utilized fitted smoothing curves and conducted threshold effect analysis. Furthermore, we conducted a two-sample Mendelian randomization (MR) study, leveraging genetic data from genome-wide association studies (GWAS) on circulating lipids, blood glucose, and SNHL. The primary analytical method for the MR study was the application of the inverse-variance-weighted (IVW) approach. Results: In our multivariate linear regression analysis, a substantial positive correlation emerged between the TyG index and SNHL [2.10 (1.80-2.44), p < 0.0001]. Furthermore, using a two-segment linear regression model, we found an L-shaped relationship between TyG index, fasting blood glucose and SNHL with an inflection point of 9.07 and 94 mg/dL, respectively. Specifically, TyG index [3.60, (1.42-9.14)] and blood glucose [1.01, (1.00-1.01)] concentration higher than the threshold values was positively associated with SNHL risk. Genetically determined triglyceride levels demonstrated a causal impact on SNHL (OR = 1.092, p = 8.006 × 10-4). In addition, blood glucose was found to have a protective effect on SNHL (OR = 0.886, p = 1.012 × 10-2). Conclusions: An L-shaped association was identified among the TyG index, fasting blood glucose, and SNHL in the American population. TyG index of more than 9.07 and blood glucose of more than 94 mg/dL were significantly and positively associated with SNHL risk, respectively.

Associations of hearing loss and structural changes in specific cortical regions: a Mendelian randomization study.

INTRODUCTION: Previous studies have suggested a correlation between hearing loss (HL) and cortical alterations, but the specific brain regions that may be affected are unknown. METHODS: Genome-wide association study (GWAS) data for 3 subtypes of HL phenotypes, sensorineural hearing loss (SNHL), conductive hearing loss, and mixed hearing loss, were selected as exposures, and GWAS data for brain structure-related traits were selected as outcomes. The inverse variance weighted method was used as the main estimation method. RESULTS: Negative associations were identified between genetically predicted SNHL and brain morphometric indicators (cortical surface area, cortical thickness, or volume of subcortical structures) in specific brain regions, including the bankssts (ß = -0.006 mm, P = 0.016), entorhinal cortex (ß = -4.856 mm2, P = 0.029), and hippocampus (ß = -24.819 cm3, P = 0.045), as well as in brain regions functionally associated with visual perception, including the pericalcarine (ß = -10.009 cm3, P = 0.013). CONCLUSION: Adaptive changes and functional remodeling of brain structures occur in patients with genetically predicted HL. Brain regions functionally associated with auditory perception, visual perception, and memory function are the main brain regions vulnerable in HL.

Hearing Loss Among Families with 2 and More Affected Members in Golestan Province, Iran: A Cross-Sectional Study of 320 Families.

BACKGROUND: Our study centers on various aspects of families who have 2 or more members with hearing loss (HL) and are living in Golestan province in Iran. We aimed to identify those families with the highest probability of hereditary HL and also to examine the impact of consanguinity among them. METHODS: The families included in the study underwent a comprehensive screening process that involved their prenatal and postnatal histories as well as family medical histories. Additionally, each patient received a thorough clinical ear examination. The evaluation also took into account factors such as patterns of inheritance, consanguinity, a 3-generation pedigree, and physical examination. Following this initial assessment, patients were referred for a complete hearing evaluation, which included pure-tone audiometry, speech recognition threshold, otoacoustic emission, and auditory brainstem response tests. RESULTS: We identified a total of 8553 individuals living in Golestan province who are hearing impaired. Among those, our records indicate that 320 families had at least 2 affected members. The rate of consanguinity marriage in non-syndromic families was 64.43%. Also, a significant number (88.12%, or n=282) of the families exhibited hereditary HL, among which a substantial proportion (89.72%, or n=253) presented with nonsyndromic forms of HL. Furthermore, bilateral, stable, and prelingual HL were the most frequently observed types, and a majority of the patients were diagnosed with sensorineural and profound HL. CONCLUSION: This study revealed a correlation between consanguinity and the incidence of familial HL, with more probability of bilateral, prelingual, sensorineural, and profound forms.

[Genetic characteristic analysis of slight-to-moderate sensorineural hearing loss in children].

Objective:To analyze genetic factors and phenotype characteristics in pediatric population with slight-to-moderate sensorineural hearing loss. Methods:Children with slight-to-moderate sensorineural hearing loss of and their parents, enrolled from the Chinese Deafness Genome Project, were studied. Hearing levels were assessed using pure tone audiometry, behavioral audiometry, auditory steady state response（ASSR）, auditory brainstem response（ABR） thresholds, and deformed partial otoacoustic emission（DPOAE）. Classification of hearing loss is according to the 2022 American College of Medical Genetics and Genomics（ACMG） Clinical Practice Guidelines for Hearing Loss. Whole exome sequencing（WES） and deafness gene Panel testing were performed on peripheral venous blood from probands and validations were performed on their parents by Sanger sequencing. Results:All 134 patients had childhood onset, exhibiting bilateral symmetrical slight-to-moderate sensorineural hearing loss, as indicated by audiological examinations. Of the 134 patients, 29（21.6%） had a family history of hearing loss, and the rest were sporadic patients. Genetic causative genes were identified in 66（49.3%） patients. A total of 11 causative genes were detected, of which GJB2 was causative in 34 cases（51.5%）, STRC in 10 cases（15.1%）, MPZL2 gene in six cases（9.1%）, and USH2A in five cases（7.6%）.The most common gene detected in slight-to-moderate hearing loss was GJB2, with c. 109G>A homozygous mutation found in 16 cases（47.1%） and c. 109G>A compound heterozygous mutation in 9 cases（26.5%）. Conclusion:This study provides a crucial genetic theory reference for early screening and detection of mild to moderate hearing loss in children, highlighting the predominance of recessive inheritance and the significance of gene like GJB2, STRC, MPZL2, USH2A.

[Genetic and phenotypic analysis of MYO15A rare variants associated with autosomal recessive hearing loss].

Objective:To analyze the phenotype and genotype characteristics of autosomal recessive hearing loss caused by MYO15A gene variants, and to provide genetic diagnosis and genetic counseling for patients and their families. Methods:Identification of MYO15A gene variants by next generation sequencing in two sporadic cases of hearing loss at Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. The sequence variants were verified by Sanger sequencing.The pathogenicity of these variants was determined according to the American College of Medical Genetics and Genomics（ACMG） variant classification guidelines, in conjuction with clinical data. Results:The probands of the two families have bilateral,severe or complete hearing loss.Four variants of MYO15A were identified, including one pathogenic variant that has been reported, two likely pathogenic variants,and one splicing variant of uncertain significance. Patient I carries c. 3524dupA（p. Ser1176Valfs*14）, a reported pathogenic variant, and a splicing variant c. 10082+3G>A of uncertain significance according to the ACMG guidelines. Patient I was treated with bilateral hearing aids with satisfactory effect, demonstrated average hearing thresholds of 37.5 dB in the right ear and 33.75 dB in the left ear. Patient Ⅱ carries c. 7441_7442del（p. Leu2481Glufs*86） and c. 10250_10252del（p. Ser3417del）,a pair of as likely pathogenic variants according to the ACMG guidelines. Patient Ⅱ, who underwent right cochlear implantation eight years ago, achieved scores of 9 on the Categorical Auditory Performance-Ⅱ（CAP-Ⅱ） and 5 on the Speech Intelligibility Rating（SIR）. Conclusion:This study's discovery of the rare c. 7441_7442del variant and the splicing variant c. 10082+3G>A in the MYO15A gene is closely associated with autosomal recessive hearing loss, expanding the MYO15A variant spectrum. Additionally, the pathogenicity assessment of the splicing variant facilitates classification of splicing variations.

[Genetic counseling for hearing loss today].

Genetic counseling for hearing loss today originated from decoding the genetic code of hereditary hearing loss, which serves as an effective strategy for preventing hearing loss and constitutes a crucial component of the diagnostic and therapeutic framework. This paper described the main principles and contents of genetic counseling for hearing loss, the key points of counseling across various genetic models and its application in tertiary prevention strategies targeting hearing impairment. The prospects of an AI-assisted genetic counseling decision system and the envisions of genetic counseling in preventing hereditary hearing loss were introduced. Genetic counseling for hearing loss today embodies the hallmark of a new era, which is inseparable from the advancements in science and technology, and will undoubtedly contribute to precise gene intervention!

[Clinical features of CAPOS syndrome caused by maternal ATP1A3 gene variation: a case report].

CAPOS syndrome is an autosomal dominant neurological disorder caused by mutations in the ATP1A3 gene. Initial symptoms, often fever-induced, include recurrent acute ataxic encephalopathy in childhood, featuring cerebellar ataxia, optic atrophy, areflflexia, sensorineural hearing loss, and in some cases, pes cavus. This report details a case of CAPOS syndrome resulting from a maternal ATP1A3 gene mutation. Both the child and her mother exhibited symptoms post-febrile induction,including severe sensorineural hearing loss in both ears, ataxia, areflexia, and decreased vision. Additionally, the patient's mother presented with pes cavus. Genetic testing revealed a c. 2452G>A（Glu818Lys） heterozygous mutation in theATP1A3 gene in the patient . This article aims to enhance clinicians' understanding of CAPOS syndrome, emphasizing the case's clinical characteristics, diagnostic process, treatment, and its correlation with genotypeic findings.

[Research progress on hereditary endocrine and metabolic diseases associated with sensorineural hearing loss].

Hereditary endocrine and metabolic diseases , caused by genetic factors, exhibit complex and diverse symptoms, including the possibility of concurrent sensorineural deafness. Currently, there is a limited clinical understanding of hereditary endocrine and metabolic diseases that manifest with deafness, the pathogenesis remains unclear,and there is a lack of effective diagnostic and treatment methods. This article summarizes the research progress of hereditary endocrine and metabolic diseases complicated with deafness from the pathogenesis, clinical phenotype, diagnosis and treatment. Understanding the current research progress and integrating genetic analysis into clinical practice are crucial for accurate diagnosis and treatment, evaluating clinical efficacy, and providing effective genetic counseling for these diseases.

Investigation of a novel TBC1D24 variation causing autosomal dominant non-syndromic hearing loss.

Hearing loss is considered one of the most common sensory neurological defects, with approximately 60% of cases attributed to genetic factors. Human pathogenic variants in the TBC1D24 gene are associated with various clinical phenotypes, including dominant nonsyndromic hearing loss DFNA65, characterized by progressive hearing loss after the development of language. This study provides an in-depth analysis of the causative gene and mutations in a family with hereditary deafness. We recruited a three-generation family with autosomal dominant nonsyndromic hearing loss (ADNSHL) and conducted detailed medical histories and relevant examinations. Next-generation sequencing (NGS) was used to identify genetic variants in the proband, which were then validated using Sanger sequencing. Multiple computational software tools were employed to predict the impact of the variant on the function and structure of the TBC1D24 protein. A series of bioinformatics tools were applied to determine the conservation characteristics of the sequence, establish a three-dimensional structural model, and investigate changes in molecular dynamics. A detailed genotype and phenotype analysis were carried out. The family exhibited autosomal dominant, progressive, postlingual, and nonsyndromic sensorineural hearing loss. A novel heterozygous variant, c.1459C>T (p.His487Tyr), in the TBC1D24 gene was identified and confirmed to be associated with the hearing loss phenotype in this family. Conservation analysis revealed high conservation of the amino acid affected by this variant across different species. The mutant protein showed alterations in thermodynamic stability, elasticity, and conformational dynamics. Molecular dynamics simulations indicated changes in RMSD, RMSF, Rg, and SASA of the mutant structure. We computed the onset age of non-syndromic hearing loss associated with mutations in the TBC1D24 gene and identified variations in the hearing progression time and annual threshold deterioration across different frequencies. The identification of a new variant associated with rare autosomal dominant nonsyndromic hereditary hearing loss in this family broadens the range of mutations in the TBC1D24 gene. This variant has the potential to influence the interaction between the TLDc domain and TBC domain, thereby affecting the protein's biological function.

Identification of common stria vascularis cellular alteration in sensorineural hearing loss based on ScRNA-seq.

BACKGROUND: The stria vascularis (SV), located in the lateral wall of the cochlea, maintains cochlear fluid homeostasis and mechanoelectrical transduction (MET) activity required for sound wave conduction. The pathogenesis of a number of human inheritable deafness syndromes, age related hearing loss, drug-induced ototoxicity and noise-induced hearing loss results from the morphological changes and functional impairments in the development of the SV. In this study, we investigate the implications of intercellular communication within the SV in the pathogenesis of sensorineural hearing loss (SNHL). We aim to identify commonly regulated signaling pathways using publicly available single-cell transcriptomic sequencing (scRNA-seq) datasets. METHODS: We analyzed scRNA-seq data, which was derived from studying the cochlear SV in mice with SNHL compared to normal adult mice. After quality control and filtering, we obtained the major cellular components of the mouse cochlear SV and integrated the data. Using Seurat's FindAllMarkers and FindMarkers packages, we searched for novel conservative genes and differential genes. We employed KEGG and GSEA to identify molecular pathways that are commonly altered among different types of SNHL. We utilized pySCENIC to discover new specific regulatory factors in SV subpopulation cells. With the help of CellChat, we identified changes in subpopulation cells showing similar trends across different SNHL types and their alterations in intercellular communication pathways. RESULTS: Through the analysis of the integrated data, we discovered new conserved genes to SV specific cells and identified common downregulated pathways in three types of SNHL. The enriched genes for these pathways showing similar trends are primarily associated with the Electron Transport Chain, related to mitochondrial energy metabolism. Using the CellChat package, we further found that there are shared pathways in the incoming signaling of specific intermediate cells in SNHL, and these pathways have common upstream regulatory transcription factor of Nfe2l2. Combining the results from pySCENIC and CellChat, we predicted the transcription factor Nfe2l2 as an upstream regulatory factor for multiple shared cellular pathways in IC. Additionally, it serves as an upstream factor for several genes within the Electron Transport Chain. CONCLUSION: Our bioinformatics analysis has revealed that downregulation of the mitochondrial electron transport chain have been observed in various conditions of SNHL. E2f1, Esrrb, Runx1, Yy1, and Gata2 could serve as novel important common TFs regulating the electron transport chain. Adm has emerged as a potential new marker gene for intermediate cells, while Itgb5 and Tesc show promise as potential new marker genes for marginal cells in the SV. These findings offer a new perspective on SV lesions in SNHL and provide additional theoretical evidence for the same drug treatment and prevention of different pathologies of SNHL.

Novel hemizygous single-nucleotide duplication in RPGR in a patient with retinal dystrophy and sensorineural hearing loss.

BACKGROUND: The RPGR gene has been associated with X-linked cone-rod dystrophy. This report describes a variant in RPGR detected with exome sequencing (ES). Genes like RPGR have not always been included in panel-based testing and thus genome-wide tests such as ES may be required for accurate diagnosis. METHODS: The Texome Project is studying the impact of ES in medically underserved patients who are in need of genomic testing to guide diagnosis and medical management. The hypothesis is that ES could uncover diagnoses not made by standard medical care. RESULTS: A 58-year-old male presented with retinitis pigmentosa, sensorineural hearing loss, and a family history of retinal diseases. A previous targeted gene panel for retinal disorders had not identified a molecular cause. ES through the Texome Project identified a novel, hemizygous variant in RPGR (NM_000328.3: c.1302dup, p.L435Sfs*18) that explained the ocular phenotype. CONCLUSIONS: Continued genetics evaluation can help to end diagnostic odysseys of patients. Careful consideration of genes represented when utilizing gene panels is crucial to ensure an accurate diagnosis. Medically underserved populations are less likely to receive comprehensive genetic testing in their diagnostic workup. Our report is an example of the medical impact of genomic medicine implementation.

Study of the factors related to air-bone gap in enlarged vestibular aqueduct.

BACKGROUND: Over half of patients with enlarged vestibular aqueducts (EVA) will have an air-bonr gap (ABG), however, current research on audiology has focused on the influencing factors of air-conducted. OBJECTIVE: To retrospectively analyse the influencing factors and clinical manifestations of the bone-conduction threshold and ABG in patients with EVA. MATERIALS AND METHODS: We included 286 patients with EVA; among them, 126 had full SLC26A4 gene sequence results. We performed a descriptive analysis of the bone-conduction threshold and explored the effect of age. Finally, we analyzed the relationship of ABG and SLC26A4 genes with the degree of vestibular aqueduct (VA) enlargement. RESULTS: Among 555 ears, 312 (57.8%) ears had ABG; approximately 94% of the patients' bone-conduction hearing is almost completely lost at frequencies of 2 and 4 kHz. There was no linear correlation between age and bone-conduction threshold (p > 0.05). ABG did not significantly differ according to the degree of VA enlargement and number of SLC26A4 allele mutations (p > 0.05). CONCLUSIONS AND SIGNIFICANCE: Among patients with EVA, ABG is mainly produced at low frequencies and is not significantly correlated with age, size of the VA opening or SLC26A4 genes, which could be attributed to the biomechanical effects.