[Evaluation of the outcomes of cochlear implant in children with auditory neuropathy].

Objective: To investigate the auditory and speech abilities of children with congenital auditory neuropathy (AN) after cochlear implant (CI), and to analyze the role of genetic testing in predicting the postoperative outcomes of CI in AN patients. Methods: Fourteen children diagnosed with AN by audiological battery test and underwent CI surgery in Xijing Hospital of the Air Force Medical University from 2002 to 2021 were included in this study (9 males and 5 females), with an implantation age of (3.1±1.7) years (mean±standard deviation, the same as follows). The preoperative audiological results and deafness gene results were analyzed. Another 52 children with ordinary sensorineural hearing loss (SNHL) were selected as the control group (30 males and 22 females), with an implantation age of (2.2±0.9) years. The demographic factors such as age and gender were matched with those of the AN group. The modified Category Auditory Performance (CAP-Ⅱ) and Speech Intelligence Rate (SIR) were used to evaluate the development of postoperative auditory and speech abilities in two groups. The Mandarin Speech Test System was used to test the speech recognition rate of monosyllabic and disyllabic words and sentences. Matlab 2022 software was used to analyze the data. Results: The results of gene in 14 children with AN showed that 6 cases had OTOF gene mutations, 2 cases (siblings) were confirmed to have TNN gene mutations through whole exome sequencing, and the remaining 6 cases were not find any clear pathogenic gene mutations. All subjects underwent CI surgery with electrodes implanted into the cochlea smoothly, and there were no postoperative complications. After surgery, all AN children had improved auditory and speech abilities, but only 64% (9/14) of AN children with CI had auditory ability scores comparable to the control group of SNHL children (including 2 children with TNN gene mutations), and 36% (5/14) of AN children had lower scores than the control group of SNHL children.The average speech recognition rate of two children with TNN gene mutations was 86.5%, and of two children with OTOF gene mutations was 83.2%. Conclusions: AN children achieved varying degrees of auditory and speech abilities after CI, but the postoperative effects varied greatly. Some children achieved similar results as ordinary SNHL children, but there were still some children whose effects were worse than those of ordinary SNHL children. The postoperative efficacy of CI in two children with AN caused by TNN pathogenic genes were comparable to that of ordinary SNHL in children. Genetic testing had certain reference value for predicting the postoperative effect of CI in AN children.

[The updates of the ACMG variant interpretation guidelines affect the pathogenicity determination of OTOF gene variations in patients with auditory neuropathy].

Objective: To compare the differences between the variation interpretation standards and guidelines issued by the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) in 2015 (The 2015ACMG/AMP guideline) and the Deafness Specialist Group of the Clinical Genome Resource (ClinGen) in 2018 for hereditary hearing loss (Healing loss, HL) issued the expert specification of the variation interpretation guide (The 2018 HL-EP guideline) in evaluating the pathogenicity of OTOF gene variation in patients with auditory neuropathy. Methods: Thirty-eight auditory neuropathy patients with OTOF gene variant were selected as the study subjects (23 males and 15 females, aged 0.3-25.9 years). Using whole-genome sequencing, whole exome sequencing or target region sequencing (Panel) combined with Sanger sequencing, 38 cases were found to carry more than two OTOF mutation sites. A total of 59 candidate variants were independently interpreted based on the 2015 ACMG/AMP guideline and 2018 HL-EP guideline. Compared with the judgment results in 2015 ACMG/AMP guideline, the variants interpreted as lower pathogenic classifications in the 2018 HL-EP guideline were defined as downgraded variants, and the variants regarded as higher pathogenic classifications were defined as upgraded variants. Statistical analysis was conducted using SPSS 20.0. Results: The concordance rate of variant classification between the guidelines was 72.9%(43/59). The 13.6%(8/59) of variants were upgraded and 13.6% (8/59) of variants downgraded in the classifications of the 2018 HL-EP guideline. A couple of rules saw significant differences between the guidelines (PVS1, PM3, PP2, PP3 and PP5). The distribution of pathogenicity of splicing mutation was statistically different (P=0.013). Conclusions: The 2018 HL-EP guideline is inconsistent with the 2015 ACMG/AMP guideline, when judging the pathogenicity of OTOF gene variants in patients with auditory neuropathy. Through the deletion and refinement of evidence and the breaking of solidification thinking, the 2018 HL-EP guideline makes the pathogenicity grading more traceable and improves the credibility.

[Distribution characteristics and correlation analysis of GJB2 variation in patients with auditory neuropathy].

Objective:To elucidate the correlation between the GJB2 gene and auditory neuropathy, aiming to provide valuable insights for genetic counseling of affected individuals and their families. Methods:The general information, audiological data（including pure tone audiometry, distorted otoacoustic emission, auditory brainstem response, electrocochlography）, imaging data and genetic test data of 117 auditory neuropathy patients, and the patients with GJB2 gene mutation were screened out for the correlation analysis of auditory neuropathy. Results:Total of 16 patients were found to have GJB2 gene mutations, all of which were pathogenic or likely pathogenic.was Among them, one patient had compound heterozygous variants GJB2[c. 427C>T][c. 358_360del], exhibiting total deafness. One was GJB2[c. 299_300delAT][c. 35_36insG]compound heterozygous variants, the audiological findings were severe hearing loss.The remaining 14 patients with GJB2 gene variants exhibited typical auditory neuropathy. Conclusion:In this study, the relationship between GJB2 gene and auditory neuropathy was preliminarily analyzed,and explained the possible pathogenic mechanism of GJB2 gene variants that may be related to auditory neuropathy.

Auditory Neuropathy Spectrum Disorder Progressing with Motor and Sensory Neuropathy Caused by an ATP1A1 Variant.

We encountered a 27-year-old Japanese woman with sensorineural deafness progressing to motor and sensory neuropathy. At 16 years old, she had developed weakness in her lower extremities and hearing impairment, which gradually deteriorated. At 22 years old, combined audiological, electrophysiological, and radiological examination results were consistent with auditory neuropathy spectrum disorder (ANSD). Genetic analyses identified a previously reported missense variant in the ATP1A1 gene (NM_000701.8:c.1799C>G, p.Pro600Arg). Although sensorineural deafness has been reported as a clinical manifestation of ATP1A1-related disorders, our case suggested that ANSD may underlie the pathogenesis of deafness in ATP1A1-related disorders. This case report broadens the genotype-phenotype spectrum of ATP1A1-related disorders.

CYLD deficiency causes auditory neuropathy due to reduced neurite outgrowth.

BACKGROUND: Auditory neuropathy is a cause of hearing loss that has been studied in a number of animal models. Signal transmission from hair cells to spiral ganglion neurons plays an important role in normal hearing. CYLD is a microtubule-binding protein, and deubiquitinase involved in the regulation of various cellular processes. In this study, we used Cyld knockout (KO) mice and nerve cell lines to examine whether CYLD is associated with auditory neuropathy. METHODS: Hearing of Cyld KO mice was studied using the TDT RZ6 auditory physiology workstation. The expression and localization of CYLD in mouse cochlea and cell lines were examined by RT-PCR, immunoblotting, and immunofluorescence. CYLD expression was knocked down in SH-SY5Y cells by shRNAs and in PC12 and N2A cells by siRNAs. Nerve growth factor and retinoic acid were used to induce neurite outgrowth, and the occurrence and length of neurites were statistically analyzed between knockdown and control groups. RESULTS: Cyld KO mice had mild hearing impairment. Moreover, CYLD was widely expressed in mouse cochlear tissues and different nerve cell lines. Knocking down CYLD significantly reduced the length and proportion of neurites growing from nerve cells. CONCLUSIONS: The abnormal hearing of Cyld KO mice might be caused by a decrease in the length and number of neurites growing from auditory nerve cells in the cochlea, suggesting that CYLD is a key protein affecting hearing.

[ADA2 deficit: a case with neurological manifestations as a predominant clinic]. / Déficit de ADA2: caso con manifestaciones neurológicas como clínica predominante.

TITLE: Déficit de ADA2: caso con manifestaciones neurológicas como clínica predominante.

[The molecular mechanisms underpinning auditory neuropathy].

Auditory neuropathy (AN) is a hearing disorder where cochlear inner hair cell and/or the auditory nerve function is disrupted while outer hair cell function is normal. It can affect people of all ages, from infancy to adulthood. People with auditory neuropathy may have normal hearing threshold, or hearing loss ranging from mild to severe; they always have poor speech-perception abilities. It is a heterogeneous disorder which can have either congenital or acquired causes. AN may result from specific loss of cochlear inner hair cells, disordered release of neurotransmitters by inner hair cell ribbon synapses, deafferentation accompanying loss of auditory nerve fibers, neural dys-synchrony or conduction block as a result of demyelination of nerve fibers and auditory nerve hypoplasia. Although the definition of AN includes the central part, its incidence is low, and the etiology and pathology are not clear. The present review aimed to provide an overview of the genetic conditions associated with AN and highlight the neural and synaptic mechanism of AN. Possible strategy for treatments of AN was also discussed.

Targeted next generation sequencing reveals OTOF mutations in auditory neuropathy spectrum disorder.

OBJECTIVE: To study the genetic etiology of auditory neuropathy spectrum disorder (ANSD) in a Chinese family and perform a literature review of OTOF mutations and cochlear implantation (CI). METHODS: Sequential targeted next generation sequencing (NGS) and CI was performed for the proband. Further, 50 DNA samples from unrelated families with nonsyndromic deafness were examined for frequency determination. The impact of OTOF mutations on hearing recovery after CI was assessed through the literature survey. RESULTS: In the proband, the targeted NGS panel revealed five suspected variants in four genes (OTOF, EYA4, PCDH15, and GIPC3), of which two mutations-c.5098G > C (p.Glu1700Gln) and c.1702C > T (p.Arg568Trp)-in the OTOF gene were found to be correlated with ANSD. The c.5098G > C allele was identified in only one child from the 50 unrelated participants. The proband's hearing and speech abilities were restored 2 years after the surgery. Most ANSD patients (90.9%; 30/33) with OTOF mutations have acceptable surgical outcomes, as indicated by existing reports. CONCLUSIONS: Our results support the feasibility of CI for patients with ANSD and OTOF mutations, and this hypothesis was supported by the review of existing data. A larger number of cases studies is required to determine possible modifies on the prognosis of surgery.

The CAPOS mutation in ATP1A3 alters Na/K-ATPase function and results in auditory neuropathy which has implications for management.

Cerebellar ataxia, areflexia, pes cavus, optic atrophy and sensorineural hearing impairment (CAPOS) is a rare clinically distinct syndrome caused by a single dominant missense mutation, c.2452G>A, p.Glu818Lys, in ATP1A3, encoding the neuron-specific alpha subunit of the Na+/K+-ATPase α3. Allelic mutations cause the neurological diseases rapid dystonia Parkinsonism and alternating hemiplegia of childhood, disorders which do not encompass hearing or visual impairment. We present detailed clinical phenotypic information in 18 genetically confirmed patients from 11 families (10 previously unreported) from Denmark, Sweden, UK and Germany indicating a specific type of hearing impairment-auditory neuropathy (AN). All patients were clinically suspected of CAPOS and had hearing problems. In this retrospective analysis of audiological data, we show for the first time that cochlear outer hair cell activity was preserved as shown by the presence of otoacoustic emissions and cochlear microphonic potentials, but the auditory brainstem responses were grossly abnormal, likely reflecting neural dyssynchrony. Poor speech perception was observed, especially in noise, which was beyond the hearing level obtained in the pure tone audiograms in several of the patients presented here. Molecular modelling and in vitro electrophysiological studies of the specific CAPOS mutation were performed. Heterologous expression studies of α3 with the p.Glu818Lys mutation affects sodium binding to, and release from, the sodium-specific site in the pump, the third ion-binding site. Molecular dynamics simulations confirm that the structure of the C-terminal region is affected. In conclusion, we demonstrate for the first time evidence for auditory neuropathy in CAPOS syndrome, which may reflect impaired propagation of electrical impulses along the spiral ganglion neurons. This has implications for diagnosis and patient management. Auditory neuropathy is difficult to treat with conventional hearing aids, but preliminary improvement in speech perception in some patients suggests that cochlear implantation may be effective in CAPOS patients.

ATP1A3 mutations can cause progressive auditory neuropathy: a new gene of auditory synaptopathy.

The etiologies and prevalence of sporadic, postlingual-onset, progressive auditory neuropathy spectrum disorder (ANSD) have rarely been documented. Thus, we aimed to evaluate the prevalence and molecular etiologies of these cases. Three out of 106 sporadic progressive hearing losses turned out to manifest ANSD. Through whole exome sequencing and subsequent bioinformatics analysis, two out of the three were found to share a de novo variant, p.E818K of ATP1A3, which had been reported to cause exclusively CAPOS (cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural hearing loss) syndrome. However, hearing loss induced by CAPOS has never been characterized to date. Interestingly, the first proband did not manifest any features of CAPOS, except subclinical areflexia; however, the phenotypes of second proband was compatible with that of CAPOS, making this the first reported CAPOS allele in Koreans. This ANSD phenotype was compatible with known expression of ATP1A3 mainly in the synapse between afferent nerve and inner hair cells. Based on this, cochlear implantation (CI) was performed in the first proband, leading to remarkable benefits. Collectively, the de novo ATP1A3 variant can cause postlingual-onset auditory synaptopathy, making this gene a significant contributor to sporadic progressive ANSD and a biomarker ensuring favorable short-term CI outcomes.

A homozygous MYO7A mutation associated to Usher syndrome and unilateral auditory neuropathy spectrum disorder.

Usher syndrome (USH) is an autosomal recessive disorder characterized by sensorineural hearing loss, progressive visual loss and night blindness due to retinitis pigmentosa (RP), with or without vestibular dysfunction. The purpose of this study was to detect the causative gene in a consanguineous Chinese family with USH. A c.3696_3706del (p.R1232Sfs*72) variant in the myosin VIIa gene (MYO7A) was identified in the homozygous state by exome sequencing. The co­segregation of the MYO7A c.3696_3706del variant with the phenotype of deafness and progressive visual loss in the USH family was confirmed by Sanger sequencing. The variant was absent in 200 healthy controls. Therefore, the c.3696_3706del variant may disrupt the interaction between myosin VIIa and other USH1 proteins, and impair melanosome transport in retinal pigment epithelial cells. Notably, bilateral auditory brainstem responses were absent in two patients of the USH family, while distortion product otoacoustic emissions were elicited in the right ears of the two patients, consistent with clinical diagnosis of unilateral auditory neuropathy spectrum disorder. These data suggested that the homozygous c.3696_3706del variant in the MYO7A gene may be the disease­causing mutation for the disorder in this family. These findings broaden the phenotype spectrum of the MYO7A gene, and may facilitate understanding of the molecular pathogenesis of the disease, and genetic counseling for the family.

Novel compound heterozygous mutations in the OTOF Gene identified by whole-exome sequencing in auditory neuropathy spectrum disorder.

BACKGROUND: Many hearing-loss diseases are demonstrated to have Mendelian inheritance caused by mutations in single gene. However, many deaf individuals have diseases that remain genetically unexplained. Auditory neuropathy is a sensorineural deafness in which sounds are able to be transferred into the inner ear normally but the transmission of the signals from inner ear to auditory nerve and brain is injured, also known as auditory neuropathy spectrum disorder (ANSD). The pathogenic mutations of the genes responsible for the Chinese ANSD population remain poorly understood. METHODS: A total of 127 patients with non-syndromic hearing loss (NSHL) were enrolled in Guangxi Zhuang Autonomous Region. A hereditary deafness gene mutation screening was performed to identify the mutation sites in four deafness-related genes (GJB2, GJB3, 12S rRNA, and SLC26A4). In addition, whole-exome sequencing (WES) was applied to explore unappreciated mutation sites in the cases with the singularity of its phenotype. RESULTS: Well-characterized mutations were found in only 8.7% (11/127) of the patients. Interestingly, two mutations in the OTOF gene were identified in two affected siblings with ANSD from a Chinese family, including one nonsense mutation c.1273C > T (p.R425X) and one missense mutation c.4994 T > C (p.L1665P). Furthermore, we employed Sanger sequencing to confirm the mutations in each subject. Two compound heterozygous mutations in the OTOF gene were observed in the two affected siblings, whereas the two parents and unaffected sister were heterozygous carriers of c.1273C > T (father and sister) and c.4994 T > C (mother). The nonsense mutation p.R425X, contributes to a premature stop codon, may result in a truncated polypeptide, which strongly suggests its pathogenicity for ANSD. The missense mutation p.L1665P results in a single amino acid substitution in a highly conserved region. CONCLUSIONS: Two mutations in the OTOF gene in the Chinese deaf population were recognized for the first time. These findings not only extend the OTOF gene mutation spectrum for ANSD but also indicate that whole-exome sequencing is an effective approach to clarify the genetic characteristics in non-syndromic ANSD patients.

International Pediatric Otolaryngology Group (IPOG) consensus recommendations: Hearing loss in the pediatric patient.

OBJECTIVE: To provide recommendations for the workup of hearing loss in the pediatric patient. METHODS: Expert opinion by the members of the International Pediatric Otolaryngology Group. RESULTS: Consensus recommendations include initial screening and diagnosis as well as the workup of sensorineural, conductive and mixed hearing loss in children. The consensus statement discusses the role of genetic testing and imaging and provides algorithms to guide the workup of children with hearing loss. CONCLUSION: The workup of children with hearing loss can be guided by the recommendations provided herein.

Performance of Cochlear Implants in Pediatric Patients with Auditory Neuropathy Spectrum Disorder.

OBJECTIVE: To describe the performance and results of CIs (cochlear implant) in patients with AN (auditory neuropathy) and to present a medical literature review. MATERIALS AND METHODS: Retrospective chart review of patients with AN who were treated with CI. The mesh terms used for the review in the Pubmed and Scopus databases were as follows: "hearing loss, cochlear implants, rehabilitation of persons with hearing impairment, auditory neuropathy". STATISTICAL ANALYSES: The Mann-Whitney test was performed. RESULTS: The sample consisted of 10 patients. The mean age at surgery was 4.3 years, range 2-16 years. The average length of CI use was 5.2 years. The comparison of hearing levels before and after CI use showed a significant improvement in all patients, with p<0.05. All of them also reported an increase in overall satisfaction 1 year after the procedure. A CI is the standard treatment for the hearing rehabilitation of patients with severe profound hearing loss who do not benefit from conventional hearing aids. There are diseases such as AN that also invoke a discussion in the literature regarding CI benefits. CONCLUSION: Individuals with an demonstrated a significant gain in hearing levels and language use with CI.

Molecular approach of auditory neuropathy / Abordagem molecular da neuropatia auditiva

INTRODUCTION: Mutations in the otoferlin gene are responsible for auditory neuropathy. OBJECTIVE: To investigate the prevalence of mutations in the mutations in the otoferlin gene in patients with and without auditory neuropathy. METHODS: This original cross-sectional case study evaluated 16 index cases with auditory neuropathy, 13 patients with sensorineural hearing loss, and 20 normal-hearing subjects. DNA was extracted from peripheral blood leukocytes, and the mutations in the otoferlin gene sites were amplified by polymerase chain reaction/restriction fragment length polymorphism. RESULTS: The 16 index cases included nine (56%) females and seven (44%) males. The 13 deaf patients comprised seven (54%) males and six (46%) females. Among the 20 normal-hearing subjects, 13 (65%) were males and seven were (35%) females. Thirteen (81%) index cases had wild-type genotype (AA) and three (19%) had the heterozygous AG genotype for IVS8-2A-G (intron 8) mutation. The 5473C-G (exon 44) mutation was found in a heterozygous state (CG) in seven (44%) index cases and nine (56%) had the wild-type allele (CC). Of these mutants, two (25%) were compound heterozygotes for the mutations found in intron 8 and exon 44. All patients with sensorineural hearing loss and normal-hearing individuals did not have mutations (100%). CONCLUSION: There are differences at the molecular level in patients with and without auditory neuropathy. .

INTRODUÇÃO: Mutações no gene da otoferlina (OTOF) são responsáveis pela neuropatia auditiva. OBJETIVO: Investigar a prevalência de mutações no gene OTOF em pacientes com e sem neuropatia auditiva. MÉTODO: Estudo de casos em corte transversal sendo avaliados 16 casos índice com neuropatia auditiva, 13 pacientes com deficiência auditiva sensorioneural (DASN) e 20 indivíduos ouvintes. DNA foi extraído de leucócitos do sangue periférico e regiões do gene OTOF foram analisadas pela técnica PCR-RFLP. RESULTADOS: Dos 16 casos índice, 9 (56%) são do gênero feminino e 7 (44%) do masculino. Dos 13 pacientes com DASN, 7 (54%) são masculinos e 6 (46%) femininos. Dos 20 ouvintes, 13 (65%) são masculinos e 7 (35%) femininos. Treze (81%) casos índice apresentam o genótipo selvagem (AA) e 3 (19%) o genótipo heterozigoto AG para a mutação IVS8-2A-G (intron 8). A mutação 5473C-G (exon 44) foi encontrada em heterozigose (CG) em 7 (44%) dos casos índice e 9 (56%) apresentam o genótipo selvagem (CC). Destes mutantes, dois (25%) são heterozigotos compostos para as mutações encontradas no intron 8 e exon 44. Os pacientes com DASN e os ouvintes não apresentam mutações (100%). CONCLUSÃO: Existem diferenças, ao nível molecular, em pacientes com e sem neuropatia audi tiva. .

DNA sequence analysis and genotype-phenotype assessment in 71 patients with syndromic hearing loss or auditory neuropathy.

OBJECTIVES: Aetiological assessment of 71 probands whose clinical presentation suggested a genetic syndrome or auditory neuropathy. METHODS: Sanger sequencing was performed on DNA isolated from peripheral blood or lymphoblastoid cell lines. Genes were selected for sequencing based on each patient's clinical presentation and suspected diagnosis. Observed DNA sequence variations were assessed for pathogenicity by review of the scientific literature, and mutation and polymorphism databases, through the use of in silico tools including sorting intolerant from tolerant (SIFT) and polymorphism phenotyping (PolyPhen), and according to the recommendations of the American College of Medical Genetics and Genomics for the interpretation of DNA sequence variations. Novel DNA sequence variations were sought in controls. RESULTS: DNA sequencing of the coding and near-coding regions of genes relevant to each patient's clinical presentation revealed 37 sequence variations of known or uncertain pathogenicity in 9 genes from 25 patients. 14 novel sequence variations were discovered. Assessment of phenotypes revealed notable findings in 9 patients. CONCLUSIONS: DNA sequencing in patients whose clinical presentation suggested a genetic syndrome or auditory neuropathy provided opportunities for aetiological assessment and more precise genetic counselling of patients and families. The failure to identify a genetic aetiology in many patients in this study highlights the extreme heterogeneity of genetic hearing loss, the incompleteness of current knowledge of aetiologies of hearing loss, and the limitations of conventional DNA sequencing strategies that evaluate only coding and near-coding segments of genes.