Patients with CDH23 mutations and the 1555A > G mitochondrial mutation are good candidates for electric acoustic stimulation (EAS)

Conclusions: CDH23 mutations and the 1555A>G mitochondrial mutation were identified among our series of electric acoustic stimulation (EAS) patients, confirming that these genes were important in hearing loss with involvement of high frequency. Successful hearing preservation as well as good outcomes from EAS indicated that patients with this combination of mutations are good candidates for EAS. Objectives: Screening for gene mutations that possibly cause hearing loss involving high frequency was performed to identify the responsible genes in patients with EAS. In addition to a review of the genetic background of the patients with residual hearing loss, the benefit of EAS for patients with particular gene mutations was evaluated. Methods: Eighteen patients (15 late-onset, 3 early-onset) with residual hearing who had received EAS were included in this study. Genetic analysis was performed to identify GJB2, CDH23, SLC26A4, and the 1555 mitochondrial mutations. Results: Three early-onset patients had CDH23 mutations. One late-onset patient had the 1555 A>G mitochondrial mutation.ArticleACTA OTO-LARYNGOLOGICA. 132(4):377-384 (2012)journal articl

TECTA mutations in Japanese with mid-frequency hearing loss affected by zona pellucida domain protein secretion

信州大学博士（医学）・学位論文・平成24年7月3日授与（乙第1146号）・茂木英明TECTA gene encodes alpha-tectorin, the major component of noncollagenous glycoprotein of the tectorial membrane, and has a role in intracochlear sound transmission. The TECTA mutations are one of the most frequent causes of autosomal dominant (AD) hearing loss and genotype-phenotype correlations are associated with mutations of TECTA in exons according to alpha-tectorin domains. In this study, we investigated the prevalence of hearing loss caused by TECTA mutations in Japanese AD hearing loss families, and confirmed genotype-phenotype correlation, as well as the intracellular localization of missense mutations in the alpha-tectorin domain. TECTA mutations were detected in 2.9% (4/139) of our Japanese AD hearing loss families, with the prevalence in moderate hearing loss being 7.7% (4/52), and all patients showed typical genotype-phenotype correlations as previously described. The present in vitro study showed differences of localization patterns between wild type and mutants, and suggested that each missense mutation may lead to a lack of assembly of secretion, and may reduce the incorporation of alpha-tectorin into the tectorial membrane. Journal of Human Genetics (2012) 57, 587-592; doi:10.1038/jhg.2012.73; published online 21 June 2012ArticleJOURNAL OF HUMAN GENETICS. 57(9):587-592 (2012)journal articl

Different cortical metabolic activation by visual stimuli possibly due to different time courses of hearing loss in patients with GJB2 and SLC26A4 mutations

Conclusion. We have demonstrated differences in cortical activation with language-related visual stimuli in patients who were profoundly deafened due to genetic mutations in GJB2 and SLC26A4. The differences in cortical processing patterns between these two cases may have been influenced by the differing clinical courses and pathogenesis of hearing loss due to genetic mutations. Our results suggest the importance of hearing during early childhood for the development of a normal cortical language network. Objectives. To investigate the cortical activation with language-related visual stimuli in patients who were profoundly deafened due to genetic mutations in GJB2 and SLC26A4. Methods: The cortical activity of two adult patients with known genetic mutations (GJB2, SLC26A4) was evaluated with fluorodeoxyglucose-positron emission tomography (FDG-PET) with a visual language task and compared with that of normal-hearing controls. Results: A patient with a GJB2 mutation showed activation in the right auditory association area [BA21, BA22], and the left auditory association area [BA42] even with visual language task; in contrast, a patient with an SLC26A4 mutation showed no significant activation in the corresponding area.ArticleACTA OTO-LARYNGOLOGICA. 131(11):1232-1236 (2011)journal articl

Achievement of hearing preservation in the presence of an electrode covering the residual hearing region

Conclusions: With full insertion with a long electrode, hearing preservation can be achieved even in the presence of a long electrode covering the residual hearing region. Objectives: Advances in developing new atraumatic concepts of electrode design as well as surgical technique have enabled hearing preservation after cochlear implantation surgery, and EAS (electric acoustic stimulation) accompanied with hearing preservation is a new trend for patients with residual hearing at the lower frequencies. However, full insertion with a long/medium electrode and hearing preservation is still a challenging field that calls for discussion. Method: In this study, round window insertion, an atraumatic electrode, and dexamethasone administration were used and atraumaticity (hearing preservation and conservation of vestibular function) was evaluated with full insertion of the electrode. Results: Postoperative evaluation after full insertion of the electrodes showed that hearing at low frequencies was well preserved in all five cases. Combined postoperative imaging with the referential tonotopic map confirmed achievement of full insertion and indicated the corresponding frequencies and the depth of the electrode. Achievement of atraumaticity of round window insertion in the present cases was confirmed from the viewpoint of the minimal drilling time as well as the preserved vestibular function.ArticleACTA OTO-LARYNGOLOGICA. 131(4):405-412 (2011)journal articl

Gene Expression Profiles of the Cochlea and Vestibular Endorgans: Localization and Function of Genes Causing Deafness

Objectives: We sought to elucidate the gene expression profiles of the causative genes as well as the localization of the encoded proteins involved in hereditary hearing loss. Methods: Relevant articles (as of September 2014) were searched in PubMed databases, and the gene symbols of the genes reported to be associated with deafness were located on the Hereditary Hearing Loss Honnepage using localization, expression, and distribution as keywords. Results: Our review of the literature allowed us to systematize the gene expression profiles for genetic deafness in the inner ear, clarifying the unique functions and specific expression patterns of these genes in the cochlea and vestibular endorgans. Conclusions: The coordinated actions of various encoded molecules are essential for the normal development and maintenance of auditory and vestibular function.ArticleANNALS OF OTOLOGY RHINOLOGY AND LARYNGOLOGY. 124:6S-48S (2015)journal articl

Digenic inheritance of mutations in EPHA2 and SLC26A4 in Pendred syndrome

Enlarged vestibular aqueduct (EVA) is one of the most commonly identified inner ear malformations in hearing loss patients including Pendred syndrome. While biallelic mutations of the SLC26A4 gene, encoding pendrin, causes non-syndromic hearing loss with EVA or Pendred syndrome, a considerable number of patients appear to carry mono-allelic mutation. This suggests faulty pendrin regulatory machinery results in hearing loss. Here we identify EPHA2 as another causative gene of Pendred syndrome with SLC26A4. EphA2 forms a protein complex with pendrin controlling pendrin localization, which is disrupted in some pathogenic forms of pendrin. Moreover, point mutations leading to amino acid substitution in the EPHA2 gene are identified from patients bearing mono-allelic mutation of SLC26A4. Ephrin-B2 binds to EphA2 triggering internalization with pendrin inducing EphA2 autophosphorylation weakly. The identified EphA2 mutants attenuate ephrin-B2- but not ephrin-A1-induced EphA2 internalization with pendrin. Our results uncover an unexpected role of the Eph/ephrin system in epithelial function

Simultaneous Screening of Multiple Mutations by Invader Assay Improves Molecular Diagnosis of Hereditary Hearing Loss: A Multicenter Study

Although etiological studies have shown genetic disorders to be a common cause of congenital/early-onset sensorineural hearing loss, there have been no detailed multicenter studies based on genetic testing. In the present report, 264 Japanese patients with bilateral sensorineural hearing loss from 33 ENT departments nationwide participated. For these patients, we first applied the Invader assay for screening 47 known mutations of 13 known deafness genes, followed by direct sequencing as necessary. A total of 78 (29.5%) subjects had at least one deafness gene mutation. Mutations were more frequently found in the patients with congenital or early-onset hearing loss, i.e., in those with an awareness age of 0–6 years, mutations were significantly higher (41.8%) than in patients with an older age of awareness (16.0%). Among the 13 genes, mutations in GJB2 and SLC26A4 were mainly found in congenital or early-onset patients, in contrast with mitochondrial mutations (12S rRNA m.1555A>G, tRNA(Leu(UUR)) m.3243A>G), which were predominantly found in older-onset patients. The present method of simultaneous screening of multiple deafness mutations by Invader assay followed by direct sequencing will enable us to detect deafness mutations in an efficient and practical manner for clinical use

Differences between acoustic trauma and other types of acute noise-induced hearing loss in terms of treatment and hearing prognosis

Objectives: To evaluate the differences between acoustic trauma (AT) and other types of acute noise-induced hearing loss (ANIHL), we performed a literature search and case reviews.Methods: The literature search based on online databases was completed in September 2016. Articles on ANIHL and steroid treatment for human subjects were reviewed. The source sounds and treatment sequelae of our accumulated cases were also reviewed. Hearing loss caused by gun-shots and explosions was categorized into the AT group, while hearing loss caused by concerts and other noises was categorized into the ANIHL group.Results: Systemic steroid treatment did not appear to be effective, at least in the AT group, based on both the literature and our case reviews. However, effective recovery after treatment including steroids was observed in the ANIHL group. The difference in hearing recovery between the AT and ANIHL groups was statistically significant (p = .030), although differences in age, days from the onset to treatment and pretreatment hearing levels were not significant.Conclusions: Hearing recovery from AT is very poor, whereas, ANIHL is recoverable to some extent. Therefore, it is essential to differentiate between these two groups for accurate prediction of the hearing prognosis and evaluation of treatment effects

Epidemiological survey of acute low-tone sensorineural hearing loss

Objectives: A nationwide epidemiological survey involving 23 hospitals in Japan was conducted and the predictive values of demographic data were examined statistically.Methods: A total of 642 patients from 23 hospitals, including 20 university hospitals, in Japan were enrolled in the study. Age ranged from 8 to 87 years, and all were diagnosed with acute low-tone sensorineural hearing loss (ALHL) between 1994 and 2016. Demographic data for the patients, such as symptoms, gender, mean age, and distribution of ALHL grading, were collected and analyzed in relation to prognosis using Student’s t-test, χ2 test and logistic regression.Results: Female gender (p < .013), younger age (p < .001), low-grade hearing loss (p < .001), and shorter interval between onset and initial visit (p < .004) were significantly predictive of a good prognosis. The prognosis for definite ALHL was significantly better than that for probable ALHL (p < .007).Conclusions: The severity of initial hearing loss, interval between onset and initial visit and age were important prognostic indicators for ALHL, while female gender was an important prognostic indicator peculiar to ALHL

The effect of initial treatment on hearing prognosis in idiopathic sudden sensorineural hearing loss : a nationwide survey in Japan

Objective: To investigate the hearing prognosis of idiopathic sudden sensorineural hearing loss (SSNHL) treated with different initial therapies.Methods: Subjects consisted of patients diagnosed with idiopathic SSNHL within 7 days from onset and showing severe hearing loss (≥60 dB), who were registered in a Japanese multicenter database between April 2014 and March 2016. Subjects were divided into four groups according to initial therapy: (1) steroids, (2) steroids + Prostaglandins (PGs), (3) intratympanic steroids (ITS), and (4) no steroids. Hearing outcomes were compared among the groups.Results: In total, 1305 patients were enrolled. The final hearing level and hearing gain of patients treated with steroids + PGs were significantly higher than those of patients treated with steroids alone or no steroids. The ratio of good prognosis (complete recovery or marked improvement) in patients treated with steroids + PGs was higher than that in patients treated with steroids alone or no steroids. There was no difference in the prognosis of patients treated with steroids alone or no steroids.Conclusion: A large number of patients with idiopathic SSNHL were registered in a multicenter database. PG use in combination with steroid administration was associated with a good hearing prognosis in patients with severe hearing loss