RESUMEN
A comprehensive gene expression investigation requires high-quality RNA extraction, in sufficient amounts for real-time quantitative polymerase chain reaction and next-generation sequencing. In this work, we compared different RNA extraction methods and evaluated different reference genes for gene expression studies in the fetal human inner ear. We compared the RNA extracted from formalin-fixed paraffin-embedded tissue with fresh tissue stored at -80 °C in RNAlater solution and validated the expression stability of 12 reference genes (from gestational week 11 to 19). The RNA from fresh tissue in RNAlater resulted in higher amounts and a better quality of RNA than that from the paraffin-embedded tissue. The reference gene evaluation exhibited four stably expressed reference genes (B2M, HPRT1, GAPDH and GUSB). The selected reference genes were then used to examine the effect on the expression outcome of target genes (OTOF and TECTA), which are known to be regulated during inner ear development. The selected reference genes displayed no differences in the expression profile of OTOF and TECTA, which was confirmed by immunostaining. The results underline the importance of the choice of the RNA extraction method and reference genes used in gene expression studies.
Asunto(s)
Perfilación de la Expresión Génica , ARN , Humanos , Perfilación de la Expresión Génica/métodos , Gliceraldehído-3-Fosfato Deshidrogenasas/genética , Expresión Génica , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
Vascular Ehlers-Danlos syndrome (vEDS) is a hereditary connective tissue disorder (HCTD) characterized by arterial dissection/aneurysm/rupture, sigmoid colon rupture, or uterine rupture. Diagnosis is confirmed by detecting heterozygous variants in COL3A1. This is the largest Asian case series and the first to apply an amplification-based next-generation sequencing through custom panels of causative genes for HCTDs, including a specific method of evaluating copy number variations. Among 429 patients with suspected HCTDs analyzed, 101 were suspected to have vEDS, and 33 of them (32.4%) were found to have COL3A1 variants. Two patients with a clinical diagnosis of Loeys-Dietz syndrome and/or familial thoracic aortic aneurysm and dissection were also found to have COL3A1 variants. Twenty cases (57.1%) had missense variants leading to glycine (Gly) substitutions in the triple helical domain, one (2.9%) had a missense variant leading to non-Gly substitution in this domain, eight (22.9%) had splice site alterations, three (8.6%) had nonsense variants, two (5.7%) had in-frame deletions, and one (2.9%) had a multi-exon deletion, including two deceased patients analyzed with formalin-fixed and paraffin-embedded samples. This is a clinically useful system to detect a wide spectrum of variants from various types of samples.
Asunto(s)
Síndrome de Ehlers-Danlos Tipo IV , Síndrome de Ehlers-Danlos , Embarazo , Femenino , Humanos , Síndrome de Ehlers-Danlos/diagnóstico , Síndrome de Ehlers-Danlos/genética , Colágeno Tipo III/genética , Variaciones en el Número de Copia de ADN , Pruebas GenéticasRESUMEN
TMC1 is a causative gene for both autosomal dominant non-syndromic hearing loss (DFNA36) and autosomal recessive non-syndromic hearing loss (DFNB7/11). To date, 125 pathogenic variants in TMC1 have been reported. Most of the TMC1 variants are responsible for autosomal recessive hearing loss, with only 8 variants reported as causative for DFNA36. Here, we reported the prevalence of TMC1-associated hearing loss in a large non-syndromic hearing loss cohort of about 12,000 subjects. As a result, we identified 26 probands with TMC1-associated hearing loss, with the estimated prevalence of TMC1-associated hearing loss in the Japanese hearing loss cohort being 0.17% among all patients. Among the 26 probands with TMC1-associated hearing loss, 15 cases were identified from autosomal dominant hearing loss families. Based on the audiometric data from the probands, family members and previously reported cases, we evaluated hearing deterioration for DFNA36 patients. In addition, we performed haplotype analysis for 11 unrelated autosomal dominant hearing loss families carrying the same variant TMC1: NM_138691:c.1627G > A:p.Asp543Asn. The results clearly indicated that the same haplotype was present despite the families being unrelated, supporting the contention that this variant occurred by founder mutation.
Asunto(s)
Pérdida Auditiva Sensorineural , Pérdida Auditiva , Sordera , Pérdida Auditiva/genética , Pérdida Auditiva Sensorineural/genética , Humanos , Proteínas de la Membrana/genética , Mutación , Linaje , PrevalenciaRESUMEN
Etiological studies have shown genetic disorders to be a major cause of sensorineural hearing loss, but there are a limited number of comprehensive etiological reports based on genetic analysis. In the present study, the same platform using a diagnostic DNA panel carrying 63 deafness genes and the same filtering algorithm were applied to 10,047 samples obtained from social health insurance-based genetic testing of hearing loss. The most remarkable result obtained in this comprehensive study was that the data first clarified the genetic epidemiology from congenital/early-onset deafness to late-onset hearing loss. The overall diagnostic rate was 38.8%, with the rate differing for each age group; 48.6% for the congenital/early-onset group (~5y.o.), 33.5% for the juvenile/young adult-onset group, and 18.0% for the 40+ y.o. group. Interestingly, each group showed a different kind of causative gene. With regard to the mutational spectra, there are certain recurrent variants that may be due to founder effects or hot spots. A series of haplotype studies have shown many recurrent variants are due to founder effects, which is compatible with human migration. It should be noted that, regardless of differences in the mutational spectrum, the clinical characteristics caused by particular genes can be considered universal. This comprehensive review clarified the detailed clinical characteristics (onset age, severity, progressiveness, etc.) of hearing loss caused by each gene, and will provide useful information for future clinical application, including genetic counseling and selection of appropriate interventions.
Asunto(s)
Sordera , Pérdida Auditiva Sensorineural , Pérdida Auditiva , Adulto , Preescolar , Sordera/genética , Pruebas Genéticas , Pérdida Auditiva/diagnóstico , Pérdida Auditiva/genética , Pérdida Auditiva Sensorineural/diagnóstico , Pérdida Auditiva Sensorineural/genética , Humanos , Seguro de Salud , Japón/epidemiología , Mutación , Adulto JovenRESUMEN
Variants in the CDH23 gene are known to be responsible for both syndromic hearing loss (Usher syndrome type ID: USH1D) and non-syndromic hearing loss (DFNB12). Our series of studies demonstrated that CDH23 variants cause a broad range of phenotypes of non-syndromic hearing loss (DFNB12); from congenital profound hearing loss to late-onset high-frequency-involved progressive hearing loss. In this study, based on the genetic and clinical data from more than 10,000 patients, the mutational spectrum, clinical characteristics and genotype/phenotype correlations were evaluated. The present results reconfirmed that the variants in CDH23 are an important cause of non-syndromic sensorineural hearing loss. In addition, we showed that the mutational spectrum in the Japanese population, which is probably representative of the East Asian population in general, as well as frequent CDH23 variants that might be due to some founder effects. The present study demonstrated CDH23 variants cause a broad range of phenotypes, from non-syndromic to syndromic hearing loss as well as from congenital to age-related hearing loss. Genotype (variant combinations) and phenotype (association with retinal pigmentosa, onset age) are shown to be well correlated and are thought to be related to the residual function defined by the CDH23 variants.
Asunto(s)
Pérdida Auditiva Sensorineural , Síndromes de Usher , Proteínas Relacionadas con las Cadherinas/genética , Cadherinas/genética , Sordera , Pérdida Auditiva Sensorineural/genética , Humanos , Mutación , Síndromes de Usher/genéticaRESUMEN
Stereocilia protrude up to 100 µm from the apical surface of vertebrate inner ear hair cells and are packed with cross-linked filamentous actin (F-actin). They function as mechanical switches to convert sound vibration into electrochemical neuronal signals transmitted to the brain. Several genes encode molecular components of stereocilia including actin monomers, actin regulatory and bundling proteins, motor proteins and the proteins of the mechanotransduction complex. A stereocilium F-actin core is a dynamic system, which is continuously being remodeled while maintaining an outwardly stable architecture under the regulation of F-actin barbed-end cappers, severing proteins and crosslinkers. The F-actin cores of stereocilia also provide a pathway for motor proteins to transport cargos including components of tip-link densities, scaffolding proteins and actin regulatory proteins. Deficiencies and mutations of stereocilia components that disturb this "dynamic equilibrium" in stereocilia can induce morphological changes and disrupt mechanotransduction causing sensorineural hearing loss, best studied in mouse and zebrafish models. Currently, at least 23 genes, associated with human syndromic and nonsyndromic hearing loss, encode proteins involved in the development and maintenance of stereocilia F-actin cores. However, it is challenging to predict how variants associated with sensorineural hearing loss segregating in families affect protein function. Here, we review the functions of several molecular components of stereocilia F-actin cores and provide new data from our experimental approach to directly evaluate the pathogenicity and functional impact of reported and novel variants of DIAPH1 in autosomal-dominant DFNA1 hearing loss using single-molecule fluorescence microscopy.
Asunto(s)
Sordera , Pérdida Auditiva Sensorineural , Actinas/genética , Animales , Sordera/genética , Sordera/metabolismo , Forminas , Cabello/metabolismo , Pérdida Auditiva Sensorineural/metabolismo , Humanos , Mecanotransducción Celular/genética , Ratones , Proteínas de Microfilamentos/genética , Estereocilios/metabolismo , Pez Cebra/genética , Pez Cebra/metabolismoRESUMEN
Mutations in the OTOF gene are a common cause of hereditary hearing loss and the main cause of auditory neuropathy spectrum disorder (ANSD). Although it is reported that most of the patients with OTOF mutations have stable, congenital or prelingual onset severe-to-profound hearing loss, some patients show atypical clinical phenotypes, and the genotype-phenotype correlation in patients with OTOF mutations is not yet fully understood. In this study, we aimed to reveal detailed clinical characteristics of OTOF-related hearing loss patients and the genotype-phenotype correlation. Detailed clinical information was available for 64 patients in our database who were diagnosed with OTOF-related hearing loss. As reported previously, most of the patients (90.6%) showed a "typical" phenotype; prelingual and severe-to-profound hearing loss. Forty-seven patients (73.4%) underwent cochlear implantation surgery and showed successful outcomes; approximately 85-90% of the patients showed a hearing level of 20-39 dB with cochlear implant and a Categories of Auditory Performance (CAP) scale level 6 or better. Although truncating mutations and p.Arg1939Gln were clearly related to severe phenotype, almost half of the patients with one or more non-truncating mutations showed mild-to-moderate hearing loss. Notably, patients with p.His513Arg, p.Ile1573Thr and p.Glu1910Lys showed "true" auditory neuropathy-like clinical characteristics. In this study, we have clarified genotype-phenotype correlation and efficacy of cochlear implantation for OTOF-related hearing loss patients in the biggest cohort studied to date. We believe that the clinical characteristics and genotype-phenotype correlation found in this study will support preoperative counseling and appropriate intervention for OTOF-related hearing loss patients.
Asunto(s)
Sordera , Pérdida Auditiva Sensorineural , Pérdida Auditiva , Estudios de Asociación Genética , Pérdida Auditiva/genética , Pérdida Auditiva Central , Pérdida Auditiva Sensorineural/genética , Humanos , Japón , Proteínas de la Membrana/genética , MutaciónRESUMEN
Genetic testing for congenital or early-onset hearing loss patients has become a common diagnostic option in many countries. On the other hand, there are few late-onset hearing loss patients receiving genetic testing, as late-onset hearing loss is believed to be a complex disorder and the diagnostic rate for genetic testing in late-onset patients is lower than that for the congenital cases. To date, the etiology of late-onset hearing loss is largely unknown. In the present study, we recruited 48 unrelated Japanese patients with late-onset bilateral sensorineural hearing loss, and performed genetic analysis of 63 known deafness gene using massively parallel DNA sequencing. As a result, we identified 25 possibly causative variants in 29 patients (60.4%). The present results clearly indicated that various genes are involved in late-onset hearing loss and a significant portion of cases of late-onset hearing loss is due to genetic causes. In addition, we identified two interesting cases for whom we could expand the phenotypic description. One case with a novel MYO7A variant showed a milder phenotype with progressive hearing loss and late-onset retinitis pigmentosa. The other case presented with Stickler syndrome with a mild phenotype caused by a homozygous frameshift COL9A3 variant. In conclusion, comprehensive genetic testing for late-onset hearing loss patients is necessary to obtain accurate diagnosis and to provide more appropriate treatment for these patients.
Asunto(s)
Pérdida Auditiva Sensorineural , Pérdida Auditiva , Antecedentes Genéticos , Pérdida Auditiva/genética , Pérdida Auditiva Sensorineural/genética , Humanos , Linaje , FenotipoRESUMEN
We present detailed comparative analyses to assess population-level differences in patterns of genetic deafness between European/American and Japanese cohorts with non-syndromic hearing loss. One thousand eighty-three audiometric test results (921 European/American and 162 Japanese) from members of 168 families (48 European/American and 120 Japanese) with non-syndromic hearing loss secondary to pathogenic variants in one of three genes (KCNQ4, TECTA, WFS1) were studied. Audioprofile characteristics, specific mutation types, and protein domains were considered in the comparative analyses. Our findings support differences in audioprofiles driven by both mutation type (non-truncating vs. truncating) and ethnic background. The former finding confirms data that ascribe a phenotypic consequence to different mutation types in KCNQ4; the latter finding suggests that there are ethnic-specific effects (genetic and/or environmental) that impact gene-specific audioprofiles for TECTA and WFS1. Identifying the drivers of ethnic differences will refine our understanding of phenotype-genotype relationships and the biology of hearing and deafness.
Asunto(s)
Proteínas de la Matriz Extracelular/genética , Genotipo , Pérdida Auditiva Sensorineural/genética , Canales de Potasio KCNQ/genética , Proteínas de la Membrana/genética , Mutación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Pueblo Asiatico , Audiometría , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Proteínas Ligadas a GPI/genética , Expresión Génica , Estudios de Asociación Genética , Pérdida Auditiva Sensorineural/diagnóstico , Pérdida Auditiva Sensorineural/etnología , Pérdida Auditiva Sensorineural/fisiopatología , Humanos , Lactante , Recién Nacido , Japón , Masculino , Persona de Mediana Edad , Linaje , Fenotipo , Estados Unidos , Población BlancaRESUMEN
Tight junctions are cellular junctions that play a major role in the epithelial barrier function. In the inner ear, claudins, occludin, tricellulin, and angulins form the bicellular or tricellular binding of membrane proteins. In these, one type of claudin gene, CLDN14, was reported to be responsible for human hereditary hearing loss, DFNB29. Until now, nine pathogenic variants have been reported, and most phenotypic features remain unclear. In the present study, genetic screening for 68 previously reported deafness causative genes was carried out to identify CLDN14 variants in a large series of Japanese hearing loss patients, and to clarify the prevalence and clinical characteristics of DFNB29 in the Japanese population. One patient had a homozygous novel variant (c.241C>T: p.Arg81Cys) (0.04%: 1/2549). The patient showed progressive bilateral hearing loss, with post-lingual onset. Pure-tone audiograms indicated a high-frequency hearing loss type, and the deterioration gradually spread to other frequencies. The patient showed normal vestibular function. Cochlear implantation improved the patient's sound field threshold levels, but not speech discrimination scores. This report indicated that claudin-14 is essential for maintaining the inner ear environment and suggested the possible phenotypic expansion of DFNB29. This is the first report of a patient with a tight junction variant receiving a cochlear implantation.
Asunto(s)
Claudinas/genética , Sordera/diagnóstico , Sordera/genética , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Variación Genética , Fenotipo , Adolescente , Adulto , Anciano , Alelos , Sustitución de Aminoácidos , Niño , Preescolar , Claudinas/metabolismo , Sordera/metabolismo , Sordera/terapia , Femenino , Estudios de Asociación Genética/métodos , Genotipo , Humanos , Lactante , Recién Nacido , Japón , Masculino , Persona de Mediana Edad , Linaje , Uniones Estrechas/genética , Uniones Estrechas/metabolismo , Adulto JovenRESUMEN
AIM: The association between cognitive function and clinical parameters of chronic kidney disease (CKD) was investigated in Japanese patients without overt dementia in a cross-sectional study. MATERIALS AND METHODS: A population of 497 patients whose cognitive function had been examined using the mini-mental state examination (MMSE) were screened for this study. After the exclusion of 306 subjects who showed overt dementia, the association between the MMSE score and clinical characteristics was investigated in 191 subjects (male: 55%, age: 69 ± 12 years). RESULTS: The mean MMSE score of the study subjects was 26.7 ± 2.0. The MMSE score was negatively correlated with the patients' age and positively with the estimated glomerular filtration rate. It was significantly associated with age and proteinuria based on a multivariate analysis. The scores of "temporal orientation", "attention and calculation", and "remote memory" subitems of MMSE were significantly lower in the subjects ≥ 70 years of age than in those < 70 years of age. The scores of "temporal orientation" (4.3 ± 0.8 vs. 4.7 ± 0.6), "attention and calculation" (2.9 ± 1.6 vs. 3.9 ± 1.5), and "stage command" (2.7 ± 0.5 vs. 2.9 ± 0.3) were significantly lower in the subjects with proteinuria than in those without. CONCLUSION: Cognitive function was disturbed even in CKD patients without overt dementia. Intervention in patients with risk factors is deemed important for preventing future reductions in cognitive and renal functions in CKD patients without dementia.â©.
Asunto(s)
Trastornos del Conocimiento , Insuficiencia Renal Crónica , Anciano , Anciano de 80 o más Años , Cognición/fisiología , Trastornos del Conocimiento/complicaciones , Trastornos del Conocimiento/epidemiología , Trastornos del Conocimiento/fisiopatología , Estudios Transversales , Femenino , Tasa de Filtración Glomerular , Humanos , Japón/epidemiología , Masculino , Pruebas de Estado Mental y Demencia , Persona de Mediana Edad , Insuficiencia Renal Crónica/complicaciones , Insuficiencia Renal Crónica/epidemiología , Insuficiencia Renal Crónica/fisiopatologíaRESUMEN
Recent advances in next-generation sequencing (NGS) have given rise to new challenges due to the difficulties in variant pathogenicity interpretation and large dataset management, including many kinds of public population databases as well as public or commercial disease-specific databases. Here, we report a new database development tool, named the "Clinical NGS Database," for improving clinical NGS workflow through the unified management of variant information and clinical information. This database software offers a two-feature approach to variant pathogenicity classification. The first of these approaches is a phenotype similarity-based approach. This database allows the easy comparison of the detailed phenotype of each patient with the average phenotype of the same gene mutation at the variant or gene level. It is also possible to browse patients with the same gene mutation quickly. The other approach is a statistical approach to variant pathogenicity classification based on the use of the odds ratio for comparisons between the case and the control for each inheritance mode (families with apparently autosomal dominant inheritance vs. control, and families with apparently autosomal recessive inheritance vs. control). A number of case studies are also presented to illustrate the utility of this database.
Asunto(s)
Biología Computacional/métodos , Bases de Datos Genéticas , Estudios de Asociación Genética/métodos , Predisposición Genética a la Enfermedad , Variación Genética , Secuenciación de Nucleótidos de Alto Rendimiento , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Programas Informáticos , Interfaz Usuario-Computador , Flujo de TrabajoRESUMEN
Usher syndrome type 1 (USH1) is the most severe of the three USH subtypes due to its profound hearing loss, absent vestibular response and retinitis pigmentosa appearing at a prepubescent age. Six causative genes have been identified for USH1, making early diagnosis and therapy possible through DNA testing. Targeted exon sequencing of selected genes using massively parallel DNA sequencing (MPS) technology enables clinicians to systematically tackle previously intractable monogenic disorders and improve molecular diagnosis. Using MPS along with direct sequence analysis, we screened 227 unrelated non-syndromic deaf children and detected recessive mutations in USH1 causative genes in five patients (2.2%): three patients harbored MYO7A mutations and one each carried CDH23 or PCDH15 mutations. As indicated by an earlier genotype-phenotype correlation study of the CDH23 and PCDH15 genes, we considered the latter two patients to have USH1. Based on clinical findings, it was also highly likely that one patient with MYO7A mutations possessed USH1 due to a late onset age of walking. This first report describing the frequency (1.3-2.2%) of USH1 among non-syndromic deaf children highlights the importance of comprehensive genetic testing for early disease diagnosis.
Asunto(s)
Estudios de Asociación Genética , Secuenciación de Nucleótidos de Alto Rendimiento , Síndromes de Usher/diagnóstico , Síndromes de Usher/genética , Alelos , Sustitución de Aminoácidos , Niño , Preescolar , Femenino , Pruebas Genéticas , Genotipo , Humanos , Lactante , Japón , Masculino , Mutación , Linaje , Fenotipo , Sistema de Registros , Síndromes de Usher/epidemiologíaRESUMEN
The diagnosis of the genetic etiology of deafness contributes to the clinical management of patients. We performed the following four genetic tests in three stages for 52 consecutive deafness subjects in one facility. We used the Invader assay for 46 mutations in 13 genes and Sanger sequencing for the GJB2 gene or SLC26A4 gene in the first-stage test, the TaqMan genotyping assay in the second-stage test and targeted exon sequencing using massively parallel DNA sequencing in the third-stage test. Overall, we identified the genetic cause in 40% (21/52) of patients. The diagnostic rates of autosomal dominant, autosomal recessive and sporadic cases were 50%, 60% and 34%, respectively. When the sporadic cases with congenital and severe hearing loss were selected, the diagnostic rate rose to 48%. The combination approach using these genetic tests appears to be useful as a diagnostic tool for deafness patients. We recommended that genetic testing for the screening of common mutations in deafness genes using the Invader assay or TaqMan genotyping assay be performed as the initial evaluation. For the remaining undiagnosed cases, targeted exon sequencing using massively parallel DNA sequencing is clinically and economically beneficial.
Asunto(s)
ADN/genética , Sordera/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , JapónRESUMEN
Hearing impairment is one of the most common sensory disorders that affect ~1 in 1000 children, and half of them are considered to be hereditary. Information about the carrier frequencies of mutations that underlie autosomal recessive disorders is indispensable for accurate genetic counseling to predict the probability of patients' children's disease. However, there have been few reports specific to the Japanese population. GJB2 mutations are reported to be the most frequent cause of hereditary hearing loss, and the mutation spectrum and frequency of GJB2 mutations were reported to vary among different ethnic groups. In this study, we investigated the carrier frequency of GJB2 mutations and the mutation spectrum in 509 individuals randomly selected from the general Japanese population. We show that the carrier frequencies of the two most common pathogenic mutations are 1.57% (8/509) for c.235delC and 1.77% (9/509) for p.Val37Ile. In addition to these mutations, we found two pathogenic variants (p.[Gly45Glu;Tyr136*] and p.Arg143Trp), and the total carrier frequency was estimated to be around 3.73% (19/509). We also detected six unclassified variants, including two novel variants (p.Cys60Tyr and p.Phe106Leu), with the former predicted to be pathogenic. These findings will provide indispensable information for genetic counseling in the Japanese population.
Asunto(s)
Pueblo Asiatico/genética , Conexinas/genética , Frecuencia de los Genes , Pérdida Auditiva/genética , Adulto , Anciano , Anciano de 80 o más Años , Conexina 26 , Femenino , Pérdida Auditiva/epidemiología , Humanos , Japón/epidemiología , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVES: To elucidate the molecular epidemiology of hearing loss in a large number of Japanese patients analyzed using massively parallel DNA sequencing (MPS) of target genes. METHODS: We performed MPS of target genes using the Ion PGM system with the Ion AmpliSeq and HiSeq 2000 systems using SureSelect in 1389 samples (1120 nonsyndromic hearing loss cases and 269 normal hearing controls). We filtered the variants identified using allele frequencies in a large number of controls and 12 predication program scores. RESULTS: We identified 8376 kinds of variants in the 1389 samples, and 409 835 total variants were detected. After filtering the variants, we selected 2631 kinds of candidate variants. The number of GJB2 mutations was exceptionally high among these variants, followed by those in CDH23, SLC26A4, MYO15A, COL11A2, MYO7A, and OTOF. CONCLUSIONS: We performed a large number of MPS analyses and clarified the genetic background of Japanese patients with hearing loss. This data set will be a powerful tool to discover rare causative gene mutations in highly heterogeneous monogenic diseases and reveal the genetic epidemiology of deafness.
Asunto(s)
Variación Genética , Análisis de Secuencia de ADN/métodos , Conexina 26 , Conexinas , Sordera/genética , Humanos , Japón , Epidemiología Molecular , MutaciónRESUMEN
OBJECTIVES: To elucidate the involvement of MYO6 mutations, known to be responsible for DFNA22/DFNB37, in Japanese hearing loss patients through the use of genetic analysis. METHODS: Genomic variations responsible for hearing loss were identified by massively parallel DNA sequencing (MPS) of 63 target candidate genes in 1120 Japanese hearing loss patients, and the detailed clinical features for the patients with MYO6 mutations were collected and analyzed. RESULTS: Four mutations were successfully found in 7 families exhibiting autosomal dominant inheritance. All of the patients showed progressive hearing loss, but hearing type and onset age varied. Further, none of the affected patients showed any associated symptoms, such as hypertrophic cardiomyopathy or retinitis pigmentosa. CONCLUSIONS: MPS is powerful tool for the identification of rare causative deafness gene mutations, such as MYO6. The clinical characteristics noted in the present study not only confirmed the findings of previous reports but provided important new clinical information.
Asunto(s)
Pueblo Asiatico/genética , Codón sin Sentido , Análisis Mutacional de ADN/métodos , Pérdida Auditiva/genética , Mutación Missense/fisiología , Cadenas Pesadas de Miosina/genética , Adolescente , Adulto , Anciano , Sordera/genética , Femenino , Humanos , Masculino , LinajeRESUMEN
OBJECTIVE: The mutation spectrum of the GJB2 and SLC26A4 genes, the 2 most common genes causing deafness, are known to be ethnic specific. In this study, the spectrum of the reported GJB2 and SLC26A4 mutations in different populations are reviewed and considered from a human migration perspective. METHODS: Fifty-two and 17 articles on GJB2 and SLC26A4 mutations, respectively, were reviewed through the PubMed database from April 1996 to September 2014. The 4 most prevalent mutations were selected and compared. A cluster analysis was subsequently performed for these selected mutations. RESULTS: The present review of frequent mutations shows the ethnic-specific GJB2 and SLC26A4 gene mutation spectrum. A cluster analysis of the GJB2 and SLC26A4 genes revealed similarities between ethnic populations. CONCLUSION: The mutation spectrum reviewed in this study clearly indicated that the frequent mutations in the GJB2 and SLC26A4 genes are consistent with the founder mutation hypothesis. A comparison with the Y-chromosome phylogenetic tree indicated that these mutations may have occurred during human migration.
Asunto(s)
Conexinas/genética , Pérdida Auditiva/etnología , Pérdida Auditiva/genética , Proteínas de Transporte de Membrana/genética , Conexina 26 , Análisis Mutacional de ADN , Humanos , Transportadores de SulfatoRESUMEN
OBJECTIVE: We present a patient who was identified with novel mutations in the LRTOMT gene and describe the clinical features of the phenotype including serial audiological findings. METHODS: One hundred six Japanese patients with mild to moderate sensorineural hearing loss from unrelated and nonconsanguineous families were enrolled in the study. Targeted genomic enrichment and massively parallel sequencing of all known nonsyndromic hearing loss genes were performed to identify the genetic cause of hearing loss. RESULTS: Compound heterozygotes with a novel frame-shift mutation and a missense mutation were identified in the LRTOMT gene. The mutated residues were segregated in both alleles of LRTOMT, present within the LRTOMT2 protein coding region. The patient had moderate sloping hearing loss at high frequencies, which progressed at 1000 Hz and higher frequencies over a period of 6 years. CONCLUSION: Hearing loss caused by mutations in the LRTOMT gene is extremely rare. This is the first case report of a compound heterozygous mutation in a nonconsanguineous family.