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Fehrmann MLA, Lanting CP, Haer-Wigman L, Yntema HG, Mylanus EAM, Huinck WJ, Pennings RJE. Long-Term Outcomes of Cochlear Implantation in Usher Syndrome. Ear Hear 2024; 45:1542-1553. [PMID: 38987893 PMCID: PMC11487040 DOI: 10.1097/aud.0000000000001544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/25/2024] [Indexed: 07/12/2024]
Abstract
OBJECTIVES Usher syndrome (USH), characterized by bilateral sensorineural hearing loss (SNHL) and retinitis pigmentosa (RP), prompts increased reliance on hearing due to progressive visual deterioration. It can be categorized into three subtypes: USH type 1 (USH1), characterized by severe to profound congenital SNHL, childhood-onset RP, and vestibular areflexia; USH type 2 (USH2), presenting with moderate to severe progressive SNHL and RP onset in the second decade, with or without vestibular dysfunction; and USH type 3 (USH3), featuring variable progressive SNHL beginning in childhood, variable RP onset, and diverse vestibular function. Previous studies evaluating cochlear implant (CI) outcomes in individuals with USH used varying or short follow-up durations, while others did not evaluate outcomes for each subtype separately. This study evaluates long-term CI performance in subjects with USH, at both short-term and long-term, considering each subtype separately. DESIGN This retrospective, observational cohort study identified 36 CI recipients (53 ears) who were categorized into four different groups: early-implanted USH1 (first CI at ≤7 years of age), late-implanted USH1 (first CI at ≥8 years of age), USH2 and USH3. Phoneme scores at 65 dB SPL with CI were evaluated at 1 year, ≥2 years (mid-term), and ≥5 years postimplantation (long-term). Each subtype was analyzed separately due to the significant variability in phenotype observed among the three subtypes. RESULTS Early-implanted USH1-subjects (N = 23 ears) achieved excellent long-term phoneme scores (100% [interquartile ranges {IQR} = 95 to 100]), with younger age at implantation significantly correlating with better CI outcomes. Simultaneously implanted subjects had significantly better outcomes than sequentially implanted subjects ( p = 0.028). Late-implanted USH1 subjects (N = 3 ears) used CI solely for sound detection and showed a mean phoneme discrimination score of 12% (IQR = 0 to 12), while still expressing satisfaction with ambient sound detection. In the USH2 group (N = 23 ears), a long-term mean phoneme score of 85% (IQR = 81 to 95) was found. Better outcomes were associated with younger age at implantation and higher preimplantation speech perception scores. USH3-subjects (N = 7 ears) achieved a mean postimplantation phoneme score of 71% (IQR = 45 to 91). CONCLUSIONS This study is currently one of the largest and most comprehensive studies evaluating CI outcomes in individuals with USH, demonstrating that overall, individuals with USH benefit from CI at both short- and long-term follow-up. Due to the considerable variability in phenotype observed among the three subtypes, each subtype was analyzed separately, resulting in smaller sample sizes. For USH1 subjects, optimal CI outcomes are expected with early simultaneous bilateral implantation. Late implantation in USH1 provides signaling function, but achieved speech recognition is insufficient for oral communication. In USH2 and USH3, favorable CI outcomes are expected, especially if individuals exhibit sufficient speech recognition with hearing aids and receive ample auditory stimulation preimplantation. Early implantation is recommended for USH2, given the progressive nature of hearing loss and concomitant severe visual impairment. In comparison with USH2, predicting outcomes in USH3 remains challenging due to the variability found. Counseling for USH2 and USH3 should highlight early implantation benefits and encourage hearing aid use.
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Affiliation(s)
- Mirthe L A Fehrmann
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Cris P Lanting
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Lonneke Haer-Wigman
- Department of Clinical Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Helger G Yntema
- Department of Clinical Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Emmanuel A M Mylanus
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Wendy J Huinck
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Ronald J E Pennings
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
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Wang S, Xu CY, Zhu Y, Ding W, Hu J, Xu B, Guo Y, Liu X. A rare transcript homozygous variants in CLRN1(USH3A) causes Usher syndrome type 3 in a Chinese family. Orphanet J Rare Dis 2024; 19:349. [PMID: 39304915 DOI: 10.1186/s13023-024-03348-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 09/02/2024] [Indexed: 09/22/2024] Open
Abstract
BACKGROUND Usher syndrome type 3 (USH3) is an autosomal recessive inherited disorder caused by pathogenic variants in the CLRN1 gene. OBJECT To evaluate the genotype-phenotype correlation of Usher syndrome type 3 (USH3) in a deaf-blind Chinese family of 3 generations with 2 patients. METHODS We collected blood samples and clinical data from all of the pedigree family members. Genomic DNA was isolated from peripheral leukocytes using standard method. Targeted next generation sequencing and Sanger sequencing were performed to find the pathogenic variants in this family. Digital PCR and plasmid overexpression assay were used to verify the pathogenicity of variant sites in different transcripts. RESULTS All patients developed bilateral sensorineural hearing loss (SHL), progressive vision loss and nyctalopia. NGS of genes for Usher syndrome, deafness and retinal dystrophy identified a locus mutation in CLRN1 that caused completely different amino acid changes in different transcripts[CLRN1:c.474T > A(P.Cys158Ter) at NM_001256819.2 or c.302T > A(p.Val101Asp) at NM_174878.3], and plasmid overexpression experiments confirmed that the c.474T > A(P.Cys158Ter, NM_001256819.2) was a pathogenic variant which has never been associated with Usher syndrome in China, and the transcript of this mutation was not the version commonly found worldwide. CONCLUSIONS The CLRN1c.474T > A(NM_001256819.2) mutation is the causative variant in the Chinese family with USH3. The pathogenicity of different transcripts should be particularly considered in pathogenicity analysis.
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Affiliation(s)
- Suyang Wang
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, No. 82 Cuiyingmen, Lanzhou, Gansu, 730030, PR China
- Department of Otolaryngology-Head and Neck Surgery, Maternal and Child Health Hospital of Gansu Province, Lanzhou, China
| | - Chen Yang Xu
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, No. 82 Cuiyingmen, Lanzhou, Gansu, 730030, PR China
| | - Yiming Zhu
- Department of Otolaryngology-Head and Neck Surgery, Gansu Provincial Hospital, Lanzhou, Gansu Province, China
| | - Wenjuan Ding
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, No. 82 Cuiyingmen, Lanzhou, Gansu, 730030, PR China
| | - Jieyu Hu
- Department of Otolaryngology-Head and Neck Surgery, Maternal and Child Health Hospital of Gansu Province, Lanzhou, China
| | - Baicheng Xu
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, No. 82 Cuiyingmen, Lanzhou, Gansu, 730030, PR China
| | - Yufen Guo
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, No. 82 Cuiyingmen, Lanzhou, Gansu, 730030, PR China.
| | - Xiaowen Liu
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, No. 82 Cuiyingmen, Lanzhou, Gansu, 730030, PR China.
- Department of Otolaryngology-Head and Neck Surgery, Maternal and Child Health Hospital of Gansu Province, Lanzhou, China.
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Serra R, Rallo V, Steri M, Olla S, Piras MG, Marongiu M, Gorospe M, Schlessinger D, Pinna A, Fiorillo E, Cucca F, Angius A. A large-scale screening identified in USH2A gene the P3272L founder pathogenic variant explaining familial Usher syndrome in Sardinia, Italy. BMC Ophthalmol 2024; 24:306. [PMID: 39044131 PMCID: PMC11265335 DOI: 10.1186/s12886-024-03578-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 07/17/2024] [Indexed: 07/25/2024] Open
Abstract
BACKGROUND Usher syndrome (USH) encompasses a group of disorders characterized by congenital sensorineural hearing loss (SNHL) and retinitis pigmentosa (RP). We described the clinical findings, natural history, and molecular analyses of USH patients identified during a large-scale screening to identify quantitative traits related to ocular disorders in the SardiNIA project cohort. METHODS We identified 3 USH-affected families out of a cohort of 6,148 healthy subjects. 9 subjects presented a pathological phenotype, with SNHL and RP. All patients and their family members underwent a complete ophthalmic examination including best-corrected visual acuity, slit-lamp biomicroscopy, fundoscopy, fundus autofluorescence, spectral-domain optical coherence tomography, and electrophysiological testing. Audiological evaluation was performed with a clinical audiometer. Genotyping was performed using several arrays integrated with whole genome sequence data providing approximately 22 million markers equally distributed for each subject analyzed. Molecular diagnostics focused on analysis of the following candidate genes: MYO7A, USH1C, CDH23, PCDH15, USH1G, CIB2, USH2A, GPR98, DFNB31, CLRN1, and PDZD7. RESULTS A single missense causal variant in USH2A gene was identified in homozygous status in all patients and in heterozygous status in unaffected parents. The presence of multiple homozygous patients with the same phenotypic severity of the syndromic form suggests that the Sardinian USH phenotype is the result of a founder effect on a specific pathogenic variant related haplotype. The frequency of heterozygotes in general Sardinian population is 1.89. Additionally, to provide new insights into the structure of usherin and the pathological mechanisms caused by small pathogenic in-frame variants, like p.Pro3272Leu, molecular dynamics simulations of native and mutant protein-protein and protein-ligand complexes were performed that predicted a destabilization of the protein with a decrease in the free energy change. CONCLUSIONS Our results suggest that our approach is effective for the genetic diagnosis of USH. Based on the heterozygous frequency, targeted screening of this variant in the general population and in families at risk or with familial USH can be suggested. This can lead to more accurate molecular diagnosis, better genetic counseling, and improved molecular epidemiology data that are critical for future intervention plans. TRIAL REGISTRATION We did not perform any health-related interventions for the participants.
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Affiliation(s)
- Rita Serra
- Institute of Genetic and Biomedical Research, National Research Council (CNR), Cittadella Universitaria Di Cagliari, C/O S.S 554 Bivio Per Sestu Km 4, 500, 09042, Monserrato, CA, Italy
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Vincenzo Rallo
- Institute of Genetic and Biomedical Research, National Research Council (CNR), Cittadella Universitaria Di Cagliari, C/O S.S 554 Bivio Per Sestu Km 4, 500, 09042, Monserrato, CA, Italy
| | - Maristella Steri
- Institute of Genetic and Biomedical Research, National Research Council (CNR), Cittadella Universitaria Di Cagliari, C/O S.S 554 Bivio Per Sestu Km 4, 500, 09042, Monserrato, CA, Italy
| | - Stefania Olla
- Institute of Genetic and Biomedical Research, National Research Council (CNR), Cittadella Universitaria Di Cagliari, C/O S.S 554 Bivio Per Sestu Km 4, 500, 09042, Monserrato, CA, Italy
| | - Maria Grazia Piras
- Institute of Genetic and Biomedical Research, National Research Council (CNR), Cittadella Universitaria Di Cagliari, C/O S.S 554 Bivio Per Sestu Km 4, 500, 09042, Monserrato, CA, Italy
| | - Michele Marongiu
- Institute of Genetic and Biomedical Research, National Research Council (CNR), Cittadella Universitaria Di Cagliari, C/O S.S 554 Bivio Per Sestu Km 4, 500, 09042, Monserrato, CA, Italy
| | - Myriam Gorospe
- Laboratory of Genetics and Genomics, National Institute On Aging, Baltimore, MD, USA
| | - David Schlessinger
- Laboratory of Genetics and Genomics, National Institute On Aging, Baltimore, MD, USA
| | - Antonio Pinna
- Department of Medicine, Surgery and Pharmacy Ophthalmology Unit, University of Sassari, Sassari, Italy
| | - Edoardo Fiorillo
- Institute of Genetic and Biomedical Research, National Research Council (CNR), Cittadella Universitaria Di Cagliari, C/O S.S 554 Bivio Per Sestu Km 4, 500, 09042, Monserrato, CA, Italy
| | - Francesco Cucca
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Andrea Angius
- Institute of Genetic and Biomedical Research, National Research Council (CNR), Cittadella Universitaria Di Cagliari, C/O S.S 554 Bivio Per Sestu Km 4, 500, 09042, Monserrato, CA, Italy.
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Xing D, Yu R, Wang L, Hu L, Yang Y, Li C, Li Z, Li X. Novel mutations of the USH2A gene cause Usher syndrome in five Chinese families. BMC Ophthalmol 2022; 22:317. [PMID: 35870892 PMCID: PMC9308926 DOI: 10.1186/s12886-022-02532-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 07/11/2022] [Indexed: 11/18/2022] Open
Abstract
Background Usher syndrome (USH) is a leading disorder of deaf–blindness. The phenotypic and genetic heterogeneity of USH makes the diagnosis of this disorder difficult. However, diagnosis can be facilitated by employing molecular approaches, especially for diseases without pronounced pathognomonic symptoms. Therefore, this study aimed to reveal the genetic defects in five USH patients using clinical targeted exome sequencing (TES). Methods USH patients and their family members from five unrelated Chinese USH families were recruited and subjected to TES. Ophthalmic information was obtained for all patients to ensure a meaningful interpretation. The TES data were analysed using an established bioinformatics pipeline to identify causative mutations. Further verification by Sanger sequencing and cosegregation analysis were performed on available family members. Results We identified genetic mutations in five USH patients using TES. Seven mutations, four of which were novel, were identified in the USH2A gene. One proband (F1-II-3) was found to have a homozygous mutation inherited from nonconsanguineous parents, and another proband (F5-III-1) was found to carry three USH2A gene mutations. Conclusion In conclusion, the study revealed the importance of TES in the clinical diagnosis of USH patients with variable phenotypes. The correlation between USH2A gene mutations and clinical phenotypes will help to refine the clinical diagnosis of USH. Supplementary Information The online version contains supplementary material available at 10.1186/s12886-022-02532-6.
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Smirnov VM, Nassisi M, Mohand-Saïd S, Bonnet C, Aubois A, Devisme C, Dib T, Zeitz C, Loundon N, Marlin S, Petit C, Bodaghi B, Sahel JA, Audo I. Retinal Phenotype of Patients with CLRN1-Associated Usher 3A Syndrome in French Light4Deaf Cohort. Invest Ophthalmol Vis Sci 2022; 63:25. [PMID: 35481838 PMCID: PMC9055553 DOI: 10.1167/iovs.63.4.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Purpose Biallelic variants in CLRN1 are responsible for Usher syndrome 3A and non-syndromic rod–cone dystrophy (RCD). Retinal findings in Usher syndrome 3A have not been well defined. We report the detailed phenotypic description of RCD associated with CLRN1 variants in a prospective cohort. Methods Patients were clinically investigated at the National Reference Center for rare ocular diseases at the Quinze-Vingts Hospital, Paris, France. Best-corrected visual acuity (BCVA) tests, Goldmann perimetry, full-field electroretinography (ffERG), retinal photography, near-infrared reflectance, short-wavelength and near-infrared autofluorescence, and optical coherence tomography (OCT) were performed for all patients. Results Four patients from four unrelated families were recruited. Mean follow-up was 11 years for three patients, and only baseline data were available for one subject. Median BCVA at baseline was 0.2 logMAR (range, 0.3–0). ffERG responses were undetectable in all subjects. The III4e isopter of the Goldmann visual field was constricted to 10°. The retinal phenotype was consistent in all patients: small whitish granular atrophic areas were organized in a network pattern around the macula and in the midperiphery. OCT showed intraretinal microcysts in all patients. Upon follow-up, all patients experienced a progressive BCVA loss and further visual field constriction. Four distinct pathogenic variants were identified in our patients: two missense (c.144T>G, p.(Asn48Lys) and c.368C>A, p.(Ala123Asp)) and two frameshift variants (c.176del, p.(Gly59Valfs*13) and c.230dup, p.(Ala78Serfs*52)). Conclusions RCD in Usher 3A syndrome has some distinctive features. It is a severe photoreceptor dystrophy with whitish granular posterior pole appearance and cystic maculopathy.
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Affiliation(s)
- Vasily M Smirnov
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,Université de Lille, Faculté de Médecine, Lille, France
| | - Marco Nassisi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Saddek Mohand-Saïd
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and DHU Sight Restore, INSERM-DGOS CIC1423, Paris, France
| | - Crystel Bonnet
- Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche en Santé 1120, INSERM, Paris, France.,Institut de l'Audition, Paris, France
| | - Anne Aubois
- CHNO des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and DHU Sight Restore, INSERM-DGOS CIC1423, Paris, France
| | - Céline Devisme
- CHNO des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and DHU Sight Restore, INSERM-DGOS CIC1423, Paris, France
| | - Thilissa Dib
- CHNO des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and DHU Sight Restore, INSERM-DGOS CIC1423, Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Natalie Loundon
- Otorhinolaryngologie Pédiatrique, APHP Hôpital Necker, Paris, France.,Centre de référence des Surdités Génétiques, Service de Génétique, APHP Hôpital Necker, Paris, France
| | - Sandrine Marlin
- Centre de référence des Surdités Génétiques, Service de Génétique, APHP Hôpital Necker, Paris, France
| | - Christine Petit
- Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche en Santé 1120, INSERM, Paris, France.,Institut de l'Audition, Paris, France.,Collège de France, Paris, France
| | | | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and DHU Sight Restore, INSERM-DGOS CIC1423, Paris, France.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Department of Ophthalmology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States.,Académie des Sciences-Institut de France, Paris, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and DHU Sight Restore, INSERM-DGOS CIC1423, Paris, France.,Institute of Ophthalmology, University College of London, London, United Kingdom
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Usher syndrome IIIA: a review of the disorder and preclinical research advances in therapeutic approaches. Hum Genet 2022; 141:759-783. [PMID: 35320418 DOI: 10.1007/s00439-022-02446-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/03/2022] [Indexed: 12/27/2022]
Abstract
Usher syndrome (USH) is an autosomal recessive disorder characterized by sensorineural hearing loss, progressive pigmentary retinopathy, and vestibular dysfunction. The degree and onset of hearing loss vary among subtypes I, II, and III, while blindness often occurs in the second to fourth decades of life. Usher type III (USH3), characterized by postlingual progressive sensorineural hearing loss, varying levels of vestibular dysfunction, and varying degrees of visual impairment, typically manifests in the first to second decades of life. While USH3 is rare, it is highly prevalent in certain populations. RP61, USH3, and USH3A symbolize the same disorder, with the latter symbol used more frequently in recent literature. This review focuses on the clinical features, epidemiology, molecular genetics, treatment, and research advances for sensory deficits in USH3A.
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Dinculescu A, Link BA, Saperstein DA. Retinal Gene Therapy for Usher Syndrome: Current Developments, Challenges, and Perspectives. Int Ophthalmol Clin 2021; 61:109-124. [PMID: 34584048 PMCID: PMC8478317 DOI: 10.1097/iio.0000000000000378] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Yoshimura H, Nishio SY, Isaka Y, Kurokawa T, Usami SI. A nationwide epidemiologic, clinical, genetic study of Usher syndrome in Japan. Acta Otolaryngol 2021; 141:841-846. [PMID: 34452594 DOI: 10.1080/00016489.2021.1966500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Usher syndrome (USH) typically leads to deaf-blindness, requiring the provision of extensive education and rehabilitation services. Therefore, investigating the prevalence is crucial to requests for proper government support for USH patients. OBJECTIVE The aim was to perform a nationwide epidemiologic survey of USH in Japan to estimate the prevalence of USH and reveal the relative frequency and characteristics of the three USH subtypes. METHODS To estimate the number of USH patients visiting hospitals over a 1-year period, 1,628 hospitals were randomly selected from all Departments of Otorhinolaryngology and Ophthalmology in Japan. Subsequently, we collected data regarding the clinical characteristics of each patient treated and the results of genetic testing, if performed. RESULTS We found that the prevalence of USH was at least 0.4 per 100,000 population. The frequency of clinical subtypes and causal genes for USH were consistent with previous reports. Also, we demonstrated the feasibility of genetic counseling for USH patients based on the results of genetic testing. CONCLUSION USH is a rare disease, but requires social support due to the severity of symptoms. To minimize these issues, understanding the clinical characteristics and performing comprehensive genetic testing could allow early and accurate diagnosis as well as medical intervention.
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Affiliation(s)
- Hidekane Yoshimura
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Shin-ya Nishio
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yuichi Isaka
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
| | - Toru Kurokawa
- Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Shin-ichi Usami
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
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Davies C, Bergman J, Misztal C, Ramchandran R, Mittal J, Bulut E, Shah V, Mittal R, Eshraghi AA. The Outcomes of Cochlear Implantation in Usher Syndrome: A Systematic Review. J Clin Med 2021; 10:jcm10132915. [PMID: 34209904 PMCID: PMC8267700 DOI: 10.3390/jcm10132915] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 12/14/2022] Open
Abstract
Objective: To systematically appraise the implementation of cochlear implantation (CI) in Usher Syndrome (USH) Types 1, 2, and 3 patients, and analyze who would benefit from CI. Data Sources: A comprehensive search of PubMed, Embase, CINAHL, and Cochrane Library electronic databases from inception through June 2020 was performed. There were no language restrictions. Study Selection: The PRISMA strategy was followed. Included studies discuss USH patients who underwent CI regardless of age, nationality, or clinical subtype. All included studies report post-implantation functional, cognitive, or quality of life outcomes. Only reviews were excluded. Results: Fifteen studies met the inclusion criteria. USH patients experienced improvements in PTA and speech perception and expression outcomes after CI, as well as improvements in phonological memory and quality of life measures. Overall, patients implanted at younger ages outperformed older patients in audiological testing. Similarly, patients with prolonged auditory deprivation had relatively poor performance outcomes in sentence recognition and speech detection following CI. Conclusions: Most USH patients benefit from CI. USH patients who undergo CI at younger ages generally achieve better hearing, speech, and cognitive outcomes. CI at older ages can still prove beneficial if appropriate auditory amplification is started at the right time. Further research is warranted to fill the gap in understanding regarding the gene mutations underlying the pathophysiology of USH that have favorable CI outcomes as well as the optimal time to perform CI.
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Affiliation(s)
- Camron Davies
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (C.D.); (J.B.); (C.M.); (R.R.); (J.M.); (E.B.); (V.S.); (R.M.)
| | - Jenna Bergman
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (C.D.); (J.B.); (C.M.); (R.R.); (J.M.); (E.B.); (V.S.); (R.M.)
| | - Carly Misztal
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (C.D.); (J.B.); (C.M.); (R.R.); (J.M.); (E.B.); (V.S.); (R.M.)
| | - Renuka Ramchandran
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (C.D.); (J.B.); (C.M.); (R.R.); (J.M.); (E.B.); (V.S.); (R.M.)
| | - Jeenu Mittal
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (C.D.); (J.B.); (C.M.); (R.R.); (J.M.); (E.B.); (V.S.); (R.M.)
| | - Erdogan Bulut
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (C.D.); (J.B.); (C.M.); (R.R.); (J.M.); (E.B.); (V.S.); (R.M.)
| | - Viraj Shah
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (C.D.); (J.B.); (C.M.); (R.R.); (J.M.); (E.B.); (V.S.); (R.M.)
| | - Rahul Mittal
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (C.D.); (J.B.); (C.M.); (R.R.); (J.M.); (E.B.); (V.S.); (R.M.)
| | - Adrien A. Eshraghi
- Cochlear Implant and Hearing Research Laboratory, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (C.D.); (J.B.); (C.M.); (R.R.); (J.M.); (E.B.); (V.S.); (R.M.)
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL 33146, USA
- Department of Pediatrics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Correspondence:
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10
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de Joya EM, Colbert BM, Tang PC, Lam BL, Yang J, Blanton SH, Dykxhoorn DM, Liu X. Usher Syndrome in the Inner Ear: Etiologies and Advances in Gene Therapy. Int J Mol Sci 2021; 22:3910. [PMID: 33920085 PMCID: PMC8068832 DOI: 10.3390/ijms22083910] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 02/06/2023] Open
Abstract
Hearing loss is the most common sensory disorder with ~466 million people worldwide affected, representing about 5% of the population. A substantial portion of hearing loss is genetic. Hearing loss can either be non-syndromic, if hearing loss is the only clinical manifestation, or syndromic, if the hearing loss is accompanied by a collage of other clinical manifestations. Usher syndrome is a syndromic form of genetic hearing loss that is accompanied by impaired vision associated with retinitis pigmentosa and, in many cases, vestibular dysfunction. It is the most common cause of deaf-blindness. Currently cochlear implantation or hearing aids are the only treatments for Usher-related hearing loss. However, gene therapy has shown promise in treating Usher-related retinitis pigmentosa. Here we review how the etiologies of Usher-related hearing loss make it a good candidate for gene therapy and discuss how various forms of gene therapy could be applied to Usher-related hearing loss.
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Affiliation(s)
- Evan M. de Joya
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Brett M. Colbert
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
- Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Pei-Ciao Tang
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
| | - Byron L. Lam
- Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, FL 33136, USA;
| | - Jun Yang
- John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT 84132, USA;
| | - Susan H. Blanton
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Derek M. Dykxhoorn
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Xuezhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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11
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Whatley M, Francis A, Ng ZY, Khoh XE, Atlas MD, Dilley RJ, Wong EYM. Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy. Front Genet 2020; 11:565216. [PMID: 33193648 PMCID: PMC7642844 DOI: 10.3389/fgene.2020.565216] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive (AR) disorder that permanently and severely affects the senses of hearing, vision, and balance. Three clinically distinct types of USH have been identified, decreasing in severity from Type 1 to 3, with symptoms of sensorineural hearing loss (SNHL), retinitis pigmentosa (RP), and vestibular dysfunction. There are currently nine confirmed and two suspected USH-causative genes, and a further three candidate loci have been mapped. The proteins encoded by these genes form complexes that play critical roles in the development and maintenance of cellular structures within the inner ear and retina, which have minimal capacity for repair or regeneration. In the cochlea, stereocilia are located on the apical surface of inner ear hair cells (HC) and are responsible for transducing mechanical stimuli from sound pressure waves into chemical signals. These signals are then detected by the auditory nerve fibers, transmitted to the brain and interpreted as sound. Disease-causing mutations in USH genes can destabilize the tip links that bind the stereocilia to each other, and cause defects in protein trafficking and stereocilia bundle morphology, thereby inhibiting mechanosensory transduction. This review summarizes the current knowledge on Usher syndrome with a particular emphasis on mutations in USH genes, USH protein structures, and functional analyses in animal models. Currently, there is no cure for USH. However, the genetic therapies that are rapidly developing will benefit from this compilation of detailed genetic information to identify the most effective strategies for restoring functional USH proteins.
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Affiliation(s)
- Meg Whatley
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Abbie Francis
- Ear Science Institute Australia, Nedlands, WA, Australia
- Emergency Medicine, The University of Western Australia, Nedlands, WA, Australia
| | - Zi Ying Ng
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Xin Ee Khoh
- Ear Science Institute Australia, Nedlands, WA, Australia
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Marcus D. Atlas
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
| | - Rodney J. Dilley
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- Centre for Cell Therapy and Regenerative Medicine, The University of Western Australia, Perth, WA, Australia
| | - Elaine Y. M. Wong
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
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12
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Toms M, Pagarkar W, Moosajee M. Usher syndrome: clinical features, molecular genetics and advancing therapeutics. Ther Adv Ophthalmol 2020; 12:2515841420952194. [PMID: 32995707 PMCID: PMC7502997 DOI: 10.1177/2515841420952194] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/27/2020] [Indexed: 01/12/2023] Open
Abstract
Usher syndrome has three subtypes, each being clinically and genetically heterogeneous characterised by sensorineural hearing loss and retinitis pigmentosa (RP), with or without vestibular dysfunction. It is the most common cause of deaf–blindness worldwide with a prevalence of between 4 and 17 in 100 000. To date, 10 causative genes have been identified for Usher syndrome, with MYO7A accounting for >50% of type 1 and USH2A contributing to approximately 80% of type 2 Usher syndrome. Variants in these genes can also cause non-syndromic RP and deafness. Genotype–phenotype correlations have been described for several of the Usher genes. Hearing loss is managed with hearing aids and cochlear implants, which has made a significant improvement in quality of life for patients. While there is currently no available approved treatment for the RP, various therapeutic strategies are in development or in clinical trials for Usher syndrome, including gene replacement, gene editing, antisense oligonucleotides and small molecule drugs.
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Affiliation(s)
- Maria Toms
- UCL Institute of Ophthalmology, London, UK; The Francis Crick Institute, London, UK
| | - Waheeda Pagarkar
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK; University College London Hospitals NHS Foundation Trust, London, UK
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
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13
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Nolen RM, Hufnagel RB, Friedman TB, Turriff AE, Brewer CC, Zalewski CK, King KA, Wafa TT, Griffith AJ, Brooks BP, Zein WM. Atypical and ultra-rare Usher syndrome: a review. Ophthalmic Genet 2020; 41:401-412. [PMID: 32372680 DOI: 10.1080/13816810.2020.1747090] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Usher syndrome has classically been described as a combination of hearing loss and rod-cone dystrophy; vestibular dysfunction is present in many patients. Three distinct clinical subtypes were documented in the late 1970s. Genotyping efforts have led to the identification of several genes associated with the disease. Recent literature has seen multiple publications referring to "atypical" Usher syndrome presentations. This manuscript reviews the molecular etiology of Usher syndrome, highlighting rare presentations and molecular causes. Reports of "atypical" disease are summarized noting the wide discrepancy in the spectrum of phenotypic deviations from the classical presentation. Guidelines for establishing a clear nomenclature system are suggested.
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Affiliation(s)
- Rosalie M Nolen
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Amy E Turriff
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
| | - Carmen C Brewer
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Christopher K Zalewski
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Kelly A King
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Talah T Wafa
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Andrew J Griffith
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
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14
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Hagag AM, Mitsios A, Gill JS, Nunez Do Rio JM, Theofylaktopoulos V, Houston S, Webster AR, Dubis AM, Moosajee M. Characterisation of microvascular abnormalities using OCT angiography in patients with biallelic variants in USH2A and MYO7A. Br J Ophthalmol 2019; 104:480-486. [PMID: 31266775 DOI: 10.1136/bjophthalmol-2019-314243] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/21/2019] [Accepted: 06/10/2019] [Indexed: 01/26/2023]
Abstract
AIMS Using optical coherence tomography angiography (OCTA) to characterise microvascular changes in the retinal plexuses and choriocapillaris (CC) of patients with MYO7A and USH2A mutations and correlate with genotype, retinal structure and function. METHODS Twenty-seven patients with molecularly confirmed USH2A (n=21) and MYO7A (n=6) mutations underwent macular 6×6 mm OCTA using the AngioVue. Heidelberg spectral-domain OCT scans and MAIA microperimetry were also performed, the preserved ellipsoid zone (EZ) band width and mean macular sensitivity (MS) were recorded. OCTA of the inner retina, superficial capillary plexus (SCP), deep capillary plexus (DCP) and CC were analysed. Vessel density (VD) was calculated from the en face OCT angiograms of retinal circulation. RESULTS Forty-eight eyes with either USH2A (n=37, mean age: 34.4±12.2 years) or MYO7A (n=11, mean age: 37.1±12.4 years), and 35 eyes from 18 age-matched healthy participants were included. VD was significantly decreased in the retinal circulation of patients with USH2A and MYO7A mutations compared with controls (p<0.001). Changes were observed in both the SCP and DCP, but no differences in retinal perfusion were detected between USH2A and MYO7A groups. No vascular defects were detected in CC of the USH2A group, but peripheral defects were detected in older MYO7A patients from the fourth decade of life. VD in the DCP showed strong association with MS and EZ width (Spearman's rho =0.64 and 0.59, respectively, p<0.001). CONCLUSION OCTA was able to detect similar retinal microvascular changes in patients with USH2A and MYO7A mutations. The CC was generally affected in MYO7A mutations. OCT angiography may further enhance our understanding of inherited eye diseases and their phenotype-genotype associations.
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Affiliation(s)
- Ahmed M Hagag
- NIHR Clinical Research Facility, Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Institute of Ophthalmology, University College London, London, UK
| | - Andreas Mitsios
- NIHR Clinical Research Facility, Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Institute of Ophthalmology, University College London, London, UK
| | - Jasdeep S Gill
- Institute of Ophthalmology, University College London, London, UK
| | | | | | - Sarah Houston
- Institute of Ophthalmology, University College London, London, UK
| | - Andrew R Webster
- Institute of Ophthalmology, University College London, London, UK.,Genetics Service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Adam M Dubis
- NIHR Clinical Research Facility, Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Institute of Ophthalmology, University College London, London, UK
| | - Mariya Moosajee
- Institute of Ophthalmology, University College London, London, UK .,Genetics Service, Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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15
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Ng TK, Tang W, Cao Y, Chen S, Zheng Y, Xiao X, Chen H. Whole exome sequencing identifies novel USH2A mutations and confirms Usher syndrome 2 diagnosis in Chinese retinitis pigmentosa patients. Sci Rep 2019; 9:5628. [PMID: 30948794 PMCID: PMC6449333 DOI: 10.1038/s41598-019-42105-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 03/11/2019] [Indexed: 02/05/2023] Open
Abstract
Retinitis pigmentosa (RP) is a common phenotype in multiple inherited retinal dystrophies (IRD). Disease gene identification can assist the clinical diagnosis of IRD patients for better clinical management, treatment and counseling. In this study, we aimed to delineate and characterize the disease-causing mutations in Chinese familial and sporadic patients with initial diagnosis of RP. Four unrelated Chinese families and 118 sporadic RP patients were recruited for whole exome sequencing analysis. A total of 5 reported and 3 novel USH2A mutations were identified in four Chinese probands. The probands and their family members showed typical RP features and mild to severe hearing impairment, confirming the diagnosis of Usher syndrome 2 (USH). Moreover, 11 sporadic RP patients were identified to carry the compound heterozygous mutations in the USH2A gene, confirming the diagnosis of USH2. The patients carried the truncating mutations had a younger age of first visit than the patients carried only the missense mutations (p = 0.017). In summary, this study revealed 8 novel USH2A variants in Chinese familial and sporadic RP patients, assuring that whole exome sequencing analysis is an adequate strategy to facilitate the clinical diagnosis of USH from the sporadic RP patients.
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Affiliation(s)
- Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
- Shantou University Medical College, Shantou, Guangdong, China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong
| | - Wenyu Tang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Yingjie Cao
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Shaowan Chen
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Yuqian Zheng
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Xiaoqiang Xiao
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Haoyu Chen
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong, China.
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16
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Geng R, Omar A, Gopal SR, Chen DHC, Stepanyan R, Basch ML, Dinculescu A, Furness DN, Saperstein D, Hauswirth W, Lustig LR, Alagramam KN. Modeling and Preventing Progressive Hearing Loss in Usher Syndrome III. Sci Rep 2017; 7:13480. [PMID: 29044151 PMCID: PMC5647385 DOI: 10.1038/s41598-017-13620-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 09/29/2017] [Indexed: 02/07/2023] Open
Abstract
Usher syndrome type III (USH3) characterized by progressive loss of vision and hearing is caused by mutations in the clarin-1 gene (CLRN1). Clrn1 knockout (KO) mice develop hair cell defects by postnatal day 2 (P2) and are deaf by P21-P25. Early onset profound hearing loss in KO mice and lack of information about the cochlear cell type that requires Clrn1 expression pose challenges to therapeutic investigation. We generated KO mice harboring a transgene, TgAC1, consisting of Clrn1-UTR (Clrn1 cDNA including its 5' and 3' UTR) under the control of regulatory elements (Atoh1 3' enhancer/β-globin basal promoter) to direct expression of Clrn1 in hair cells during development and down regulate it postnatally. The KO-TgAC1 mice displayed delayed onset progressive hearing loss associated with deterioration of the hair bundle structure, leading to the hypothesis that hair cell expression of Clrn1 is essential for postnatal preservation of hair cell structure and hearing. Consistent with that hypothesis, perinatal transfection of hair cells in KO-TgAC1 mice with a single injection of AAV-Clrn1-UTR vector showed correlative preservation of the hair bundle structure and hearing through adult life. Further, the efficacy of AAV-Clrn1 vector was significantly attenuated, revealing the potential importance of UTR in gene therapy.
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Affiliation(s)
- Ruishuang Geng
- Department of Otolaryngology-Head and Neck Surgery, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, 44016, USA
| | - Akil Omar
- Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Suhasini R Gopal
- Department of Otolaryngology-Head and Neck Surgery, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, 44016, USA
| | - Daniel H-C Chen
- Department of Otolaryngology-Head and Neck Surgery, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, 44016, USA
| | - Ruben Stepanyan
- Department of Otolaryngology-Head and Neck Surgery, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, 44016, USA
| | - Martin L Basch
- Department of Otolaryngology-Head and Neck Surgery, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, 44016, USA
| | - Astra Dinculescu
- Department of Ophthalmology, University of Florida, Gainesville, FL, 32610, USA
| | - David N Furness
- School of Life Sciences, Keele University, Keele, Staffordshire, ST5 5BG, UK
| | | | - William Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, FL, 32610, USA
| | - Lawrence R Lustig
- Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, San Francisco, CA, 94143, USA.
- Department of Otolaryngology-Head and Neck Surgery, Columbia University, New York, NY, 10032, USA.
| | - Kumar N Alagramam
- Department of Otolaryngology-Head and Neck Surgery, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, 44016, USA.
- Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, 44016, USA.
- Neurosciences, Case Western Reserve University, Cleveland, Ohio, 44016, USA.
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17
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Alagramam KN, Gopal SR, Geng R, Chen DHC, Nemet I, Lee R, Tian G, Miyagi M, Malagu KF, Lock CJ, Esmieu WRK, Owens AP, Lindsay NA, Ouwehand K, Albertus F, Fischer DF, Bürli RW, MacLeod AM, Harte WE, Palczewski K, Imanishi Y. A small molecule mitigates hearing loss in a mouse model of Usher syndrome III. Nat Chem Biol 2016; 12:444-51. [PMID: 27110679 PMCID: PMC4871731 DOI: 10.1038/nchembio.2069] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 03/08/2016] [Indexed: 12/30/2022]
Abstract
Usher syndrome type III (USH3), characterized by progressive deafness, variable balance disorder and blindness, is caused by destabilizing mutations in the gene encoding the clarin-1 (CLRN1) protein. Here we report a new strategy to mitigate hearing loss associated with a common USH3 mutation CLRN1(N48K) that involves cell-based high-throughput screening of small molecules capable of stabilizing CLRN1(N48K), followed by a secondary screening to eliminate general proteasome inhibitors, and finally an iterative process to optimize structure-activity relationships. This resulted in the identification of BioFocus 844 (BF844). To test the efficacy of BF844, we developed a mouse model that mimicked the progressive hearing loss associated with USH3. BF844 effectively attenuated progressive hearing loss and prevented deafness in this model. Because the CLRN1(N48K) mutation causes both hearing and vision loss, BF844 could in principle prevent both sensory deficiencies in patients with USH3. Moreover, the strategy described here could help identify drugs for other protein-destabilizing monogenic disorders.
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Affiliation(s)
- Kumar N Alagramam
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA.,Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, USA.,Neurosciences, Case Western Reserve University, Cleveland, Ohio, USA
| | - Suhasini R Gopal
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ruishuang Geng
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Daniel H-C Chen
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ina Nemet
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Richard Lee
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Guilian Tian
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Masaru Miyagi
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Karine F Malagu
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - Christopher J Lock
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - William R K Esmieu
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - Andrew P Owens
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - Nicola A Lindsay
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | | | | | | | - Roland W Bürli
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - Angus M MacLeod
- BioFocus, a Charles River company, Chesterford Research Park, Saffron Walden, UK
| | - William E Harte
- Office of Translation and Innovation, Case Western Reserve University, Cleveland, Ohio, USA
| | - Krzysztof Palczewski
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yoshikazu Imanishi
- Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, USA
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18
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Zebrafish Models for the Mechanosensory Hair Cell Dysfunction in Usher Syndrome 3 Reveal That Clarin-1 Is an Essential Hair Bundle Protein. J Neurosci 2015; 35:10188-201. [PMID: 26180195 DOI: 10.1523/jneurosci.1096-15.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Usher syndrome type III (USH3) is characterized by progressive loss of hearing and vision, and varying degrees of vestibular dysfunction. It is caused by mutations that affect the human clarin-1 protein (hCLRN1), a member of the tetraspanin protein family. The missense mutation CLRN1(N48K), which affects a conserved N-glycosylation site in hCLRN1, is a common causative USH3 mutation among Ashkenazi Jews. The affected individuals hear at birth but lose that function over time. Here, we developed an animal model system using zebrafish transgenesis and gene targeting to provide an explanation for this phenotype. Immunolabeling demonstrated that Clrn1 localized to the hair cell bundles (hair bundles). The clrn1 mutants generated by zinc finger nucleases displayed aberrant hair bundle morphology with diminished function. Two transgenic zebrafish that express either hCLRN1 or hCLRN1(N48K) in hair cells were produced to examine the subcellular localization patterns of wild-type and mutant human proteins. hCLRN1 localized to the hair bundles similarly to zebrafish Clrn1; in contrast, hCLRN1(N48K) largely mislocalized to the cell body with a small amount reaching the hair bundle. We propose that this small amount of hCLRN1(N48K) in the hair bundle provides clarin-1-mediated function during the early stages of life; however, the presence of hCLRN1(N48K) in the hair bundle diminishes over time because of intracellular degradation of the mutant protein, leading to progressive loss of hair bundle integrity and hair cell function. These findings and genetic tools provide an understanding and path forward to identify therapies to mitigate hearing loss linked to the CLRN1 mutation. SIGNIFICANCE STATEMENT Mutations in the clarin-1 gene affect eye and ear function in humans. Individuals with the CLRN1(N48K) mutation are born able to hear but lose that function over time. Here, we develop an animal model system using zebrafish transgenesis and gene targeting to provide an explanation for this phenotype. This approach illuminates the role of clarin-1 and the molecular mechanism linked to the CLRN1(N48K) mutation in sensory hair cells of the inner ear. Additionally, the investigation provided an in vivo model to guide future drug discovery to rescue the hCLRN1(N48K) in hair cells.
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Toms M, Bitner-Glindzicz M, Webster A, Moosajee M. Usher syndrome: a review of the clinical phenotype, genes and therapeutic strategies. EXPERT REVIEW OF OPHTHALMOLOGY 2015. [DOI: 10.1586/17469899.2015.1033403] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Yoshimura H, Oshikawa C, Nakayama J, Moteki H, Usami SI. Identification of a novel CLRN1 gene mutation in Usher syndrome type 3: two case reports. Ann Otol Rhinol Laryngol 2015; 124 Suppl 1:94S-9S. [PMID: 25743179 DOI: 10.1177/0003489415574069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE This study examines the CLRN1 gene mutation analysis in Japanese patients who were diagnosed with Usher syndrome type 3 (USH3) on the basis of clinical findings. METHODS Genetic analysis using massively parallel DNA sequencing (MPS) was conducted to search for 9 causative USH genes in 2 USH3 patients. RESULTS We identified the novel pathogenic mutation in the CLRN1 gene in 2 patients. The missense mutation was confirmed by functional prediction software and segregation analysis. Both patients were diagnosed as having USH3 caused by the CLRN1 gene mutation. CONCLUSION This is the first report of USH3 with a CLRN1 gene mutation in Asian populations. Validating the presence of clinical findings is imperative for properly differentiating among USH subtypes. In addition, mutation screening using MPS enables the identification of causative mutations in USH. The clinical diagnosis of this phenotypically variable disease can then be confirmed.
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Affiliation(s)
- Hidekane Yoshimura
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Chie Oshikawa
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Jun Nakayama
- Department of Otorhinolaryngology, Shiga University School of Medical Science, Otsu, Japan
| | - Hideaki Moteki
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Science, Shinshu University School of Medicine, Matsumoto, Japan
| | - Shin-Ichi Usami
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Science, Shinshu University School of Medicine, Matsumoto, Japan
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Salvatore S, Fishman GA, Genead MA. Treatment of cystic macular lesions in hereditary retinal dystrophies. Surv Ophthalmol 2013; 58:560-84. [DOI: 10.1016/j.survophthal.2012.11.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 11/14/2012] [Accepted: 11/20/2012] [Indexed: 12/25/2022]
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Västinsalo H, Jalkanen R, Bergmann C, Neuhaus C, Kleemola L, Jauhola L, Bolz HJ, Sankila EM. Extended mutation spectrum of Usher syndrome in Finland. Acta Ophthalmol 2013; 91:325-34. [PMID: 22681893 DOI: 10.1111/j.1755-3768.2012.02397.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
PURPOSE The Finnish distribution of clinical Usher syndrome (USH) types is 40% USH3, 34% USH1 and 12% USH2. All patients with USH3 carry the founder mutation in clarin 1 (CLRN1), whereas we recently reported three novel myosin VIIA (MYO7A) mutations in two unrelated patients with USH1. This study was carried out to further investigate the USH mutation spectrum in Finnish patients. METHODS We analysed samples from nine unrelated USH patients/families without known mutations and two USH3 families with atypically severe phenotype. The Asper Ophthalmics USH mutation chip was used to screen for known mutations and to evaluate the chip in molecular diagnostics of Finnish patients. RESULTS The chip revealed a heterozygous usherin (USH2A) mutation, p.N346H, in one patient. Sequencing of MYO7A and/or USH2A in three index patients revealed two novel heterozygous mutations, p.R873W in MYO7A and c.14343+2T>C in USH2A. We did not identify definite pathogenic second mutations in the patients, but identified several probably nonpathogenic variations that may modify the disease phenotype. Possible digenism could not be excluded in two families segregating genomic variations in both MYO7A and USH2A, and two families with CLRN1 and USH2A. CONCLUSION We conclude that there is considerable genetic heterogeneity of USH1 and USH2 in Finland, making molecular diagnostics and genetic counselling of patients and families challenging.
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Affiliation(s)
- Hanna Västinsalo
- The Folkhälsan Institute of Genetics, Biomedicum Helsinki, Helsinki, Finland.
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Ratnam K, Västinsalo H, Roorda A, Sankila EMK, Duncan JL. Cone structure in patients with usher syndrome type III and mutations in the Clarin 1 gene. JAMA Ophthalmol 2013; 131:67-74. [PMID: 22964989 DOI: 10.1001/2013.jamaophthalmol.2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To study macular structure and function in patients with Usher syndrome type III (USH3) caused by mutations in the Clarin 1 gene (CLRN1). METHODS High-resolution macular images were obtained by adaptive optics scanning laser ophthalmoscopy and spectral domain optical coherence tomography in 3 patients with USH3 and were compared with those of age-similar control subjects. Vision function measures included best-corrected visual acuity, kinetic and static perimetry, and full-field electroretinography. Coding regions of the CLRN1 gene were sequenced. RESULTS CLRN1 mutations were present in all the patients; a 20-year-old man showed compound heterozygous mutations (p.N48K and p.S188X), and 2 unrelated women aged 25 and 32 years had homozygous mutations (p.N48K). Best-corrected visual acuity ranged from 20/16 to 20/40, with scotomas beginning at 3° eccentricity. The inner segment-outer segment junction or the inner segment ellipsoid band was disrupted within 1° to 4° of the fovea, and the foveal inner and outer segment layers were significantly thinner than normal. Cones near the fovea in patients 1 and 2 showed normal spacing, and the preserved region ended abruptly. Retinal pigment epithelial cells were visible in patient 3 where cones were lost. CONCLUSIONS Cones were observed centrally but not in regions with scotomas, and retinal pigment epithelial cells were visible in regions without cones in patients with CLRN1 mutations. High-resolution measures of retinal structure demonstrate patterns of cone loss associated with CLRN1 mutations. CLINICAL RELEVANCE These findings provide insight into the effect of CLRN1 mutations on macular cone structure, which has implications for the development of treatments for USH3. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00254605.
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Affiliation(s)
- Kavitha Ratnam
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143-0730, USA
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Akoury E, El Zir E, Mansour A, Mégarbané A, Majewski J, Slim R. A novel 5-bp deletion in Clarin 1 in a family with Usher syndrome. Ophthalmic Genet 2011; 32:245-9. [PMID: 21675857 DOI: 10.3109/13816810.2011.587083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND To identify the genetic defect in a Lebanese family with two sibs diagnosed with Usher Syndrome. MATERIALS AND METHODS Exome capture and sequencing were performed on DNA from one affected member using Agilent in solution bead capture, followed by Illumina sequencing. RESULTS This analysis revealed the presence of a novel homozygous 5-bp deletion, in Clarin 1 (CLRN1), a known gene responsible for Usher syndrome type III. The deletion is inherited from both parents and segregates with the disease phenotype in the family. The 5-bp deletion, c.301_305delGTCAT, p.Val101SerfsX27, is predicted to result in a frameshift and protein truncation after 27 amino acids. Sequencing all the coding regions of the CLRN1 gene in the proband did not reveal any other mutation or variant. CONCLUSION Here we describe a novel deletion in CLRN1. Our data support previously reported intra familial variability in the clinical features of Usher syndrome type I and III.
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Affiliation(s)
- Elie Akoury
- Department of Human Genetics, McGill University Health Centre, Montreal, Canada
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Abstract
PURPOSE To report a case of pigmentary glaucoma (PG) accompanied by Usher syndrome. DESIGN Case report. METHODS The results were presented after standard ocular examination, visual field test, anterior segment and fundus photography, electroretinography, and otolaryngology consultation were conducted. RESULTS Typical retinitis pigmentosa, flat electroretinography, congenital sensorineural hearing loss, high intraocular pressure, Krukenberg spindle, iris concavity, radial iris transillumination defect, severe pigment deposition on the trabecular meshwork, and glaucomatous optic nerve damage were indicative of PG accompanied by Usher syndrome. CONCLUSIONS In some rare cases, PG may coexist with Usher syndrome. Common findings of Usher syndrome, including night blindness, impaired vision, visual field defects, and retinal changes may distract the clinician from considering the diagnosis of glaucoma. Such association should be borne in mind to make a timely diagnosis and treatment possible.
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McGee TL, Seyedahmadi BJ, Sweeney MO, Dryja TP, Berson EL. Novel mutations in the long isoform of the USH2A gene in patients with Usher syndrome type II or non-syndromic retinitis pigmentosa. J Med Genet 2010; 47:499-506. [PMID: 20507924 DOI: 10.1136/jmg.2009.075143] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Usher syndrome type II (USH2) is an autosomal recessive disorder characterised by retinitis pigmentosa (RP) and mild to moderate sensorineural hearing loss. Mutations in the USH2A gene are the most common cause of USH2 and are also a cause of some forms of RP without hearing loss (ie, non-syndromic RP). The USH2A gene was initially identified as a transcript comprised of 21 exons but subsequently a longer isoform containing 72 exons was identified. METHODS The 51 exons unique to the long isoform of USH2A were screened for mutations among a core set of 108 patients diagnosed with USH2 and 80 patients with non-syndromic RP who were all included in a previously reported screen of the short isoform of USH2A. For several exons, additional patients were screened. RESULTS In total, 35 deleterious mutations were identified including 17 nonsense mutations, 9 frameshift mutations, 5 splice-site mutations, and 4 small in-frame deletions or insertions. Twenty-seven mutations were novel. In addition, 65 rare missense changes were identified. A method of classifying the deleterious effect of the missense changes was developed using the summed results of four different mutation assessment algorithms, SIFT, pMUT, PolyPhen, and AGVGD. This system classified 8 of the 65 changes as 'likely deleterious' and 9 as 'possibly deleterious'. CONCLUSION At least one mutation was identified in 57-63% of USH2 cases and 19-23% of cases of non-syndromic recessive RP (calculated without and including probable/possible deleterious changes) thus supporting that USH2A is the most common known cause of RP in the USA.
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Affiliation(s)
- Terri L McGee
- Ocular Molecular Genetics Institute, Harvard Medical School, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA
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Abstract
Usher syndrome (USH) comprises a group of autosomal recessively inherited disorders characterized by a dual sensory impairment of the audiovestibular and visual systems. Three major clinical subtypes (USH type I, USH type II and USH type III) are distinguished on the basis of the severity of the hearing loss, the presence or absence of vestibular dysfunction and the age of onset of retinitis pigmentosa (RP). Since the cloning of the first USH gene (MYO7A) in 1995, there have been remarkable advances in elucidating the genetic basis for this disorder, as evidence for 11 distinct loci have been obtained and genes for 9 of them have been identified. The USH genes encode proteins of different classes and families, including motor proteins, scaffold proteins, cell adhesion molecules and transmembrane receptor proteins. Extensive information has emerged from mouse models and molecular studies regarding pathogenesis of this disorder and the wide phenotypic variation in both audiovestibular and/or visual function. A unifying hypothesis is that the USH proteins are integrated into a protein network that regulates hair bundle morphogenesis in the inner ear. This review addresses genetics and pathological mechanisms of USH. Understanding the molecular basis of phenotypic variation and pathogenesis of USH is important toward discovery of new molecular targets for diagnosis, prevention and treatment of this debilitating disorder.
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Affiliation(s)
- Denise Yan
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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Mutation analysis in the long isoform of USH2A in American patients with Usher Syndrome type II. J Hum Genet 2009; 54:732-8. [PMID: 19881469 DOI: 10.1038/jhg.2009.107] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Usher syndrome type II (USH2) is an autosomal recessive disorder characterized by moderate to severe hearing impairment and progressive visual loss due to retinitis pigmentosa (RP). To identify novel mutations and determine the frequency of USH2A mutations as a cause of USH2, we have carried out mutation screening of all 72 coding exons and exon-intron splice sites of the USH2A gene. A total of 20 USH2 American probands of European descent were analyzed using single strand conformational polymorphism (SSCP) and direct sequencing methods. Ten different USH2A mutations were identified in 55% of the probands, five of which were novel mutations. The detected mutations include three missense, three frameshifts and four nonsense mutations, with c.2299delG/p.E767fs mutation, accounting for 38.9% of the pathological alleles. Two cases were homozygotes, two cases were compound heterozygotes and one case had complex allele with three variants. In seven probands, only one USH2A mutation was detected and no pathological mutation was found in the remaining eight individuals. Altogether, our data support the fact that c.2299delG/p.E767fs is indeed the most common USH2A mutation found in USH2 patients of European Caucasian background. Thus, if screening for mutations in USH2A is considered, it is reasonable to screen for the c.2299delG mutation first.
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Pakarinen L, Sankila EM, Tuppurainen K, Karjalainen S, Helena K. Usher syndrome type III (USH3): The clinical manifestations in 42 patients. ACTA ACUST UNITED AC 2009. [DOI: 10.3109/14015439509098741] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
PURPOSE OF REVIEW The present review addresses the mechanisms, genetics and pathogenesis of Usher syndrome. RECENT FINDINGS Recent molecular findings have provided more information regarding the pathogenesis of this disorder and the wide phenotypic variation in both audiovestibular and/or visual systems. Evidence has begun to emerge supporting a theory of a protein interactome involving the Usher proteins in both the inner ear and the retina. This interactome appears to be important for hair cell development in the ear but its role in the retina remains unclear. SUMMARY Understanding clinical disease progression and molecular pathways is important in the progress towards developing gene therapy to prevent blindness due to Usher syndrome as well as delivering prognostic information to affected individuals.
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Identification of two new mutations in the GPR98 and the PDE6B genes segregating in a Tunisian family. Eur J Hum Genet 2008; 17:474-82. [PMID: 18854872 DOI: 10.1038/ejhg.2008.167] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Autosomal recessive retinitis pigmentosa (ARRP) is a genetically heterogeneous disorder. ARRP could be associated with extraocular manifestations that define specific syndromes such as Usher syndrome (USH) characterized by retinal degeneration and congenital hearing loss (HL). The USH type II (USH2) associates RP and mild-to-moderate HL with preserved vestibular function. At least three genes USH2A, the very large G-protein-coupled receptor, GPR98, and DFNB31 are responsible for USH2 syndrome. Here, we report on the segregation of non-syndromic ARRP and USH2 syndrome in a consanguineous Tunisian family, which was previously used to define USH2B locus. With regard to the co-occurrence of these two different pathologies, clinical and genetic reanalysis of the extended family showed (i) phenotypic heterogeneity within USH2 patients and (ii) excluded linkage to USH2B locus. Indeed, linkage analysis disclosed the cosegregation of the USH2 phenotype with the USH2C locus markers, D5S428 and D5S618, whereas the ARRP perfectly segregates with PDE6B flanking markers D4S3360 and D4S2930. Molecular analysis revealed two new missense mutations, p.Y6044C and p.W807R, occurring in GPR98 and PDE6B genes, respectively. In conclusion, our results show that the USH2B locus at chromosome 3p23-24.2 does not exist, and we therefore withdraw this locus designation. The combination of molecular findings for GPR98 and PDE6B genes enable us to explain the phenotypic heterogeneity and particularly the severe ocular affection first observed in one USH2 patient. This report presents an illustration of how consanguinity could increase familial clustering of multiple hereditary diseases within the same family.
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Abstract
Hearing impairment is a frequent condition in humans. Identification of the causative genes for the early onset forms of isolated deafness began 15 years ago and has been very fruitful. To date, approximately 50 causative genes have been identified. Yet, limited information regarding the underlying pathogenic mechanisms can be derived from hearing tests in deaf patients. This chapter describes the success of mouse models in the elucidation of some pathophysiological processes in the auditory sensory organ, the cochlea. These models have revealed a variety of defective structures and functions at the origin of deafness genetic forms. This is illustrated by three different examples: (1) the DFNB9 deafness form, a synaptopathy of the cochlear sensory cells where otoferlin is defective; (2) the Usher syndrome, in which deafness is related to abnormal development of the hair bundle, the mechanoreceptive structure of the sensory cells to sound; (3) the DFNB1 deafness form, which is the most common form of inherited deafness in Caucasian populations, mainly caused by connexin-26 defects that alter gap junction communication between nonsensory cochlear cells.
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Affiliation(s)
- Michel Leibovici
- Institut Pasteur, Unite de Genetique et Physiologie de l'Audition, Paris, France
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Abstract
Usher syndrome is both genetically and phenotypically heterogeneous. Traditionally, the condition has been classified into three clinical types, differentiated by the severity and progression of the hearing impairment and by the presence or absence of vestibular symptoms. Recent advances in molecular genetics have enabled researchers to study the phenotypic expression in confirmed molecular groups of Usher. In response to the expansion of clinical and genetic information on Usher, we report an up to date review of the different clinical forms of Usher in known molecular groups and use the emerging evidence to appraise the diagnostic utility of the traditional classification of Usher. Our findings undermine the traditional view that the clinical types of Usher have distinct genetic causes. The pleiotropic effects of some of the major causes of Usher lead to considerable overlap between the different clinical types, with very little evidence for phenotypic-genotypic correlations. The novel synthesis emerging from this review suggests more productive approaches to the diagnosis of Usher in hearing-impaired children which would provide more accurate prognostic information to families.
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Affiliation(s)
- Mazal Cohen
- Human Communication and Deafness, School of Psychological Sciences, University of Manchester, Manchester, UK.
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Budzynski E, Lee Y, Sakamoto K, Naggert JK, Nishina PM. From vivarium to bedside: lessons learned from animal models. Ophthalmic Genet 2007; 27:123-37. [PMID: 17148039 DOI: 10.1080/13816810600977192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In this review, we focus primarily on information obtained by studying mouse models of heritable ocular diseases. These models have proven to be important in advancing our understanding of disease etiology and of pathological consequences of heritable disorders. Careful phenotypic analyses of these models have lead to hypotheses regarding the function of various molecules as well as the mechanisms underlying the observed pathologies. Specific examples of the utility of mouse models in vision research are discussed.
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Plantinga RF, Pennings RJE, Huygen PLM, Sankila EM, Tuppurainen K, Kleemola L, Cremers CWRJ, Deutman AF. Visual impairment in Finnish Usher syndrome type III. ACTA ACUST UNITED AC 2006; 84:36-41. [PMID: 16445437 DOI: 10.1111/j.1600-0420.2005.00507.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate visual impairment in Finnish Usher syndrome type 3 (USH3) and compare this with visual impairment in Usher syndrome types 1b (USH1b) and 2a (USH2a). METHODS We carried out a retrospective study of 28 Finnish USH3 patients, 24 Dutch USH2a patients and 17 Dutch USH1b patients. Cross-sectional regression analyses of the functional acuity score (FAS), functional field score (FFS*) and functional vision score (FVS*) related to age were performed for all patients. The FFS* and FVS* were calculated using the isoptre V-4 test target instead of the usual III-4 target. Statistical tests relating to regression lines and Student's t-test were used to compare between USH3 patients and the other genetic subtypes of Usher syndrome. RESULTS Cross-sectional analyses revealed significant deterioration in the FAS (1.3% per year), FFS* (1.4% per year) and FVS* (1.8% per year) with advancing age in the USH3 patient group. At a given age the USH3 patients showed significantly poorer visual field function than the USH2a patients. CONCLUSIONS The rate of deterioration in visual function in Finnish USH3 patients was fairly similar to that in Dutch USH1b or USH2a patients. At a given age, visual field impairment in USH3 patients was similar to that in USH1b patients but poorer than in USH2a patients.
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Affiliation(s)
- Rutger F Plantinga
- Department of Ophthalmology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
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Weleber RG, Gregory-Evans K. Retinitis Pigmentosa and Allied Disorders. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50023-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Aller E, Jaijo T, Oltra S, Alió J, Galán F, Nájera C, Beneyto M, Millán JM. Mutation screening of USH3 gene (clarin-1) in Spanish patients with Usher syndrome: low prevalence and phenotypic variability. Clin Genet 2005; 66:525-9. [PMID: 15521980 DOI: 10.1111/j.1399-0004.2004.00352.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Usher syndrome type III is an autosomal recessive disorder clinically characterized by the association of retinitis pigmentosa (RP), variable presence of vestibular dysfunction and progressive hearing loss, being the progression of the hearing impairment the critical parameter classically used to distinguish this form from Usher syndrome type I and Usher syndrome type II. Usher syndrome type III clinical subtype is the rarest form of Usher syndrome in Spain, accounting only for 6% of all Usher syndrome Spanish cases. The gene responsible for Usher syndrome type III is named clarin-1 and it is thought to be involved in hair cell and photoreceptor cell synapses. Here, we report a screening for mutations in clarin-1 gene among our series of Usher syndrome Spanish patients. Clarin-1 has been found to be responsible for the disease in only two families: the first one is a previously reported family homozygous for Y63X mutation and the second one, described here, is homozygous for C40G. This accounts for 1.7% of Usher syndrome Spanish families. It is noticeable that, whereas C40G family is clinically compatible with Usher syndrome type III due to the progression of the hearing loss, Y63X family could be diagnosed as Usher syndrome type I because the hearing impairment is profound and stable. Thus, we consider that the progression of hearing loss is not the definitive key parameter to distinguish Usher syndrome type III from Usher syndrome type I and Usher syndrome type II.
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Affiliation(s)
- E Aller
- Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario La Fe, Spain
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Abstract
Usher syndrome (USH) is an autosomal recessive disorder characterized by the association of sensorineural hearing loss and retinitis pigmentosa (RP). Usher syndrome is both clinically and genetically heterogeneous. Three clinical subtypes are defined with respect to vestibular dysfunction and the degree of hearing loss. Type I (USH1) patients have profound hearing loss and vestibular dysfunction from birth. Type II (USH2) is the most frequent and patients tend to have less severe hearing impairment and normal vestibular response. Type III (USH3) is characterized by a progressive loss of hearing and is found more frequently among Finnish patients. Recently, major breakthroughs have been made in the molecular genetics of Usher syndrome as a number of chromosomal loci and causative genes have been identified in each clinical subtype. Twelve loci are known and the corresponding genes have been cloned for six of them. Although their functions are not always clearly established, a common role is emerging for the proteins identified within each subtype. As a result, each subtype could emanate from defects affecting distinct cellular mechanisms.
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Affiliation(s)
- A-F Roux
- Laboratoire de Génétique Moléculaire, Institut Universitaire de Recherche Clinique, 641 avenue du Doyen G. Giraud 34295, Montpellier Cedex 05, France
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Sadeghi M, Cohn ES, Kimberling WJ, Tranebjaerg L, Möller C. Audiological and vestibular features in affected subjects with USH3: a genotype/phenotype correlation. Int J Audiol 2005; 44:307-16. [PMID: 16028794 DOI: 10.1080/14992020500060610] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The aims were to compare the genotype/phenotype relationship between USH3 mutations and the consequent hearing and vestibular phenotype; and to compare hearing loss (HL) progression between Usher syndrome types IB, IIA and USH3. Genetic, audiometric and vestibular examinations were performed in 28 subjects with USH3. Five different mutations in USH3 were identified. Severe HL was present from an early age (4 to 6 years) in 35% of subjects with USH3. Progression of HL begins in the first decade, and approximately 50% of subjects with USH3 become profoundly deaf by age 40. Various vestibular abnormalities were found in about half (10/22) of the tested subjects with USH3. Depending on the severity of HL, subjects with USH3 might be misdiagnosed as either Usher type IB or IIA. The results from this study can be used as discriminatory features in differential diagnosis of this syndrome.
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Affiliation(s)
- Mehdi Sadeghi
- The Sahlgrenska Academy, Institute of Selected Clinical Sciences, Dept. of Audiology, Box 452, SE-405 30 Gothenburg, Sweden.
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van Wijk E, Pennings RJE, te Brinke H, Claassen A, Yntema HG, Hoefsloot LH, Cremers FPM, Cremers CWRJ, Kremer H. Identification of 51 novel exons of the Usher syndrome type 2A (USH2A) gene that encode multiple conserved functional domains and that are mutated in patients with Usher syndrome type II. Am J Hum Genet 2004; 74:738-44. [PMID: 15015129 PMCID: PMC1181950 DOI: 10.1086/383096] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Accepted: 01/15/2004] [Indexed: 11/03/2022] Open
Abstract
The USH2A gene is mutated in patients with Usher syndrome type IIa, which is the most common subtype of Usher syndrome and is characterized by hearing loss and retinitis pigmentosa. Since mutation analysis by DNA sequencing of exons 1-21 revealed only ~63% of the expected USH2A mutations, we searched for so-far-uncharacterized exons of the gene. We identified 51 novel exons at the 3' end of the gene, and we obtained indications for alternative splicing. The putative protein encoded by the longest open reading frame harbors, in addition to the known functional domains, two laminin G and 28 fibronectin type III repeats, as well as a transmembrane region followed by an intracellular domain with a PDZ-binding domain at its C-terminal end. Semiquantitative expression profile analysis suggested a low level of expression for both the long and the short isoform(s) and partial overlap in spatial and temporal expression patterns. Mutation analysis in 12 unrelated patients with Usher syndrome, each with one mutation in exons 1-21, revealed three different truncating mutations in four patients and two missense mutations in one patient. The presence of pathogenic mutations in the novel exons indicates that at least one of the putative long isoforms of the USH2A protein plays a role in both hearing and vision.
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Affiliation(s)
- Erwin van Wijk
- Departments of Otorhinolaryngology and Human Genetics, University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Ronald J. E. Pennings
- Departments of Otorhinolaryngology and Human Genetics, University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Heleen te Brinke
- Departments of Otorhinolaryngology and Human Genetics, University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Annemarie Claassen
- Departments of Otorhinolaryngology and Human Genetics, University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Helger G. Yntema
- Departments of Otorhinolaryngology and Human Genetics, University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Lies H. Hoefsloot
- Departments of Otorhinolaryngology and Human Genetics, University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Frans P. M. Cremers
- Departments of Otorhinolaryngology and Human Genetics, University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Cor. W. R. J. Cremers
- Departments of Otorhinolaryngology and Human Genetics, University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Hannie Kremer
- Departments of Otorhinolaryngology and Human Genetics, University Medical Center Nijmegen, Nijmegen, The Netherlands
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42
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Abstract
There are hundreds of different mutated genes associated with hearing loss. However, recent findings indicate that a large proportion of both syndromic and nonsyndromic forms of deafness in some Jewish populations is caused by a small number of founder mutations. This review is focused on genetic disorders such as nonsyndromic deafness, Usher syndrome and Alport syndrome, in which hearing loss is a major part of the phenotype and in which the underlying prevalent founder mutations have been recently identified in different Jewish populations. These and other examples of common mutations within a distinct population allow for sensitive and specific use of genetic testing for carrier screening and diagnosis, and are an impetus for development of therapeutic strategies.
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Affiliation(s)
- Tamar Ben-Yosef
- Section on Human Genetics, Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, 5 Research Court, Rockville, MD 20850, USA
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43
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Pennings RJE, Fields RR, Huygen PLM, Deutman AF, Kimberling WJ, Cremers CWRJ. Usher syndrome type III can mimic other types of Usher syndrome. Ann Otol Rhinol Laryngol 2003; 112:525-30. [PMID: 12834121 DOI: 10.1177/000348940311200608] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Clinical and genetic characteristics are presented of 2 patients from a Dutch Usher syndrome type III family who have a new homozygous USH3 gene mutation: 149-152delCAGG + insTGTCCAAT. One individual (IV:1) is profoundly hearing impaired and has normal vestibular function and retinitis punctata albescens (RPA). The other individual is also profoundly hearing impaired, but has well-developed speech, vestibular areflexia, and retinitis pigmentosa sine pigmento (RPSP). These findings suggest that Usher syndrome type III can be clinically misdiagnosed as either Usher type I or II; that Usher syndrome patients who are profoundly hearing impaired and have normal vestibular function should be tested for USH3 mutations; and that RPA and RPSP can occur as fundoscopic manifestations of pigmentary retinopathy in Usher syndrome.
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Affiliation(s)
- Ronald J E Pennings
- Department of Otorhinolaryngology, University Medical Centre St Radboud, Nijmegen, the Netherlands
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44
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Reisser CFV, Kimberling WJ, Otterstedde CR. Hearing loss in Usher syndrome type II is nonprogressive. Ann Otol Rhinol Laryngol 2002; 111:1108-11. [PMID: 12498372 DOI: 10.1177/000348940211101208] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Usher syndrome is an autosomal recessive disorder characterized by sensorineural hearing loss and progressive visual loss secondary to retinitis pigmentosa. In the literature, a possible progression of the moderate to severe hearing loss in Usher syndrome type II (Usher II) is controversial. We studied the development of the hearing loss of 125 patients with a clinical diagnosis of Usher syndrome type II intraindividually and interindividually by repeatedly performing complete audiological and neuro-otologic examinations. Our data show a very characteristic slope of the hearing curve in all Usher II patients and no clinically relevant progression of the hearing loss over up to 17 years. The subjective impression of a deterioration of the communicative abilities of Usher II patients must therefore be attributed to the progressive visual loss. The patients should be reassured that changes in their hearing abilities are unlikely and should be provided with optimally fitted modern hearing aids.
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MESH Headings
- Acoustic Impedance Tests
- Adolescent
- Adult
- Age Factors
- Aged
- Audiometry
- Disease Progression
- Evoked Potentials, Auditory, Brain Stem
- Genes, Recessive
- Genetic Diseases, Inborn/classification
- Genetic Diseases, Inborn/diagnosis
- Genetic Diseases, Inborn/genetics
- Genetic Diseases, Inborn/physiopathology
- Germany
- Hearing Loss, Sensorineural/classification
- Hearing Loss, Sensorineural/diagnosis
- Hearing Loss, Sensorineural/genetics
- Hearing Loss, Sensorineural/physiopathology
- Humans
- Linear Models
- Longitudinal Studies
- Middle Aged
- Otoacoustic Emissions, Spontaneous
- Retinitis Pigmentosa/genetics
- Severity of Illness Index
- Syndrome
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Affiliation(s)
- Christoph F V Reisser
- Department of Otolaryngology-Head and Neck Surgery, University of Heidelberg, Heidelberg, Germany
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45
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Adato A, Vreugde S, Joensuu T, Avidan N, Hamalainen R, Belenkiy O, Olender T, Bonne-Tamir B, Ben-Asher E, Espinos C, Millán JM, Lehesjoki AE, Flannery JG, Avraham KB, Pietrokovski S, Sankila EM, Beckmann JS, Lancet D. USH3A transcripts encode clarin-1, a four-transmembrane-domain protein with a possible role in sensory synapses. Eur J Hum Genet 2002; 10:339-50. [PMID: 12080385 DOI: 10.1038/sj.ejhg.5200831] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2002] [Revised: 04/26/2002] [Accepted: 05/01/2002] [Indexed: 11/09/2022] Open
Abstract
Usher syndrome type 3 (USH3) is an autosomal recessive disorder characterised by the association of post-lingual progressive hearing loss, progressive visual loss due to retinitis pigmentosa and variable presence of vestibular dysfunction. Because the previously defined transcripts do not account for all USH3 cases, we performed further analysis and revealed the presence of additional exons embedded in longer human and mouse USH3A transcripts and three novel USH3A mutations. Expression of Ush3a transcripts was localised by whole mount in situ hybridisation to cochlear hair cells and spiral ganglion cells. The full length USH3A transcript encodes clarin-1, a four-transmembrane-domain protein, which defines a novel vertebrate-specific family of three paralogues. Limited sequence homology to stargazin, a cerebellar synapse four-transmembrane-domain protein, suggests a role for clarin-1 in hair cell and photoreceptor cell synapses, as well as a common pathophysiological pathway for different Usher syndromes.
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Affiliation(s)
- Avital Adato
- Department of Molecular Genetics and The Crown Human Genome Center, The Weizmann Institute of Science, Rehovot, 76100, Israel.
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46
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Abstract
The cliché 'a picture is worth a thousand words' is a testament to the power of the visual system in helping us deal with our physical environment. Rarely do perturbations to the visual system, even minor ones, go unnoticed. Major defects in eye development may occur in the absence of systemic problems which threaten health. Ocular anomalies offer a window into many developmental events which would otherwise be difficult to study.
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Affiliation(s)
- R A Saleem
- Department of Medical Genetics, University of Alberta, Edmonton, Canada
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47
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Abstract
Usher syndrome (USH) is defined by the association of sensorineural deafness and visual impairment due to retinitis pigmentosa. The syndrome has three distinct clinical subtypes, referred to as USH1, USH2, and USH3. Each subtype is genetically heterogeneous, and 12 loci have been detected so far. Four genes have been identified, namely, USH1B, USH1C, USH1D, and USH2A. USH1B, USH1C, and USH1D encode an unconventional myosin (myosin VIIA), a PDZ domain-containing protein (harmonin), and a cadherin-like protein (cadherin-23), respectively. Mutations of these genes cause primary defects of the sensory cells in the inner ear, and probably also in the retina. In the inner ear, the USH1 genes, I propose, are involved in the same signaling pathway, which may control development and/or maintenance of the hair bundles of sensory cells via an adhesion force (a) at the junctions between these cells and supporting cells and (b) at the level of the lateral links that interconnect the stereocilia. In contrast, the molecular pathogenesis of USH2A, which is owing to a defect of a novel extracellular matrix protein, is likely to be different from that of USH1.
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Affiliation(s)
- C Petit
- Unité de Génétique des Déficits Sensoriels, CNRS URA 1968 Institut Pasteur, Paris, Cedex 15, 75724 France.
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48
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Otterstedde CR, Spandau U, Blankenagel A, Kimberling WJ, Reisser C. A new clinical classification for Usher's syndrome based on a new subtype of Usher's syndrome type I. Laryngoscope 2001; 111:84-6. [PMID: 11192904 DOI: 10.1097/00005537-200101000-00014] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Usher's syndrome is an autosomal recessive disorder characterized by sensorineural hearing loss and progressive visual loss secondary to retinitis pigmentosa. Usher's syndrome is both clinically and genetically heterogeneous. Three clinical types are known today. METHODS We conducted a study on 74 patients with Usher's syndrome, performing complete audiological and neurotological examinations. RESULTS Twenty-six patients had total profound hearing loss and retinitis pigmentosa (Usher's syndrome type I), and 48 patients had moderate to severe sensorineural hearing loss and retinitis pigmentosa (Usher's syndrome type II). We identified 9 of the 26 Usher's syndrome patients with profound hearing loss who showed a normal response to bithermal vestibular testing. CONCLUSIONS The combination of profound hearing loss and normal response to bithermal vestibular testing has not been previously described in Usher's syndrome. Therefore we describe a new subtype of Usher's syndrome type I and suggest a modified clinical classification for Usher's syndrome.
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Affiliation(s)
- C R Otterstedde
- Department of Otolaryngology-Head and Neck Surgery, University of Heidelberg, Germany
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49
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Bharadwaj AK, Kasztejna JP, Huq S, Berson EL, Dryja TP. Evaluation of the myosin VIIA gene and visual function in patients with Usher syndrome type I. Exp Eye Res 2000; 71:173-81. [PMID: 10930322 DOI: 10.1006/exer.2000.0863] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Usher syndrome type I (USH1) is a recessively-inherited disorder consisting of retinitis pigmentosa, profound congenital deafness, and vestibular ataxia. It can be caused by mutations in at least six different loci (USH1A-1F). The gene encoding human myosin VIIA (MYO7A) is the USH1B locus. In this study, 66 unrelated patients with USH1 were evaluated for defects in MYO7A using single-strand conformation polymorphism analysis and direct genomic sequencing. Twenty-nine per cent of cases were found to have likely pathogenic MYO7A mutations. A total of 22 likely pathogenic changes were identified, 18 of which were novel. Cosegregation analysis of mutations in five available families showed that the MYO7A changes segregated with the disease in an autosomal recessive fashion. Average visual function as measured by visual acuity, visual field area, and ERG amplitude was not significantly different between the group of patients with likely pathogenic MYO7A changes and the group in which no likely pathogenic MYO7A changes were detected.
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Affiliation(s)
- A K Bharadwaj
- Ocular Molecular Genetics Institute, Harvard Medical School, Boston, MA, USA
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50
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Joensuu T, Hämäläinen R, Lehesjoki AE, de la Chapelle A, Sankila EM. A sequence-ready map of the Usher syndrome type III critical region on chromosome 3q. Genomics 2000; 63:409-16. [PMID: 10704288 DOI: 10.1006/geno.1999.6096] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Usher syndrome type 3 (USH3; MIM 276902) is an autosomal recessive disorder associated with progressive hearing loss and retinal degeneration. We recently refined the localization of USH3 to a 1-cM genetic interval between markers D3S1299 and D3S3625. We have now constructed a bacterial artificial chromosome contig over the region. Novel polymorphic markers were generated and physically fine-mapped, allowing further narrowing of the critical interval to a 250-kb genomic fragment. Of seven ESTs mapping to the initial critical region, WI-11588 and SHGC-133 represent the human SIAH2 gene, which was excluded as a candidate for USH3 by sequencing and subsequently, by its position. KIAA0001 and D3S3882 derive from the transcript of a putative G-protein-coupled receptor gene that was excluded as a candidate by sequencing of patient DNA. These data provide a basis for the sequencing and final characterization of the USH3 region and isolation of the disease gene.
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Affiliation(s)
- T Joensuu
- Haartman Institute, University of Helsinki, Helsinki, 00014, Finland
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