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Cuzzuol BR, Apolonio JS, da Silva Júnior RT, de Carvalho LS, Santos LKDS, Malheiro LH, Silva Luz M, Calmon MS, Crivellaro HDL, Lemos FFB, Freire de Melo F. Usher syndrome: Genetic diagnosis and current therapeutic approaches. World J Otorhinolaryngol 2024; 11:1-17. [DOI: 10.5319/wjo.v11.i1.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/21/2023] [Accepted: 01/05/2024] [Indexed: 01/17/2024] Open
Abstract
Usher Syndrome (USH) is the most common deaf-blind syndrome, affecting approximately 1 in 6000 people in the deaf population. This genetic condition is characterized by a combination of hearing loss (HL), retinitis pigmentosa, and, in some cases, vestibular areflexia. Among the subtypes of USH, USH type 1 is considered the most severe form, presenting profound bilateral congenital deafness, vestibular areflexia, and early onset RP. USH type 2 is the most common form, exhibiting congenital moderate to severe HL for low frequencies and severe to profound HL for high frequencies. Conversely, type 3 is the rarest, initially manifesting mild symptoms during childhood that become more prominent in the first decades of life. The dual impact of USH on both visual and auditory senses significantly impairs patients’ quality of life, restricting their daily activities and interactions with society. To date, 9 genes have been confirmed so far for USH: MYO7A, USH1C, CDH23, PCDH15, USH1G, USH2A, ADGRV1, WHRN and CLRN1. These genes are inherited in an autosomal recessive manner and encode proteins expressed in the inner ear and retina, leading to functional loss. Although non-genetic methods can assist in patient triage and disease extension evaluation, genetic and molecular tests play a pivotal role in providing genetic counseling, enabling appropriate gene therapy, and facilitating timely cochlear implantation (CI). The CRISPR/Cas9 system and viral-based gene replacement therapy have recently emerged as highly promising techniques for treating USH. Regarding drug therapy, PTC-124 and Nb54 have been identified as promising drug interventions for genetic HL in USH. Simultaneously, CI has proven to be critical in the restoration of hearing. This review aims to summarize the genetic and molecular diagnosis of USH and highlight the importance of early diagnosis in guiding appropriate treatment strategies and improving patient prognosis.
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Affiliation(s)
- Beatriz Rocha Cuzzuol
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
| | - Jonathan Santos Apolonio
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
| | | | - Lorena Sousa de Carvalho
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
| | - Luana Kauany de Sá Santos
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
| | - Luciano Hasimoto Malheiro
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
| | - Marcel Silva Luz
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
| | - Mariana Santos Calmon
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
| | - Henrique de Lima Crivellaro
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
| | - Fabian Fellipe Bueno Lemos
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
| | - Fabrício Freire de Melo
- Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Bahia, Brazil
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Iannaccone A, Brewer CC, Cheng P, Duncan JL, Maguire MG, Audo I, Ayala AR, Bernstein PS, Bidelman GM, Cheetham JK, Doty RL, Durham TA, Hufnagel RB, Myers MH, Stingl K, Zein WM. Auditory and olfactory findings in patients with USH2A-related retinal degeneration-Findings at baseline from the rate of progression in USH2A-related retinal degeneration natural history study (RUSH2A). Am J Med Genet A 2021; 185:3717-3727. [PMID: 34331386 DOI: 10.1002/ajmg.a.62437] [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] [Received: 04/16/2021] [Revised: 06/25/2021] [Accepted: 07/03/2021] [Indexed: 11/09/2022]
Abstract
Sensorineural hearing loss (SNHL) is characteristic of Usher syndrome type 2 (USH2), but less is known about SNHL in nonsyndromic autosomal recessive retinitis pigmentosa (ARRP) and olfaction in USH2A-associated retinal degeneration. The Rate of Progression of USH2A-related Retinal Degeneration (RUSH2A) is a natural history study that enrolled 127 participants, 80 with USH2 and 47 with ARRP. Hearing was measured by pure-tone thresholds and word recognition scores, and olfaction by the University of Pennsylvania Smell Identification Test (UPSIT). SNHL was moderate in 72% of USH2 participants and severe or profound in 25%, while 9% of ARRP participants had moderate adult-onset SNHL. Pure-tone thresholds worsened with age in ARRP but not in USH2 participants. The degree of SNHL was not associated with other participant characteristics in either USH2 or ARRP. Median pure-tone thresholds in ARRP participants were significantly higher than the normative population (p < 0.001). Among 14 USH2 participants reporting newborn hearing screening results, 7 reported passing. Among RUSH2A participants, 7% had mild microsmia and 5% had moderate or severe microsmia. Their mean (±SD) UPSIT score was 35 (±3), similar to healthy controls (34 [±3]; p = 0.39). Olfaction differed by country (p = 0.02), but was not significantly associated with clinical diagnosis, age, gender, race/ethnicity, smoking status, visual measures, or hearing. Hearing loss in USH2A-related USH2 did not progress with age. ARRP patients had higher pure-tone thresholds than normal. Newborn hearing screening did not identify all USH2A-related hearing loss. Olfaction was not significantly worse than normal in participants with USH2A-related retinal degeneration.
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Affiliation(s)
- Alessandro Iannaccone
- Duke Eye Center, Department of Ophthalmology, Duke University Medical School, Durham, North Carolina, USA
| | - Carmen C Brewer
- National Institute on Deafness and Other Communication Disorders, Bethesda, Maryland, USA
| | - Peiyao Cheng
- Jaeb Center for Health Research, Tampa, Florida, USA
| | - Jacque L Duncan
- University of California, San Francisco, San Francisco, California, USA
| | | | - Isabelle Audo
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France.,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC1423, Paris, France
| | | | | | | | | | - Richard L Doty
- University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Todd A Durham
- Foundation Fighting Blindness, Columbia, Maryland, USA
| | | | - Mark H Myers
- University of Tennessee Health and Science Center, Memphis, Tennessee, USA
| | - Katarina Stingl
- University Eye Hospital, Center for Ophthalmology, University of Tübingen, Tübingen, Germany.,Center for Rare Eye Diseases, University of Tübingen, Tübingen, Germany
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Meng X, Liu X, Li Y, Guo T, Yang L. Correlation between Genotype and Phenotype in 69 Chinese Patients with USH2A Mutations: A comparative study of the patients with Usher Syndrome and Nonsyndromic Retinitis Pigmentosa. Acta Ophthalmol 2021; 99:e447-e460. [PMID: 33124170 DOI: 10.1111/aos.14626] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 08/16/2020] [Accepted: 08/18/2020] [Indexed: 12/18/2022]
Abstract
PURPOSE The aim of this study was to analyse 69 Chinese patients with USH2A mutations and to assess the genotype-phenotype correlation. METHODS All 36 Usher syndrome type IIA patients and 33 nonsyndromic RP (retinitis pigmentosa) patients underwent clinical examinations. Eye examinations included best-corrected visual acuity, slit-lamp biomicroscopy, fundus examination with dilated pupils, fundus fluorescent angiography, visual field test, full-field electroretinography and optic coherence tomography; audiological assessment included pure tone audiometry and hearing thresholds. The molecular diagnosis of genotype combined the single-gene Sanger sequencing and next-generation sequencing. This study is a retrospective study. RESULTS The mean age of first symptoms with Usher syndrome type IIa and nonsyndromic RP patients was 13.7 versus 29.8 years (ocular phenotypes, p < 0.001); 17.7 versus 29.9 years (nyctalopia, p < 0.001); 44.7 versus 54.8 years (low vision based on VF, p < 0.001); 41.7 versus 54.7 years (low vision based on VA, p < 0.001); and 46.0 versus 56.7 years (legal blindness based on VF, p < 0.001). There was significant difference in variants in the two groups (p < 0.05). Among patients with mutation c.2802T > G (p.Cys934Trp), more (66.7%) presented with normal hearing. All patients (3/3, 100%) with the variant c.8232G > C (p.Trp2744Cys) had hearing loss. Furthermore, we identified 23 novel variants in USH2A. CONCLUSIONS Patients with Usher syndrome type IIa had an earlier onset of the disease, inferior visual function and presented with more truncating variants, compared with the nonsyndromic RP patients.
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Affiliation(s)
- Xiang Meng
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
| | - XiaoZhen Liu
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
| | - YingYing Li
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
| | - Tong Guo
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
| | - Liping Yang
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
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Mei C, Dong H, Nisenbaum E, Thielhelm T, Nourbakhsh A, Yan D, Smeal M, Lundberg Y, Hoffer ME, Angeli S, Telischi F, Nie G, Blanton SH, Liu X. Genetics and the Individualized Therapy of Vestibular Disorders. Front Neurol 2021; 12:633207. [PMID: 33613440 PMCID: PMC7892966 DOI: 10.3389/fneur.2021.633207] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
Background: Vestibular disorders (VDs) are a clinically divergent group of conditions that stem from pathology at the level of the inner ear, vestibulocochlear nerve, or central vestibular pathway. No etiology can be identified in the majority of patients with VDs. Relatively few families have been reported with VD, and so far, no causative genes have been identified despite the fact that more than 100 genes have been identified for inherited hearing loss. Inherited VDs, similar to deafness, are genetically heterogeneous and follow Mendelian inheritance patterns with all modes of transmission, as well as multifactorial inheritance. With advances in genetic sequencing, evidence of familial clustering in VD has begun to highlight the genetic causes of these disorders, potentially opening up new avenues of treatment, particularly in Meniere's disease and disorders with comorbid hearing loss, such as Usher syndrome. In this review, we aim to present recent findings on the genetics of VDs, review the role of genetic sequencing tools, and explore the potential for individualized medicine in the treatment of these disorders. Methods: A search of the PubMed database was performed for English language studies relevant to the genetic basis of and therapies for vestibular disorders, using search terms including but not limited to: “genetics,” “genomics,” “vestibular disorders,” “hearing loss with vestibular dysfunction,” “individualized medicine,” “genome-wide association studies,” “precision medicine,” and “Meniere's syndrome.” Results: Increasing numbers of studies on vestibular disorder genetics have been published in recent years. Next-generation sequencing and new genetic tools are being utilized to unearth the significance of the genomic findings in terms of understanding disease etiology and clinical utility, with growing research interest being shown for individualized gene therapy for some disorders. Conclusions: The genetic knowledge base for vestibular disorders is still in its infancy. Identifying the genetic causes of balance problems is imperative in our understanding of the biology of normal function of the vestibule and the disease etiology and process. There is an increasing effort to use new and efficient genetic sequencing tools to discover the genetic causes for these diseases, leading to the hope for precise and personalized treatment for these patients.
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Affiliation(s)
- Christine Mei
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Hongsong Dong
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States.,Shenzhen Second People's Hospital, Shenzhen, China
| | - Eric Nisenbaum
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Torin Thielhelm
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Aida Nourbakhsh
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Denise Yan
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Molly Smeal
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Yesha Lundberg
- Department of Otolaryngology, Boys Town National Research Hospital, Omaha, NE, United States
| | - Michael E Hoffer
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Simon Angeli
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Fred Telischi
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Guohui Nie
- Shenzhen Second People's Hospital, Shenzhen, China
| | - Susan H Blanton
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
| | - Xuezhong Liu
- Department of Otolaryngology, University of Miami, Coral Gables, FL, United States
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Ambrosio L, Hansen RM, Moskowitz A, Oza A, Barrett D, Manganella J, Medina G, Kawai K, Fulton AB, Kenna M. Dark-adapted threshold and electroretinogram for diagnosis of Usher syndrome. Doc Ophthalmol 2021; 143:39-51. [PMID: 33511521 DOI: 10.1007/s10633-021-09818-y] [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] [Received: 09/12/2020] [Accepted: 01/07/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE To determine the utility of ophthalmology evaluation, dark-adapted threshold, and full-field electroretinogram for early detection of Usher syndrome in young patients with bilateral sensorineural hearing loss. METHODS We identified 39 patients with secure genetic diagnoses of Usher Syndrome. Visual acuity, spherical equivalent, fundus appearance, dark-adapted threshold, and full-field electroretinogram results were summarized and compared to those in a group of healthy controls with normal hearing. In those Usher patients with repeated measures, regression analysis was done to evaluate for change in visual acuity and dark-adapted threshold with age. Spherical equivalent and full-field electroretinogram responses from dark- and light-adapted eyes were evaluated as a function of age. RESULTS The majority of initial visual acuity and spherical equivalent results were within normal limits for age. Visual acuity and dark-adapted threshold worsened significantly with age in Usher type 1 but not in Usher type 2. At initial test, full-field electroretinogram responses from dark- and light-adapted eyes were abnormal in 53% of patients. Remarkably, nearly half of our patients (17% of Usher type 1 and 30% of Usher type 2) would have been missed by tests of retinal function alone if evaluated before age 10. CONCLUSIONS Although there is an association of abnormal dark-adapted threshold and full-field electroretinogram at young ages in Usher patients, it appears that a small but important proportion of patients would not be detected by tests of retinal function alone. Thus, genetic testing is needed to secure a diagnosis of Usher syndrome.
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Affiliation(s)
- Lucia Ambrosio
- Department of Ophthalmology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA. .,Department of Ophthalmology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA.
| | - Ronald M Hansen
- Department of Ophthalmology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Ophthalmology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Anne Moskowitz
- Department of Ophthalmology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Ophthalmology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Andrea Oza
- Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, 65 Landsdowne Street, Cambridge, MA, 02139, USA
| | - Devon Barrett
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Juliana Manganella
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Genevieve Medina
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Kosuke Kawai
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Otolaryngology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Anne B Fulton
- Department of Ophthalmology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Ophthalmology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Margaret Kenna
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Otolaryngology, Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
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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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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: 37] [Impact Index Per Article: 9.3] [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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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: 12] [Impact Index Per Article: 3.0] [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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Nair G, Dham R, Sekhar A, Kumar RS, Kameswaran M. Cochlear Implantation in Children with Usher's Syndrome: A South Asian Experience. Indian J Otolaryngol Head Neck Surg 2020; 72:140-144. [PMID: 32158671 PMCID: PMC7040150 DOI: 10.1007/s12070-019-01759-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/02/2019] [Indexed: 10/25/2022] Open
Abstract
Usher's syndrome is an autosomal recessive disorder characterized by dual sensory impairment involving both the ears and eyes. Cochlear implantation paves a way to restore hearing loss in such individuals but poor vision among these patients poses additional challenges for the habilitationists. This study aimed to compare the habilitation outcomes and hearing-related quality of life scores of cochlear implantees having Usher syndrome with age-matched cochlear implantees with no such syndromic association. 27 patients aged 1-6 years with Usher syndrome underwent cochlear Implantation over a period of 10 years from 2006 to 2016 and were included in this study along with an age-matched cohort of 30 implantees with no additional disabilities. Category of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) scores were compared at 3, 6, 9 and 12 months respectively. Glasgow Benefit Inventory and Health Utility Index (HUI 3.0) questionnaires were used to assess the hearing-related quality of life in both groups at 1 year post implantation. There was significant difference in CAP and SIR scores between children with Usher's syndrome and the control group (p < 0.05). The overall scores in terms of quality of life as well were statistically different (p < 0.05). Though there was improvement in speech and language acquisition after cochlear Implantation this was found to be of lesser extent than the normative cohort. These children with additional visual disabilities required intensive, individualized therapy catering to their complex needs. Their family's perception of expected benefit from cochlear Implantation was guarded and needed to be appraised in detail prior to surgery. This experience helped prepare an institutional protocol for counseling such implantees in future.
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Affiliation(s)
- Geetha Nair
- Government Medical College, Ernakulam, Kochi, Kerala India
| | - Ruchima Dham
- Madras ENT Research Foundation, Chennai, Tamil Nadu India
| | - Arpana Sekhar
- Madras ENT Research Foundation, Chennai, Tamil Nadu India
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Magliulo G, Iannella G, Gagliardi S, Iozzo N, Plateroti R, Mariottini A, Torricelli F. Usher's Syndrome Type II: A Comparative Study of Genetic Mutations and Vestibular System Evaluation. Otolaryngol Head Neck Surg 2017; 157:853-860. [PMID: 28653555 DOI: 10.1177/0194599817715235] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Objective Usher's syndrome type II (USH2) is characterized by moderate to profound congenital hearing loss, later onset of retinitis pigmentosa, and normal vestibular function. Recently, a study investigating the vestibular function of USH2 patients demonstrated a pathologic response to vestibular tests. In this cross-sectional study we performed vestibular tests of a group patients with genetic diagnosis of USH2 syndrome to demonstrate if vestibular damage is present in USH2 patients. Study Design Cross-sectional study. Setting Tertiary referral center. Subjects and Methods Mutated genes of 7 patients with a clinical diagnosis of USH2 were evaluated. Vestibular function was investigated by audiometry, Fitzgerald-Hallpike caloric vestibular testing, cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and video head impulse test (v-HIT). Results Genetic tests confirmed the USH2 diagnosis in 5 of 7 patients examined, with 1 patient reporting a unique mutation on genetic tests. Four (80%) of the 5 patients with a genetic diagnosis of USH2 showed pathological O-VEMPs. Two patients (40%) reported bilateral absent or abnormal values of C-VEMPs. The superior semicircular canal presented a significant deficit in 2 (40%) patients. The same 2 cases showed a pathologic response of the v-HIT of the horizontal semicircular canal. Finally, the posterior semicircular canal presented a significant deficit in 4 (40.0%) patients. Conclusion A vestibular evaluation with vestibular evoked myogenic potentials and v-HIT seems to identify latent damage to the vestibular receptors of USH2 patients.
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Affiliation(s)
| | | | - Silvia Gagliardi
- 1 Organi di Senso Department, University "la Sapienza," Rome, Italy
| | - Nicola Iozzo
- 1 Organi di Senso Department, University "la Sapienza," Rome, Italy
| | - Rocco Plateroti
- 1 Organi di Senso Department, University "la Sapienza," Rome, Italy
| | - Alessandro Mariottini
- 2 Department of Genetic Diagnosis, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy
| | - Francesca Torricelli
- 2 Department of Genetic Diagnosis, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy
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11
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Hartel BP, Löfgren M, Huygen PLM, Guchelaar I, Lo-A-Njoe Kort N, Sadeghi AM, van Wijk E, Tranebjærg L, Kremer H, Kimberling WJ, Cremers CWRJ, Möller C, Pennings RJE. A combination of two truncating mutations in USH2A causes more severe and progressive hearing impairment in Usher syndrome type IIa. Hear Res 2016; 339:60-8. [PMID: 27318125 DOI: 10.1016/j.heares.2016.06.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/31/2016] [Accepted: 06/13/2016] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Usher syndrome is an inherited disorder that is characterized by hearing impairment (HI), retinitis pigmentosa, and in some cases vestibular dysfunction. Usher syndrome type IIa is caused by mutations in USH2A. HI in these patients is highly heterogeneous and the present study evaluates the effects of different types of USH2A mutations on the audiometric phenotype. Data from two large centres of expertise on Usher Syndrome in the Netherlands and Sweden were combined in order to create a large combined sample of patients to identify possible genotype-phenotype correlations. DESIGN A retrospective study on HI in 110 patients (65 Dutch and 45 Swedish) genetically diagnosed with Usher syndrome type IIa. We used methods especially designed for characterizing and testing differences in audiological phenotype between patient subgroups. These methods included Age Related Typical Audiograms (ARTA) and a method to evaluate the difference in the degree of HI developed throughout life between subgroups. RESULTS Cross-sectional linear regression analysis of last-visit audiograms for the best hearing ear demonstrated a gradual decline of hearing over decades. The congenital level of HI was in the range of 16-33 dB at 0.25-0.5 kHz, and in the range of 51-60 dB at 1-8 kHz. The annual threshold deterioration was in the range of 0.4-0.5 dB/year at 0.25-2 kHz and in the range of 0.7-0.8 dB/year at 4-8 kHz. Patients with two truncating mutations, including homozygotes for the common c.2299delG mutation, developed significantly more severe HI throughout life than patients with one truncating mutation combined with one nontruncating mutation, and patients with two nontruncating mutations. CONCLUSIONS The results have direct implications for patient counselling in terms of prognosis of hearing and may serve as baseline measures for future (genetic) therapeutic interventions.
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Affiliation(s)
- Bas P Hartel
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Maria Löfgren
- Swedish Institute for Disability Research (SIDR) Linköping, Sweden; Audiological Research Centre, Örebro University Hospital, Örebro, Sweden; School of Medicine and Health, Örebro University, Örebro, Sweden
| | - Patrick L M Huygen
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Iris Guchelaar
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Nicole Lo-A-Njoe Kort
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Andre M Sadeghi
- The Sahlgrenska Academy, Institute of Neuroscience and Physiology, Department of Audiology, Göteborg, Sweden; Hearing and Deafness Activities Organization, Habilitation & Health, Göteborg, Sweden
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lisbeth Tranebjærg
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Otorhinolaryngology, Head and Neck Surgery and Audiology, Bispebjerg Hospital/Rigshospitalet, Copenhagen, Denmark
| | - Hannie Kremer
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - William J Kimberling
- Department of Otolaryngology, Molecular Otolaryngology, and Renal Research Laboratories, University of Iowa, Iowa City, IA, USA
| | - Cor W R J Cremers
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands; Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Claes Möller
- Swedish Institute for Disability Research (SIDR) Linköping, Sweden; Audiological Research Centre, Örebro University Hospital, Örebro, Sweden; School of Medicine and Health, Örebro University, Örebro, Sweden
| | - Ronald J E Pennings
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behaviour, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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12
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Usher's Syndrome: Evaluation of the Vestibular System with Cervical and Ocular Vestibular Evoked Myogenic Potentials and the Video Head Impulse Test. Otol Neurotol 2016; 36:1421-7. [PMID: 26192261 DOI: 10.1097/mao.0000000000000832] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE The Usher's syndrome (USH) is composed of a group of inherited disorders characterized by a dual sensory impairment of the audiovestibular and visual systems. Despite the established hearing loss, few authors have investigated vestibular dysfunction in these patients.The aim of this article is to investigate otolith or ampullary dysfunction in a group of patients affected by USH by means of a diagnostic protocol using caloric vestibular tests, cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and video head impulse test (v-HIT) to show any selective damage of the vestibular nerve and also to identify if it is present in patients with a previous diagnosis of USH Type II. STUDY DESIGN Prospective study with C-VEMPs, O-VEMPs, and v-HIT. SETTING Tertiary referral center. PATIENTS Fifteen patients with USH. INTERVENTION Evaluation of otolith dysfunction with caloric test, C-VEMPs, and O-VEMPs and the measurement of the vestibular-ocular reflex using the v-HIT. RESULTS Only three cases showed normal values of all the vestibular tests performed. O-VEMPs and C-VEMPs appeared pathologic in nine and seven cases, respectively. V-HITs showed ampullary dysfunction in 10 patients. In our study, eight of the 11 patients belonging to the group of USH Type II showed a pathologic response to at least one of the vestibular tests performed. CONCLUSION Today, in patients affected by USH, any vestibular diagnostic protocol must include VEMPs and v-HIT to confirm the vestibular damage, identify selective deficit of the vestibular nerve, and provide useful information for a correct classification of USH.
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13
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Whole-exome sequencing revealed two novel mutations in Usher syndrome. Gene 2015; 563:215-8. [DOI: 10.1016/j.gene.2015.03.060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 03/25/2015] [Accepted: 03/27/2015] [Indexed: 11/24/2022]
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14
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Henricson C, Lidestam B, Lyxell B, Möller C. Cognitive skills and reading in adults with Usher syndrome type 2. Front Psychol 2015; 6:326. [PMID: 25859232 PMCID: PMC4373271 DOI: 10.3389/fpsyg.2015.00326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/06/2015] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE To investigate working memory (WM), phonological skills, lexical skills, and reading comprehension in adults with Usher syndrome type 2 (USH2). DESIGN The participants performed tests of phonological processing, lexical access, WM, and reading comprehension. The design of the test situation and tests was specifically considered for use with persons with low vision in combination with hearing impairment. The performance of the group with USH2 on the different cognitive measures was compared to that of a matched control group with normal hearing and vision (NVH). STUDY SAMPLE Thirteen participants with USH2 aged 21-60 years and a control group of 10 individuals with NVH, matched on age and level of education. RESULTS The group with USH2 displayed significantly lower performance on tests of phonological processing, and on measures requiring both fast visual judgment and phonological processing. There was a larger variation in performance among the individuals with USH2 than in the matched control group. CONCLUSION The performance of the group with USH2 indicated similar problems with phonological processing skills and phonological WM as in individuals with long-term hearing loss. The group with USH2 also had significantly longer reaction times, indicating that processing of visual stimuli is difficult due to the visual impairment. These findings point toward the difficulties in accessing information that persons with USH2 experience, and could be part of the explanation of why individuals with USH2 report high levels of fatigue and feelings of stress (Wahlqvist et al., 2013).
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Affiliation(s)
- Cecilia Henricson
- Swedish Institute for Disability Research (SIDR)Linköping, Sweden
- Linnaeus Centre for Research on Hearing and Deafness (HEAD)Linköping, Sweden
- Department of Behavioral Sciences and Learning, Linköping UniversityLinköping, Sweden
| | - Björn Lidestam
- Linnaeus Centre for Research on Hearing and Deafness (HEAD)Linköping, Sweden
- Department of Behavioral Sciences and Learning, Linköping UniversityLinköping, Sweden
| | - Björn Lyxell
- Swedish Institute for Disability Research (SIDR)Linköping, Sweden
- Linnaeus Centre for Research on Hearing and Deafness (HEAD)Linköping, Sweden
- Department of Behavioral Sciences and Learning, Linköping UniversityLinköping, Sweden
| | - Claes Möller
- Swedish Institute for Disability Research (SIDR)Linköping, Sweden
- Audiological Research Centre, Örebro University HospitalÖrebro, Sweden
- School of Medicine and Health, Örebro UniversityÖrebro, Sweden
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15
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16
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Sadeghi AM, Cohn ES, Kimberling WJ, Halvarsson G, Möller C. Expressivity of hearing loss in cases with Usher syndrome type IIA. Int J Audiol 2013; 52:832-7. [PMID: 24160897 DOI: 10.3109/14992027.2013.839885] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The purpose of this study was to compare the genotype/phenotype relationship between siblings with identical USH2A pathologic mutations and the consequent audiologic phenotypes, in particular degree of hearing loss (HL). Decade audiograms were also compared among two groups of affected subjects with different mutations of USH2A. DESIGN DNA samples from patients with Usher syndrome type II were analysed. The audiological features of patients and affected siblings with USH2A mutations were also examined to identify genotype-phenotype correlations. STUDY SAMPLE Genetic and audiometric examinations were performed in 18 subjects from nine families with Usher syndrome type IIA. RESULTS Three different USH2A mutations were identified in the affected subjects. Both similarities and differences of the auditory phenotype were seen in families with several affected siblings. A variable degree of hearing loss, ranging from mild to profound, was observed among affected subjects. No significant differences in hearing thresholds were found the group of affected subjects with different pathological mutations. CONCLUSIONS Our results indicate that mutations in the USH2A gene and the resulting phenotype are probably modulated by other variables, such as modifying genes, epigenetics or environmental factors which may be of importance for better understanding the etiology of Usher syndrome.
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Affiliation(s)
- André M Sadeghi
- * Department of Audiology, The Sahlgrenska Academy, Institute of Neuroscience and Physiology , Göteborg , Sweden
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17
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A Novel Frameshift Mutation of the USH2A Gene in a Korean Patient with Usher Syndrome Type II. Clin Exp Otorhinolaryngol 2011; 6:41-4. [PMID: 23526569 PMCID: PMC3604269 DOI: 10.3342/ceo.2013.6.1.41] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 06/17/2010] [Accepted: 07/29/2010] [Indexed: 11/13/2022] Open
Abstract
Usher syndrome type II (USH2) is the most common form of Usher syndrome, characterized by moderate to severe hearing impairment and progressive visual loss due to retinitis pigmentosa. It has been shown that mutations in the USH2A gene are responsible for USH2. The authors herein describe a 34-year-old Korean woman with the typical clinical manifestation of USH2; she had bilateral hearing disturbance and progressive visual deterioration, without vestibular dysfunction. Molecular genetic study of the USH2A gene revealed a novel frameshift mutation (c.2310delA; Glu771LysfsX17). She was heterozygous for this mutation, and no other mutation was found in USH2A, suggesting the possibility of an intronic or large genomic rearrangement mutation. To the best of our knowledge, this is the first report of a genetically confirmed case of USH2 in Korea. More investigations are needed to delineate genotype-phenotype correlations and ethnicity-specific genetic background of Usher syndrome.
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18
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Abadie C, Blanchet C, Baux D, Larrieu L, Besnard T, Ravel P, Biboulet R, Hamel C, Malcolm S, Mondain M, Claustres M, Roux AF. Audiological findings in 100 USH2 patients. Clin Genet 2011; 82:433-8. [PMID: 21895633 DOI: 10.1111/j.1399-0004.2011.01772.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Bilateral sensorineural hearing loss (HL), classically described as mild to severe with a typically down-sloping audiometric configuration, is the earliest symptom occurring in Usher syndrome type II (USH2). Audiological findings were analyzed in a total of 100 USH2 patients (92 families) divided into three groups according to the gene involved: 88 USH2A, 10 GPR98 and 2 DFNB31 patients. A fine analysis of audiograms was performed (pure tone average, degree of severity, configuration). The median age of HL diagnosis was 5 years (range 8 months-31 years) although the median age at USH2 diagnosis was 34.5 (range 8-76). Moderate HL was predominant (76%) and a gently down-sloping configuration characterized most audiograms (66%). No statistically significant difference was found between USH2A and GPR98 patients but a tendency was clearly noted for more GPR98 patients to present with severe hearing loss. It is not possible to predict the mutated gene from audiograms.
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Affiliation(s)
- C Abadie
- CHU Montpellier, Laboratoire de Génétique Moléculaire, 641 Avenue du Doyen Gaston Giraud, Montpellier, France
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19
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Nakanishi H, Ohtsubo M, Iwasaki S, Hotta Y, Mizuta K, Mineta H, Minoshima S. Identification of 11 novel mutations in USH2A among Japanese patients with Usher syndrome type 2. Clin Genet 2009; 76:383-91. [PMID: 19737284 DOI: 10.1111/j.1399-0004.2009.01257.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Usher syndrome (USH) is an autosomal recessive disorder characterized by retinitis pigmentosa and hearing loss. USH type 2 (USH2) is the most common type of USH and is frequently caused by mutations in USH2A, which accounts for 74-90% of USH2 cases. This is the first study reporting the results of scanning for USH2A mutations in Japanese patients with USH2. In 8 of 10 unrelated patients, we identified 14 different mutations. Of these mutations, 11 were novel. Although the mutation spectrum that we identified differed from that for Caucasians, the incidence of mutations in USH2A was 80% for all patients tested, which is consistent with previous findings. Further, c.8559-2A>G was identified in four patients and accounted for 26.7% of mutated alleles; it is thus a frequent mutation in Japanese patients. Hence, mutation screening for c.8559-2A>G in USH2A may prove very effective for the early diagnosis of USH2.
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Affiliation(s)
- H Nakanishi
- Department of Otolaryngology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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20
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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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21
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Ebermann I, Scholl HPN, Charbel Issa P, Becirovic E, Lamprecht J, Jurklies B, Millán JM, Aller E, Mitter D, Bolz H. A novel gene for Usher syndrome type 2: mutations in the long isoform of whirlin are associated with retinitis pigmentosa and sensorineural hearing loss. Hum Genet 2006; 121:203-11. [PMID: 17171570 DOI: 10.1007/s00439-006-0304-0] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Accepted: 11/18/2006] [Indexed: 10/23/2022]
Abstract
Usher syndrome is an autosomal recessive condition characterized by sensorineural hearing loss, variable vestibular dysfunction, and visual impairment due to retinitis pigmentosa (RP). The seven proteins that have been identified for Usher syndrome type 1 (USH1) and type 2 (USH2) may interact in a large protein complex. In order to identify novel USH genes, we followed a candidate strategy, assuming that mutations in proteins interacting with this "USH network" may cause Usher syndrome as well. The DFNB31 gene encodes whirlin, a PDZ scaffold protein with expression in both hair cell stereocilia and retinal photoreceptor cells. Whirlin represents an excellent candidate for USH2 because it binds to Usherin (USH2A) and VLGR1b (USH2C). Genotyping of microsatellite markers specific for the DFNB31 gene locus on chromosome 9q32 was performed in a German USH2 family that had been excluded for all known USH loci. Patients showed common haplotypes. Sequence analysis of DFNB31 revealed compound heterozygosity for a nonsense mutation, p.Q103X, in exon 1, and a mutation in the splice donor site of exon 2, c.837+1G>A. DFNB31 mutations appear to be a rare cause of Usher syndrome, since no mutations were identified in an additional 96 USH2 patients. While mutations in the C-terminal half of whirlin have previously been reported in non-syndromic deafness (DFNB31), both alterations identified in our USH2 family affect the long protein isoform. We propose that mutations causing Usher syndrome are probably restricted to exons 1-6 that are specific for the long isoform and probably crucial for retinal function. We describe a novel genetic subtype for Usher syndrome, which we named USH2D and which is caused by mutations in whirlin. Moreover, this is the first case of USH2 that is allelic to non-syndromic deafness.
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Affiliation(s)
- Inga Ebermann
- Institute of Human Genetics, University Hospital of Cologne, Kerpener Str. 34, 50931 Cologne, Germany
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22
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McGee J, Goodyear RJ, McMillan DR, Stauffer EA, Holt JR, Locke KG, Birch DG, Legan PK, White PC, Walsh EJ, Richardson GP. The very large G-protein-coupled receptor VLGR1: a component of the ankle link complex required for the normal development of auditory hair bundles. J Neurosci 2006; 26:6543-53. [PMID: 16775142 PMCID: PMC2682555 DOI: 10.1523/jneurosci.0693-06.2006] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Sensory hair bundles in the inner ear are composed of stereocilia that can be interconnected by a variety of different link types, including tip links, horizontal top connectors, shaft connectors, and ankle links. The ankle link antigen is an epitope specifically associated with ankle links and the calycal processes of photoreceptors in chicks. Mass spectrometry and immunoblotting were used to identify this antigen as the avian ortholog of the very large G-protein-coupled receptor VLGR1, the product of the Usher syndrome USH2C (Mass1) locus. Like ankle links, Vlgr1 is expressed transiently around the base of developing hair bundles in mice. Ankle links fail to form in the cochleae of mice carrying a targeted mutation in Vlgr1 (Vlgr1/del7TM), and the bundles become disorganized just after birth. FM1-43 [N-(3-triethylammonium)propyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide] dye loading and whole-cell recordings indicate mechanotransduction is impaired in cochlear, but not vestibular, hair cells of early postnatal Vlgr1/del7TM mutant mice. Auditory brainstem recordings and distortion product measurements indicate that these mice are severely deaf by the third week of life. Hair cells from the basal half of the cochlea are lost in 2-month-old Vlgr1/del7TM mice, and retinal function is mildly abnormal in aged mutants. Our results indicate that Vlgr1 is required for formation of the ankle link complex and the normal development of cochlear hair bundles.
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MESH Headings
- Acoustic Stimulation/methods
- Age Factors
- Animals
- Animals, Newborn
- Blotting, Western/methods
- Chickens
- Cochlea/cytology
- Cochlea/growth & development
- Dose-Response Relationship, Radiation
- Electroretinography/methods
- Epitopes/immunology
- Evoked Potentials, Auditory, Brain Stem/physiology
- Fluorescent Antibody Technique/methods
- Hair Cells, Auditory/growth & development
- Hair Cells, Auditory/metabolism
- Hair Cells, Auditory/ultrastructure
- Immunoprecipitation/methods
- In Vitro Techniques
- Mass Spectrometry/methods
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Membrane Potentials/radiation effects
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Electron, Scanning
- Microscopy, Immunoelectron/methods
- Patch-Clamp Techniques/methods
- Pyridinium Compounds/pharmacokinetics
- Quaternary Ammonium Compounds/pharmacokinetics
- Receptors, G-Protein-Coupled/deficiency
- Receptors, G-Protein-Coupled/physiology
- Retina/metabolism
- Retina/ultrastructure
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Sadeghi AM, Eriksson K, Kimberling WJ, Sjöström A, Möller C. Longterm visual prognosis in Usher syndrome types 1 and 2. ACTA ACUST UNITED AC 2006; 84:537-44. [PMID: 16879578 DOI: 10.1111/j.1600-0420.2006.00675.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
PURPOSE To estimate the age at diagnosis of retinitis pigmentosa and to determine visual acuity deterioration, visual field impairment and the frequency of cataracts in Usher syndrome types 1 and 2. METHODS We carried out a retrospective study of 328 affected subjects with Usher syndrome types 1 and 2. Study subjects were divided into seven different age groups by decade. Data were analysed using descriptive statistics, general linear model anova and survival analysis. RESULTS Retinitis pigmentosa was diagnosed significantly earlier in subjects with Usher syndrome type 1 than in those with type 2. Visual acuity was significantly more impaired in affected subjects with Usher syndrome type 1 than in those with type 2 from 50 years of age onwards. Survival analysis revealed a significant difference in visual field loss (<or= 10 degrees) between the two groups, with type 2 subjects tending to be more impaired, while comparison indicated no significant differences between the groups in any of the other visual field categories. Cataract was found to be generally more common in Usher syndrome type 1 than type 2. CONCLUSIONS Progressive loss of visual acuity and visual field begins to be substantial between the second and third decades of life in both Usher types. The rate of degeneration varies between individuals in both groups. The data are useful for the counselling of affected subjects with Usher syndrome types 1 and 2.
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Affiliation(s)
- André M Sadeghi
- Sahlgrenska Academy, Institute of Neurology and Physiology, Department of Audiology, Gothenburg, Sweden.
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24
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Bernal S, Medà C, Solans T, Ayuso C, Garcia-Sandoval B, Valverde D, Del Rio E, Baiget M. Clinical and genetic studies in Spanish patients with Usher syndrome type II: description of new mutations and evidence for a lack of genotype--phenotype correlation. Clin Genet 2005; 68:204-14. [PMID: 16098008 DOI: 10.1111/j.1399-0004.2005.00481.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Patients with Usher syndrome type II (USH2) show moderate-to-severe hearing loss (HL), retinitis pigmentosa and normal vestibular function. The progression of HL remains controversial. To evaluate whether a phenotype-genotype correlation exists regarding the issue of progression of HL, only USH2 patients with a defined genotype were selected. Ophthalmologic, vestibular and audiometric examination along with a mutation analysis of the USH2A gene (exons 1--21) was performed in twenty-eight Spanish USH2 patients. Ten different pathogenic mutations and 17 sequence variants not associated with the disease were found. Six of the 10 mutations are novel. Disease alleles were identified in 13 of the 28 families tested. Eight of these 13 families had a mutation found in both alleles. In the other five families, only one mutation was identified. The phenotypic data provide evidence for the existence of phenotypic differences between patients with the same genotype. These differences were observed at both the interfamilial and intrafamilial levels.
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Affiliation(s)
- S Bernal
- Servei de Genètica, Universidad de Vigo, Vigo, Spain
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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: 19] [Impact Index Per Article: 1.0] [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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