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The genetic and phenotypic landscapes of Usher syndrome: from disease mechanisms to a new classification. Hum Genet 2022; 141:709-735. [PMID: 35353227 PMCID: PMC9034986 DOI: 10.1007/s00439-022-02448-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/04/2022] [Indexed: 12/16/2022]
Abstract
Usher syndrome (USH) is the most common cause of deaf–blindness in humans, with a prevalence of about 1/10,000 (~ 400,000 people worldwide). Cochlear implants are currently used to reduce the burden of hearing loss in severe-to-profoundly deaf patients, but many promising treatments including gene, cell, and drug therapies to restore the native function of the inner ear and retinal sensory cells are under investigation. The traditional clinical classification of Usher syndrome defines three major subtypes—USH1, 2 and 3—according to hearing loss severity and onset, the presence or absence of vestibular dysfunction, and age at onset of retinitis pigmentosa. Pathogenic variants of nine USH genes have been initially reported: MYO7A, USH1C, PCDH15, CDH23, and USH1G for USH1, USH2A, ADGRV1, and WHRN for USH2, and CLRN1 for USH3. Based on the co-occurrence of hearing and vision deficits, the list of USH genes has been extended to few other genes, but with limited supporting information. A consensus on combined criteria for Usher syndrome is crucial for the development of accurate diagnosis and to improve patient management. In recent years, a wealth of information has been obtained concerning the properties of the Usher proteins, related molecular networks, potential genotype–phenotype correlations, and the pathogenic mechanisms underlying the impairment or loss of hearing, balance and vision. The advent of precision medicine calls for a clear and more precise diagnosis of Usher syndrome, exploiting all the existing data to develop a combined clinical/genetic/network/functional classification for Usher syndrome.
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Perrino PA, Talbot L, Kirkland R, Hill A, Rendall AR, Mountford HS, Taylor J, Buscarello AN, Lahiri N, Saggar A, Fitch RH, Newbury DF. Multi-level evidence of an allelic hierarchy of USH2A variants in hearing, auditory processing and speech/language outcomes. Commun Biol 2020; 3:180. [PMID: 32313182 PMCID: PMC7170883 DOI: 10.1038/s42003-020-0885-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/11/2020] [Indexed: 11/30/2022] Open
Abstract
Language development builds upon a complex network of interacting subservient systems. It therefore follows that variations in, and subclinical disruptions of, these systems may have secondary effects on emergent language. In this paper, we consider the relationship between genetic variants, hearing, auditory processing and language development. We employ whole genome sequencing in a discovery family to target association and gene x environment interaction analyses in two large population cohorts; the Avon Longitudinal Study of Parents and Children (ALSPAC) and UK10K. These investigations indicate that USH2A variants are associated with altered low-frequency sound perception which, in turn, increases the risk of developmental language disorder. We further show that Ush2a heterozygote mice have low-level hearing impairments, persistent higher-order acoustic processing deficits and altered vocalizations. These findings provide new insights into the complexity of genetic mechanisms serving language development and disorders and the relationships between developmental auditory and neural systems. Peter Perrino et al. identify variants in USH2A linked to a dominant language disorder in a human family and find that these variants are also associated with low-frequency hearing at the population level. They investigate the function of USH2A variants in mice, showing that mutations in this gene are responsible for hearing loss.
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Affiliation(s)
- Peter A Perrino
- Department of Psychological Science/Behavioral Neuroscience, University of Connecticut, Storrs, CT, USA.,UConn Institute of Brain and Cognitive Sciences; UConn Murine Behavioral Neurogenetics Facility, Storrs, CT, USA
| | - Lidiya Talbot
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Rose Kirkland
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Headington, Oxford, OX3 7BN, UK.,School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, UK
| | - Amanda Hill
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, BS8 2BN, UK
| | - Amanda R Rendall
- Department of Psychological Science/Behavioral Neuroscience, University of Connecticut, Storrs, CT, USA.,UConn Institute of Brain and Cognitive Sciences; UConn Murine Behavioral Neurogenetics Facility, Storrs, CT, USA
| | - Hayley S Mountford
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Jenny Taylor
- Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Headington, Oxford, OX3 7BN, UK.,NIHR Biomedical Research Centre, John Radcliffe Hospital, Headley Way, Headington, Oxford, OX3 9DU, UK
| | | | - Alexzandrea N Buscarello
- Department of Psychological Science/Behavioral Neuroscience, University of Connecticut, Storrs, CT, USA.,UConn Institute of Brain and Cognitive Sciences; UConn Murine Behavioral Neurogenetics Facility, Storrs, CT, USA
| | - Nayana Lahiri
- Institute of Molecular and Clinical Sciences, St George's, University of London & St George's University Hospitals NHS Foundation Trust, London, UK
| | - Anand Saggar
- Institute of Molecular and Clinical Sciences, St George's, University of London & St George's University Hospitals NHS Foundation Trust, London, UK
| | - R Holly Fitch
- Department of Psychological Science/Behavioral Neuroscience, University of Connecticut, Storrs, CT, USA. .,UConn Institute of Brain and Cognitive Sciences; UConn Murine Behavioral Neurogenetics Facility, Storrs, CT, USA.
| | - Dianne F Newbury
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK.
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The retinal phenotype of Usher syndrome: pathophysiological insights from animal models. C R Biol 2014; 337:167-77. [PMID: 24702843 DOI: 10.1016/j.crvi.2013.12.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 12/03/2013] [Indexed: 01/26/2023]
Abstract
The Usher syndrome (USH) is the most prevalent cause of inherited deaf-blindness. Three clinical subtypes, USH1-3, have been defined, and ten USH genes identified. The hearing impairment due to USH gene defects has been shown to result from improper organisation of the hair bundle, the sound receptive structure of sensory hair cells. In contrast, the cellular basis of the visual defect is less well understood as this phenotype is absent in almost all the USH mouse models that faithfully mimic the human hearing impairment. Structural and molecular interspecies discrepancies regarding photoreceptor calyceal processes and the association with the distribution of USH1 proteins have recently been unravelled, and have led to the conclusion that a defect in the USH1 protein complex-mediated connection between the photoreceptor outer segment and the surrounding calyceal processes (in both rods and cones), and the inner segment (in rods only), probably causes the USH1 retinal dystrophy in humans.
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Abstract
While the functions of many of the proteins located in or associated with the photoreceptor cilia are poorly understood, disruption of the function of these proteins may result in a wide variety of phenotypes ranging from isolated retinal degeneration to more pleiotropic phenotypes. Systemic findings include neurosensory hearing loss, developmental delay, situs-inversus, infertility, disorders of limb and digit development, obesity, kidney disease, liver disease, and respiratory disease. The concept of "retinal ciliopathies" brings to attention the importance of further molecular analysis of this organelle as well as provides a potential common target for therapies for these disorders. The retinal ciliopathies include retinitis pigmentosa, macular degeneration, cone-dystrophy, cone-rod dystrophy, Leber congenital amaurosis, as well as retinal degenerations associated with Usher syndrome, primary ciliary dyskinesia, Senior-Loken syndrome, Joubert syndrome, Bardet-Biedl syndrome, Laurence-Moon syndrome, McKusick-Kaufman syndrome, and Biemond syndrome. Mutations for these disorders have been found in retinitis pigmentosa-1 (RP1), retinitis pigmentosa GTPase regulator (RPGR), retinitis pigmentosa GTPase regulator interacting protein (RPGR-IP), as well as the Usher, Bardet-Biedl, and nephronophthisis genes. Other systemic disorders associated with retinal degenerations that may also involve ciliary abnormalities include: Alstrom, Edwards-Sethi, Ellis-van Creveld, Jeune, Meckel-Gruber, Orofaciodigital Type 9, and Gurrieri syndromes. Understanding these conditions as ciliopathies may help the ophthalmologist to recognize associations between seemingly unrelated diseases and have a high degree of suspicion that a systemic finding may be present.
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Affiliation(s)
- N A Adams
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
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Fishman GA, Bozbeyoglu S, Massof RW, Kimberling W. Natural course of visual field loss in patients with Type 2 Usher syndrome. Retina 2007; 27:601-8. [PMID: 17558323 DOI: 10.1097/01.iae.0000246675.88911.2c] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To evaluate the natural course of visual field loss in patients with Type 2 Usher syndrome and different patterns of visual field loss. METHODS Fifty-eight patients with Type 2 Usher syndrome who had at least three visual field measurements during a period of at least 3 years were studied. Kinetic visual fields measured on a standard calibrated Goldmann perimeter with II4e and V4e targets were analyzed. The visual field areas in both eyes were determined by planimetry with the use of a digitalizing tablet and computer software and expressed in square inches. The data for each visual field area measurement were transformed to a natural log unit. Using a mixed model regression analysis, values for the half-life of field loss (time during which half of the remaining field area is lost) were estimated. Three different patterns of visual field loss were identified, and the half-life time for each pattern of loss was calculated. RESULTS Of the 58 patients, 11 were classified as having pattern type I, 12 with pattern type II, and 14 with pattern type III. Of 21 patients whose visual field loss was so advanced that they could not be classified, 15 showed only a small residual central field (Group A) and 6 showed a residual central field with a peripheral island (Group B). The average half-life times varied between 3.85 and 7.37 for the II4e test target and 4.59 to 6.42 for the V4e target. There was no statistically significant difference in the half-life times between the various patterns of field loss or for the test targets. CONCLUSION The average half-life times for visual field loss in patients with Usher syndrome Type 2 were statistically similar among those patients with different patterns of visual field loss. These findings will be useful for counseling patients with Type 2 Usher syndrome as to their prognosis for anticipated visual field loss.
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Affiliation(s)
- Gerald A Fishman
- Department of Ophthalmology and Visual Sciences, UIC Eye Center, University of Illinois at Chicago, 1855 W. Taylor Street, Chicago, IL 60612, USA.
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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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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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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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Pennings RJE, Huygen PLM, Weston MD, van Aarem A, Wagenaar M, Kimberling WJ, Cremers CWRJ. Pure tone hearing thresholds and speech recognition scores in Dutch patients carrying mutations in the USH2A gene. Otol Neurotol 2003; 24:58-63. [PMID: 12544030 DOI: 10.1097/00129492-200301000-00013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To establish the audiometric profile and speech recognition characteristics in 36 Usher IIa patients, carrying one (A) or two (B) pathogenic mutations in the gene. STUDY DESIGN Family study. SETTING Tertiary referral center. PATIENTS Thirty six Usher IIa patients from 21 Dutch families. METHODS Ophthalmologic, vestibular, and audiometric examinations were performed on all patients. Cross-sectional analysis was performed on pure tone threshold data at 0.25 to 8 kHz and on speech phoneme recognition scores. Progression was evaluated using linear regression analysis on raw and presbyacusis corrected data. RESULTS A downsloping audiogram was found, with a mean threshold slope of -9 dB per octave, that was mildly progressive, i.e., by approximately 0.5 dB per year. Individual monaural maximum phoneme recognition scores (% correct) were analyzed in 30 patients in relation to the patient's age and level of hearing impairment characterized by a pure tone average (PTA(1-4 kHz)). The speech recognition score started to deteriorate from a score of 90% at 38 years at a rate of 0.4% per year. The 90% level was attained at 69 dB hearing level (PTA(1-4 kHz)); at higher levels of impairment, the score deteriorated at a slope of 0.6% per dB hearing level. There was no significant difference between group A and B in pure tone threshold, with or without presbyacusis correction, or phoneme recognition score as related to age or PTA(1-4 kHz). CONCLUSIONS Patients with various mutations in have moderate to severe hearing impairment showing mild progression at approximately 0.5 dB hearing level per year.
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Affiliation(s)
- Ronald J E Pennings
- Departmentof Otorhinolaryngology, University Medical Center Radboud, Nijegen, The Netherlands.
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