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Busi M, Castiglione A. Navigating the Usher Syndrome Genetic Landscape: An Evaluation of the Associations between Specific Genes and Quality Categories of Cochlear Implant Outcomes. Audiol Res 2024; 14:254-263. [PMID: 38525684 PMCID: PMC10961690 DOI: 10.3390/audiolres14020023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/26/2024] Open
Abstract
Usher syndrome (US) is a clinically and genetically heterogeneous disorder that involves three main features: sensorineural hearing loss, retinitis pigmentosa (RP), and vestibular impairment. With a prevalence of 4-17/100,000, it is the most common cause of deaf-blindness worldwide. Genetic research has provided crucial insights into the complexity of US. Among nine confirmed causative genes, MYO7A and USH2A are major players in US types 1 and 2, respectively, whereas CRLN1 is the sole confirmed gene associated with type 3. Variants in these genes also contribute to isolated forms of hearing loss and RP, indicating intersecting molecular pathways. While hearing loss can be adequately managed with hearing aids or cochlear implants (CIs), approved RP treatment modalities are lacking. Gene replacement and editing, antisense oligonucleotides, and small-molecule drugs hold promise for halting RP progression and restoring vision, enhancing patients' quality of life. Massively parallel sequencing has identified gene variants (e.g., in PCDH15) that influence CI results. Accordingly, preoperative genetic examination appears valuable for predicting CI success. To explore genetic mutations in CI recipients and establish correlations between implant outcomes and involved genes, we comprehensively reviewed the literature to gather data covering a broad spectrum of CI outcomes across all known US-causative genes. Implant outcomes were categorized as excellent or very good, good, poor or fair, and very poor. Our review of 95 cochlear-implant patients with US, along with their CI outcomes, revealed the importance of presurgical genetic testing to elucidate potential challenges and provide tailored counseling to improve auditory outcomes. The multifaceted nature of US demands a comprehensive understanding and innovative interventions. Genetic insights drive therapeutic advancements, offering potential remedies for the retinal component of US. The synergy between genetics and therapeutics holds promise for individuals with US and may enhance their sensory experiences through customized interventions.
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Affiliation(s)
- Micol Busi
- Department of Audiology, Orebro University Hospital, Interdisciplinary Research in Clinical Audiology—IRCA, Orebro University, 70116 Orebro, Sweden;
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Riaz S, Sethna S, Duncan T, Naeem MA, Redmond TM, Riazuddin S, Riazuddin S, Carvalho LS, Ahmed ZM. Dual AAV-based PCDH15 gene therapy achieves sustained rescue of visual function in a mouse model of Usher syndrome 1F. Mol Ther 2023; 31:3490-3501. [PMID: 37864333 PMCID: PMC10727994 DOI: 10.1016/j.ymthe.2023.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/20/2023] [Accepted: 10/18/2023] [Indexed: 10/22/2023] Open
Abstract
Mutations in the PCDH15 gene, encoding protocadherin-15, are among the leading causes of Usher syndrome type 1 (USH1F), and account for up to 12% USH1 cases worldwide. A founder truncating variant of PCDH15 has a ∼2% carrier frequency in Ashkenazi Jews accounting for nearly 60% of their USH1 cases. Although cochlear implants can restore hearing perception in USH1 patients, presently there are no effective treatments for the vision loss due to retinitis pigmentosa. We established a founder allele-specific Pcdh15 knockin mouse model as a platform to ascertain therapeutic strategies. Using a dual-vector approach to circumvent the size limitation of adeno-associated virus, we observed robust expression of exogenous PCDH15 in the retinae of Pcdh15KI mice, sustained recovery of electroretinogram amplitudes and key retinoid oxime, substantially improved light-dependent translocation of phototransduction proteins, and enhanced levels of retinal pigment epithelium-derived enzymes. Thus, our data raise hope and pave the way for future gene therapy trials in USH1F subjects.
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Affiliation(s)
- Sehar Riaz
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 54500, Pakistan
| | - Saumil Sethna
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Todd Duncan
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Muhammad A Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 54500, Pakistan
| | - T Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sheikh Riazuddin
- Jinnah Burn and Reconstructive Surgery Centre, Allama Iqbal Medical Research, University of Health Sciences, Lahore 54500, Pakistan
| | - Saima Riazuddin
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Molecular Biology and Biochemistry, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Livia S Carvalho
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA 6009, Australia; Retinal Genomics and Therapy Group, Lions Eye Institute Ltd, Nedlands, WA 6009, Australia
| | - Zubair M Ahmed
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Molecular Biology and Biochemistry, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Peters CW, Hanlon KS, Ivanchenko MV, Zinn E, Linarte EF, Li Y, Levy JM, Liu DR, Kleinstiver BP, Indzhykulian AA, Corey DP. Rescue of hearing by adenine base editing in a humanized mouse model of Usher syndrome type 1F. Mol Ther 2023; 31:2439-2453. [PMID: 37312453 PMCID: PMC10421997 DOI: 10.1016/j.ymthe.2023.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 04/03/2023] [Accepted: 06/08/2023] [Indexed: 06/15/2023] Open
Abstract
Usher syndrome type 1F (USH1F), characterized by congenital lack of hearing and balance and progressive loss of vision, is caused by mutations in the PCDH15 gene. In the Ashkenazi population, a recessive truncation mutation accounts for a large proportion of USH1F cases. The truncation is caused by a single C→T mutation, which converts an arginine codon to a stop (R245X). To test the potential for base editors to revert this mutation, we developed a humanized Pcdh15R245X mouse model for USH1F. Mice homozygous for the R245X mutation were deaf and exhibited profound balance deficits, while heterozygous mice were unaffected. Here we show that an adenine base editor (ABE) is capable of reversing the R245X mutation to restore the PCDH15 sequence and function. We packaged a split-intein ABE into dual adeno-associated virus (AAV) vectors and delivered them into cochleas of neonatal USH1F mice. Hearing was not restored in a Pcdh15 constitutive null mouse despite base editing, perhaps because of early disorganization of cochlear hair cells. However, injection of vectors encoding the split ABE into a late-deletion conditional Pcdh15 knockout rescued hearing. This study demonstrates the ability of an ABE to correct the PCDH15 R245X mutation in the cochlea and restore hearing.
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Affiliation(s)
- Cole W Peters
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Killian S Hanlon
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - Eric Zinn
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA 02114, USA
| | | | - Yaqiao Li
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jonathan M Levy
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Benjamin P Kleinstiver
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | - Artur A Indzhykulian
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - David P Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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Abstract
Usher syndrome (USH) is the most common genetic condition responsible for combined loss of hearing and vision. Balance disorders and bilateral vestibular areflexia are also observed in some cases. The syndrome was first described by Albrecht von Graefe in 1858, but later named by Charles Usher, who presented a large number of cases with hearing loss and retinopathy in 1914. USH has been grouped into three main clinical types: 1, 2, and 3, which are caused by mutations in different genes and are further divided into different subtypes. To date, nine causative genes have been identified and confirmed as responsible for the syndrome when mutated: MYO7A, USH1C, CDH23, PCDH15, and USH1G (SANS) for Usher type 1; USH2A, ADGRV1, and WHRN for Usher type 2; CLRN1 for Usher type 3. USH is inherited in an autosomal recessive pattern. Digenic, bi-allelic, and polygenic forms have also been reported, in addition to dominant or nonsyndromic forms of genetic mutations. This narrative review reports the causative forms, diagnosis, prognosis, epidemiology, rehabilitation, research, and new treatments of USH.
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Yusuf IH, Garrett A, MacLaren RE, Issa PC. Retinal cadherins and the retinal cadherinopathies: Current concepts and future directions. Prog Retin Eye Res 2022; 90:101038. [DOI: 10.1016/j.preteyeres.2021.101038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 12/13/2021] [Accepted: 12/20/2021] [Indexed: 12/18/2022]
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Sethna S, Zein WM, Riaz S, Giese AP, Schultz JM, Duncan T, Hufnagel RB, Brewer CC, Griffith AJ, Redmond TM, Riazuddin S, Friedman TB, Ahmed ZM. Proposed therapy, developed in a Pcdh15-deficient mouse, for progressive loss of vision in human Usher syndrome. eLife 2021; 10:67361. [PMID: 34751129 PMCID: PMC8577840 DOI: 10.7554/elife.67361] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 10/20/2021] [Indexed: 12/15/2022] Open
Abstract
Usher syndrome type I (USH1) is characterized by deafness, vestibular areflexia, and progressive retinal degeneration. The protein-truncating p.Arg245* founder variant of PCDH15 (USH1F) has an ~2% carrier frequency amongst Ashkenazi Jews accounts for ~60% of their USH1 cases. Here, longitudinal phenotyping in 13 USH1F individuals revealed progressive retinal degeneration, leading to severe vision loss with macular atrophy by the sixth decade. Half of the affected individuals were legally blind by their mid-50s. The mouse Pcdh15R250X variant is equivalent to human p.Arg245*. Homozygous Pcdh15R250X mice also have visual deficits and aberrant light-dependent translocation of the phototransduction cascade proteins, arrestin, and transducin. Retinal pigment epithelium (RPE)-specific retinoid cycle proteins, RPE65 and CRALBP, were also reduced in Pcdh15R250X mice, indicating a dual role for protocadherin-15 in photoreceptors and RPE. Exogenous 9-cis retinal improved ERG amplitudes in Pcdh15R250X mice, suggesting a basis for a clinical trial of FDA-approved retinoids to preserve vision in USH1F patients.
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Affiliation(s)
- Saumil Sethna
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Sehar Riaz
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States.,National Center of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Arnaud Pj Giese
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States
| | - Julie M Schultz
- Laboratory of Molecular Genetics, National Institute of Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Todd Duncan
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Carmen C Brewer
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, Bethesda, United States
| | - Andrew J Griffith
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, Bethesda, United States
| | - T Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Saima Riazuddin
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute of Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Zubair M Ahmed
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States.,Departments of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, United States.,Departments of Molecular Biology and Biochemistry, University of Maryland School of Medicine, Baltimore, United States
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Yahalom C, Macarov M, Lazer-Derbeko G, Altarescu G, Imbar T, Hyman JH, Eldar-Geva T, Blumenfeld A. Preimplantation genetic diagnosis as a strategy to prevent having a child born with an heritable eye disease. Ophthalmic Genet 2018; 39:450-456. [PMID: 29781739 DOI: 10.1080/13816810.2018.1474368] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND In developed countries, genetically inherited eye diseases are responsible for a high percentage of childhood visual impairment. We aim to report our experience using preimplantation genetic diagnostics (PGD) in order to avoid transmitting a genetic form of eye disease associated with childhood visual impairment and ocular cancer. MATERIAL AND METHODS Retrospective case series of women who underwent in vitro fertilization (IVF) and PGD due to a familial history of inherited eye disease and/or ocular cancer, in order to avoid having a child affected with the known familial disease. Each family underwent genetic testing in order to identify the underlying disease-causing mutation. IVF and PGD treatment were performed; unaffected embryos were implanted in their respective mothers. RESULTS Thirty-five unrelated mothers underwent PGD, and the following hereditary conditions were identified in their families: albinism (10 families); retinitis pigmentosa (7 families); retinoblastoma (4 families); blue cone monochromatism, achromatopsia, and aniridia (2 families each); and Hermansky-Pudlak syndrome, Leber congenital amaurosis, Norrie disease, papillorenal syndrome, primary congenital cataract, congenital glaucoma, Usher syndrome type 1F, and microphthalmia with coloboma (1 family each). Following a total of 88 PGD cycles, 18 healthy (i.e., unaffected) children were born. CONCLUSIONS Our findings underscore the importance an ophthalmologist plays in informing patients regarding the options now available for using prenatal and preimplantation genetic diagnosis to avoid having a child with a potentially devastating genetic form of eye disease or ocular cancer. This strategy is highly relevant, particularly given the limited options currently available for treating these conditions.
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Affiliation(s)
- Claudia Yahalom
- a Department of Ophthalmology , Hadassah-Hebrew University Medical Center , Jerusalem , Israel
| | - Michal Macarov
- a Department of Ophthalmology , Hadassah-Hebrew University Medical Center , Jerusalem , Israel
| | - Galit Lazer-Derbeko
- b Medical Genetics Institute, Shaare Zedek Medical Center , Jerusalem , Israel
| | - Gheona Altarescu
- b Medical Genetics Institute, Shaare Zedek Medical Center , Jerusalem , Israel
| | - Tal Imbar
- c Department of Obstetrics & Gynecology , Hadassah-Hebrew University Medical Center , Jerusalem , Israel
| | - Jordana H Hyman
- c Department of Obstetrics & Gynecology , Hadassah-Hebrew University Medical Center , Jerusalem , Israel
| | - Talia Eldar-Geva
- d Department of Obstetrics and Gynecology , Shaare Zedek Medical Center , Jerusalem , Israel
| | - Anat Blumenfeld
- a Department of Ophthalmology , Hadassah-Hebrew University Medical Center , Jerusalem , Israel
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Yoshimura H, Miyagawa M, Kumakawa K, Nishio SY, Usami SI. Frequency of Usher syndrome type 1 in deaf children by massively parallel DNA sequencing. J Hum Genet 2016; 61:419-22. [PMID: 26791358 PMCID: PMC4893503 DOI: 10.1038/jhg.2015.168] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 12/07/2015] [Accepted: 12/08/2015] [Indexed: 01/18/2023]
Abstract
Usher syndrome type 1 (USH1) is the most severe of the three USH subtypes due to its profound hearing loss, absent vestibular response and retinitis pigmentosa appearing at a prepubescent age. Six causative genes have been identified for USH1, making early diagnosis and therapy possible through DNA testing. Targeted exon sequencing of selected genes using massively parallel DNA sequencing (MPS) technology enables clinicians to systematically tackle previously intractable monogenic disorders and improve molecular diagnosis. Using MPS along with direct sequence analysis, we screened 227 unrelated non-syndromic deaf children and detected recessive mutations in USH1 causative genes in five patients (2.2%): three patients harbored MYO7A mutations and one each carried CDH23 or PCDH15 mutations. As indicated by an earlier genotype–phenotype correlation study of the CDH23 and PCDH15 genes, we considered the latter two patients to have USH1. Based on clinical findings, it was also highly likely that one patient with MYO7A mutations possessed USH1 due to a late onset age of walking. This first report describing the frequency (1.3–2.2%) of USH1 among non-syndromic deaf children highlights the importance of comprehensive genetic testing for early disease diagnosis.
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Affiliation(s)
- Hidekane Yoshimura
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Maiko Miyagawa
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan.,Department of Hearing Implant Science, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kozo Kumakawa
- Department of Otolaryngology, Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan
| | - Shin-Ya Nishio
- 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
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An Usher syndrome type 1 patient diagnosed before the appearance of visual symptoms by MYO7A mutation analysis. Int J Pediatr Otorhinolaryngol 2013; 77:298-302. [PMID: 23237960 DOI: 10.1016/j.ijporl.2012.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 11/06/2012] [Accepted: 11/09/2012] [Indexed: 01/18/2023]
Abstract
Usher syndrome type 1 (USH1) appears to have only profound non-syndromic hearing loss in childhood and retinitis pigmentosa develops in later years. This study examined the frequency of USH1 before the appearance of visual symptoms in Japanese deaf children by MYO7A mutation analysis. We report the case of 6-year-old male with profound hearing loss, who did not have visual symptoms. The frequency of MYO7A mutations in profound hearing loss children is also discussed. We sequenced all exons of the MYO7A gene in 80 Japanese children with severe to profound non-syndromic HL not due to mutations of the GJB2 gene (ages 0-14 years). A total of nine DNA variants were found and six of them were presumed to be non-pathogenic variants. In addition, three variants of them were found in two patients (2.5%) with deafness and were classified as possible pathogenic variants. Among them, at least one nonsense mutation and one missense mutation from the patient were confirmed to be responsible for deafness. After MYO7A mutation analysis, the patient was diagnosed with RP, and therefore, also diagnosed with USH1. This is the first case report to show the advantage of MYO7A mutation analysis to diagnose USH1 before the appearance of visual symptoms. We believed that MYO7A mutation analysis is valid for the early diagnosis of USH1.
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Jaworek TJ, Bhatti R, Latief N, Khan SN, Riazuddin S, Ahmed ZM. USH1K, a novel locus for type I Usher syndrome, maps to chromosome 10p11.21-q21.1. J Hum Genet 2012; 57:633-7. [PMID: 22718019 PMCID: PMC3596105 DOI: 10.1038/jhg.2012.79] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We ascertained two large Pakistani consanguineous families (PKDF231 and PKDF608) segregating profound hearing loss, vestibular dysfunction, and retinitis pigmentosa; the defining features of Usher syndrome type 1 (USH1). To date, seven USH1 loci have been reported. Here, we map a novel locus, USH1K, on chromosome 10p11.21-q21.1. In family PKDF231, we performed a genome-wide linkage screen and found a region of homozygosity shared among the affected individuals at chromosome 10p11.21-q21.1. Meiotic recombination events in family PKDF231 define a critical interval of 11.74 cM (20.20 Mb) bounded by markers D10S1780 (63.83 cM) and D10S546 (75.57 cM). Affected individuals of family PKDF608 were also homozygous for chromosome 10p11.21-q21.1-linked STR markers. Of the 85 genes within the linkage interval, PCDH15, GJD4, FZD4, RET and LRRC18 were sequenced in both families, but no potential pathogenic mutation was identified. The USH1K locus overlaps the non-syndromic deafness locus DFNB33 raising the possibility that the two disorders may be caused by allelic mutations.
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Affiliation(s)
- Thomas J Jaworek
- Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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Huang Y, Enzmann V, Ildstad ST. Stem cell-based therapeutic applications in retinal degenerative diseases. Stem Cell Rev Rep 2011; 7:434-45. [PMID: 20859770 DOI: 10.1007/s12015-010-9192-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Retinal degenerative diseases that target photoreceptors or the adjacent retinal pigment epithelium (RPE) affect millions of people worldwide. Retinal degeneration (RD) is found in many different forms of retinal diseases including retinitis pigmentosa (RP), age-related macular degeneration (AMD), diabetic retinopathy, cataracts, and glaucoma. Effective treatment for retinal degeneration has been widely investigated. Gene-replacement therapy has been shown to improve visual function in inherited retinal disease. However, this treatment was less effective with advanced disease. Stem cell-based therapy is being pursued as a potential alternative approach in the treatment of retinal degenerative diseases. In this review, we will focus on stem cell-based therapies in the pipeline and summarize progress in treatment of retinal degenerative disease.
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Affiliation(s)
- Yiming Huang
- Institute for Cellular Therapeutics, University of Louisville, 570 S. Preston Street, Suite 404, Louisville, KY 40202-1760, USA
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Brownstein Z, Friedman LM, Shahin H, Oron-Karni V, Kol N, Abu Rayyan A, Parzefall T, Lev D, Shalev S, Frydman M, Davidov B, Shohat M, Rahile M, Lieberman S, Levy-Lahad E, Lee MK, Shomron N, King MC, Walsh T, Kanaan M, Avraham KB. Targeted genomic capture and massively parallel sequencing to identify genes for hereditary hearing loss in Middle Eastern families. Genome Biol 2011; 12:R89. [PMID: 21917145 PMCID: PMC3308052 DOI: 10.1186/gb-2011-12-9-r89] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 08/08/2011] [Accepted: 09/14/2011] [Indexed: 01/29/2023] Open
Abstract
Background Identification of genes responsible for medically important traits is a major challenge in human genetics. Due to the genetic heterogeneity of hearing loss, targeted DNA capture and massively parallel sequencing are ideal tools to address this challenge. Our subjects for genome analysis are Israeli Jewish and Palestinian Arab families with hearing loss that varies in mode of inheritance and severity. Results A custom 1.46 MB design of cRNA oligonucleotides was constructed containing 246 genes responsible for either human or mouse deafness. Paired-end libraries were prepared from 11 probands and bar-coded multiplexed samples were sequenced to high depth of coverage. Rare single base pair and indel variants were identified by filtering sequence reads against polymorphisms in dbSNP132 and the 1000 Genomes Project. We identified deleterious mutations in CDH23, MYO15A, TECTA, TMC1, and WFS1. Critical mutations of the probands co-segregated with hearing loss. Screening of additional families in a relevant population was performed. TMC1 p.S647P proved to be a founder allele, contributing to 34% of genetic hearing loss in the Moroccan Jewish population. Conclusions Critical mutations were identified in 6 of the 11 original probands and their families, leading to the identification of causative alleles in 20 additional probands and their families. The integration of genomic analysis into early clinical diagnosis of hearing loss will enable prediction of related phenotypes and enhance rehabilitation. Characterization of the proteins encoded by these genes will enable an understanding of the biological mechanisms involved in hearing loss.
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Affiliation(s)
- Zippora Brownstein
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Scott SA, Edelmann L, Liu L, Luo M, Desnick RJ, Kornreich R. Experience with carrier screening and prenatal diagnosis for 16 Ashkenazi Jewish genetic diseases. Hum Mutat 2010; 31:1240-50. [PMID: 20672374 DOI: 10.1002/humu.21327] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The success of prenatal carrier screening as a disease prevention strategy in the Ashkenazi Jewish (AJ) population has driven the expansion of screening panels as disease-causing founder mutations have been identified. However, the carrier frequencies of many of these mutations have not been reported in large AJ cohorts. We determined the carrier frequencies of over 100 mutations for 16 recessive disorders in the New York metropolitan area AJ population. Among the 100% AJ-descended individuals, screening for 16 disorders resulted in ∼1 in 3.3 being a carrier for one disease and ∼1 in 24 for two diseases. The carrier frequencies ranged from 0.066 (1 in 15.2; Gaucher disease) to 0.006 (1 in 168; nemaline myopathy), which averaged ∼15% higher than those for all screenees. Importantly, over 95% of screenees chose to be screened for all possible AJ diseases, including disorders with lower carrier frequencies and/or detectability. Carrier screening also identified rare individuals homozygous for disease-causing mutations who had previously unrecognized clinical manifestations. Additionally, prenatal testing results and experience for all 16 disorders (n = 574) are reported. Together, these data indicate the general acceptance, carrier frequencies, and prenatal testing results for an expanded panel of 16 diseases in the AJ population.
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Affiliation(s)
- Stuart A Scott
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine of New York University, New York, NY 10029, 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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16
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Abstract
The identification of the molecular basis of deafness in the last decade has made a remarkable impact on genetic counseling and diagnostics for the hearing impaired population. Since the discovery of the most prevalent form of deafness associated with mutations in the GJB2 (connexin 26) gene, many other genes have been found worldwide, with a subset of these, including unique mutations, in Israel. Here, we review the current status of deafness genes in Israel and report one known mutation in a syndromic form of deafness, Usher syndrome, described in the Jewish Israeli population for the first time. In the future, the identification of specific mutations may be relevant for specific types of treatment.
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Affiliation(s)
- Zippora Brownstein
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978 Israel.
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17
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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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Doucette L, Merner ND, Cooke S, Ives E, Galutira D, Walsh V, Walsh T, MacLaren L, Cater T, Fernandez B, Green JS, Wilcox ER, Shotland LI, Shotland L, Li XC, Li XC, Lee M, King MC, Young TL. Profound, prelingual nonsyndromic deafness maps to chromosome 10q21 and is caused by a novel missense mutation in the Usher syndrome type IF gene PCDH15. Eur J Hum Genet 2008; 17:554-64. [PMID: 19107147 DOI: 10.1038/ejhg.2008.231] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We studied a consanguineous family (Family A) from the island of Newfoundland with an autosomal recessive form of prelingual, profound, nonsyndromic sensorineural hearing loss. A genome-wide scan mapped the deafness trait to 10q21-22 (max LOD score of 4.0; D10S196) and fine mapping revealed a 16 Mb ancestral haplotype in deaf relatives. The PCDH15 gene was mapped within the critical region and was an interesting candidate because truncating mutations cause Usher syndrome type IF (USH1F) and two missense mutations have been previously associated with isolated deafness (DFNB23). Sequencing of the PCDH15 gene revealed 33 sequencing variants. Three of these variants were homozygous exclusively in deaf siblings but only one of them was not seen in ethnically matched controls. This novel c.1583 T>A transversion predicts an amino-acid substitution of a valine with an aspartic acid at codon 528 (V528D). Like the two DFNB23 mutations, the V528D mutation in Family A occurs in a highly conserved extracellular cadherin (EC) domain of PCDH15 and is predicted to be more deleterious than the previously identified DFNB23 missense mutations (R134G and G262D). Physical assessment, vestibular and visual function testing in deaf adults ruled out syndromic deafness because of Usher syndrome. This study validates the DFNB23 designation and supports the hypothesis that missense mutations in conserved motifs of PCDH15 cause nonsyndromic hearing loss. This emerging genotype-phenotype correlation in USH1F is similar to that in several other USH1 genes and cautions against a prognosis of a dual sensory loss in deaf children found to be homozygous for hypomorphic mutations at the USH1F locus.
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Affiliation(s)
- Lance Doucette
- Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, St John's, Newfoundland and Labrador, Canada
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Ahmed ZM, Riazuddin S, Khan SN, Friedman PL, Riazuddin S, Friedman TB. USH1H, a novel locus for type I Usher syndrome, maps to chromosome 15q22-23. Clin Genet 2008; 75:86-91. [PMID: 18505454 DOI: 10.1111/j.1399-0004.2008.01038.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Usher syndrome (USH) is a hereditary disorder associated with sensorineural hearing impairment, progressive loss of vision attributable to retinitis pigmentosa (RP) and variable vestibular function. Three clinical types have been described with type I (USH1) being the most severe. To date, six USH1 loci have been reported. We ascertained two large Pakistani consanguineous families segregating profound hearing loss, vestibular dysfunction, and RP, the defining features of USH1. In these families, we excluded linkage of USH to the 11 known USH loci and subsequently performed a genome-wide linkage screen. We found a novel USH1 locus designated USH1H that mapped to chromosome 15q22-23 in a 4.92-cM interval. This locus overlaps the non-syndromic deafness locus DFNB48 raising the possibility that the two disorders may be caused by allelic mutations.
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Affiliation(s)
- Z M Ahmed
- Section on Human Genetics, Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, MD 20850, USA
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Rebibo-Sabbah A, Nudelman I, Ahmed ZM, Baasov T, Ben-Yosef T. In vitro and ex vivo suppression by aminoglycosides of PCDH15 nonsense mutations underlying type 1 Usher syndrome. Hum Genet 2007; 122:373-81. [PMID: 17653769 DOI: 10.1007/s00439-007-0410-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 07/19/2007] [Indexed: 11/28/2022]
Abstract
Type 1 Usher syndrome (USH1) is a recessively inherited condition, characterized by profound prelingual deafness, vestibular areflexia, and prepubertal onset of retinitis pigmentosa (RP). While the auditory component of USH1 can be treated by cochlear implants, to date there is no effective treatment for RP. USH1 can be caused by mutations in each of at least six genes. While truncating mutations of these genes cause USH1, some missense mutations of the same genes cause nonsyndromic deafness. These observations suggest that partial or low level activity of the encoded proteins may be sufficient for normal retinal function, although not for normal hearing. In individuals with USH1 due to nonsense mutations, interventions enabling partial translation of a full-length functional protein may delay the onset and/or progression of RP. One such possible therapeutic approach is suppression of nonsense mutations by small molecules such as aminoglycosides. We decided to test this approach as a potential therapy for RP in USH1 patients due to nonsense mutations. We initially focused on nonsense mutations of the PCDH15 gene, underlying USH1F. Here, we show suppression of several PCDH15 nonsense mutations, both in vitro and ex vivo. Suppression was achieved both by commercial aminoglycosides and by NB30, a new aminoglycoside-derivative developed by us. NB30 has reduced cytotoxicity in comparison to commercial aminoglycosides, and thus may be more efficiently used for therapeutic purposes. The research described here has important implications for the development of targeted interventions that are effective for patients with USH1 caused by various nonsense mutations.
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Affiliation(s)
- Annie Rebibo-Sabbah
- Department of Genetics, The Rappaport Family Institute for Research in the Medical Sciences, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Bat Galim, Haifa 31096, Israel
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21
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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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