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Ouarhache M, Kettani O, Fizazi KE, Bouguenouch L, Ouldim K. A novel homozygous missense variant identified in the myosin VIIA motor domain of a Moroccan patient with usher syndrome. Mol Biol Rep 2024; 51:683. [PMID: 38796585 DOI: 10.1007/s11033-024-09603-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 05/01/2024] [Indexed: 05/28/2024]
Abstract
BACKGROUND Usher syndrome 1 (USH1) is the most severe subtype of Usher syndrome characterized by severe sensorineural hearing impairment, retinitis pigmentosa, and vestibular areflexia. USH1 is usually induced by variants in MYO7A, a gene that encodes the myosin-VIIa protein. Myosin-VIIA is effectively involved in intracellular molecular traffic essential for the proper function of the cochlea, the retinal photoreceptors, and the retinal pigmented epithelial cells. METHODS AND RESULTS In this study, we report a new homozygous missense variant (NM_000260.4: c.1657 C > T p.(His553Tyr)) in MYO7A of a 28-year-old female with symptoms consistent with USH1. This variant, c.1657 C > T p.(His553Tyr) is positioned in the highly conserved myosin-VIIA motor domain. Previous studies showed that variants in this domain might disrupt the ability of the protein to bind to actin and thus cause the disorder. CONCLUSIONS Our findings contribute to our understanding of the phenotypic and mutational spectrum of USH1 associated with autosomal recessive MYO7A variants and emphasize the important role of molecular testing in accurately diagnosing this syndrome. More advanced research is required to understand the functional effect of the identified variant and the genotype-phonotype correlations of MYO7A-related Usher syndrome 1.
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Affiliation(s)
- Maryem Ouarhache
- Faculty of Medicine, Pharmacy and Dentistry, Biomedical and Translational Research Laboratory, Sidi Mohammed Ben Abdellah University, Fez, Morocco.
- Medical Genetics and Oncogenetics Unit, University Hospital Center Hassan II, Fez, Morocco.
| | - Oussama Kettani
- Medical Genetics and Oncogenetics Department, University Hospital Center Mohammed VI, Tangier, Morocco
| | - Khawla El Fizazi
- Medical Genetics and Oncogenetics Unit, University Hospital Center Hassan II, Fez, Morocco
| | - Laila Bouguenouch
- Faculty of Medicine, Pharmacy and Dentistry, Biomedical and Translational Research Laboratory, Sidi Mohammed Ben Abdellah University, Fez, Morocco
- Medical Genetics and Oncogenetics Unit, University Hospital Center Hassan II, Fez, Morocco
| | - Karim Ouldim
- Faculty of Medicine, Pharmacy and Dentistry, Biomedical and Translational Research Laboratory, Sidi Mohammed Ben Abdellah University, Fez, Morocco
- Medical Genetics and Oncogenetics Unit, University Hospital Center Hassan II, Fez, Morocco
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2
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Nonarath HJT, Simpson SL, Slobodianuk TL, Collery RF, Dinculescu A, Link BA. The USH3A causative gene clarin1 functions in Müller glia to maintain retinal photoreceptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582878. [PMID: 38464015 PMCID: PMC10925332 DOI: 10.1101/2024.02.29.582878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Mutations in CLRN1 cause Usher syndrome type IIIA (USH3A), an autosomal recessive disorder characterized by hearing and vision loss, and often accompanied by vestibular balance issues. The identity of the cell types responsible for the pathology and mechanisms leading to vision loss in USH3A remains elusive. To address this, we employed CRISPR/Cas9 technology to delete a large region in the coding and untranslated (UTR) region of zebrafish clrn1. Retina of clrn1 mutant larvae exhibited sensitivity to cell stress, along with age-dependent loss of function and degeneration in the photoreceptor layer. Investigation revealed disorganization in the outer retina in clrn1 mutants, including actin-based structures of the Müller glia and photoreceptor cells. To assess cell-specific contributions to USH3A pathology, we specifically re-expressed clrn1 in either Müller glia or photoreceptor cells. Müller glia re-expression of clrn1 prevented the elevated cell death observed in larval clrn1 mutant zebrafish exposed to high-intensity light. Notably, the degree of phenotypic rescue correlated with the level of Clrn1 re-expression. Surprisingly, high levels of Clrn1 expression enhanced cell death in both wild-type and clrn1 mutant animals. However, rod- or cone-specific Clrn1 re-expression did not rescue the extent of cell death. Taken together, our findings underscore three crucial insights. First, clrn1 mutant zebrafish exhibit key pathological features of USH3A; second, Clrn1 within Müller glia plays a pivotal role in photoreceptor maintenance, with its expression requiring controlled regulation; third, the reliance of photoreceptors on Müller glia suggests a structural support mechanism, possibly through direct interactions between Müller glia and photoreceptors mediated in part by Clrn1 protein.
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Affiliation(s)
- Hannah J. T. Nonarath
- Department Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Samantha L. Simpson
- Department of Ophthalmology and Vision Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Tricia L. Slobodianuk
- Department Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Ross F. Collery
- Department of Ophthalmology and Vision Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Astra Dinculescu
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32611
| | - Brian A. Link
- Department Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
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Gilmore WB, Hultgren NW, Chadha A, Barocio SB, Zhang J, Kutsyr O, Flores-Bellver M, Canto-Soler MV, Williams DS. Expression of two major isoforms of MYO7A in the retina: Considerations for gene therapy of Usher syndrome type 1B. Vision Res 2023; 212:108311. [PMID: 37586294 PMCID: PMC10984346 DOI: 10.1016/j.visres.2023.108311] [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: 05/03/2023] [Revised: 07/25/2023] [Accepted: 07/28/2023] [Indexed: 08/18/2023]
Abstract
Usher syndrome type 1B (USH1B) is a deaf-blindness disorder, caused by mutations in the MYO7A gene, which encodes the heavy chain of an unconventional actin-based motor protein. Here, we examined the two retinal isoforms of MYO7A, IF1 and IF2. We compared 3D models of the two isoforms and noted that the 38-amino acid region that is present in IF1 but absent from IF2 affects the C lobe of the FERM1 domain and the opening of a cleft in this potentially important protein binding domain. Expression of each of the two isoforms of human MYO7A and pig and mouse Myo7a was detected in the RPE and neural retina. Quantification by qPCR showed that the expression of IF2 was typically ∼ 7-fold greater than that of IF1. We discuss the implications of these findings for any USH1B gene therapy strategy. Given the current incomplete knowledge of the functions of each isoform, both isoforms should be considered for targeting both the RPE and the neural retina in gene augmentation therapies.
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Affiliation(s)
- W Blake Gilmore
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Nan W Hultgren
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Abhishek Chadha
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Sonia B Barocio
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Joyce Zhang
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Oksana Kutsyr
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, CO, USA
| | - Miguel Flores-Bellver
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, CO, USA
| | - M Valeria Canto-Soler
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, CO, USA
| | - David S Williams
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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4
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Malvasi M, Casillo L, Avogaro F, Abbouda A, Vingolo EM. Gene Therapy in Hereditary Retinal Dystrophies: The Usefulness of Diagnostic Tools in Candidate Patient Selections. Int J Mol Sci 2023; 24:13756. [PMID: 37762059 PMCID: PMC10531171 DOI: 10.3390/ijms241813756] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/24/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
PURPOSE Gene therapy actually seems to have promising results in the treatment of Leber Congenital Amaurosis and some different inherited retinal diseases (IRDs); the primary goal of this strategy is to change gene defects with a wild-type gene without defects in a DNA sequence to achieve partial recovery of the photoreceptor function and, consequently, partially restore lost retinal functions. This approach led to the introduction of a new drug (voretigene neparvovec-rzyl) for replacement of the RPE65 gene in patients affected by Leber Congenital Amaurosis (LCA); however, the treatment results are inconstant and with variable long-lasting effects due to a lack of correctly evaluating the anatomical and functional conditions of residual photoreceptors. These variabilities may also be related to host immunoreactive reactions towards the Adenovirus-associated vector. A broad spectrum of retinal dystrophies frequently generates doubt as to whether the disease or the patient is a good candidate for a successful gene treatment, because, very often, different diseases share similar genetic characteristics, causing an inconstant genotype/phenotype correlation between clinical characteristics also within the same family. For example, mutations on the RPE65 gene cause Leber Congenital Amaurosis (LCA) but also some forms of Retinitis Pigmentosa (RP), Bardet Biedl Syndrome (BBS), Congenital Stationary Night Blindness (CSNB) and Usher syndrome (USH), with a very wide spectrum of clinical manifestations. These confusing elements are due to the different pathways in which the product protein (retinoid isomer-hydrolase) is involved and, consequently, the overlapping metabolism in retinal function. Considering this point and the cost of the drug (over USD one hundred thousand), it would be mandatory to follow guidelines or algorithms to assess the best-fitting disease and candidate patients to maximize the output. Unfortunately, at the moment, there are no suggestions regarding who to treat with gene therapy. Moreover, gene therapy might be helpful in other forms of inherited retinal dystrophies, with more frequent incidence of the disease and better functional conditions (actually, gene therapy is proposed only for patients with poor vision, considering possible side effects due to the treatment procedures), in which this approach leads to better function and, hopefully, visual restoration. But, in this view, who might be a disease candidate or patient to undergo gene therapy, in relationship to the onset of clinical trials for several different forms of IRD? Further, what is the gold standard for tests able to correctly select the patient? Our work aims to evaluate clinical considerations on instrumental morphofunctional tests to assess candidate subjects for treatment and correlate them with clinical and genetic defect analysis that, often, is not correspondent. We try to define which parameters are an essential and indispensable part of the clinical rationale to select patients with IRDs for gene therapy. This review will describe a series of models used to characterize retinal morphology and function from tests, such as optical coherence tomography (OCT) and electrophysiological evaluation (ERG), and its evaluation as a primary outcome in clinical trials. A secondary aim is to propose an ancillary clinical classification of IRDs and their accessibility based on gene therapy's current state of the art. MATERIAL AND METHODS OCT, ERG, and visual field examinations were performed in different forms of IRDs, classified based on clinical and retinal conditions; compared to the gene defect classification, we utilized a diagnostic algorithm for the clinical classification based on morphofunctional information of the retina of patients, which could significantly improve diagnostic accuracy and, consequently, help the ophthalmologist to make a correct diagnosis to achieve optimal clinical results. These considerations are very helpful in selecting IRD patients who might respond to gene therapy with possible therapeutic success and filter out those in which treatment has a lower chance or no chance of positive results due to bad retinal conditions, avoiding time-consuming patient management with unsatisfactory results.
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Affiliation(s)
- Mariaelena Malvasi
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
| | - Lorenzo Casillo
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
| | - Filippo Avogaro
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
| | - Alessandro Abbouda
- Department of Ophthalmology, Fiorini Hospital Terracina AUSL, 04019 Terracina, Italy
| | - Enzo Maria Vingolo
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
- Department of Ophthalmology, Fiorini Hospital Terracina AUSL, 04019 Terracina, Italy
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Boye SE, Durham T, Laster A, Gelfman CM, Sahel JA. Identifying and Overcoming Challenges in Developing Effective Treatments for Usher 1B: A Workshop Report. Transl Vis Sci Technol 2023; 12:2. [PMID: 36723965 PMCID: PMC9904327 DOI: 10.1167/tvst.12.2.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Purpose To identify challenges and opportunities for the development of treatments for Usher syndrome (USH) type 1B. Methods In September 2021, the Foundation Fighting Blindness hosted a virtual workshop of clinicians, academic and industry researchers, advocates, and affected individuals and their families to discuss the challenges and opportunities for USH1B treatment development. Results The workshop began with insights from individuals affected by USH1B. Presentation topics included myosin VIIA protein function in the ear and eye and its role in disease pathology; challenges with the USH1B mouse model most used in disease research to date; new investigations into alternative disease models that may provide closer analogues to USH1B in the human retina, including retinal organoids and large animal models; and learnings from and limitations of available disease natural history data. Participants discussed the need for an open dialogue between researchers and regulators to design USH1B clinical trials with appropriate outcome measures of vision improvement, along with multimodal imaging of the retina and other testing approaches that can help inform trial designs. The workshop concluded with presentations and a roundtable reviewing emerging treatments, including USH1B-targeted genetic augmentation therapy and gene-agnostic approaches. Conclusions Initiatives like this workshop are important to foster all stakeholders in support of achieving the shared goal of treating and curing USH1B. Translational Relevance Presentations and discussions focused on overcoming disease modeling and clinical trial design challenges to facilitate development, testing, and implementation of effective USH1B treatments.
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Affiliation(s)
- Shannon E. Boye
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA,Atsena Therapeutics, Inc., Durham, NC, USA
| | - Todd Durham
- Foundation Fighting Blindness, Columbia, MD, USA
| | - Amy Laster
- Foundation Fighting Blindness, Columbia, MD, USA
| | | | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France,Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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6
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Calabro KR, Boye SL, Boye SE. Optimization of Capillary-Based Western Blotting for MYO7A. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:125-130. [PMID: 37440024 DOI: 10.1007/978-3-031-27681-1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Myosin VIIA (MYO7A)-associated Usher syndrome type 1B (USH1B) is a severe disorder that impacts the auditory, vestibular, and visual systems of affected patients. Due to the large size (~7.5 kb) of the MYO7A coding sequence, we have designed a dual adeno-associated virus (AAV) vector-based approach for the treatment of USH1B-related vision loss. Due to the added complexity of dual-AAV gene therapy, careful attention must be paid to the protein products expressed following vector recombination. In order to improve the sensitivity and quantifiability of our immunoassays, we adapted our traditional western blot protocol for use with the Jess™ Simple Western System. Following several rounds of testing, we optimized our protocol for the detection of MYO7A in two of our most frequently used sample types, mouse eyes, and infected HEK293 cell lysates.
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Affiliation(s)
- Kaitlyn R Calabro
- Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Sanford L Boye
- Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Shannon E Boye
- Department of Pediatrics, University of Florida, Gainesville, FL, USA.
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7
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Lin Q, Yang D, Shen Z, Zhou X. New splice site mutations in MYO7A causing Usher syndrome type 1: a study on a Chinese consanguineous family. Int Ophthalmol 2022; 43:2091-2099. [DOI: 10.1007/s10792-022-02611-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022]
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8
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Ryu J, Statz JP, Chan W, Burch FC, Brigande JV, Kempton B, Porsov EV, Renner L, McGill T, Burwitz BJ, Hanna CB, Neuringer M, Hennebold JD. CRISPR/Cas9 editing of the MYO7A gene in rhesus macaque embryos to generate a primate model of Usher syndrome type 1B. Sci Rep 2022; 12:10036. [PMID: 35710827 PMCID: PMC9203743 DOI: 10.1038/s41598-022-13689-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/26/2022] [Indexed: 12/02/2022] Open
Abstract
Mutations in the MYO7A gene lead to Usher syndrome type 1B (USH1B), a disease characterized by congenital deafness, vision loss, and balance impairment. To create a nonhuman primate (NHP) USH1B model, CRISPR/Cas9 was used to disrupt MYO7A in rhesus macaque zygotes. The targeting efficiency of Cas9 mRNA and hybridized crRNA-tracrRNA (hyb-gRNA) was compared to Cas9 nuclease (Nuc) protein and synthetic single guide (sg)RNAs. Nuc/sgRNA injection led to higher editing efficiencies relative to mRNA/hyb-gRNAs. Mutations were assessed by preimplantation genetic testing (PGT) and those with the desired mutations were transferred into surrogates. A pregnancy was established from an embryo where 92.1% of the PGT sequencing reads possessed a single G insertion that leads to a premature stop codon. Analysis of single peripheral blood leukocytes from the infant revealed that half the cells possessed the homozygous single base insertion and the remaining cells had the wild-type MYO7A sequence. The infant showed sensitive auditory thresholds beginning at 3 months. Although further optimization is needed, our studies demonstrate that it is feasible to use CRISPR technologies for creating NHP models of human diseases.
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Affiliation(s)
- Junghyun Ryu
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA
| | - John P Statz
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - William Chan
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA
- University of Texas Southwestern Medical School, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Fernanda C Burch
- Assisted Reproductive Technologies Core, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA
| | - John V Brigande
- Department of Otolaryngology, Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Beth Kempton
- Department of Otolaryngology, Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Edward V Porsov
- Department of Otolaryngology, Oregon Hearing Research Center, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Lauren Renner
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA
| | - Trevor McGill
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA
- Department of Ophthalmology, Casey Eye Institute, Oregon Health and Science University, Beaverton, OR, 97006, USA
| | - Benjamin J Burwitz
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, OR, 97006, USA
| | - Carol B Hanna
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA
- Assisted Reproductive Technologies Core, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA
| | - Martha Neuringer
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA
- Department of Ophthalmology, Casey Eye Institute, Oregon Health and Science University, Beaverton, OR, 97006, USA
| | - Jon D Hennebold
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, 97006, USA.
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR, 97239, USA.
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9
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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: 36] [Impact Index Per Article: 18.0] [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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Markova TG, Alekseeva NN, Belov OA, Chugunova TI, Tsygankova ER. [Hearing loss due to mutations in the genes responsible for Usher syndrome]. Vestn Otorinolaringol 2022; 87:52-59. [PMID: 35274893 DOI: 10.17116/otorino20228701152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Usher syndrome is characterized by congenital bilateral sensorineural hearing loss and progressive retinitis pigmentosa, and has an autosomal recessive type of inheritance. The purpose of this work is to summarize the modern data of a clinical picture of Usher syndrome and analyse hearing impairment properties. The frequency of the syndrome among children suffering from hearing loss and deafness is from 3 to 10%. The prevalence of the syndrome in the world is estimated as 4.4 per 100.000 population. The complexity of the diagnosis of the syndrome lies in the significant clinical and genetic heterogeneity. Hearing and vision problems begin at different ages. Primary diagnosis begins with the clinical diagnosis of bilateral hearing loss and visual impairment manifests later. In this case the initial diagnosis of nonsyndromal hearing loss will not be definitive. Molecular genetic studies contribute to the early clinical diagnosis of the syndrome. Understanding the cause of the disease allows to conduct correct medical and genetic counseling and get closer to solving treatment problems.
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Affiliation(s)
- T G Markova
- National Research Centre for Audiology and Hearing Rehabilitation, Moscow, Russia
- Russian Medical Academy for Continuous Professional Education Audiology Department, Moscow, Russia
| | - N N Alekseeva
- National Research Centre for Audiology and Hearing Rehabilitation, Moscow, Russia
- Russian Medical Academy for Continuous Professional Education Audiology Department, Moscow, Russia
| | - O A Belov
- National Research Centre for Audiology and Hearing Rehabilitation, Moscow, Russia
| | - T I Chugunova
- National Research Centre for Audiology and Hearing Rehabilitation, Moscow, Russia
| | - E R Tsygankova
- National Research Centre for Audiology and Hearing Rehabilitation, Moscow, Russia
- Russian Medical Academy for Continuous Professional Education Audiology Department, Moscow, Russia
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11
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Pavlenkova Z, Varga L, Borecka S, Karhanek M, Huckova M, Skopkova M, Profant M, Gasperikova D. Comprehensive molecular-genetic analysis of mid-frequency sensorineural hearing loss. Sci Rep 2021; 11:22488. [PMID: 34795337 PMCID: PMC8602250 DOI: 10.1038/s41598-021-01876-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/27/2021] [Indexed: 12/14/2022] Open
Abstract
The genetic heterogeneity of sensorineural hearing loss (SNHL) is a major hurdle to the detection of disease-causing variants. We aimed to identify underlying causal genes associated with mid-frequency hearing loss (HL), which contributes to less than about 1% of SNHL cases, by whole exome sequencing (WES). Thirty families segregating mid-frequency SNHL, in whom biallelic GJB2 mutations had been previously excluded, were selected from among 851 families in our DNA repository of SNHL. DNA samples from the probands were subjected to WES analysis and searched for candidate variants associated with SNHL. We were able to identify the genetic aetiology in six probands (20%). In total, we found three pathogenic and three likely pathogenic variants in four genes (COL4A5, OTOGL, TECTA, TMPRSS3). One more proband was a compound heterozygote for a pathogenic variant and a variant of uncertain significance (VUS) in MYO15A gene. To date, MYO15A and TMPRSS3 have not yet been described in association with mid-frequency SNHL. In eight additional probands, eight candidate VUS variants were detected in five genes (DIAPH1, MYO7A, TECTA, TMC1, TSPEAR). Seven of these 16 variants have not yet been published or mentioned in the available databases. The most prevalent gene was TECTA, identified in 23% of all tested families. Furthermore, we confirmed the hypothesis that a substantive portion of cases with this conspicuous audiogram shape is a consequence of a genetic disorder.
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Affiliation(s)
- Zuzana Pavlenkova
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Medicine and University Hospital, Comenius University, Bratislava, Slovakia.,DIABGENE Laboratory, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Lukas Varga
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Medicine and University Hospital, Comenius University, Bratislava, Slovakia. .,DIABGENE Laboratory, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia.
| | - Silvia Borecka
- DIABGENE Laboratory, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Miloslav Karhanek
- Laboratory of Bioinformatics, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Miloslava Huckova
- DIABGENE Laboratory, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Martina Skopkova
- DIABGENE Laboratory, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Milan Profant
- Department of Otorhinolaryngology-Head and Neck Surgery, Faculty of Medicine and University Hospital, Comenius University, Bratislava, Slovakia
| | - Daniela Gasperikova
- DIABGENE Laboratory, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
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12
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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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13
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Dinculescu A, Link BA, Saperstein DA. Retinal Gene Therapy for Usher Syndrome: Current Developments, Challenges, and Perspectives. Int Ophthalmol Clin 2021; 61:109-124. [PMID: 34584048 PMCID: PMC8478317 DOI: 10.1097/iio.0000000000000378] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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14
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Krishnan AK, Roman AJ, Swider M, Jacobson SG, Cideciyan AV. Macular Rod Function in Retinitis Pigmentosa Measured With Scotopic Microperimetry. Transl Vis Sci Technol 2021; 10:3. [PMID: 34473224 PMCID: PMC8419874 DOI: 10.1167/tvst.10.11.3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Purpose To investigate the validity and reliability of macular rod photoreceptor function measurement with a microperimeter. Methods Macular sensitivity in dark-adapted retinitis pigmentosa (RP) patients (22 eyes; 9–67 years of age) and controls (five eyes; 22–55 years of age) was assessed with a modified Humphrey field analyzer (mHFA), as well as a scotopic microperimeter (Nidek MP-1S). Sensitivity loss (SL) was estimated at rod-mediated locations. All RP eyes were re-evaluated at a second visit 6 months later. The dynamic range of the MP-1S was expanded with a range of neutral-density filters (NDFs). Results In controls, a 4 NDF was used at all macular locations tested. In patients with RP, 0 to 3 NDFs were used, depending on the local disease severity. At rod-mediated locations (n = 281), SL estimates obtained with the MP-1S were highly correlated (r = 0.80) with those of the mHFA. The inter-perimeter difference of SL averaged less than 3 decibels (dB) with all NDFs, except those with most severe locations evaluated with a 0 NDF, where the difference averaged more than 6 dB. The results were similar on the second visit. Conclusions The MP-1S estimates of SL are highly correlated with those of the mHFA over a wide range of disease severity replicated at two visits; however, there was an unexplained bias in the magnitude of SL estimated by the MP-1S especially at loci with severe disease. Translational Relevance MP-1S scotopic microperimetry can be used to evaluate changes to macular rod function, but evaluation of treatment potential by quantitative comparison of SL to retinal structure will be more challenging.
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Affiliation(s)
- Arun K Krishnan
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alejandro J Roman
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Artur V Cideciyan
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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15
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Cideciyan AV, Krishnan AK, Roman AJ, Sumaroka A, Swider M, Jacobson SG. Measures of Function and Structure to Determine Phenotypic Features, Natural History, and Treatment Outcomes in Inherited Retinal Diseases. Annu Rev Vis Sci 2021; 7:747-772. [PMID: 34255540 DOI: 10.1146/annurev-vision-032321-091738] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Inherited retinal diseases (IRDs) are at the forefront of innovative gene-specific treatments because of the causation by single genes, the availability of microsurgical access for treatment delivery, and the relative ease of quantitative imaging and vision measurement. However, it is not always easy to choose a priori, from scores of potential measures, an appropriate subset to evaluate efficacy outcomes considering the wide range of disease stages with different phenotypic features. This article reviews measurements of visual function and retinal structure that our group has used over the past three decades to understand the natural history of IRDs. We include measures of light sensitivity, retinal structure, mapping of natural fluorophores, evaluation of pupillary light reflex, and oculomotor control. We provide historical context and examples of applicability. We also review treatment trial outcomes using these measures of function and structure. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Artur V Cideciyan
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Arun K Krishnan
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Alejandro J Roman
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Alexander Sumaroka
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Malgorzata Swider
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
| | - Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA;
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16
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Fry LE, McClements ME, MacLaren RE. Analysis of Pathogenic Variants Correctable With CRISPR Base Editing Among Patients With Recessive Inherited Retinal Degeneration. JAMA Ophthalmol 2021; 139:319-328. [PMID: 33507217 DOI: 10.1001/jamaophthalmol.2020.6418] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Importance Many common inherited retinal diseases are not easily treated with gene therapy. Gene editing with base editors may allow the targeted repair of single-nucleotide transition variants in DNA and RNA. It is unknown how many patients have pathogenic variants that are correctable with a base editing strategy. Objective To assess the prevalence and spectrum of pathogenic single-nucleotide variants amenable to base editing in common large recessively inherited genes that are associated with inherited retinal degeneration. Design, Setting, and Participants In this retrospective cross-sectional study, nonidentifiable records of patients with biallelic pathogenic variants of genes associated with inherited retinal degeneration between July 2013 and December 2019 were analyzed using data from the Oxford University Hospitals Medical Genetics Laboratories, the Leiden Open Variation Database, and previously published studies. Six candidate genes (ABCA4, CDH23, CEP290, EYS, MYO7A, and USH2A), which were determined to be the most common recessive genes with coding sequences not deliverable in a single adeno-associated viral vector, were examined. Data were analyzed from April 16 to May 11, 2020. Main Outcomes and Measures Proportion of alleles with a pathogenic transition variant that is potentially correctable with a base editing strategy and proportion of patients with a base-editable allele. Results A total of 12 369 alleles from the Leiden Open Variation Database and 179 patients who received diagnoses through the genetic service of the Oxford University Hospitals Medical Genetics Laboratories were analyzed. Editable variants accounted for 53% of all pathogenic variants in the candidate genes contained in the Leiden Open Variation Database. The proportion of pathogenic alleles that were editable varied by gene; 63.1% of alleles in ABCA4, 62.7% of alleles in CDH23, 53.8% of alleles in MYO7A, 41.6% of alleles in CEP290, 37.3% of alleles in USH2A, and 22.2% of alleles in EYS were editable. The 5 most common editable pathogenic variants of each gene accounted for a mean (SD) of 19.1% (9.5%) of all pathogenic alleles within each gene. In the Oxford cohort, 136 of 179 patients (76.0%) had at least 1 editable allele. A total of 53 of 107 patients (49.5%) with biallelic pathogenic variants in the gene ABCA4 and 16 of 56 patients (28.6%) with biallelic pathogenic variants in the gene USH2A had 1 of the 5 most common editable alleles. Conclusions and Relevance This study found that pathogenic variants amenable to base editing commonly occur in inherited retinal degeneration. These findings, if generalized to other cohorts, provide an approach for developing base editing therapies to treat retinal degeneration not amenable to gene therapy.
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Affiliation(s)
- Lewis E Fry
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford University Hospitals National Health Service Foundation Trust, Oxford, United Kingdom
| | - Michelle E McClements
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford University Hospitals National Health Service Foundation Trust, Oxford, United Kingdom
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.,Oxford Eye Hospital, Oxford University Hospitals National Health Service Foundation Trust, Oxford, United Kingdom
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17
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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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18
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Abstract
Myosins constitute a superfamily of actin-based molecular motor proteins that mediates a variety of cellular activities including muscle contraction, cell migration, intracellular transport, the formation of membrane projections, cell adhesion, and cell signaling. The 12 myosin classes that are expressed in humans share sequence similarities especially in the N-terminal motor domain; however, their enzymatic activities, regulation, ability to dimerize, binding partners, and cellular functions differ. It is becoming increasingly apparent that defects in myosins are associated with diseases including cardiomyopathies, colitis, glomerulosclerosis, neurological defects, cancer, blindness, and deafness. Here, we review the current state of knowledge regarding myosins and disease.
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19
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Rod function deficit in retained photoreceptors of patients with class B Rhodopsin mutations. Sci Rep 2020; 10:12552. [PMID: 32724127 PMCID: PMC7387454 DOI: 10.1038/s41598-020-69456-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/09/2020] [Indexed: 12/27/2022] Open
Abstract
A common inherited retinal disease is caused by mutations in RHO expressed in rod photoreceptors that provide vision in dim ambient light. Approximately half of all RHO mutations result in a Class B phenotype where mutant rods are retained in some retinal regions but show severe degeneration in other regions. We determined the natural history of dysfunction and degeneration of retained rods by serially evaluating patients. Even when followed for more than 20 years, rod function and structure at some retinal locations could remain unchanged. Other locations showed loss of both vision and photoreceptors but the rate of rod vision loss was greater than the rate of photoreceptor degeneration. This unexpected divergence in rates with disease progression implied the development of a rod function deficit beyond loss of cells. The divergence of progression rates was also detectable over a short interval of 2 years near the health-disease transition in the superior retina. A model of structure–function relationship supported the existence of a large rod function deficit which was also most prominent near regions of health-disease transition. Our studies support the realistic therapeutic goal of improved night vision for retinal regions specifically preselected for rod function deficit in patients.
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20
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Garafalo AV, Cideciyan AV, Héon E, Sheplock R, Pearson A, WeiYang Yu C, Sumaroka A, Aguirre GD, Jacobson SG. Progress in treating inherited retinal diseases: Early subretinal gene therapy clinical trials and candidates for future initiatives. Prog Retin Eye Res 2020; 77:100827. [PMID: 31899291 PMCID: PMC8714059 DOI: 10.1016/j.preteyeres.2019.100827] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 12/21/2019] [Accepted: 12/26/2019] [Indexed: 12/15/2022]
Abstract
Due to improved phenotyping and genetic characterization, the field of 'incurable' and 'blinding' inherited retinal diseases (IRDs) has moved substantially forward. Decades of ascertainment of IRD patient data from Philadelphia and Toronto centers illustrate the progress from Mendelian genetic types to molecular diagnoses. Molecular genetics have been used not only to clarify diagnoses and to direct counseling but also to enable the first clinical trials of gene-based treatment in these diseases. An overview of the recent reports of gene augmentation clinical trials by subretinal injections is used to reflect on the reasons why there has been limited success in this early venture into therapy. These first-in human experiences have taught that there is a need for advancing the techniques of delivery of the gene products - not only for refining further subretinal trials, but also for evaluating intravitreal delivery. Candidate IRDs for intravitreal gene delivery are then suggested to illustrate some of the disorders that may be amenable to improvement of remaining central vision with the least photoreceptor trauma. A more detailed understanding of the human IRDs to be considered for therapy and the calculated potential for efficacy should be among the routine prerequisites for initiating a clinical trial.
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Affiliation(s)
- Alexandra V Garafalo
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Artur V Cideciyan
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Rebecca Sheplock
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Alexander Pearson
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Caberry WeiYang Yu
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Alexander Sumaroka
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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21
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Costela FM, Pesudovs K, Sandberg MA, Weigel-DiFranco C, Woods RL. Validation of a vision-related activity scale for patients with retinitis pigmentosa. Health Qual Life Outcomes 2020; 18:196. [PMID: 32571342 PMCID: PMC7310073 DOI: 10.1186/s12955-020-01427-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 05/29/2020] [Indexed: 12/31/2022] Open
Abstract
Purpose There have been few systematic reports of vision-related activity limitations of people with retinitis pigmentosa (RP). We report a merging of data from the National Eye Institute Visual Function Questionnaire (NEI-VFQ) obtained in five previous studies. We asked whether the Vision Function Scale (VFS; Pesudovs et al., 2010) which was developed for cataract patients would apply in this new population (condition). Methods Five hundred ninety-four individuals completed a total of 1753 questionnaires, with 209 participants providing responses over at least 4 years. Rasch analysis showed that the 15-item VFS was poorly targeted. A new instrument created by adding four driving-related items to the VFS had better targeting. As an indirect validation, VFS-plus person scores were compared to visual field area measured using a Goldmann perimeter, to the summed score for the combined 30–2 and 30/60–1 Humphrey Field Analyzer programs (HFA), to 30-Hz full-field cone electroretinogram (ERG) amplitude, and to ETDRS visual acuity. Changes in VFS-plus person scores with age and between four common heredity groups were also examined. Results The Rasch model of responses to the 19 VFS-plus items had person and item separation of 2.66 and 24.43 respectively. The VFS-plus person scores were related to each vision measure (p < 0.001). Over a five-year period, there was a reduction in person scores of 0.5 logits (p < 0.001). Person scores fell by an average of 0.34 logits per decade (p < 0.0001). Participants with an X-linked hereditary pattern had, on average, lower person scores (p < 0.001). Conclusions The VFS-plus instrument quantified a highly-significant annual reduction in perceived vision-related ability over a five-year period. The outcome was consistent with clinical measures of vision, and detected lower perceived vision-related ability in participants with X-linked disease. It may be of use in future studies, but this needs to be tested in a representative population sample.
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Affiliation(s)
- Francisco M Costela
- Schepens Eye Research Institute, 20 Staniford St, Boston, MA, 02114, USA. .,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
| | - Konrad Pesudovs
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Michael A Sandberg
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.,Massachusetts Eye and Ear, Boston, MA, USA
| | | | - Russell L Woods
- Schepens Eye Research Institute, 20 Staniford St, Boston, MA, 02114, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
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22
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Roborel de Climens A, Tugaut B, Piscopo A, Arnould B, Buggage R, Brun-Strang C. Living with type I Usher syndrome: insights from patients and their parents. Ophthalmic Genet 2020; 41:240-251. [DOI: 10.1080/13816810.2020.1737947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | | | - Andrea Piscopo
- Global HEVA Early Portfolio, Sanofi, Chilly-Mazarin, France
| | | | - Ronald Buggage
- Research and Development, Sanofi, Chilly-Mazarin, France
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23
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Calabro KR, Boye SL, Choudhury S, Fajardo D, Peterson JJ, Li W, Crosson SM, Kim MJ, Ding D, Salvi R, Someya S, Boye SE. A Novel Mouse Model of MYO7A USH1B Reveals Auditory and Visual System Haploinsufficiencies. Front Neurosci 2019; 13:1255. [PMID: 31824252 PMCID: PMC6883748 DOI: 10.3389/fnins.2019.01255] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 11/05/2019] [Indexed: 12/20/2022] Open
Abstract
Usher’s syndrome is the most common combined blindness–deafness disorder with USH1B, caused by mutations in MYO7A, resulting in the most severe phenotype. The existence of numerous, naturally occurring shaker1 mice harboring variable MYO7A mutations on different genetic backgrounds has complicated the characterization of MYO7A knockout (KO) and heterozygote mice. We generated a novel MYO7A KO mouse (Myo7a–/–) that is easily genotyped, maintained, and confirmed to be null for MYO7A in both the eye and inner ear. Like USH1B patients, Myo7a–/– mice are profoundly deaf, and display near complete loss of inner and outer cochlear hair cells (HCs). No gross structural changes were observed in vestibular HCs. Myo7a–/– mice exhibited modest declines in retinal function but, unlike patients, no loss of retinal structure. We attribute the latter to differential expression of MYO7A in mouse vs. primate retina. Interestingly, heterozygous Myo7a+/– mice had reduced numbers of cochlear HCs and concomitant reductions in auditory function relative to Myo7a+/+ controls. Notably, this is the first report that loss of a single Myo7a allele significantly alters auditory structure and function and suggests that audiological characterization of USH1B carriers is warranted. Maintenance of vestibular HCs in Myo7a–/– mice suggests that gene replacement could be used to correct the vestibular dysfunction in USH1B patients. While Myo7a–/– mice do not exhibit sufficiently robust retinal phenotypes to be used as a therapeutic outcome measure, they can be used to assess expression of vectored MYO7A on a null background and generate valuable pre-clinical data toward the treatment of USH1B.
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Affiliation(s)
- Kaitlyn R Calabro
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Sanford L Boye
- Department of Pediatrics, University of Florida, Gainesville, FL, United States
| | - Shreyasi Choudhury
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Diego Fajardo
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - James J Peterson
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Wei Li
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Sean M Crosson
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Mi-Jung Kim
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States
| | - Dalian Ding
- Department of Communicative Disorders and Sciences, The State University of New York at Buffalo, Buffalo NY, United States
| | - Richard Salvi
- Department of Communicative Disorders and Sciences, The State University of New York at Buffalo, Buffalo NY, United States
| | - Shinichi Someya
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, United States
| | - Shannon E Boye
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
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24
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Webb AA, Ruhe AL, Neff MW. A missense mutation in MYO7A is associated with bilateral deafness and vestibular dysfunction in the Doberman pinscher breed. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2019; 83:142-148. [PMID: 31097876 PMCID: PMC6450158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 04/11/2018] [Indexed: 06/09/2023]
Abstract
Bilateral deafness with concurrent vestibular dysfunction was first reported in the Doberman pinscher in 1980. Here, we identify a coding mutation in the MYO7A gene that is perfectly associated with the disorder. The lack of visual deficits in affected dogs suggests that, like rodents but unlike humans, MYO7A is not required for retinal function. DNA testing of the mutation will enable dog breeders to manage the incidence of this genetic defect.
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Affiliation(s)
- Aubrey A Webb
- CullenWebb Animal Eye Specialists, Riverview, New-Brunswick E1B 4X2 (Webb); Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta T2N 1N4 (Webb); ProjectDog, Davis, California 95616, USA (Ruhe); Van Andel Research Institute, Grand Rapids, Michigan 49503, USA (Ruhe, Neff); Translational Genomics Research Institute, Phoenix, Arizona 85004, USA (Neff)
| | - Alison L Ruhe
- CullenWebb Animal Eye Specialists, Riverview, New-Brunswick E1B 4X2 (Webb); Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta T2N 1N4 (Webb); ProjectDog, Davis, California 95616, USA (Ruhe); Van Andel Research Institute, Grand Rapids, Michigan 49503, USA (Ruhe, Neff); Translational Genomics Research Institute, Phoenix, Arizona 85004, USA (Neff)
| | - Mark W Neff
- CullenWebb Animal Eye Specialists, Riverview, New-Brunswick E1B 4X2 (Webb); Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta T2N 1N4 (Webb); ProjectDog, Davis, California 95616, USA (Ruhe); Van Andel Research Institute, Grand Rapids, Michigan 49503, USA (Ruhe, Neff); Translational Genomics Research Institute, Phoenix, Arizona 85004, USA (Neff)
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Efficacy Outcome Measures for Clinical Trials of USH2A Caused by the Common c.2299delG Mutation. Am J Ophthalmol 2018; 193:114-129. [PMID: 29953849 DOI: 10.1016/j.ajo.2018.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 06/12/2018] [Accepted: 06/19/2018] [Indexed: 12/27/2022]
Abstract
PURPOSE To determine the change in vision and retinal structure in patients with the common c.2299delG mutation in the USH2A gene in anticipation of clinical trials of therapy. DESIGN Retrospective observational case series. METHODS Eighteen patients, homozygotes or compound heterozygotes with the c.2299delG mutation in USH2A, were studied with regard to visual acuity, kinetic perimetry, dark- and light-adapted static perimetry, optical coherence tomography (OCT), and autofluorescence (AF) imaging. Serial data were available for at least half of the patients, depending on the parameter analyzed. RESULTS The kinetics of disease progression in this specific molecular form of USH2A differed between the measured parameters. Visual acuity could remain normal for decades. Kinetic and light-adapted static perimetry across the entire visual field had similar rates of decline that were slower than those of rod-based perimetry. Horizontal OCT scans through the macula showed that inner segment/outer segment line width had a similar rate of constriction as co-localized AF imaging and cone-based light-adapted sensitivity extent. The rate of constriction of rod-based sensitivity extent across this same region was twice as rapid as that of cones. CONCLUSIONS In patients with the c.2299delG mutation in USH2A, rod photoreceptors are the cells that express disease early and more aggressively than cones. Rod-based vision measurements in central or extracentral-peripheral retinal regions warrant monitoring in order to complete a clinical trial in a timely manner.
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Lu Y, Zhou D, King R, Zhu S, Simpson CL, Jones BC, Zhang W, Geisert EE, Lu L. The genetic dissection of Myo7a gene expression in the retinas of BXD mice. Mol Vis 2018; 24:115-126. [PMID: 29430167 PMCID: PMC5802760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 01/31/2018] [Indexed: 11/16/2022] Open
Abstract
Purpose Usher syndrome (US) is characterized by a loss of vision due to retinitis pigmentosa (RP) and deafness. US has three clinical subtypes, but even within each subtype, the severity varies. Myosin VIIA, coded by Myo7a, has been identified as one of the causal genes of US. This study aims to identify pathways and other genes through which Myo7a interacts to affect the presentation of US symptoms. Methods In this study, we used the retinal tissue of BXD recombinant inbred (RI) mice to examine the expression of Myo7a and perform genetic mapping. Expression quantitative trait locus (eQTL), single nucleotide polymorphism (SNP), and gene correlation analysis were performed using GeneNetwork. Gene set enrichment analysis was performed using WebGestalt, and gene network construction was performed using the Gene Cohesion Analysis Tool. Results We found Myo7a to be cis-regulated, with varied levels of expression across BXD strains. Here, we propose a genetic network with 40 genes whose expression is highly correlated with Myo7a. Among these genes, six have been linked to retinal diseases, three to deafness, and five share a transcription factor with Myo7a. Gene ontology and pathway analysis revealed a strong connection among ion channel activity, Myo7a, and US. Conclusions Although Myo7a is a causal gene of US type I, this gene works with many other genes and pathways to affect the severity of US. Many of the genes found in the genetic network, pathways, and gene ontology categories of Myo7a are related to either deafness or blindness. Further investigation is needed to examine the specific relationships between these genes, which may assist in the treatment of US.
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Affiliation(s)
- Ye Lu
- Department of Ophthalmology, The First Affiliated Hospital, Zhejiang University College of Medicine, Hangzhou, China
| | - Diana Zhou
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Rebecca King
- Department of Ophthalmology and Emory Eye Center, Emory University, Atlanta, GA
| | - Shuang Zhu
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, TX
| | - Claire L. Simpson
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Byron C. Jones
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
| | - Wenbo Zhang
- Department of Ophthalmology & Visual Sciences, University of Texas Medical Branch, Galveston, TX
| | - Eldon E. Geisert
- Department of Ophthalmology and Emory Eye Center, Emory University, Atlanta, GA
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN
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CLINICAL PRESENTATION AND DISEASE COURSE OF USHER SYNDROME BECAUSE OF MUTATIONS IN MYO7A OR USH2A. Retina 2018; 37:1581-1590. [PMID: 27828912 DOI: 10.1097/iae.0000000000001389] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE To evaluate differences in the visual phenotype and natural history of Usher syndrome caused by mutations in MYO7A or USH2A, the most commonly affected genes of Usher syndrome Type I (USH1) and Type II (USH2), respectively. METHODS Eighty-eight patients with a clinical diagnosis of USH1 (26 patients) or USH2 (62 patients) were retrospectively evaluated. Of these, 48 patients had 2 disease-causing mutations in MYO7A (10 USH1 patients), USH2A (33 USH2 patients), and other USH (5 patients) genes. Clinical investigation included best-corrected visual acuity, Goldmann visual field, fundus photography, electroretinography, and audiologic and vestibular assessments. Longitudinal analysis was performed over a median follow-up time of 3.5 years. RESULTS Patients carrying mutations in MYO7A had a younger age of onset of hearing and visual impairments than those carrying mutations in USH2A, leading to an earlier diagnosis of the disease in the former patients. Longitudinal analysis showed that visual acuity and visual field decreased more rapidly in subjects carrying MYO7A mutations than in those carrying USH2A mutations (mean annual exponential rates of decline of 3.92 vs. 3.44% and of 8.52 vs. 4.97%, respectively), and the former patients reached legal blindness on average 15 years earlier than the latter. CONCLUSION The current study confirmed a more severe progression of the retinal disease in USH1 patients rather than in USH2 patients. Furthermore, most visual symptoms (i.e., night blindness, visual acuity worsening) occurred at an earlier age in USH1 patients carrying mutations in MYO7A.
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Targeted next generation sequencing identified a novel mutation in MYO7A causing Usher syndrome type 1 in an Iranian consanguineous pedigree. Int J Pediatr Otorhinolaryngol 2018; 104:10-13. [PMID: 29287847 DOI: 10.1016/j.ijporl.2017.10.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 10/13/2017] [Accepted: 10/13/2017] [Indexed: 12/29/2022]
Abstract
BACKGROUND Usher syndrome (USH) is characterized by congenital hearing loss and retinitis pigmentosa (RP) with a later onset. It is an autosomal recessive trait with clinical and genetic heterogeneity which makes the molecular diagnosis much difficult. In this study, we introduce a pedigree with two affected members with USH type 1 and represent a cost and time effective approach for genetic diagnosis of USH as a genetically heterogeneous disorder. METHODS Target region capture in the genes of interest, followed by next generation sequencing (NGS) was used to determine the causative mutations in one of the probands. Then segregation analysis in the pedigree was conducted using PCR-Sanger sequencing. RESULTS Targeted NGS detected a novel homozygous nonsense variant c.4513G > T (p.Glu1505Ter) in MYO7A. The variant is segregating in the pedigree with an autosomal recessive pattern. CONCLUSION In this study, a novel stop gained variant c.4513G > T (p.Glu1505Ter) in MYO7A was found in an Iranian pedigree with two affected members with USH type 1. Bioinformatic as well as pedigree segregation analyses were in line with pathogenic nature of this variant. Targeted NGS panel was showed to be an efficient method for mutation detection in hereditary disorders with locus heterogeneity.
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29
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Abdelkader E, Enani L, Schatz P, Safieh L. Severe retinal degeneration at an early age in Usher syndrome type 1B associated with homozygous splice site mutations in MYO7A gene. Saudi J Ophthalmol 2017; 32:119-125. [PMID: 29942180 PMCID: PMC6010603 DOI: 10.1016/j.sjopt.2017.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 10/08/2017] [Accepted: 10/17/2017] [Indexed: 01/10/2023] Open
Abstract
Purpose Usher syndrome is the most common cause of deafness associated with visual loss of a genetic origin. The purpose of this paper is to report very severe phenotypic features of type 1B Usher syndrome in a Saudi family affected by positive homozygous splice site mutation in MYO7A gene. Methods Affected siblings went through detailed history. Complete ophthalmic examination was done. Imaging with colour fundus photography, fundus autofluorescence (AF), and optical coherence tomography (OCT) scans was performed. Full field electroretinogram (ffERG) was recorded. Molecular genetic testing was done using next-generation sequencing. Results Visual acuity was more reduced (range 20/300–20/40) in older siblings (age>30 years), than in younger (age <30 years) siblings (range 20/70–20/25). OCT scans showed macular atrophy in all but one case that has cystoid macular edema (CME). AF demonstrated atrophy outside a small foveal area showing high signal. FfERG was flat in all cases. The homozygous splice site mutation c.470+1G>A in intron 5 of the MYO7A gene was detected in all affected siblings. Conclusions This mutation manifested with advanced retinal degeneration at a young age. This may have implications regarding future gene therapy in Usher syndrome cases with this genotype.
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Affiliation(s)
- Ehab Abdelkader
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Ophthalmology Department, Menoufia University, Shebin El-Kom, Egypt
| | - Lama Enani
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Patrik Schatz
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.,Department of Ophthalmology, Clinical Sciences, Skane University Hospital, University of Lund, Sweden
| | - Leen Safieh
- Genetic Laboratory, Research Department, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
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30
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EYS Mutations Causing Autosomal Recessive Retinitis Pigmentosa: Changes of Retinal Structure and Function with Disease Progression. Genes (Basel) 2017; 8:genes8070178. [PMID: 28704921 PMCID: PMC5541311 DOI: 10.3390/genes8070178] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 07/06/2017] [Accepted: 07/06/2017] [Indexed: 11/24/2022] Open
Abstract
Mutations in the EYS (eyes shut homolog) gene are a common cause of autosomal recessive (ar) retinitis pigmentosa (RP). Without a mammalian model of human EYS disease, there is limited understanding of details of disease expression and rates of progression of the retinal degeneration. We studied clinically and with chromatic static perimetry, spectral-domain optical coherence tomography (OCT), and en face autofluoresence imaging, a cohort of 15 patients (ages 12–51 at first visit), some of whom had longitudinal data of function and structure. Rod sensitivity was able to be measured by chromatic perimetry in most patients at their earliest visits and some patients retained patchy rod function into the fifth decade of life. As expected from RP, cone sensitivity persisted after rod function was no longer measurable. The photoreceptor nuclear layer of the central retina was abnormal except at the fovea in most patients at first visit. Perifoveal disease measured over a period of years indicated that photoreceptor structural loss was followed by dysmorphology of the inner retina and loss of retinal pigment epithelial integrity. Although there could be variability in severity, preliminary analyses of the rates of vision loss suggested that EYS is a more rapidly progressive disease than other ciliopathies causing arRP, such as USH2A and MAK.
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Neuhaus C, Eisenberger T, Decker C, Nagl S, Blank C, Pfister M, Kennerknecht I, Müller-Hofstede C, Charbel Issa P, Heller R, Beck B, Rüther K, Mitter D, Rohrschneider K, Steinhauer U, Korbmacher HM, Huhle D, Elsayed SM, Taha HM, Baig SM, Stöhr H, Preising M, Markus S, Moeller F, Lorenz B, Nagel-Wolfrum K, Khan AO, Bolz HJ. Next-generation sequencing reveals the mutational landscape of clinically diagnosed Usher syndrome: copy number variations, phenocopies, a predominant target for translational read-through, and PEX26 mutated in Heimler syndrome. Mol Genet Genomic Med 2017; 5:531-552. [PMID: 28944237 PMCID: PMC5606877 DOI: 10.1002/mgg3.312] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/06/2017] [Accepted: 06/09/2017] [Indexed: 12/23/2022] Open
Abstract
Background Combined retinal degeneration and sensorineural hearing impairment is mostly due to autosomal recessive Usher syndrome (USH1: congenital deafness, early retinitis pigmentosa (RP); USH2: progressive hearing impairment, RP). Methods Sanger sequencing and NGS of 112 genes (Usher syndrome, nonsyndromic deafness, overlapping conditions), MLPA, and array‐CGH were conducted in 138 patients clinically diagnosed with Usher syndrome. Results A molecular diagnosis was achieved in 97% of both USH1 and USH2 patients, with biallelic mutations in 97% (USH1) and 90% (USH2), respectively. Quantitative readout reliably detected CNVs (confirmed by MLPA or array‐CGH), qualifying targeted NGS as one tool for detecting point mutations and CNVs. CNVs accounted for 10% of identified USH2A alleles, often in trans to seemingly monoallelic point mutations. We demonstrate PTC124‐induced read‐through of the common p.Trp3955* nonsense mutation (13% of detected USH2A alleles), a potential therapy target. Usher gene mutations were found in most patients with atypical Usher syndrome, but the diagnosis was adjusted in case of double homozygosity for mutations in OTOA and NR2E3, genes implicated in isolated deafness and RP. Two patients with additional enamel dysplasia had biallelic PEX26 mutations, for the first time linking this gene to Heimler syndrome. Conclusion Targeted NGS not restricted to Usher genes proved beneficial in uncovering conditions mimicking Usher syndrome.
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Affiliation(s)
| | | | | | - Sandra Nagl
- Bioscientia Center for Human GeneticsIngelheimGermany
| | | | - Markus Pfister
- HNO-Praxis SarnenSarnenSwitzerland.,Molecular Genetics, THRCDepartment of OtolaryngologyUniversity of TübingenTübingenGermany
| | - Ingo Kennerknecht
- Institute of Human GeneticsWestfälische Wilhelms-UniversitätMünsterGermany
| | | | - Peter Charbel Issa
- Department of OphthalmologyUniversity of BonnBonnGermany.,Center for Rare Diseases Bonn (ZSEB)University of BonnBonnGermany.,Oxford Eye HospitalUniversity of OxfordOxfordUK
| | - Raoul Heller
- Institute of Human GeneticsUniversity Hospital of CologneCologneGermany
| | - Bodo Beck
- Institute of Human GeneticsUniversity Hospital of CologneCologneGermany
| | | | - Diana Mitter
- Institute of Human GeneticsUniversity of Leipzig Hospitals and ClinicsLeipzigGermany
| | | | | | - Heike M Korbmacher
- Department of OrthodonticsGiessen and Marburg University Hospital, Marburg CampusMarburgGermany
| | | | - Solaf M Elsayed
- Medical Genetics CenterCairoEgypt.,Children's HospitalAin Shams UniversityCairoEgypt
| | | | - Shahid M Baig
- Human Molecular Genetics LaboratoryHealth Biotechnology DivisionNational Institute for Biotechnology and Genetic Engineering (NIBGE)FaisalabadPakistan
| | - Heidi Stöhr
- Department of Human GeneticsUniversity Medical Center RegensburgRegensburgGermany
| | - Markus Preising
- Department of OphthalmologyJustus-Liebig-University GiessenGiessenGermany
| | | | - Fabian Moeller
- Department of Cell and Matrix BiologyInstitute of Zoology, Johannes GutenbergUniversity of MainzMainzGermany
| | - Birgit Lorenz
- Department of OphthalmologyJustus-Liebig-University GiessenGiessenGermany
| | - Kerstin Nagel-Wolfrum
- Department of Cell and Matrix BiologyInstitute of Zoology, Johannes GutenbergUniversity of MainzMainzGermany
| | - Arif O Khan
- Division of Pediatric OphthalmologyKing Khaled Eye Specialist HospitalRiyadhSaudi Arabia.,Eye InstituteCleveland ClinicAbu DhabiUAE
| | - Hanno J Bolz
- Bioscientia Center for Human GeneticsIngelheimGermany.,Institute of Human GeneticsUniversity Hospital of CologneCologneGermany
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Jacobson SG, Cideciyan AV, Sumaroka A, Roman AJ, Charng J, Lu M, Choudhury S, Schwartz SB, Heon E, Fishman GA, Boye SE. Defining Outcomes for Clinical Trials of Leber Congenital Amaurosis Caused by GUCY2D Mutations. Am J Ophthalmol 2017; 177:44-57. [PMID: 28212877 DOI: 10.1016/j.ajo.2017.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 02/01/2017] [Accepted: 02/03/2017] [Indexed: 11/19/2022]
Abstract
PURPOSE To determine outcome measures for a clinical trial of Leber congenital amaurosis (LCA) associated with mutations in the GUCY2D gene. DESIGN Retrospective observational case series. METHODS Twenty-eight patients with GUCY2D-LCA (aged 2-59 years) were studied clinically and with chromatic full-field sensitivity testing (FST), optical coherence tomography (OCT), pupillometry, and the NEI Visual Function Questionnaire (VFQ). RESULTS FST permitted quantitation of cone and rod sensitivity in these patients with severe visual impairment. For most patients, the degree of rod and cone sensitivity losses showed a relationship, thereby providing an opportunity to divide patients into cohorts by severity of rod and cone dysfunction. OCT analyses indicated that retinal structure could be used not only as an objective safety measure but also as an exploratory efficacy outcome. A foveal bulge was not present in 67% of patients. The intensity of inner segment/outer segment (ellipsoid zone line) reflectivity was reduced significantly at the fovea and in the rod-dense superior retina. Based on OCT and FST parameters, most patients had dissociation of structure and function. Abnormal pupillometry sensitivity in the majority of GUCY2D-LCA patients provided another objective efficacy outcome. NEI VFQ scores showed a similar range of findings to those of other severe retinal diseases. CONCLUSION Conventional outcome measures, such as visual acuity and the NEI VFQ, will need to be complemented by methods more specific to this GUCY2D-LCA population. Any therapeutic strategy should determine if there is an effect on rod as well as cone function and structure. FST provides a photoreceptor-based subjective outcome; and OCT in 2 retinal regions, fovea and superior retina, can assess photoreceptor structure. A change in the relationship of structure and function away from baseline becomes evidence of efficacy.
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Affiliation(s)
- Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
| | - Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alejandro J Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jason Charng
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Monica Lu
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Shreyasi Choudhury
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida
| | - Sharon B Schwartz
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Elise Heon
- Department of Ophthalmology and Vision Sciences, Program of Genetics and Genomic Biology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Gerald A Fishman
- Pangere Center for Hereditary Retinal Diseases, The Chicago Lighthouse, Chicago, Illinois
| | - Shannon E Boye
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida
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Kletke S, Batmanabane V, Dai T, Vincent A, Li S, Gordon KA, Papsin BC, Cushing SL, Héon E. The combination of vestibular impairment and congenital sensorineural hearing loss predisposes patients to ocular anomalies, including Usher syndrome. Clin Genet 2017; 92:26-33. [PMID: 27743452 DOI: 10.1111/cge.12895] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/05/2016] [Accepted: 10/12/2016] [Indexed: 11/29/2022]
Abstract
The co-occurrence of hearing impairment and visual dysfunction is devastating. Most deaf-blind etiologies are genetically determined, the commonest being Usher syndrome (USH). While studies of the congenitally deaf population reveal a variable degree of visual problems, there are no effective ophthalmic screening guidelines. We hypothesized that children with congenital sensorineural hearing loss (SNHL) and vestibular impairment were at an increased risk of having USH. A retrospective chart review of 33 cochlear implants recipients for severe to profound SNHL and measured vestibular dysfunction was performed to determine the ocular phenotype. All the cases had undergone ocular examination and electroretinogram (ERG). Patients with an abnormal ERG underwent genetic testing for USH. We found an underlying ocular abnormality in 81.81% (27/33) of cases; of which 75% had refractive errors, and 50% of those patients showed visual improvement with refractive correction. A total of 14 cases (42.42%; 14/33) had generalized rod-cone dysfunction on ERG suggestive of Usher syndrome type 1, confirmed by mutational analysis. This work shows that adding vestibular impairment as a criterion for requesting an eye exam and adding the ERG to detect USH increases the chances of detecting ocular anomalies, when compared with previous literature focusing only on congenital SNHL.
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Affiliation(s)
- S Kletke
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada
| | - V Batmanabane
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - T Dai
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada
| | - A Vincent
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - S Li
- Program of Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - K A Gordon
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.,Department of Otolaryngology - Head & Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - B C Papsin
- Department of Otolaryngology - Head & Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - S L Cushing
- Department of Otolaryngology - Head & Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - E Héon
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada.,Program of Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
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Charng J, Cideciyan AV, Jacobson SG, Sumaroka A, Schwartz SB, Swider M, Roman AJ, Sheplock R, Anand M, Peden MC, Khanna H, Heon E, Wright AF, Swaroop A. Variegated yet non-random rod and cone photoreceptor disease patterns in RPGR-ORF15-associated retinal degeneration. Hum Mol Genet 2016; 25:5444-5459. [PMID: 27798110 PMCID: PMC6078602 DOI: 10.1093/hmg/ddw361] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/16/2016] [Accepted: 10/18/2016] [Indexed: 12/13/2022] Open
Abstract
Mutations in the ORF15 exon of the RPGR gene cause a common form of X-linked retinitis pigmentosa, which often results in severe loss of vision. In dogs and mice, gene augmentation therapy has been shown to arrest the progressive degeneration of rod and cone photoreceptors. However, the distribution of potentially treatable photoreceptors across the human retinas and the rate of degeneration are not known. Here, we have defined structural and functional features of the disease in 70 individuals with ORF15 mutations. We also correlated the features observed in patients with those of three Rpgr-mutant (Rpgr-ko, Rd9, and Rpgr-cko) mice. In patients, there was pronounced macular disease. Across the retina, rod and cone dysfunction showed a range of patterns and a spectrum of severity between individuals, but a high symmetry was observed between eyes of each individual. Genotype was not related to disease expression. In the Rpgr-ko mice, there were intra-retinal differences in rhodopsin and cone opsin trafficking. In Rd9 and Rpgr-cko mice, retinal degeneration showed inter-ocular symmetry. Longitudinal results in patients revealed localized rod and cone dysfunction with progression rates of 0.8 to 1.3 log per decade in sensitivity loss. Relatively retained rod and cone photoreceptors in mid- and far-peripheral temporal-inferior and nasal-inferior visual field regions should be good targets for future localized gene therapies in patients.
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Affiliation(s)
- Jason Charng
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Sharon B. Schwartz
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Alejandro J. Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Manisha Anand
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, MA, USA
| | - Marc C. Peden
- Retina Associates of Florida, Tampa, Florida, FL, USA
| | - Hemant Khanna
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, MA, USA
| | - Elise Heon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Alan F. Wright
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, Scotland, UK
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, MD, USA
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Ku CA, Hariprasad SM, Pennesi ME. Gene Therapy Trial Update: A Primer for Vitreoretinal Specialists. Ophthalmic Surg Lasers Imaging Retina 2016; 47:6-12. [PMID: 26731203 DOI: 10.3928/23258160-20151214-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Guzmán HO, Palacios AM, De Almada MI, Utrera RA. A novel homozygous MYO7A mutation involved in a Venezuelan population with high frequency of USHER1B. Ophthalmic Genet 2016; 37:328-30. [DOI: 10.3109/13816810.2015.1071410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Horbelys O. Guzmán
- Departamento de Biología Celular, Laboratorio de Genética Molecular Humana, Universidad Simón Bolívar, Caracas, Venezuela
| | - Aura M. Palacios
- Servicio de Otorrinolaringología, Hospital Universitario de Caracas, Caracas, Venezuela
| | - María I. De Almada
- Servicio de Otorrinolaringología, Hospital Universitario de Caracas, Caracas, Venezuela
| | - René A. Utrera
- Departamento de Biología Celular, Laboratorio de Genética Molecular Humana, Universidad Simón Bolívar, Caracas, Venezuela
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Matsui R, Cideciyan AV, Schwartz SB, Sumaroka A, Roman AJ, Swider M, Huang WC, Sheplock R, Jacobson SG. Molecular Heterogeneity Within the Clinical Diagnosis of Pericentral Retinal Degeneration. Invest Ophthalmol Vis Sci 2016; 56:6007-18. [PMID: 26393467 DOI: 10.1167/iovs.15-17174] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To characterize in detail the phenotype and genotype of patients with pericentral retinal degeneration (PRD). METHODS Patients were screened for an annular ring scotoma ranging from 3° to 40° (n = 28, ages 24-71) with kinetic perimetry. All patients had pigmentary retinopathy in the region of the dysfunction. Further studies included cross-sectional and en face imaging, static chromatic perimetry, and electroretinography. Molecular screening was performed. RESULTS Genotypes of 14 of 28 PRD patients were identified: There were mutations in eight different genes previously associated with autosomal dominant or autosomal recessive RDs. Kinetic fields monitored in some patients over years to more than a decade could be stable or show increased extent of the scotoma. Electroretinograms were recordable but with different severities of dysfunction. Patterns of photoreceptor outer nuclear layer (ONL) loss corresponded to the distribution of visual dysfunction. Outer nuclear layer thickness topography and en face imaging indicated that the greatest disease expression was in the area of known highest rod photoreceptor density. CONCLUSIONS Molecular heterogeneity was a feature of the PRD phenotype. Many of the molecular causes were also associated with other phenotypes, such as maculopathies, typical retinitis pigmentosa (RP) and cone-rod dystrophy. The pericentral pattern of retinal degeneration is thus confirmed to be an uncommon phenotype of many different genotypes rather than a distinct disease entity.
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Abstract
Hearing loss is the most common congenital sensory impairment. According to National Health and Nutrition Examination Survey data from 2001 to 2008, 20.3% of subjects aged greater than or equal to 12 had unilateral or bilateral hearing loss. The World Health Organization notes that, worldwide, there are 360 million people with disabling hearing loss, with 50% preventable. Although many hearing losses are acquired, many others are manifestations of preexisting conditions. The purpose of a pediatric hearing evaluation is to identify the degree and type of hearing loss and etiology and to outline a comprehensive strategy that supports language and social development and communication.
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Affiliation(s)
- Margaret A Kenna
- Otolaryngology and Communication Enhancement, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, BCH3129, Boston, MA 02115, USA.
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Lopes VS, Williams DS. Gene Therapy for the Retinal Degeneration of Usher Syndrome Caused by Mutations in MYO7A. Cold Spring Harb Perspect Med 2015; 5:cshperspect.a017319. [PMID: 25605753 DOI: 10.1101/cshperspect.a017319] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Usher syndrome is a deaf-blindness disorder. One of the subtypes, Usher 1B, is caused by loss of function of the gene encoding the unconventional myosin, MYO7A. A variety of different viral-based delivery approaches have been tested for retinal gene therapy to prevent the blindness of Usher 1B, and a clinical trial based on one of these approaches has begun. This review evaluates the different approaches.
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Affiliation(s)
- Vanda S Lopes
- Stein Eye Institute, University of California at Los Angeles, Los Angeles, California 90095-7000
| | - David S Williams
- Stein Eye Institute, University of California at Los Angeles, Los Angeles, California 90095-7000
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Zein WM, Falsini B, Tsilou ET, Turriff AE, Schultz JM, Friedman TB, Brewer CC, Zalewski CK, King KA, Muskett JA, Rehman AU, Morell RJ, Griffith AJ, Sieving PA. Cone responses in Usher syndrome types 1 and 2 by microvolt electroretinography. Invest Ophthalmol Vis Sci 2014; 56:107-14. [PMID: 25425308 DOI: 10.1167/iovs.14-15355] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Progressive decline of psychophysical cone-mediated measures has been reported in type 1 (USH1) and type 2 (USH2) Usher syndrome. Conventional cone electroretinogram (ERG) responses in USH demonstrate poor signal-to-noise ratio. We evaluated cone signals in USH1 and USH2 by recording microvolt level cycle-by-cycle (CxC) ERG. METHODS Responses of molecularly genotyped USH1 (n = 18) and USH2 (n = 24) subjects (age range, 15-69 years) were compared with those of controls (n = 12). A subset of USH1 (n = 9) and USH2 (n = 9) subjects was examined two to four times over 2 to 8 years. Photopic CxC ERG and conventional 30-Hz flicker ERG were recorded on the same visits. RESULTS Usher syndrome subjects showed considerable cone flicker ERG amplitude losses and timing phase delays (P < 0.01) compared with controls. USH1 and USH2 had similar rates of progressive logarithmic ERG amplitude decline with disease duration (-0.012 log μV/y). Of interest, ERG phase delays did not progress over time. Two USH1C subjects retained normal response timing despite reduced amplitudes. The CxC ERG method provided reliable responses in all subjects, whereas conventional ERG was undetectable in 7 of 42 subjects. CONCLUSIONS Cycle-by-cycle ERG showed progressive loss of amplitude in both USH1 and USH2 subjects, comparable to that reported with psychophysical measures. Usher subjects showed abnormal ERG response latency, but this changed less than amplitude with time. In USH syndrome, CxC ERG is more sensitive than conventional ERG and warrants consideration as an outcome measure in USH treatment trials.
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Affiliation(s)
- Wadih M Zein
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Benedetto Falsini
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Ekaterina T Tsilou
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Amy E Turriff
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Julie M Schultz
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Carmen C Brewer
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Christopher K Zalewski
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Kelly A King
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Julie A Muskett
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Atteeq U Rehman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Robert J Morell
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Andrew J Griffith
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
| | - Paul A Sieving
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States
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Dyka FM, Boye SL, Chiodo VA, Hauswirth WW, Boye SE. Dual adeno-associated virus vectors result in efficient in vitro and in vivo expression of an oversized gene, MYO7A. Hum Gene Ther Methods 2014; 25:166-77. [PMID: 24568220 DOI: 10.1089/hgtb.2013.212] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Usher syndrome 1B (USH1B) is a severe, autosomal recessive, deaf-blind disorder caused by mutations in myosin 7A (MYO7A). Patients are born profoundly deaf and exhibit progressive loss of vision starting in their first decade. MYO7A is expressed in human photoreceptors and retinal pigment epithelium, but disease pathology begins in photoreceptors, highlighting the need to develop a gene replacement strategy that effectively targets this cell type. For its safety and efficacy in clinical trials and ability to transduce postmitotic photoreceptors, we have focused on developing a clinically applicable adeno-associated virus (AAV) platform for delivering full-length MYO7A cDNA (∼6.7 kb). Packaging of full-length MYO7A cDNA in AAV produces vectors with heterogeneous, fragmented genomes ("fAAV") capable of reconstituting full-length cDNA postinfection. We previously showed that fAAV vectors effectively delivered full-length MYO7A in vitro and in vivo. However, fAAV vectors are relatively inefficient and their heterogeneous genomes preclude definitive characterization, a drawback for clinical translatability. The aim of this study was to overcome these limitations by creating dual-AAV-vector platforms for USH1B with defined genomes. Human MYO7A was cloned in AAV vector pairs, each containing genomes <5 kb and intact inverted terminal repeats. One vector contained a promoter and 5' portion of the cDNA and the partner vector contained a 3' portion and polyadenylation signal. "Simple overlap" vectors share a central part of the MYO7A cDNA sequence. "Trans-splicing" and "hybrid" vectors utilize splice donor and acceptor sites with and without an additional central recombinogenic sequence, respectively. Vector pairs expressed full-length MYO7A in vitro and in vivo with equal or higher efficiency than fAAV, with a hybrid platform being most efficient. Importantly, analysis of MYO7A mRNA derived from each dual-vector platform revealed 100% fidelity to the predicted sequence. Our results suggest that dual AAV vectors with defined genetic payloads are a potential treatment option for USH1B.
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Affiliation(s)
- Frank M Dyka
- Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, FL 32610
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Lopes VS, Diemer T, Williams DS. Assessment of different virus-mediated approaches for retinal gene therapy of Usher 1B. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:725-31. [PMID: 24664764 DOI: 10.1007/978-1-4614-3209-8_91] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Usher syndrome type 1B, which is characterized by congenital deafness and progressive retinal degeneration, is caused by the loss of the function of MYO7A. Prevention of the retinal degeneration should be possible by delivering functional MYO7A to retinal cells. Although this approach has been used successfully in clinical trials for Leber congenital amaurosis (LCA2), it remains a challenge for Usher 1B because of the large size of the MYO7A cDNA. Different viral vectors have been tested for use in MYO7A gene therapy. Here, we review approaches with lentiviruses, which can accommodate larger genes, as well as attempts to use adeno-associated virus (AAV), which has a smaller packaging capacity. In conclusion, both types of viral vector appear to be effective. Despite concerns about the ability of lentiviruses to access the photoreceptor cells, a phenotype of the photoreceptors of Myo7a-mutant mice can be corrected. And although MYO7A cDNA is significantly larger than the nominal carrying capacity of AAV, AAV-MYO7A in single vectors also corrected Myo7a-mutant phenotypes in photoreceptor and RPE cells. Interestingly, however, a dual AAV vector approach was found to be much less effective.
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Affiliation(s)
- Vanda S Lopes
- Stein Eye Institute, UCLA David Geffen School of Medicine, 90095-7008, Los Angeles, CA, USA,
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Sadigh S, Luo X, Cideciyan AV, Sumaroka A, Boxley SL, Hall LM, Sheplock R, Feuer WJ, Stambolian DS, Jacobson SG. Drusen and photoreceptor abnormalities in African-Americans with intermediate non-neovascular age-related macular degeneration. Curr Eye Res 2014; 40:398-406. [PMID: 24912073 DOI: 10.3109/02713683.2014.925934] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE/AIM To investigate the relationship of drusen and photoreceptor abnormalities in African-American (AA) patients with intermediate non-neovascular age-related macular degeneration (AMD). MATERIALS AND METHODS AA patients with intermediate AMD (n = 11; age 52-77 years) were studied with spectral-domain optical coherence tomography. Macular location and characteristics of large drusen (≥125 µm) were determined. Thickness of photoreceptor laminae was quantified overlying drusen and in other macular regions. A patient with advanced AMD (age 87) was included to illustrate the disease spectrum. RESULTS In this AA patient cohort, the spectrum of changes known to occur in AMD, including large drusen, sub-retinal drusenoid deposits and geographic atrophy, were identified. In intermediate AMD eyes (n = 17), there were 183 large drusen, the majority of which were pericentral in location. Overlying the drusen there was significant thinning of the photoreceptor outer nuclear layer (termed ONL(+)) as well as the inner and outer segments (IS + OS). The reductions in IS + OS thickness were directly related to ONL(+) thickness. In a fraction (∼8%) of paradrusen locations with normal lamination sampled within ∼280 µm of peak drusen height, ONL(+) was significantly thickened compared to age and retinal-location-matched normal values. Topographical maps of the macula confirmed ONL thickening in regions neighboring and distant to large drusen. CONCLUSIONS We confirm there is a pericentral distribution of drusen across AA-AMD maculae rather than the central localization in Caucasian AMD. Reductions in the photoreceptor laminae overlying drusen are evident. ONL(+) thickening in some macular areas of AA-AMD eyes may be an early phenotypic marker for photoreceptor stress.
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Affiliation(s)
- Sam Sadigh
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania , Philadelphia, PA , USA
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Eisenberger T, Di Donato N, Baig SM, Neuhaus C, Beyer A, Decker E, Mürbe D, Decker C, Bergmann C, Bolz HJ. Targeted and genomewide NGS data disqualify mutations in MYO1A, the "DFNA48 gene", as a cause of deafness. Hum Mutat 2014; 35:565-70. [PMID: 24616153 DOI: 10.1002/humu.22532] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 02/14/2014] [Indexed: 12/18/2022]
Abstract
MYO1A is considered the gene underlying autosomal dominant nonsyndromic hearing loss DFNA48, based on six missense variants, one small in-frame insertion, and one nonsense mutation. Results from NGS targeting 66 deafness genes in 109 patients identified three families challenging this assumption: two novel nonsense (p.Tyr740* and p.Arg262*) and a known missense variant were identified heterozygously not only in index patients, but also in unaffected relatives. Deafness in these families clearly resulted from mutations in other genes (MYO7A, EYA1, and CIB2). Most of the altogether 10 MYO1A mutations are annotated in dbSNP, and population frequencies (dbSNP, 1000 Genomes, Exome Sequencing Project) above 0.1% contradict pathogenicity under a dominant model. One healthy individual was even homozygous for p.Arg262*, compatible with homozygous Myo1a knockout mice lacking any overt pathology. MYO1A seems dispensable for hearing and overall nonessential. MYO1A adds to the list of "erroneous disease genes", which will expand with increasing availability of large-scale sequencing data.
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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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Lenassi E, Saihan Z, Cipriani V, Le Quesne Stabej P, Moore AT, Luxon LM, Bitner-Glindzicz M, Webster AR. Natural history and retinal structure in patients with Usher syndrome type 1 owing to MYO7A mutation. Ophthalmology 2013; 121:580-7. [PMID: 24199935 DOI: 10.1016/j.ophtha.2013.09.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 09/17/2013] [Accepted: 09/17/2013] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To evaluate the phenotypic variability and natural history of ocular disease in a cohort of 28 individuals with MYO7A-related disease. Mutations in the MYO7A gene are the most common cause of Usher syndrome type 1, characterized by profound congenital deafness, vestibular arreflexia, and progressive retinal degeneration. DESIGN Retrospective case series. PARTICIPANTS Twenty-eight patients from 26 families (age range, 3-65 years; median, 32) with 2 likely disease-causing variants in MYO7A. METHODS Clinical investigations included fundus photography, optical coherence tomography, fundus autofluorescence (FAF) imaging, and audiologic and vestibular assessments. Longitudinal visual acuity and FAF data (over a 3-year period) were available for 20 and 10 study subjects, respectively. MAIN OUTCOME MEASURES Clinical, structural, and functional characteristics. RESULTS All patients with MYO7A mutations presented with features consistent with Usher type 1. The median visual acuity for the cohort was 0.39 logarithm of the minimum angle of resolution (logMAR; range, 0.0-2.7) and visual acuity in logMAR correlated with age (Spearman's rank correlation coefficient, r = 0.71; P<0.0001). Survival analysis revealed that acuity ≤ 0.22 logMAR was maintained in 50% of studied subjects until age 33.9; legal blindness based on loss of acuity (≥ 1.00 logMAR) or loss of field (≤ 20°) was reached at a median age of 40.6 years. Three distinct patterns were observed on FAF imaging: 13 of 22 patients tested had relatively preserved foveal autofluorescence surrounded by a ring of high density, 4 of 22 had increased signal in the fovea with no obvious hyperautofluorescent ring, and 5 of 22 had widespread hypoautofluorescence corresponding to retinal pigment epithelial atrophy. Despite a number of cases presenting with a milder phenotype, there seemed to be no obvious genotype-phenotype correlation. CONCLUSIONS MYO7A-related ocular disease is variable. Central vision typically remains preserved at least until the third decade of life, with 50% of affected individuals reaching legal blindness by 40 years of age. Distinct phenotypic subsets were identified on FAF imaging. A specific allele, previously reported in nonsyndromic deafness, may be associated with a mild retinopathy.
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Affiliation(s)
- Eva Lenassi
- UCL Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom; Eye Hospital, University Medical Centre, Ljubljana, Slovenia
| | | | - Valentina Cipriani
- UCL Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | | | - Anthony T Moore
- UCL Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | | | | | - Andrew R Webster
- UCL Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom.
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Samuels IS, Bell BA, Sturgill-Short G, Ebke LA, Rayborn M, Shi L, Nishina PM, Peachey NS. Myosin 6 is required for iris development and normal function of the outer retina. Invest Ophthalmol Vis Sci 2013; 54:7223-33. [PMID: 24106123 DOI: 10.1167/iovs.13-12887] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the molecular basis and the pathologic consequences of a chemically induced mutation in the translational vision research models 89 (tvrm89) mouse model with ERG defects. METHODS Mice from a G3 N-ethyl-N-nitrosourea mutagenesis program were screened for behavioral abnormalities and defects in retinal function by ERGs. The chromosomal position for the recessive tvrm89 mutation was determined in a genome-wide linkage analysis. The critical region was refined, and candidate genes were screened by direct sequencing. The tvrm89 phenotype was characterized by circling behavior, in vivo ocular imaging, detailed ERG-based studies of the retina and RPE, and histological analysis of these structures. RESULTS The tvrm89 mutation was localized to a region on chromosome 9 containing Myo6. Sequencing identified a T→C point mutation in the codon for amino acid 480 in Myo6 that converts a leucine to a proline. This mutation does not confer a loss of protein expression levels; however, mice homozygous for the Myo6(tvrm89) mutation display an abnormal iris shape and attenuation of both strobe-flash ERGs and direct-current ERGs by 4 age weeks, neither of which is associated with photoreceptor loss. CONCLUSIONS The tvrm89 phenotype mimics that reported for Myosin6-null mice, suggesting that the mutation confers a loss of myosin 6 protein function. The observation that homozygous Myo6(tvrm89) mice display reduced ERG a-wave and b-wave components, as well as components of the ERG attributed to RPE function, indicates that myosin 6 is necessary for the generation of proper responses of the outer retina to light.
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Affiliation(s)
- Ivy S Samuels
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio
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48
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Colella P, Sommella A, Marrocco E, Di Vicino U, Polishchuk E, Garrido MG, Seeliger MW, Polishchuk R, Auricchio A. Myosin7a deficiency results in reduced retinal activity which is improved by gene therapy. PLoS One 2013; 8:e72027. [PMID: 23991031 PMCID: PMC3753344 DOI: 10.1371/journal.pone.0072027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 07/04/2013] [Indexed: 12/22/2022] Open
Abstract
Mutations in MYO7A cause autosomal recessive Usher syndrome type IB (USH1B), one of the most frequent conditions that combine severe congenital hearing impairment and retinitis pigmentosa. A promising therapeutic strategy for retinitis pigmentosa is gene therapy, however its pre-clinical development is limited by the mild retinal phenotype of the shaker1 (sh1−/−) murine model of USH1B which lacks both retinal functional abnormalities and degeneration. Here we report a significant, early-onset delay of sh1−/− photoreceptor ability to recover from light desensitization as well as a progressive reduction of both b-wave electroretinogram amplitude and light sensitivity, in the absence of significant loss of photoreceptors up to 12 months of age. We additionally show that subretinal delivery to the sh1−/− retina of AAV vectors encoding the large MYO7A protein results in significant improvement of sh1−/− photoreceptor and retinal pigment epithelium ultrastructural anomalies which is associated with improvement of recovery from light desensitization. These findings provide new tools to evaluate the efficacy of experimental therapies for USH1B. In addition, although AAV vectors expressing large genes might have limited clinical applications due to their genome heterogeneity, our data show that AAV-mediated MYO7A gene transfer to the sh1−/− retina is effective.
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Affiliation(s)
| | - Andrea Sommella
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Elena Marrocco
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | | | - Elena Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Marina Garcia Garrido
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
| | - Mathias W. Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
| | - Roman Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
- Medical Genetics, Department of Medical Translational Sciences, University of Naples Federico II, Naples, Italy
- * E-mail:
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Papal S, Cortese M, Legendre K, Sorusch N, Dragavon J, Sahly I, Shorte S, Wolfrum U, Petit C, El-Amraoui A. The giant spectrin βV couples the molecular motors to phototransduction and Usher syndrome type I proteins along their trafficking route. Hum Mol Genet 2013; 22:3773-88. [PMID: 23704327 DOI: 10.1093/hmg/ddt228] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mutations in the myosin VIIa gene cause Usher syndrome type IB (USH1B), characterized by deaf-blindness. A delay of opsin trafficking has been observed in the retinal photoreceptor cells of myosin VIIa-deficient mice. We identified spectrin βV, the mammalian β-heavy spectrin, as a myosin VIIa- and rhodopsin-interacting partner in photoreceptor cells. Spectrin βV displays a polarized distribution from the Golgi apparatus to the base of the outer segment, which, unlike that of other β spectrins, matches the trafficking route of opsin and other phototransduction proteins. Formation of spectrin βV-rhodopsin complex could be detected in the differentiating photoreceptors as soon as their outer segment emerges. A failure of the spectrin βV-mediated coupling between myosin VIIa and opsin molecules thus probably accounts for the opsin transport delay in myosin VIIa-deficient mice. We showed that spectrin βV also associates with two USH1 proteins, sans (USH1G) and harmonin (USH1C). Spectrins are supposed to function as heteromers of α and β subunits, but fluorescence resonance energy transfer and in vitro binding experiments indicated that spectrin βV can also form homodimers, which likely supports its αII-independent βV functions. Finally, consistent with its distribution along the connecting cilia axonemes, spectrin βV binds to several subunits of the microtubule-based motor proteins, kinesin II and the dynein complex. We therefore suggest that spectrin βV homomers couple some USH1 proteins, opsin and other phototransduction proteins to both actin- and microtubule-based motors, thereby contributing to their transport towards the photoreceptor outer disks.
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Affiliation(s)
- Samantha Papal
- Institut Pasteur, Unité de génétique et physiologie de l'audition, Paris, France
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Roman AJ, Cideciyan AV, Schwartz SB, Olivares MB, Heon E, Jacobson SG. Intervisit variability of visual parameters in Leber congenital amaurosis caused by RPE65 mutations. Invest Ophthalmol Vis Sci 2013; 54:1378-83. [PMID: 23341016 DOI: 10.1167/iovs.12-11341] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the intervisit variability of kinetic visual fields and visual acuity in patients with Leber congenital amaurosis (LCA) caused by mutations in the RPE65 (Retinal Pigment Epithelium-specific protein 65kDa) gene. METHODS RPE65-LCA patients (n = 20; ages 11-40 years) were studied on at least two visits separated by fewer than 120 days using Goldmann visual field (GVF) and ETDRS visual acuity (VA) in a retrospective review. GVFs were quantified by computing the spherical coordinates of their vertices and calculating the solid angle subtended, and reported in normalized solid-angle units (nsu) as a percentage of average normal field extent. Repeatability coefficients were calculated using 95% confidence intervals on log(10)-converted variables. RESULTS Visual field extents in RPE65-LCA spanned a wide range from 4 to 95 nsu. The repeatability coefficient was 0.248 (log(10)nsu), suggesting cutoffs for significant change (in nsu) of +77% for improvement and -44% for worsening. VA in RPE65-LCA ranged from logMAR = 0.14 to 1.96 (20/40 to 20/1250). The repeatability coefficient was 0.170 (logMAR) (±8.5 ETDRS letters). Comparisons with published studies of ungenotyped retinitis pigmentosa showed that the RPE65-LCA patients had higher variability in kinetic field extent. VA variability in RPE65-LCA fell within reported results for retinitis pigmentosa. CONCLUSIONS Variability data for GVF and VA are provided to permit interpretation of the significance of increases and decreases of these functional outcomes in ongoing and planned clinical trials of therapy for LCA caused by RPE65 mutations.
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Affiliation(s)
- Alejandro J Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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