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Cao W, Kuang L, Gan R, Huang T, Yan X. A novel compound heterozygous variant of MYO7A in Usher syndrome type 1. Exp Eye Res 2024; 247:110047. [PMID: 39151776 DOI: 10.1016/j.exer.2024.110047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 08/08/2024] [Accepted: 08/13/2024] [Indexed: 08/19/2024]
Abstract
Usher syndrome (USH) is a recessive genetic disorder manifested by congenital sensorineural hearing loss and progressive retinitis pigmentosa, which leads to audiovisual impairment. We report a patient with Usher syndrome type 1 with new compound heterozygous MYO7A variants. A total of four members from the USH family were included. Medical history and retinal examinations were taken and genomic DNA from peripheral blood was extracted in the proband and other members. 381 retinal disease-associated genes were screened using targeted sequence capture array technology and Sanger sequencing was used to confirm the screening results. Scanning laser ophthalmoscope showed bone spicule pigmentary deposits in the mid-peripheral retina and whitish and thin retinal blood vessels especially in the arterioles. Optical coherence tomography showed that the centrality of the macular ellipsoid band disappeared in both eyes, and only remained near the fovea. Visual field examination showed a progressive loss of the visual field in a concentric pattern in both eyes. The electroretinography showed a significant decrease in the amplitudes of a- and b-waves in the scotopic and photopic condition. DNA sequencing identified the compound heterozygous variants including c.1003+1G > A: p. (?) and c.5957_5958del: p.G1987Lfs*50 of MYO7A, with the latter being novel. In this study, we found a novel compound heterozygous variant in MYO7A, which enriched the mutation spectrum and expanded our understanding of the heterogeneity of phenotype and genotype of Usher syndrome type 1.
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Affiliation(s)
- Wenchao Cao
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Longhao Kuang
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Run Gan
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Tao Huang
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Xiaohe Yan
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China.
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2
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Giese APJ, Weng WH, Kindt KS, Chang HHV, Montgomery JS, Ratzan EM, Beirl AJ, Rivera RA, Lotthammer JM, Walujkar S, Foster MP, Zobeiri OA, Holt JR, Riazuddin S, Cullen KE, Sotomayor M, Ahmed ZM. Complexes of vertebrate TMC1/2 and CIB2/3 proteins form hair-cell mechanotransduction cation channels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.26.542533. [PMID: 37398045 PMCID: PMC10312449 DOI: 10.1101/2023.05.26.542533] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Calcium and integrin-binding protein 2 (CIB2) and CIB3 bind to transmembrane channel-like 1 (TMC1) and TMC2, the pore-forming subunits of the inner-ear mechano-electrical transduction (MET) apparatus. These interactions have been proposed to be functionally relevant across mechanosensory organs and vertebrate species. Here we show that both CIB2 and CIB3 can form heteromeric complexes with TMC1 and TMC2 and are integral for MET function in mouse cochlea and vestibular end organs as well as in zebrafish inner ear and lateral line. Our AlphaFold 2 models suggest that vertebrate CIB proteins can simultaneously interact with at least two cytoplasmic domains of TMC1 and TMC2 as validated using nuclear magnetic resonance spectroscopy of TMC1 fragments interacting with CIB2 and CIB3. Molecular dynamics simulations of TMC1/2 complexes with CIB2/3 predict that TMCs are structurally stabilized by CIB proteins to form cation channels. Overall, our work demonstrates that intact CIB2/3 and TMC1/2 complexes are integral to hair-cell MET function in vertebrate mechanosensory epithelia.
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Affiliation(s)
- Arnaud P J Giese
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Wei-Hsiang Weng
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Katie S Kindt
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | | | - Jonathan S Montgomery
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
| | - Evan M Ratzan
- Departments of Otolaryngology and Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alisha J Beirl
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Roberto Aponte Rivera
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Jeffrey M Lotthammer
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Sanket Walujkar
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Mark P Foster
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
| | - Omid A Zobeiri
- Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Jeffrey R Holt
- Departments of Otolaryngology and Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Saima Riazuddin
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kathleen E Cullen
- Departments of Biomedical Engineering, Neuroscience, and Otolaryngology and Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
| | - Zubair M Ahmed
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
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3
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Betzler IR, Hempel M, Mütze U, Kölker S, Winkler E, Dikow N, Garbade SF, Schaaf CP, Brennenstuhl H. Comparative analysis of gene and disease selection in genomic newborn screening studies. J Inherit Metab Dis 2024. [PMID: 38757337 DOI: 10.1002/jimd.12750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/19/2024] [Accepted: 04/30/2024] [Indexed: 05/18/2024]
Abstract
Genomic newborn screening (gNBS) is on the horizon given the decreasing costs of sequencing and the advanced understanding of the impact of genetic variants on health and diseases. Key to ongoing gNBS pilot studies is the selection of target diseases and associated genes to be included. In this study, we present a comprehensive analysis of seven published gene-disease lists from gNBS studies, evaluating gene-disease count, composition, group proportions, and ClinGen curations of individual disorders. Despite shared selection criteria, we observe substantial variation in total gene count (median 480, range 237-889) and disease group composition. An intersection was identified for 53 genes, primarily inherited metabolic diseases (83%, 44/53). Each study investigated a subset of exclusive gene-disease pairs, and the total number of exclusive gene-disease pairs was positively correlated with the total number of genes included per study. While most pairs receive "Definitive" or "Strong" ClinGen classifications, some are labeled as "Refuted" (n = 5) or "Disputed" (n = 28), particularly in genetic cardiac diseases. Importantly, 17%-48% of genes lack ClinGen curation. This study underscores the current absence of consensus recommendations for selection criteria for target diseases for gNBS resulting in diversity in proposed gene-disease pairs, their coupling with gene variations and the use of ClinGen curation. Our findings provide crucial insights into the selection of target diseases and accompanying gene variations for future gNBS program, emphasizing the necessity for ongoing collaboration and discussion about criteria harmonization for panel selection to ensure the screening's objectivity, integrity, and broad acceptance.
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Affiliation(s)
- Isabel R Betzler
- Institute of Human Genetics, Heidelberg University and University Hospital Heidelberg, Heidelberg, Germany
| | - Maja Hempel
- Institute of Human Genetics, Heidelberg University and University Hospital Heidelberg, Heidelberg, Germany
| | - Ulrike Mütze
- Centre for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg University and University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kölker
- Centre for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg University and University Hospital Heidelberg, Heidelberg, Germany
| | - Eva Winkler
- Section of Translational Medical Ethics, National Center for Tumour Diseases, Heidelberg University and University Hospital Heidelberg, Heidelberg, Germany
| | - Nicola Dikow
- Institute of Human Genetics, Heidelberg University and University Hospital Heidelberg, Heidelberg, Germany
| | - Sven F Garbade
- Centre for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg University and University Hospital Heidelberg, Heidelberg, Germany
| | - Christian P Schaaf
- Institute of Human Genetics, Heidelberg University and University Hospital Heidelberg, Heidelberg, Germany
| | - Heiko Brennenstuhl
- Institute of Human Genetics, Heidelberg University and University Hospital Heidelberg, Heidelberg, Germany
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4
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Shadab M, Abbasi AA, Ejaz A, Ben-Mahmoud A, Gupta V, Kim HG, Vona B. Autosomal recessive non-syndromic hearing loss genes in Pakistan during the previous three decades. J Cell Mol Med 2024; 28:e18119. [PMID: 38534090 DOI: 10.1111/jcmm.18119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 11/29/2023] [Accepted: 01/02/2024] [Indexed: 03/28/2024] Open
Abstract
Hearing loss is a clinically and genetically heterogeneous disorder, with over 148 genes and 170 loci associated with its pathogenesis. The spectrum and frequency of causal variants vary across different genetic ancestries and are more prevalent in populations that practice consanguineous marriages. Pakistan has a rich history of autosomal recessive gene discovery related to non-syndromic hearing loss. Since the first linkage analysis with a Pakistani family that led to the mapping of the DFNB1 locus on chromosome 13, 51 genes associated with this disorder have been identified in this population. Among these, 13 of the most prevalent genes, namely CDH23, CIB2, CLDN14, GJB2, HGF, MARVELD2, MYO7A, MYO15A, MSRB3, OTOF, SLC26A4, TMC1 and TMPRSS3, account for more than half of all cases of profound hearing loss, while the prevalence of other genes is less than 2% individually. In this review, we discuss the most common autosomal recessive non-syndromic hearing loss genes in Pakistani individuals as well as the genetic mapping and sequencing approaches used to discover them. Furthermore, we identified enriched gene ontology terms and common pathways involved in these 51 autosomal recessive non-syndromic hearing loss genes to gain a better understanding of the underlying mechanisms. Establishing a molecular understanding of the disorder may aid in reducing its future prevalence by enabling timely diagnostics and genetic counselling, leading to more effective clinical management and treatments of hearing loss.
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Affiliation(s)
- Madiha Shadab
- Department of Zoology, Mirpur University of Science and Technology, Mirpur, Pakistan
| | - Ansar Ahmed Abbasi
- Department of Zoology, Mirpur University of Science and Technology, Mirpur, Pakistan
| | - Ahsan Ejaz
- Department of Physics, University of Kotli Azad Jammu and Kashmir, Kotli, Pakistan
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou, China
| | - Afif Ben-Mahmoud
- Neurological Disorders Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha, Qatar
| | - Vijay Gupta
- Neurological Disorders Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha, Qatar
| | - Hyung-Goo Kim
- Neurological Disorders Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Doha, Qatar
- College of Health & Life Sciences, Hamad Bin Khalifa University (HBKU), Doha, Qatar
| | - Barbara Vona
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
- Institute for Auditory Neuroscience and Inner Ear Lab, University Medical Center Göttingen, Göttingen, Germany
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5
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Guimaraes TACD, Arram E, Shakarchi AF, Georgiou M, Michaelides M. Inherited causes of combined vision and hearing loss: clinical features and molecular genetics. Br J Ophthalmol 2023; 107:1403-1414. [PMID: 36162969 DOI: 10.1136/bjo-2022-321790] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 09/07/2022] [Indexed: 11/04/2022]
Abstract
Combined vision and hearing loss, also known as dual sensory impairment, can occur in several genetic conditions, including ciliopathies such as Usher and Bardet-Biedl syndrome, mitochondrial DNA disorders and systemic diseases, such as CHARGE, Stickler, Waardenburg, Alport and Alstrom syndrome. The retinal phenotype may point to the diagnosis of such disorders. Herein, we aim to provide a comprehensive review of the molecular genetics and clinical features of the most common non-chromosomal inherited disorders to cause dual sensory impairment.
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Affiliation(s)
| | - Elizabeth Arram
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Ahmed F Shakarchi
- Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Michalis Georgiou
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
- Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Michel Michaelides
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
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Aristizábal-Ramírez I, Dragich AK, Giese APJ, Sofia Zuluaga-Osorio K, Watkins J, Davies GK, Hadi SE, Riazuddin S, Vander Kooi CW, Ahmed ZM, Frolenkov GI. Calcium and Integrin-binding protein 2 (CIB2) controls force sensitivity of the mechanotransducer channels in cochlear outer hair cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.09.545606. [PMID: 37461484 PMCID: PMC10350036 DOI: 10.1101/2023.07.09.545606] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Calcium and Integrin-Binding Protein 2 (CIB2) is an essential subunit of the mechano-electrical transduction (MET) complex in mammalian auditory hair cells. CIB2 binds to pore-forming subunits of the MET channel, TMC1/2 and is required for their transport and/or retention at the tips of mechanosensory stereocilia. Since genetic ablation of CIB2 results in complete loss of MET currents, the exact role of CIB2 in the MET complex remains elusive. Here, we generated a new mouse strain with deafness-causing p.R186W mutation in Cib2 and recorded small but still measurable MET currents in the cochlear outer hair cells. We found that R186W variant causes increase of the resting open probability of MET channels, steeper MET current dependence on hair bundle deflection (I-X curve), loss of fast adaptation, and increased leftward shifts of I-X curves upon hair cell depolarization. Combined with AlphaFold2 prediction that R186W disrupts one of the multiple interacting sites between CIB2 and TMC1/2, our data suggest that CIB2 mechanically constraints TMC1/2 conformations to ensure proper force sensitivity and dynamic range of the MET channels. Using a custom piezo-driven stiff probe deflecting the hair bundles in less than 10 µs, we also found that R186W variant slows down the activation of MET channels. This phenomenon, however, is unlikely to be due to direct effect on MET channels, since we also observed R186W-evoked disruption of the electron-dense material at the tips of mechanotransducing stereocilia and the loss of membrane-shaping BAIAP2L2 protein from the same location. We concluded that R186W variant of CIB2 disrupts force sensitivity of the MET channels and force transmission to these channels.
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Linnert J, Knapp B, Güler BE, Boldt K, Ueffing M, Wolfrum U. Usher syndrome proteins ADGRV1 (USH2C) and CIB2 (USH1J) interact and share a common interactome containing TRiC/CCT-BBS chaperonins. Front Cell Dev Biol 2023; 11:1199069. [PMID: 37427378 PMCID: PMC10323441 DOI: 10.3389/fcell.2023.1199069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
The human Usher syndrome (USH) is the most common form of a sensory hereditary ciliopathy characterized by progressive vision and hearing loss. Mutations in the genes ADGRV1 and CIB2 have been associated with two distinct sub-types of USH, namely, USH2C and USH1J. The proteins encoded by the two genes belong to very distinct protein families: the adhesion G protein-coupled receptor ADGRV1 also known as the very large G protein-coupled receptor 1 (VLGR1) and the Ca2+- and integrin-binding protein 2 (CIB2), respectively. In the absence of tangible knowledge of the molecular function of ADGRV1 and CIB2, pathomechanisms underlying USH2C and USH1J are still unknown. Here, we aimed to enlighten the cellular functions of CIB2 and ADGRV1 by the identification of interacting proteins, a knowledge that is commonly indicative of cellular functions. Applying affinity proteomics by tandem affinity purification in combination with mass spectrometry, we identified novel potential binding partners of the CIB2 protein and compared these with the data set we previously obtained for ADGRV1. Surprisingly, the interactomes of both USH proteins showed a high degree of overlap indicating their integration in common networks, cellular pathways and functional modules which we confirmed by GO term analysis. Validation of protein interactions revealed that ADGRV1 and CIB2 mutually interact. In addition, we showed that the USH proteins also interact with the TRiC/CCT chaperonin complex and the Bardet Biedl syndrome (BBS) chaperonin-like proteins. Immunohistochemistry on retinal sections demonstrated the co-localization of the interacting partners at the photoreceptor cilia, supporting the role of USH proteins ADGRV1 and CIB2 in primary cilia function. The interconnection of protein networks involved in the pathogenesis of both syndromic retinal dystrophies BBS and USH suggest shared pathomechanisms for both syndromes on the molecular level.
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Affiliation(s)
- Joshua Linnert
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Barbara Knapp
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Baran E. Güler
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Karsten Boldt
- Institute for Ophthalmic Research, Eberhard Karls University of Tuebingen, Tubingen, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, Eberhard Karls University of Tuebingen, Tubingen, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
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Calcium signaling and genetic rare diseases: An auditory perspective. Cell Calcium 2023; 110:102702. [PMID: 36791536 DOI: 10.1016/j.ceca.2023.102702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/07/2023]
Abstract
Deafness is a highly heterogeneous disorder which stems, for 50%, from genetic origins. Sensory transduction relies mainly on sensory hair cells of the cochlea, in the inner ear. Calcium is key for the function of these cells and acts as a fundamental signal transduction. Its homeostasis depends on three factors: the calcium influx, through the mechanotransduction channel at the apical pole of the hair cell as well as the voltage-gated calcium channel at the base of the cells; the calcium buffering via Ca2+-binding proteins in the cytoplasm, but also in organelles such as mitochondria and the reticulum endoplasmic mitochondria-associated membranes with specialized proteins; and the calcium extrusion through the Ca-ATPase pump, located all over the plasma membrane. In addition, the synaptic transmission to the central nervous system is also controlled by calcium. Genetic studies of inherited deafness have tremendously helped understand the underlying molecular pathways of calcium signaling. In this review, we discuss these different factors in light of the associated genetic diseases (syndromic and non-syndromic deafness) and the causative genes.
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9
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Caprara GA, Peng AW. Mechanotransduction in mammalian sensory hair cells. Mol Cell Neurosci 2022; 120:103706. [PMID: 35218890 PMCID: PMC9177625 DOI: 10.1016/j.mcn.2022.103706] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 02/14/2022] [Accepted: 02/18/2022] [Indexed: 11/23/2022] Open
Abstract
In the inner ear, the auditory and vestibular systems detect and translate sensory information regarding sound and balance. The sensory cells that transform mechanical input into an electrical signal in these systems are called hair cells. A specialized organelle on the apical surface of hair cells called the hair bundle detects mechanical signals. Displacement of the hair bundle causes mechanotransduction channels to open. The morphology and organization of the hair bundle, as well as the properties and characteristics of the mechanotransduction process, differ between the different hair cell types in the auditory and vestibular systems. These differences likely contribute to maximizing the transduction of specific signals in each system. This review will discuss the molecules essential for mechanotransduction and the properties of the mechanotransduction process, focusing our attention on recent data and differences between the auditory and vestibular systems.
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Affiliation(s)
- Giusy A Caprara
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Anthony W Peng
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America.
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Maudoux A, Vitry S, El-Amraoui A. Vestibular Deficits in Deafness: Clinical Presentation, Animal Modeling, and Treatment Solutions. Front Neurol 2022; 13:816534. [PMID: 35444606 PMCID: PMC9013928 DOI: 10.3389/fneur.2022.816534] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/23/2022] [Indexed: 11/13/2022] Open
Abstract
The inner ear is responsible for both hearing and balance. These functions are dependent on the correct functioning of mechanosensitive hair cells, which convert sound- and motion-induced stimuli into electrical signals conveyed to the brain. During evolution of the inner ear, the major changes occurred in the hearing organ, whereas the structure of the vestibular organs remained constant in all vertebrates over the same period. Vestibular deficits are highly prevalent in humans, due to multiple intersecting causes: genetics, environmental factors, ototoxic drugs, infections and aging. Studies of deafness genes associated with balance deficits and their corresponding animal models have shed light on the development and function of these two sensory systems. Bilateral vestibular deficits often impair individual postural control, gaze stabilization, locomotion and spatial orientation. The resulting dizziness, vertigo, and/or falls (frequent in elderly populations) greatly affect patient quality of life. In the absence of treatment, prosthetic devices, such as vestibular implants, providing information about the direction, amplitude and velocity of body movements, are being developed and have given promising results in animal models and humans. Novel methods and techniques have led to major progress in gene therapies targeting the inner ear (gene supplementation and gene editing), 3D inner ear organoids and reprograming protocols for generating hair cell-like cells. These rapid advances in multiscale approaches covering basic research, clinical diagnostics and therapies are fostering interdisciplinary research to develop personalized treatments for vestibular disorders.
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Affiliation(s)
- Audrey Maudoux
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
- Center for Balance Evaluation in Children (EFEE), Otolaryngology Department, Assistance Publique des Hôpitaux de Paris, Robert-Debré University Hospital, Paris, France
| | - Sandrine Vitry
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
| | - Aziz El-Amraoui
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
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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: 42] [Impact Index Per Article: 21.0] [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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12
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Dal Cortivo G, Dell’Orco D. Calcium- and Integrin-Binding Protein 2 (CIB2) in Physiology and Disease: Bright and Dark Sides. Int J Mol Sci 2022; 23:ijms23073552. [PMID: 35408910 PMCID: PMC8999013 DOI: 10.3390/ijms23073552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/19/2022] [Accepted: 03/22/2022] [Indexed: 12/04/2022] Open
Abstract
Calcium- and integrin-binding protein 2 (CIB2) is a small EF-hand protein capable of binding Mg2+ and Ca2+ ions. While its biological function remains largely unclear, an increasing number of studies have shown that CIB2 is an essential component of the mechano-transduction machinery that operates in cochlear hair cells. Mutations in the gene encoding CIB2 have been associated with non-syndromic deafness. In addition to playing an important role in the physiology of hearing, CIB2 has been implicated in a multitude of very different processes, ranging from integrin signaling in platelets and skeletal muscle to autophagy, suggesting extensive functional plasticity. In this review, we summarize the current understanding of biochemical and biophysical properties of CIB2 and the biological roles that have been proposed for the protein in a variety of processes. We also highlight the many molecular aspects that remain unclarified and deserve further investigation.
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Velde HM, Reurink J, Held S, Li CHZ, Yzer S, Oostrik J, Weeda J, Haer-Wigman L, Yntema HG, Roosing S, Pauleikhoff L, Lange C, Whelan L, Dockery A, Zhu J, Keegan DJ, Farrar GJ, Kremer H, Lanting CP, Damme M, Pennings RJE. Usher syndrome type IV: clinically and molecularly confirmed by novel ARSG variants. Hum Genet 2022; 141:1723-1738. [PMID: 35226187 PMCID: PMC9556359 DOI: 10.1007/s00439-022-02441-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/10/2022] [Indexed: 12/16/2022]
Abstract
AbstractUsher syndrome (USH) is an autosomal recessively inherited disease characterized by sensorineural hearing loss (SNHL) and retinitis pigmentosa (RP) with or without vestibular dysfunction. It is highly heterogeneous both clinically and genetically. Recently, variants in the arylsulfatase G (ARSG) gene have been reported to underlie USH type IV. This distinct type of USH is characterized by late-onset RP with predominantly pericentral and macular changes, and late onset SNHL without vestibular dysfunction. In this study, we describe the USH type IV phenotype in three unrelated subjects. We identified three novel pathogenic variants, two novel likely pathogenic variants, and one previously described pathogenic variant in ARSG. Functional experiments indicated a loss of sulfatase activity of the mutant proteins. Our findings confirm that ARSG variants cause the newly defined USH type IV and support the proposed extension of the phenotypic USH classification.
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Affiliation(s)
- Hedwig M. Velde
- Hearing and Genes, Department of Otorhinolaryngology, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - Janine Reurink
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
| | - Sebastian Held
- Department of Biochemistry, University of Kiel, Kiel, Germany
| | - Catherina H. Z. Li
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
- Department of Ophthalmology, Radboudumc, Nijmegen, The Netherlands
| | - Suzanne Yzer
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
- Department of Ophthalmology, Radboudumc, Nijmegen, The Netherlands
| | - Jaap Oostrik
- Hearing and Genes, Department of Otorhinolaryngology, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - Jack Weeda
- Department of Ophthalmology, Radboudumc, Nijmegen, The Netherlands
| | - Lonneke Haer-Wigman
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
| | - Helger G. Yntema
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
| | - Susanne Roosing
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
| | - Laurenz Pauleikhoff
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Clemens Lange
- Eye Center, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Laura Whelan
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Adrian Dockery
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
- Next Generation Sequencing Laboratory, Pathology Department, The Mater Misericordiae University Hospital, Dublin, Ireland
| | - Julia Zhu
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin, Ireland
| | - David J. Keegan
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin, Ireland
| | - G. Jane Farrar
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Hannie Kremer
- Hearing and Genes, Department of Otorhinolaryngology, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
| | - Cornelis P. Lanting
- Hearing and Genes, Department of Otorhinolaryngology, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - Markus Damme
- Department of Biochemistry, University of Kiel, Kiel, Germany
| | - Ronald J. E. Pennings
- Hearing and Genes, Department of Otorhinolaryngology, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
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Abstract
Usher syndrome (USH) is the most common genetic condition responsible for combined loss of hearing and vision. Balance disorders and bilateral vestibular areflexia are also observed in some cases. The syndrome was first described by Albrecht von Graefe in 1858, but later named by Charles Usher, who presented a large number of cases with hearing loss and retinopathy in 1914. USH has been grouped into three main clinical types: 1, 2, and 3, which are caused by mutations in different genes and are further divided into different subtypes. To date, nine causative genes have been identified and confirmed as responsible for the syndrome when mutated: MYO7A, USH1C, CDH23, PCDH15, and USH1G (SANS) for Usher type 1; USH2A, ADGRV1, and WHRN for Usher type 2; CLRN1 for Usher type 3. USH is inherited in an autosomal recessive pattern. Digenic, bi-allelic, and polygenic forms have also been reported, in addition to dominant or nonsyndromic forms of genetic mutations. This narrative review reports the causative forms, diagnosis, prognosis, epidemiology, rehabilitation, research, and new treatments of USH.
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Abstract
Usher syndrome (USH) encompasses a group of clinically and genetically heterogenous disorders defined by the triad of sensorineural hearing loss (SNHL), vestibular dysfunction, and vision loss. USH is the most common cause of deaf blindness. USH is divided clinically into three subtypes-USH1, USH2, and USH3-based on symptom severity, progression, and age of onset. The underlying genetics of these USH forms are, however, significantly more complex, with over a dozen genes linked to the three primary clinical subtypes and other atypical USH phenotypes. Several of these genes are associated with other deaf-blindness syndromes that share significant clinical overlap with USH, pointing to the limits of a clinically based classification system. The genotype-phenotype relationships among USH forms also may vary significantly based on the location and type of mutation in the gene of interest. Understanding these genotype-phenotype relationships and associated natural disease histories is necessary for the successful development and application of gene-based therapies and precision medicine approaches to USH. Currently, the state of knowledge varies widely depending on the gene of interest. Recent studies utilizing next-generation sequencing technology have expanded the list of known pathogenic mutations in USH genes, identified new genes associated with USH-like phenotypes, and proposed algorithms to predict the phenotypic effects of specific categories of allelic variants. Further work is required to validate USH gene causality, and better define USH genotype-phenotype relationships and disease natural histories-particularly for rare mutations-to lay the groundwork for the future of USH treatment.
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Kinoshita S, Ando M, Ando J, Ishii M, Furukawa Y, Tomita O, Azusawa Y, Shirane S, Kishita Y, Yatsuka Y, Eguchi H, Okazaki Y, Komatsu N. Trigenic ADH5/ ALDH2/ ADGRV1 mutations in myelodysplasia with Usher syndrome. Heliyon 2021; 7:e07804. [PMID: 34458631 PMCID: PMC8379464 DOI: 10.1016/j.heliyon.2021.e07804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/19/2021] [Accepted: 08/12/2021] [Indexed: 11/27/2022] Open
Abstract
Trio-next generation sequencing is useful to identify undiagnosed inherited diseases. We have attended a patient with trigenic ADH5/ALDH2/ADGRV1 pathogenic variants, which caused two distinct diseases, myelodysplastic syndrome and Usher syndrome. Whole genome sequencing of peripheral blood from the patient and his parents were applied to identify disease-causing genes. Sanger sequencing was performed to validate the identified ADH5/ALDH2/ADGRV1 variants. Our results identified disease-associated variants in ADGRV1 (disease inheritance autosomal recessive) and in ADH5 (disease inheritance also autosomal recessive) and a variant in ALDH2 (disease inheritance autosomal dominant). Although the variants identified in ADH5 and ALDH2 have been reported, their co-existence in association with disease-causing variation in a third gene has not. They broaden the spectrum of ADGRV1 in Usher syndrome. Findings on next generation sequencing guided rapid and accurate diagnosis, resulting in patient-tailored therapeutic intervention. Trigenic ADH5 / ALDH2 / ADGRV1 variants in myelodysplastic syndrome with Usher syndrome were identified. Two novel pathogenic frameshift variants in ADGRV1 in compound heterozygous state with Usher syndrome type II were described. Findings on next generation sequencing guided rapid and accurate diagnosis, resulting in patient-tailored therapy.
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Affiliation(s)
- Shintaro Kinoshita
- Department of Hematology, Juntendo University School of Medicine, Tokyo, Japan
| | - Miki Ando
- Department of Hematology, Juntendo University School of Medicine, Tokyo, Japan.,Division of Stem Cell Therapy, Distinguished Professor Unit, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Jun Ando
- Department of Hematology, Juntendo University School of Medicine, Tokyo, Japan.,Department of Transfusion Medicine and Stem Cell Regulation, Juntendo University School of Medicine, Tokyo, Japan
| | - Midori Ishii
- Department of Hematology, Juntendo University School of Medicine, Tokyo, Japan
| | - Yoshiki Furukawa
- Department of Hematology, Juntendo University School of Medicine, Tokyo, Japan
| | - Osamu Tomita
- Department of Pediatrics, Juntendo University School of Medicine, Tokyo, Japan
| | - Yoko Azusawa
- Department of Transfusion Medicine and Stem Cell Regulation, Juntendo University School of Medicine, Tokyo, Japan
| | - Shuichi Shirane
- Department of Hematology, Juntendo University School of Medicine, Tokyo, Japan
| | - Yoshihito Kishita
- Diagnostic and Therapeutics of Intractable Diseases, Graduate School of Medicine and Intractable Disease Research Center, Juntendo University, Tokyo, Japan
| | - Yukiko Yatsuka
- Diagnostic and Therapeutics of Intractable Diseases, Graduate School of Medicine and Intractable Disease Research Center, Juntendo University, Tokyo, Japan
| | - Hidetaka Eguchi
- Diagnostic and Therapeutics of Intractable Diseases, Graduate School of Medicine and Intractable Disease Research Center, Juntendo University, Tokyo, Japan
| | - Yasushi Okazaki
- Diagnostic and Therapeutics of Intractable Diseases, Graduate School of Medicine and Intractable Disease Research Center, Juntendo University, Tokyo, Japan
| | - Norio Komatsu
- Department of Hematology, Juntendo University School of Medicine, Tokyo, Japan
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Fuster-García C, García-Bohórquez B, Rodríguez-Muñoz A, Aller E, Jaijo T, Millán JM, García-García G. Usher Syndrome: Genetics of a Human Ciliopathy. Int J Mol Sci 2021; 22:6723. [PMID: 34201633 PMCID: PMC8268283 DOI: 10.3390/ijms22136723] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/21/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive syndromic ciliopathy characterized by sensorineural hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. There are three clinical types depending on the severity and age of onset of the symptoms; in addition, ten genes are reported to be causative of USH, and six more related to the disease. These genes encode proteins of a diverse nature, which interact and form a dynamic protein network called the "Usher interactome". In the organ of Corti, the USH proteins are essential for the correct development and maintenance of the structure and cohesion of the stereocilia. In the retina, the USH protein network is principally located in the periciliary region of the photoreceptors, and plays an important role in the maintenance of the periciliary structure and the trafficking of molecules between the inner and the outer segments of photoreceptors. Even though some genes are clearly involved in the syndrome, others are controversial. Moreover, expression of some USH genes has been detected in other tissues, which could explain their involvement in additional mild comorbidities. In this paper, we review the genetics of Usher syndrome and the spectrum of mutations in USH genes. The aim is to identify possible mutation associations with the disease and provide an updated genotype-phenotype correlation.
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Affiliation(s)
- Carla Fuster-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Belén García-Bohórquez
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Ana Rodríguez-Muñoz
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Elena Aller
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Teresa Jaijo
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - José M. Millán
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Gema García-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
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Unraveling the genetic complexities of combined retinal dystrophy and hearing impairment. Hum Genet 2021; 141:785-803. [PMID: 34148116 PMCID: PMC9035000 DOI: 10.1007/s00439-021-02303-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/15/2021] [Indexed: 12/11/2022]
Abstract
Usher syndrome, the most prevalent cause of combined hereditary vision and hearing impairment, is clinically and genetically heterogeneous. Moreover, several conditions with phenotypes overlapping Usher syndrome have been described. This makes the molecular diagnosis of hereditary deaf–blindness challenging. Here, we performed exome sequencing and analysis on 7 Mexican and 52 Iranian probands with combined retinal degeneration and hearing impairment (without intellectual disability). Clinical assessment involved ophthalmological examination and hearing loss questionnaire. Usher syndrome, most frequently due to biallelic variants in MYO7A (USH1B in 16 probands), USH2A (17 probands), and ADGRV1 (USH2C in 7 probands), was diagnosed in 44 of 59 (75%) unrelated probands. Almost half of the identified variants were novel. Nine of 59 (15%) probands displayed other genetic entities with dual sensory impairment, including Alström syndrome (3 patients), cone-rod dystrophy and hearing loss 1 (2 probands), and Heimler syndrome (1 patient). Unexpected findings included one proband each with Scheie syndrome, coenzyme Q10 deficiency, and pseudoxanthoma elasticum. In four probands, including three Usher cases, dual sensory impairment was either modified/aggravated or caused by variants in distinct genes associated with retinal degeneration and/or hearing loss. The overall diagnostic yield of whole exome analysis in our deaf–blind cohort was 92%. Two (3%) probands were partially solved and only 3 (5%) remained without any molecular diagnosis. In many cases, the molecular diagnosis is important to guide genetic counseling, to support prognostic outcomes and decisions with currently available and evolving treatment modalities.
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Liu S, Wang S, Zou L, Xiong W. Mechanisms in cochlear hair cell mechano-electrical transduction for acquisition of sound frequency and intensity. Cell Mol Life Sci 2021; 78:5083-5094. [PMID: 33871677 PMCID: PMC11072359 DOI: 10.1007/s00018-021-03840-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/30/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Sound signals are acquired and digitized in the cochlea by the hair cells that further transmit the coded information to the central auditory pathways. Any defect in hair cell function may induce problems in the auditory system and hearing-based brain function. In the past 2 decades, our understanding of auditory transduction has been substantially deepened because of advances in molecular, structural, and functional studies. Results from these experiments can be perfectly embedded in the previously established profile from anatomical, histological, genetic, and biophysical research. This review aims to summarize the progress on the molecular and cellular mechanisms of the mechano-electrical transduction (MET) channel in the cochlear hair cells, which is involved in the acquisition of sound frequency and intensity-the two major parameters of an acoustic cue. We also discuss recent studies on TMC1, the molecule likely to form the MET channel pore.
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Affiliation(s)
- Shuang Liu
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Shufeng Wang
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Wei Xiong
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China.
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China.
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de Joya EM, Colbert BM, Tang PC, Lam BL, Yang J, Blanton SH, Dykxhoorn DM, Liu X. Usher Syndrome in the Inner Ear: Etiologies and Advances in Gene Therapy. Int J Mol Sci 2021; 22:3910. [PMID: 33920085 PMCID: PMC8068832 DOI: 10.3390/ijms22083910] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 02/06/2023] Open
Abstract
Hearing loss is the most common sensory disorder with ~466 million people worldwide affected, representing about 5% of the population. A substantial portion of hearing loss is genetic. Hearing loss can either be non-syndromic, if hearing loss is the only clinical manifestation, or syndromic, if the hearing loss is accompanied by a collage of other clinical manifestations. Usher syndrome is a syndromic form of genetic hearing loss that is accompanied by impaired vision associated with retinitis pigmentosa and, in many cases, vestibular dysfunction. It is the most common cause of deaf-blindness. Currently cochlear implantation or hearing aids are the only treatments for Usher-related hearing loss. However, gene therapy has shown promise in treating Usher-related retinitis pigmentosa. Here we review how the etiologies of Usher-related hearing loss make it a good candidate for gene therapy and discuss how various forms of gene therapy could be applied to Usher-related hearing loss.
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Affiliation(s)
- Evan M. de Joya
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Brett M. Colbert
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
- Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Pei-Ciao Tang
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
| | - Byron L. Lam
- Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, FL 33136, USA;
| | - Jun Yang
- John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT 84132, USA;
| | - Susan H. Blanton
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Derek M. Dykxhoorn
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
| | - Xuezhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (E.M.J.); (B.M.C.); (P.-C.T.); (S.H.B.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA;
- Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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Wafa TT, Faridi R, King KA, Zalewski C, Yousaf R, Schultz JM, Morell RJ, Muskett J, Turriff A, Tsilou E, Griffith AJ, Friedman TB, Zein WM, Brewer CC. Vestibular phenotype-genotype correlation in a cohort of 90 patients with Usher syndrome. Clin Genet 2021; 99:226-235. [PMID: 33089500 PMCID: PMC7821283 DOI: 10.1111/cge.13868] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 10/14/2020] [Accepted: 10/18/2020] [Indexed: 12/11/2022]
Abstract
Usher syndrome has been historically categorized into one of three classical types based on the patient phenotype. However, the vestibular phenotype does not infallibly predict which Usher genes are mutated. Conversely, the Usher syndrome genotype is not sufficient to reliably predict vestibular function. Here we present a characterization of the vestibular phenotype of 90 patients with clinical presentation of Usher syndrome (59 females), aged 10.9 to 75.5 years, with genetic variants in eight Usher syndromic genes and expand the description of atypical Usher syndrome. We identified unexpected horizontal semicircular canal reactivity in response to caloric and rotational stimuli in 12.5% (3 of 24) and 41.7% (10 of 24), respectively, of our USH1 cohort. These findings are not consistent with the classical phenotypic definition of vestibular areflexia in USH1. Similarly, 17% (6 of 35) of our cohort with USH2A mutations had saccular dysfunction as evidenced by absent cervical vestibular evoked myogenic potentials in contradiction to the classical assumption of normal vestibular function. The surprising lack of consistent genotypic to vestibular phenotypic findings as well as no clear vestibular phenotypic patterns among atypical USH cases, indicate that even rigorous vestibular phenotyping data will not reliably differentiate the three USH types.
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Affiliation(s)
- Talah T. Wafa
- Otolaryngology BranchNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
| | - Rabia Faridi
- Laboratory of Molecular GeneticsNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
| | - Kelly A. King
- Otolaryngology BranchNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
| | - Christopher Zalewski
- Otolaryngology BranchNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
| | - Rizwan Yousaf
- Laboratory of Molecular GeneticsNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
| | - Julie M. Schultz
- Laboratory of Molecular GeneticsNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
- Review Analysis DepartmentGeneDxGaithersburgMarylandUSA
| | - Robert J. Morell
- Genomics and Computational Biology CoreNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
| | - Julie Muskett
- Otolaryngology BranchNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
| | - Amy Turriff
- Ophthalmic Genetics and Visual Function BranchNational Eye Institute, National Institutes of HealthBethesdaMarylandUSA
| | - Ekaterini Tsilou
- Ophthalmic Genetics and Visual Function BranchNational Eye Institute, National Institutes of HealthBethesdaMarylandUSA
| | - Andrew J. Griffith
- Otolaryngology BranchNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
| | - Thomas B. Friedman
- Laboratory of Molecular GeneticsNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
| | - Wadih M. Zein
- Ophthalmic Genetics and Visual Function BranchNational Eye Institute, National Institutes of HealthBethesdaMarylandUSA
| | - Carmen C. Brewer
- Otolaryngology BranchNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthBethesdaMarylandUSA
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Souissi A, Ben Said M, Ben Ayed I, Elloumi I, Bouzid A, Mosrati MA, Hasnaoui M, Belcadhi M, Idriss N, Kamoun H, Gharbi N, Gibriel AA, Tlili A, Masmoudi S. Novel pathogenic mutations and further evidence for clinical relevance of genes and variants causing hearing impairment in Tunisian population. J Adv Res 2021; 31:13-24. [PMID: 34194829 PMCID: PMC8240103 DOI: 10.1016/j.jare.2021.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/14/2020] [Accepted: 01/07/2021] [Indexed: 12/22/2022] Open
Abstract
Introduction Hearing impairment (HI) is characterized by complex genetic heterogeneity. The evolution of next generation sequencing, including targeted enrichment panels, has revolutionized HI diagnosis. Objectives In this study, we investigated genetic causes in 22 individuals with non-GJB2 HI. Methods We customized a HaloplexHS kit to include 30 genes known to be associated with autosomal recessive nonsyndromic HI (ARNSHI) and Usher syndrome in North Africa. Results In accordance with the ACMG/AMP guidelines, we report 11 pathogenic variants; as follows; five novel variants including three missense (ESRRB-Tyr295Cys, MYO15A-Phe2089Leu and MYO7A-Tyr560Cys) and two nonsense (USH1C-Gln122Ter and CIB2-Arg104Ter) mutations; two previously reported mutations (OTOF-Glu57Ter and PNPT1-Glu475Gly), but first time identified among Tunisian families; and four other identified mutations namely WHRN-Gly808AspfsX11, SLC22A4-Cys113Tyr and two MYO7A compound heterozygous splice site variants that were previously described in Tunisia. Pathogenic variants in WHRN and CIB2 genes, in patients with convincing phenotype ruling out retinitis pigmentosa, provide strong evidence supporting their association with ARNSHI. Moreover, we shed lights on the pathogenic implication of mutations in PNPT1 gene in auditory function providing new evidence for its association with ARNSHI. Lack of segregation of a previously identified causal mutation OTOA-Val603Phe further supports its classification as variant of unknown significance. Our study reports absence of otoacoustic emission in subjects using bilateral hearing aids for several years indicating the importance of screening genetic alteration in OTOF gene for proper management of those patients. Conclusion In conclusion, our findings do not only expand the spectrum of HI mutations in Tunisian patients, but also improve our knowledge about clinical relevance of HI causing genes and variants.
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Affiliation(s)
- Amal Souissi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Tunisia
| | - Mariem Ben Said
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Tunisia
| | - Ikhlas Ben Ayed
- Medical Genetic Department, University Hedi Chaker Hospital of Sfax, Tunisia
- Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Ines Elloumi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Tunisia
| | - Amal Bouzid
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Tunisia
| | - Mohamed Ali Mosrati
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Tunisia
| | - Mehdi Hasnaoui
- Department of Otorhinolaryngology, Taher Sfar University Hospital of Mahdia, Tunisia
| | - Malek Belcadhi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Tunisia
| | - Nabil Idriss
- Department of Otorhinolaryngology, Taher Sfar University Hospital of Mahdia, Tunisia
| | - Hassen Kamoun
- Medical Genetic Department, University Hedi Chaker Hospital of Sfax, Tunisia
- Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Nourhene Gharbi
- Medical Genetic Department, University Hedi Chaker Hospital of Sfax, Tunisia
- Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Abdullah A. Gibriel
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy. The British University in Egypt (BUE) Cairo, Egypt
| | - Abdelaziz Tlili
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates
- Human Genetics and Stem Cell Laboratory, Research Institute of Sciences and Engineering, University of Sharjah, Sharjah, United Arab Emirates
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Tunisia
- Corresponding author at: Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, Sidi Mansour road Km 6, BP “1177”, 3018 Sfax, Tunisia.
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23
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Toualbi L, Toms M, Moosajee M. USH2A-retinopathy: From genetics to therapeutics. Exp Eye Res 2020; 201:108330. [PMID: 33121974 PMCID: PMC8417766 DOI: 10.1016/j.exer.2020.108330] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/21/2023]
Abstract
Bilallelic variants in the USH2A gene can cause Usher syndrome type 2 and non-syndromic retinitis pigmentosa. In both disorders, the retinal phenotype involves progressive rod photoreceptor loss resulting in nyctalopia and a constricted visual field, followed by subsequent cone degeneration, leading to the loss of central vision and severe visual impairment. The USH2A gene raises many challenges for researchers and clinicians due to a broad spectrum of mutations, a large gene size hampering gene therapy development and limited knowledge on its pathogenicity. Patients with Usher type 2 may benefit from hearing aids or cochlear implants to correct their hearing defects, but there are currently no approved treatments available for the USH2A-retinopathy. Several treatment strategies, including antisense oligonucleotides and translational readthrough inducing drugs, have shown therapeutic promise in preclinical studies. Further understanding of the pathogenesis and natural history of USH2A-related disorders is required to develop innovative treatments and design clinical trials based on reliable outcome measures. The present review will discuss the current knowledge about USH2A, the emerging therapeutics and existing challenges.
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Affiliation(s)
- Lyes Toualbi
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Maria Toms
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK; Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, EC1V 2PD, UK; Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK.
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24
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Whatley M, Francis A, Ng ZY, Khoh XE, Atlas MD, Dilley RJ, Wong EYM. Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy. Front Genet 2020; 11:565216. [PMID: 33193648 PMCID: PMC7642844 DOI: 10.3389/fgene.2020.565216] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive (AR) disorder that permanently and severely affects the senses of hearing, vision, and balance. Three clinically distinct types of USH have been identified, decreasing in severity from Type 1 to 3, with symptoms of sensorineural hearing loss (SNHL), retinitis pigmentosa (RP), and vestibular dysfunction. There are currently nine confirmed and two suspected USH-causative genes, and a further three candidate loci have been mapped. The proteins encoded by these genes form complexes that play critical roles in the development and maintenance of cellular structures within the inner ear and retina, which have minimal capacity for repair or regeneration. In the cochlea, stereocilia are located on the apical surface of inner ear hair cells (HC) and are responsible for transducing mechanical stimuli from sound pressure waves into chemical signals. These signals are then detected by the auditory nerve fibers, transmitted to the brain and interpreted as sound. Disease-causing mutations in USH genes can destabilize the tip links that bind the stereocilia to each other, and cause defects in protein trafficking and stereocilia bundle morphology, thereby inhibiting mechanosensory transduction. This review summarizes the current knowledge on Usher syndrome with a particular emphasis on mutations in USH genes, USH protein structures, and functional analyses in animal models. Currently, there is no cure for USH. However, the genetic therapies that are rapidly developing will benefit from this compilation of detailed genetic information to identify the most effective strategies for restoring functional USH proteins.
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Affiliation(s)
- Meg Whatley
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Abbie Francis
- Ear Science Institute Australia, Nedlands, WA, Australia
- Emergency Medicine, The University of Western Australia, Nedlands, WA, Australia
| | - Zi Ying Ng
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Xin Ee Khoh
- Ear Science Institute Australia, Nedlands, WA, Australia
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Marcus D. Atlas
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
| | - Rodney J. Dilley
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- Centre for Cell Therapy and Regenerative Medicine, The University of Western Australia, Perth, WA, Australia
| | - Elaine Y. M. Wong
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
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25
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Buonfiglio P, Bruque CD, Luce L, Giliberto F, Lotersztein V, Menazzi S, Paoli B, Elgoyhen AB, Dalamón V. GJB2 and GJB6 Genetic Variant Curation in an Argentinean Non-Syndromic Hearing-Impaired Cohort. Genes (Basel) 2020; 11:E1233. [PMID: 33096615 PMCID: PMC7589744 DOI: 10.3390/genes11101233] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/08/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
Genetic variants in GJB2 and GJB6 genes are the most frequent causes of hereditary hearing loss among several deaf populations worldwide. Molecular diagnosis enables proper genetic counseling and medical prognosis to patients. In this study, we present an update of testing results in a cohort of Argentinean non-syndromic hearing-impaired individuals. A total of 48 different sequence variants were detected in genomic DNA from patients referred to our laboratory. They were manually curated and classified based on the American College of Medical Genetics and Genomics/Association for Molecular Pathology ACMG/AMP standards and hearing-loss-gene-specific criteria of the ClinGen Hearing Loss Expert Panel. More than 50% of sequence variants were reclassified from their previous categorization in ClinVar. These results provide an accurately interpreted set of variants to be taken into account by clinicians and the scientific community, and hence, aid the precise genetic counseling to patients.
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Affiliation(s)
- Paula Buonfiglio
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas—INGEBI/CONICET, C1428ADN Ciudad Autónoma de Buenos Aires, Argentina; (P.B.); (A.B.E.)
| | - Carlos D. Bruque
- Centro Nacional de Genética Médica, ANLIS-Malbrán, C1425 Ciudad Autónoma de Buenos Aires, Argentina;
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas—IBYME/CONICET, C1428ADN Ciudad Autónoma de Buenos Aires, Argentina
| | - Leonela Luce
- Laboratorio de Distrofinopatías, Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina; (L.L.); (F.G.)
- Instituto de Inmunología, Genética y Metabolismo—INIGEM/CONICET, Universidad de Buenos Aires, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina
| | - Florencia Giliberto
- Laboratorio de Distrofinopatías, Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina; (L.L.); (F.G.)
- Instituto de Inmunología, Genética y Metabolismo—INIGEM/CONICET, Universidad de Buenos Aires, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina
| | - Vanesa Lotersztein
- Servicio de Genética, Hospital Militar Central “Dr. Cosme Argerich”, C1426 Ciudad Autónoma de Buenos Aires, Argentina;
| | - Sebastián Menazzi
- Servicio de Genética, Hospital de Clínicas “José de San Martín”, C1120AAR Ciudad Autónoma de Buenos Aires, Argentina;
| | - Bibiana Paoli
- Servicio de Otorrinolaringología Infantil, Hospital de Clínicas “José de San Martín”, C1120AAR Ciudad Autónoma de Buenos Aires, Argentina;
| | - Ana Belén Elgoyhen
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas—INGEBI/CONICET, C1428ADN Ciudad Autónoma de Buenos Aires, Argentina; (P.B.); (A.B.E.)
- Departamento de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, C1121ABG Ciudad Autónoma de Buenos Aires, Argentina
| | - Viviana Dalamón
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas—INGEBI/CONICET, C1428ADN Ciudad Autónoma de Buenos Aires, Argentina; (P.B.); (A.B.E.)
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26
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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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27
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Vona B, Doll J, Hofrichter MA, Haaf T. Non-syndromic hearing loss: clinical and diagnostic challenges. MED GENET-BERLIN 2020. [DOI: 10.1515/medgen-2020-2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Abstract
Hereditary hearing loss is clinically and genetically heterogeneous. There are presently over 120 genes that have been associated with non-syndromic hearing loss and many more that are associated with syndromic forms. Despite an increasing number of genes that have been implemented into routine molecular genetic diagnostic testing, the diagnostic yield from European patient cohorts with hereditary hearing loss remains around the 50 % mark. This attests to the many gaps of knowledge the field is currently working toward resolving. It can be expected that many more genes await identification. However, it can also be expected, for example, that the mutational signatures of the known genes are still unclear, especially variants in non-coding or regulatory regions influencing gene expression. This review summarizes several challenges in the clinical and diagnostic setting for hereditary hearing loss with emphasis on syndromes that mimic non-syndromic forms of hearing loss in young children and other factors that heavily influence diagnostic rates. A molecular genetic diagnosis for patients with hearing loss opens several additional avenues, such as patient tailored selection of the best currently available treatment modalities, an understanding of the prognosis, and supporting family planning decisions. In the near future, a genetic diagnosis may enable patients to engage in preclinical trials for the development of therapeutics.
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Affiliation(s)
- Barbara Vona
- Tübingen Hearing Research Centre, Department of Otolaryngology – Head & Neck Surgery , Eberhard Karls University , Elfriede-Aulhorn-Strasse 5 , Tübingen , Germany
| | - Julia Doll
- Institute of Human Genetics , Julius Maximilians University , Würzburg , Germany
| | | | - Thomas Haaf
- Institute of Human Genetics , Julius-Maximilians University Würzburg , Biozentrum, Am Hubland , Würzburg , Germany
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28
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Bolz HJ. Usher syndrome: diagnostic approach, differential diagnoses and proposal of an updated function-based genetic classification. MED GENET-BERLIN 2020. [DOI: 10.1515/medgen-2020-2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abstract
Usher syndrome (USH) manifests with congenital and apparently isolated hearing loss, followed by retinal degeneration in later life. Therefore, and because of its high prevalence in the congenitally hearing-impaired population, USH is one of the most relevant deafness syndromes. Next-generation sequencing (NGS)-based testing can now provide most analyzed USH patients with a molecular diagnosis, based on mutations in 11 genes. Given the availability of several excellent articles on the clinical and biochemical basis of USH, this short review focuses on critical assessment of new genes announced as USH genes, clinical and genetic differential diagnoses and therapeutic developments. Because obsolete loci, disproved USH genes and the inclusion of genes whose mutations cause similar phenotypes have increasingly blurred genetic classification, a revision based on phenotype restricted to genes related to the Usher protein complex is proposed.
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Affiliation(s)
- Hanno J. Bolz
- Senckenberg Centre for Human Genetics , Weismüllerstr. 50 , Frankfurt am Main , Germany
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29
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DiStefano MT, Hughes MY, Patel MJ, Wilcox EH, Oza AM. Expert interpretation of genes and variants in hereditary hearing loss. MED GENET-BERLIN 2020. [DOI: 10.1515/medgen-2020-2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Background:
Hearing loss (HL) is the most common sensory deficit from birth, with at least 50 % due to an underlying genetic etiology. A genetic evaluation is a recommended component to the medical workup for HL, and a genetic diagnosis can impact medical management and provide prognostic and recurrence risk information. The accuracy of a genetic diagnosis relies on the evidence supporting the gene–disease relationship, as well as the evidence supporting individual variant classifications. As such, the ClinGen Hearing Loss Working Group was formed and tasked with curating genes associated with genetic hearing loss and developing specifications of the ACMG/AMP variant interpretation guidelines with the goal of improving the genetic diagnosis of patients with HL.
Objectives:
To describe the prioritization and expert curation of genes and variants associated with HL performed under the purview of the ClinGen Hearing Loss Gene and Variant Expert Panels (HL GCEP and VCEP).
Materials and methods:
HL genes were taken from clinical testing panels in the Genetic Testing Registry and prioritized based on a nonsyndromic presentation. Variants were taken from ClinVar and those with diverse data types and medically significant conflicts were prioritized to test the specified variant interpretation guidelines and to resolve classification discrepancies, respectively.
Conclusions:
The ClinGen HL GCEP has curated 174 gene–disease pairs. The HL VCEP has submitted 77 variants, including the previously controversial p.Met34Thr and p.Val37Ile variants in GJB2, into ClinVar, as an FDA-recognized database. Collaboration across clinics and laboratories were crucial to these curations and highlight the impact that data sharing can have on patient care.
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Affiliation(s)
- Marina T. DiStefano
- The Broad Institute of MIT and Harvard , Cambridge , MA , USA
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine , Cambridge , MA , USA
| | | | - Mayher J. Patel
- The Broad Institute of MIT and Harvard , Cambridge , MA , USA
| | - Emma H. Wilcox
- The Broad Institute of MIT and Harvard , Cambridge , MA , USA
| | - Andrea M. Oza
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine , 65 Landsdowne Street Suite 350 , Cambridge , MA , USA
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Vaché C, Puechberty J, Faugère V, Darmaisin F, Liquori A, Baux D, Blanchet C, Garcia-Garcia G, Meunier I, Pellestor F, Koenig M, Roux AF. A 4.6 Mb Inversion Leading to PCDH15- LINC00844 and BICC1- PCDH15 Fusion Transcripts as a New Pathogenic Mechanism Implicated in Usher Syndrome Type 1. Front Genet 2020; 11:623. [PMID: 32714370 PMCID: PMC7343966 DOI: 10.3389/fgene.2020.00623] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 05/22/2020] [Indexed: 01/17/2023] Open
Abstract
Usher type 1 syndrome is a rare autosomal recessive disorder involving congenital severe-to-profound hearing loss, development of vision impairment in the first decade, and severe balance difficulties. The PCDH15 gene, one of the five genes implicated in this disease, is involved in 8–20% of cases. In this study, we aimed to identify and characterize the two causal variants in a French patient with typical Usher syndrome clinical features. Massively parallel sequencing-based gene panel and screening for large rearrangements were used, which detected a single multi-exon deletion in the PCDH15 gene. As the second pathogenic event was likely localized in the unscreened regions of the gene, PCDH15 transcripts from cultured nasal cells were analyzed and revealed a loss of junction between exon 13 and exon 14. This aberration could be explained by the identification of two fusion transcripts, PCDH15-LINC00844 and BICC1-PCDH15, originating from a 4.6 Mb inversion. This complex chromosomal rearrangement could not be detected by our diagnostic approach but was instead characterized by long-read sequencing, which offers the possibility of detecting balanced structural variants (SVs). This finding extends our knowledge of the mutational spectrum of the PCDH15 gene with the first ever identification of a large causal paracentric inversion of chromosome 10 and illustrates the utility of screening balanced SVs in an exhaustive molecular diagnostic approach.
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Affiliation(s)
- Christel Vaché
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | | | - Valérie Faugère
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Floriane Darmaisin
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Alessandro Liquori
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - David Baux
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Catherine Blanchet
- Service ORL, CHU de Montpellier, Montpellier, France.,Centre de Référence Maladies Sensorielles Génétiques, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Gema Garcia-Garcia
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Isabelle Meunier
- Centre de Référence Maladies Sensorielles Génétiques, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Franck Pellestor
- Laboratoire de Génétique Chromosomique, Plateforme ChromoStem, CHU de Montpellier, Montpellier, France
| | - Michel Koenig
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Anne-Françoise Roux
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
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Novel loss-of-function mutations in COCH cause autosomal recessive nonsyndromic hearing loss. Hum Genet 2020; 139:1565-1574. [PMID: 32562050 DOI: 10.1007/s00439-020-02197-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/12/2020] [Indexed: 12/12/2022]
Abstract
COCH is the most abundantly expressed gene in the cochlea. Unsurprisingly, mutations in COCH underly hearing loss in mice and humans. Two forms of hearing loss are linked to mutations in COCH, the well-established autosomal dominant nonsyndromic hearing loss, with or without vestibular dysfunction (DFNA9) via a gain-of-function/dominant-negative mechanism, and more recently autosomal recessive nonsyndromic hearing loss (DFNB110) via nonsense variants. Using a combination of targeted gene panels, exome sequencing, and functional studies, we identified four novel pathogenic variants (two nonsense variants, one missense, and one inframe deletion) in COCH as the cause of autosomal recessive hearing loss in a multi-ethnic cohort. To investigate whether the non-truncating variants exert their effect via a loss-of-function mechanism, we used minigene splicing assays. Our data showed both the missense and inframe deletion variants altered RNA splicing by creating an exon splicing silencer and abolishing an exon splicing enhancer, respectively. Both variants create frameshifts and are predicted to result in a null allele. This study confirms the involvement of loss-of-function mutations in COCH in autosomal recessive nonsyndromic hearing loss, expands the mutational landscape of DFNB110 to include coding variants that alter RNA splicing, and highlights the need to investigate the effect of coding variants on RNA splicing.
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Cesca F, Bettella E, Polli R, Leonardi E, Aspromonte MC, Sicilian B, Stanzial F, Benedicenti F, Sensi A, Ciorba A, Bigoni S, Cama E, Scimemi P, Santarelli R, Murgia A. Frequency of Usher gene mutations in non-syndromic hearing loss: higher variability of the Usher phenotype. J Hum Genet 2020; 65:855-864. [PMID: 32467589 DOI: 10.1038/s10038-020-0783-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/05/2020] [Accepted: 05/15/2020] [Indexed: 11/09/2022]
Abstract
Non-syndromic hearing loss (NSHL) is characterized by a vast genetic heterogeneity; some syndromic forms as Usher syndrome (USH) have onset as isolated deafness and then evolve later in life. We developed an NGS targeted gene-panel containing 59 genes and a customized bioinformatic pipeline for the analysis of DNA samples from clinically highly selected subjects with sensorineural hearing loss, previously resulted negative for GJB2 mutations/GJB6 deletions. Among the 217 tested subjects, 24 (11.1%) were found to carry mutations in genes involved both in NSHL and USH. For 6 out of 24 patients a diagnosis of USH was performed. Eleven subjects out of 24 had hearing loss without vestibular or ocular dysfunction and, due to their young age, it was not possible to establish whether their phenotype could be NSHL or USH. Seven subjects were diagnosed with NSHL, due to their age and phenotype. A total of 41 likely pathogenic/pathogenic mutations were identified, among which 17 novel ones. We report a high frequency of mutations in genes involved both in NSHL and in USH in a cohort of individuals tested for seemingly isolated deafness. Our data also highlight a wider than expected phenotypic variability in the USH phenotype.
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Affiliation(s)
- Federica Cesca
- Laboratory of Molecular Genetics of Neurodevelopment, Department of Women's and Children's Health, University of Padua, Padua, Italy.,Fondazione Istituto di Ricerca Pediatrica (IRP), Città della Speranza, Padua, Italy
| | - Elisa Bettella
- Laboratory of Molecular Genetics of Neurodevelopment, Department of Women's and Children's Health, University of Padua, Padua, Italy.,Fondazione Istituto di Ricerca Pediatrica (IRP), Città della Speranza, Padua, Italy
| | - Roberta Polli
- Laboratory of Molecular Genetics of Neurodevelopment, Department of Women's and Children's Health, University of Padua, Padua, Italy.,Fondazione Istituto di Ricerca Pediatrica (IRP), Città della Speranza, Padua, Italy
| | - Emanuela Leonardi
- Laboratory of Molecular Genetics of Neurodevelopment, Department of Women's and Children's Health, University of Padua, Padua, Italy.,Fondazione Istituto di Ricerca Pediatrica (IRP), Città della Speranza, Padua, Italy
| | - Maria Cristina Aspromonte
- Laboratory of Molecular Genetics of Neurodevelopment, Department of Women's and Children's Health, University of Padua, Padua, Italy.,Fondazione Istituto di Ricerca Pediatrica (IRP), Città della Speranza, Padua, Italy
| | - Barbara Sicilian
- Medical Center of Phoniatrics, Casa di Cura Trieste, Padua, Italy
| | - Franco Stanzial
- Genetic Counseling Service, Regional Hospital of Bolzano, Bolzano, Italy
| | | | - Alberto Sensi
- U.O. Medical Genetics Romagna, AULS Romagna, Cesena, Italy
| | - Andrea Ciorba
- ENT and Audiology Department, University Hospital of Ferrara, Ferrara, Italy
| | - Stefania Bigoni
- Medical Genetics Unit, University Hospital of Ferrara, Ferrara, Italy
| | - Elona Cama
- Department of Neurosciences, University of Padua, Padua, Italy.,Audiology Service, Santi Giovanni e Paolo Hospital, ULSS3 Serenissima, Venice, Italy
| | - Pietro Scimemi
- Department of Neurosciences, University of Padua, Padua, Italy.,Audiology Service, Santi Giovanni e Paolo Hospital, ULSS3 Serenissima, Venice, Italy
| | - Rosamaria Santarelli
- Department of Neurosciences, University of Padua, Padua, Italy.,Audiology Service, Santi Giovanni e Paolo Hospital, ULSS3 Serenissima, Venice, Italy
| | - Alessandra Murgia
- Laboratory of Molecular Genetics of Neurodevelopment, Department of Women's and Children's Health, University of Padua, Padua, Italy. .,Fondazione Istituto di Ricerca Pediatrica (IRP), Città della Speranza, Padua, Italy.
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Nolen RM, Hufnagel RB, Friedman TB, Turriff AE, Brewer CC, Zalewski CK, King KA, Wafa TT, Griffith AJ, Brooks BP, Zein WM. Atypical and ultra-rare Usher syndrome: a review. Ophthalmic Genet 2020; 41:401-412. [PMID: 32372680 DOI: 10.1080/13816810.2020.1747090] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Usher syndrome has classically been described as a combination of hearing loss and rod-cone dystrophy; vestibular dysfunction is present in many patients. Three distinct clinical subtypes were documented in the late 1970s. Genotyping efforts have led to the identification of several genes associated with the disease. Recent literature has seen multiple publications referring to "atypical" Usher syndrome presentations. This manuscript reviews the molecular etiology of Usher syndrome, highlighting rare presentations and molecular causes. Reports of "atypical" disease are summarized noting the wide discrepancy in the spectrum of phenotypic deviations from the classical presentation. Guidelines for establishing a clear nomenclature system are suggested.
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Affiliation(s)
- Rosalie M Nolen
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Amy E Turriff
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
| | - Carmen C Brewer
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Christopher K Zalewski
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Kelly A King
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Talah T Wafa
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Andrew J Griffith
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, National Institutes of Health , Bethesda, MD, USA
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health , Bethesda, MD, USA
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Géléoc GGS, El-Amraoui A. Disease mechanisms and gene therapy for Usher syndrome. Hear Res 2020; 394:107932. [PMID: 32199721 DOI: 10.1016/j.heares.2020.107932] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/03/2020] [Accepted: 02/26/2020] [Indexed: 12/11/2022]
Abstract
Usher syndrome (USH) is a major cause of deaf-blindness in humans, affecting ∼400 000 patients worldwide. Three clinical subtypes, USH1-3, have been defined, with 10 USH genes identified so far. In recent years, in addition to identification of new Usher genes and diagnostic tools, major progress has been made in understanding the role of Usher proteins and how they cooperate through interaction networks to ensure proper development, architecture and function of the stereociliary bundle at the apex of sensory hair cells in the inner ear. Several Usher mouse models of known human Usher genes have been characterized. These mice faithfully reproduce the auditory phenotype associated with Usher syndrome and the vestibular phenotype associated with some mutations in USH genes, particularly USH1. Interestingly, very few mouse models of Usher syndrome recapitulate the retinal phenotype associated with the disease in human. Usher patients can benefit from hearing aids or cochlear implants, which partially alleviate auditory sensory deprivation. However, there are currently no biological treatments available for auditory or visual dysfunction in Usher patients. Development of novel therapies for Usher syndrome has sprouted over the past decade, building on recent progress in gene transfer and new gene editing tools. Promising success demonstrating recovery of hearing and balance functions have been obtained via distinct therapeutic strategies in animal models. Clinical translation to Usher patients, however, calls for further improvements and concerted efforts to overcome the challenges ahead.
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Affiliation(s)
- Gwenaelle G S Géléoc
- Boston Children's Hospital and Harvard Medical School, 3, Blackfan circle, Center for Life Science, 03001, Boston, MA, 02115, United States.
| | - Aziz El-Amraoui
- Unit Progressive Sensory Disorders, Institut Pasteur, INSERM-UMRS1120, Sorbonne Université, 25 rue du Dr. Roux, 75015, Paris, France.
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Role of Targeted Next Generation Sequencing in the Etiological Work-Up of Congenitally Deaf Children. Otol Neurotol 2019; 39:732-738. [PMID: 29889784 DOI: 10.1097/mao.0000000000001847] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVES The purpose of this study is to report the results of a comprehensive etiological work-up for congenitally deaf children including targeted next generation sequencing. STUDY DESIGN Retrospective case review. SETTING Tertiary referral center. PATIENTS Fifty children with congenital, bilateral profound hearing loss (HL) (>90 dBnHL). INTERVENTIONS Etiological work-up included testing for pathogenic variants in GJB2, a phenotype driven genetic analysis, screening for congenital infections and imaging. When no etiology could be found, comprehensive genetic testing was performed using a HL gene panel including 45 syndromic and 96 non-syndromic HL genes. RESULTS Eleven patients carried bi-allelic pathogenic variants in GJB2. Phenotype driven genetic analysis identified two homozygous KCNQ1 patients (Jervell and Lange Nielsen syndrome) and one heterozygous CHD7 patient (CHARGE syndrome). One patient was diagnosed with achondroplasia and one had a clinical diagnosis of Waardenburg syndrome. A deafness gene panel evaluated 16 patients. In 12 out of 16, we identified a pathogenic (n = 12) or likely pathogenic (n = 2) variant and one variant of unknown significance (VUS). A definite diagnosis of non-syndromic or syndromic HL was made in 18 and seven patients, respectively. Non-genetic causes were congenital cytomegalovirus infection (n = 11), anatomic abnormalities (n = 2), neurological/metabolic/polymalformative conditions (n = 3), meningitis (n = 1), and auditory neuropathy (n = 1). CONCLUSIONS A definite genetic cause was found in 25 (50%) of congenital, bilaterally deaf children. Our data show that implementation of a gene panel improves the diagnostic yield for etiological work-up of congenital profound HL to 86%. Identification of the etiology of congenital HL may contribute to predicting outcomes of cochlear implantation.
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Corey DP, Akyuz N, Holt JR. Function and Dysfunction of TMC Channels in Inner Ear Hair Cells. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033506. [PMID: 30291150 DOI: 10.1101/cshperspect.a033506] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The TMC1 channel was identified as a protein essential for hearing in mouse and human, and recognized as one of a family of eight such proteins in mammals. The TMC family is part of a superfamily of seven branches, which includes the TMEM16s. Vertebrate hair cells express both TMC1 and TMC2. They are located at the tips of stereocilia and are required for hair cell mechanotransduction. TMC1 assembles as a dimer and its similarity to the TMEM16s has enabled a predicted tertiary structure with an ion conduction pore in each subunit of the dimer. Cysteine mutagenesis of the pore supports the role of TMC1 and TMC2 as the core channel proteins of a larger mechanotransduction complex that includes PCDH15 and LHFPL5, and perhaps TMIE, CIB2 and others.
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Affiliation(s)
- David P Corey
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Nurunisa Akyuz
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Jeffrey R Holt
- Departments of Otolaryngology and Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115
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Lee SY, Han JH, Kim BJ, Oh SH, Lee S, Oh DY, Choi BY. Identification of a Potential Founder Effect of a Novel PDZD7 Variant Involved in Moderate-to-Severe Sensorineural Hearing Loss in Koreans. Int J Mol Sci 2019; 20:ijms20174174. [PMID: 31454969 PMCID: PMC6747409 DOI: 10.3390/ijms20174174] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 08/14/2019] [Accepted: 08/21/2019] [Indexed: 12/14/2022] Open
Abstract
PDZD7, a PDZ domain-containing scaffold protein, is critical for the organization of Usher syndrome type 2 (USH2) interactome. Recently, biallelic PDZD7 variants have been associated with autosomal-recessive, non-syndromic hearing loss (ARNSHL). Indeed, we identified novel, likely pathogenic PDZD7 variants based on the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines from Korean families manifesting putative moderate-to-severe prelingual ARNSHL; these were c.490C>T (p.Arg164Trp), c.1669delC (p.Arg557Glyfs*13), and c.1526G>A (p.Gly509Glu), with p.Arg164Trp being a predominantly recurring variant. Given the recurring missense variant (p.Arg164Trp) from our cohort, we compared the genotyping data using six short tandem-repeat (STR) markers within or flanking PDZD7 between four probands carrying p.Arg164Trp and 81 normal-hearing controls. We observed an identical haplotype across three out of six STR genotyping markers exclusively shared by two unrelated hearing impaired probands but not by any of the 81 normal-hearing controls, suggesting a potential founder effect. However, STR genotyping, based on six STR markers, revealed various p.Arg164Trp-linked haplotypes shared by all of the affected subjects. In conclusion, PDZD7 can be an important causative gene for moderate to severe ARNSHL in Koreans. Moreover, at least some, if not all, p.Arg164Trp alleles in Koreans could exert a potential founder effect and arise from diverse haplotypes as a mutational hot spot.
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Affiliation(s)
- Sang-Yeon Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul 04401, Korea
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam 13620, Korea
| | - Jin Hee Han
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam 13620, Korea
| | - Bong Jik Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Chungnam National University Hospital, Daejeon 35015, Korea
| | - Seung Ha Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul 04401, Korea
| | - Seungmin Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam 13620, Korea
| | - Doo-Yi Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam 13620, Korea
| | - Byung Yoon Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seongnam 13620, Korea.
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38
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Oza AM, DiStefano MT, Hemphill SE, Cushman BJ, Grant AR, Siegert RK, Shen J, Chapin A, Boczek NJ, Schimmenti LA, Murry JB, Hasadsri L, Nara K, Kenna M, Booth KT, Azaiez H, Griffith A, Avraham KB, Kremer H, Rehm HL, Amr SS, Abou Tayoun AN. Expert specification of the ACMG/AMP variant interpretation guidelines for genetic hearing loss. Hum Mutat 2019; 39:1593-1613. [PMID: 30311386 DOI: 10.1002/humu.23630] [Citation(s) in RCA: 291] [Impact Index Per Article: 58.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/23/2018] [Accepted: 08/25/2018] [Indexed: 12/23/2022]
Abstract
Due to the high genetic heterogeneity of hearing loss (HL), current clinical testing includes sequencing large numbers of genes, which often yields a significant number of novel variants. Therefore, the standardization of variant interpretation is crucial to provide consistent and accurate diagnoses. The Hearing Loss Variant Curation Expert Panel was created within the Clinical Genome Resource to provide expert guidance for standardized genomic interpretation in the context of HL. As one of its major tasks, our Expert Panel has adapted the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines for the interpretation of sequence variants in HL genes. Here, we provide a comprehensive illustration of the newly specified ACMG/AMP HL rules. Three rules remained unchanged, four rules were removed, and the remaining 21 rules were specified. These rules were further validated and refined using a pilot set of 51 variants assessed by curators and disease experts. Of the 51 variants evaluated in the pilot, 37% (19/51) changed category based upon application of the expert panel specified rules and/or aggregation of evidence across laboratories. These HL-specific ACMG/AMP rules will help standardize variant interpretation, ultimately leading to better care for individuals with HL.
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Affiliation(s)
- Andrea M Oza
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts.,Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, Boston, Massachusetts
| | - Marina T DiStefano
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts.,Harvard Medical School, Boston, Massachusetts
| | - Sarah E Hemphill
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts
| | - Brandon J Cushman
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts
| | - Andrew R Grant
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts
| | - Rebecca K Siegert
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts
| | - Jun Shen
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts.,Harvard Medical School, Boston, Massachusetts.,Department of Pathology, Brigham & Women's Hospital, Boston, Massachusetts
| | | | - Nicole J Boczek
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Lisa A Schimmenti
- Department of Otorhinolaryngology, Clinical Genomics and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Jaclyn B Murry
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts
| | - Linda Hasadsri
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Kiyomitsu Nara
- Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Margaret Kenna
- Department of Otolaryngology and Communication Enhancement, Boston Children's Hospital, Boston, Massachusetts.,Harvard Medical School, Boston, Massachusetts
| | - Kevin T Booth
- Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology, University of Iowa Hospital and Clinics, Iowa City, Iowa.,The Interdisciplinary Graduate Program in Molecular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Hela Azaiez
- Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology, University of Iowa Hospital and Clinics, Iowa City, Iowa
| | - Andrew Griffith
- Audiology Unit, National Institute on Deafness and Other Communication Disorders (NIDCD), NIH, Bethesda, Maryland
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Hannie Kremer
- Department of Otorhinolaryngology and Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Heidi L Rehm
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts.,Harvard Medical School, Boston, Massachusetts.,Center for Genomic Medicine, Massachusetts General Hospital, Boston, Massachusetts.,The Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Sami S Amr
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts.,Harvard Medical School, Boston, Massachusetts.,Department of Pathology, Brigham & Women's Hospital, Boston, Massachusetts
| | - Ahmad N Abou Tayoun
- The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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Santana EE, Fuster-García C, Aller E, Jaijo T, García-Bohórquez B, García-García G, Millán JM, Lantigua A. Genetic Screening of the Usher Syndrome in Cuba. Front Genet 2019; 10:501. [PMID: 31231422 PMCID: PMC6558366 DOI: 10.3389/fgene.2019.00501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/07/2019] [Indexed: 11/17/2022] Open
Abstract
Background Usher syndrome (USH) is a recessive inherited disease characterized by sensorineural hearing loss, retinitis pigmentosa, and sometimes, vestibular dysfunction. Although the molecular epidemiology of Usher syndrome has been well studied in Europe and United States, there is a lack of studies in other regions like Africa or Central and South America. Methods We designed a NGS panel that included the 10 USH causative genes (MYO7A, USH1C, CDH23, PCDH15, USH1G, CIB2, USH2A, ADGRV1, WHRN, and CLRN1), four USH associated genes (HARS, PDZD7, CEP250, and C2orf71), and the region comprising the deep-intronic c.7595-2144A>G mutation in USH2A. Results NGS sequencing was performed in 11 USH patients from Cuba. All the cases were solved. We found the responsible mutations in the USH2A, ADGRV1, CDH23, PCDH15, and CLRN1 genes. Four mutations have not been previously reported. Two mutations are recurrent in this study: c.619C>T (p.Arg207∗) in CLRN1, previously reported in two unrelated Spanish families of Basque origin, and c.4488G>C (p.Gln1496His) in CDH23, first described in a large Cuban family. Additionally, c.4488G>C has been reported two more times in the literature in two unrelated families of Spanish origin. Conclusion Although the sample size is very small, it is tempting to speculate that the gene frequencies in Cuba are distinct from other populations mainly due to an “island effect” and genetic drift. The two recurrent mutations appear to be of Spanish origin. Further studies with a larger cohort are needed to elucidate the real genetic landscape of Usher syndrome in the Cuban population.
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Affiliation(s)
- Elayne E Santana
- Centro Provincial de Genética, Universidad de Ciencias Médicas de Holguín, Holguín, Cuba
| | - Carla Fuster-García
- Health Research Institute La Fe, University Hospital La Fe, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - Elena Aller
- Health Research Institute La Fe, University Hospital La Fe, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - Teresa Jaijo
- Health Research Institute La Fe, University Hospital La Fe, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | | | - Gema García-García
- Health Research Institute La Fe, University Hospital La Fe, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - José M Millán
- Health Research Institute La Fe, University Hospital La Fe, Valencia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
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40
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Richard EM, Santos-Cortez RLP, Faridi R, Rehman AU, Lee K, Shahzad M, Acharya A, Khan AA, Imtiaz A, Chakchouk I, Takla C, Abbe I, Rafeeq M, Liaqat K, Chaudhry T, Bamshad MJ, Schrauwen I, Khan SN, Morell RJ, Zafar S, Ansar M, Ahmed ZM, Ahmad W, Riazuddin S, Friedman TB, Leal SM, Riazuddin S. Global genetic insight contributed by consanguineous Pakistani families segregating hearing loss. Hum Mutat 2019; 40:53-72. [PMID: 30303587 PMCID: PMC6296877 DOI: 10.1002/humu.23666] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/04/2018] [Accepted: 10/07/2018] [Indexed: 12/14/2022]
Abstract
Consanguineous Pakistani pedigrees segregating deafness have contributed decisively to the discovery of 31 of the 68 genes associated with nonsyndromic autosomal recessive hearing loss (HL) worldwide. In this study, we utilized genome-wide genotyping, Sanger and exome sequencing to identify 163 DNA variants in 41 previously reported HL genes segregating in 321 Pakistani families. Of these, 70 (42.9%) variants identified in 29 genes are novel. As expected from genetic studies of disorders segregating in consanguineous families, the majority of affected individuals (94.4%) are homozygous for HL-associated variants, with the other variants being compound heterozygotes. The five most common HL genes in the Pakistani population are SLC26A4, MYO7A, GJB2, CIB2 and HGF, respectively. Our study provides a profile of the genetic etiology of HL in Pakistani families, which will allow for the development of more efficient genetic diagnostic tools, aid in accurate genetic counseling, and guide application of future gene-based therapies. These findings are also valuable in interpreting pathogenicity of variants that are potentially associated with HL in individuals of all ancestries. The Pakistani population, and its infrastructure for studying human genetics, will continue to be valuable to gene discovery for HL and other inherited disorders.
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Affiliation(s)
- Elodie M. Richard
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA
| | - Regie LP. Santos-Cortez
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Rabia Faridi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Atteeq U. Rehman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kwanghyuk Lee
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Mohsin Shahzad
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA
- Shaheed Zulfiqar Ali Bhutto Medical University, Pakistan Institute of Medical Sciences, Islamabad, 44000, Pakistan
| | - Anushree Acharya
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Asma A. Khan
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Ayesha Imtiaz
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Imen Chakchouk
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Christina Takla
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Izoduwa Abbe
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Maria Rafeeq
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Khurram Liaqat
- Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Taimur Chaudhry
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michael J. Bamshad
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | | | - Isabelle Schrauwen
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Shaheen N. Khan
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore 53700, Pakistan
| | - Robert J. Morell
- The Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892
| | - Saba Zafar
- Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University, Multan, 59300, Pakistan
| | - Muhammad Ansar
- Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Zubair M. Ahmed
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA
| | - Wasim Ahmad
- Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Sheik Riazuddin
- Shaheed Zulfiqar Ali Bhutto Medical University, Pakistan Institute of Medical Sciences, Islamabad, 44000, Pakistan
- Allama Iqbal Medical College, University of Health Sciences, Lahore, 54500, Pakistan
| | - Thomas B. Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Suzanne M. Leal
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Saima Riazuddin
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA
- Shaheed Zulfiqar Ali Bhutto Medical University, Pakistan Institute of Medical Sciences, Islamabad, 44000, Pakistan
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Vallone R, Dal Cortivo G, D'Onofrio M, Dell'Orco D. Preferential Binding of Mg 2+ Over Ca 2+ to CIB2 Triggers an Allosteric Switch Impaired in Usher Syndrome Type 1J. Front Mol Neurosci 2018; 11:274. [PMID: 30174586 PMCID: PMC6107761 DOI: 10.3389/fnmol.2018.00274] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 07/20/2018] [Indexed: 12/20/2022] Open
Abstract
Calcium and integrin binding protein 2 (CIB2) shares with the other members of the CIB family the ability to bind Ca2+ and Mg2+ via two functional EF-hand motifs, namely EF3 and EF4. As a cation sensor, CIB2 is able to switch to a conformation likely associated with specific biological functions yet to be clarified. Recent findings demonstrate the involvement of CIB2 in hearing physiology and a single, conservative point mutation (p.E64D) has been related to Usher Syndrome type 1J (USH1J) and non-syndromic hearing loss. We present an exhaustive biochemical and biophysical characterization of human wild type (WT) and E64D CIB2. We found that CIB2 does not possibly work as a calcium sensor under physiological conditions, its affinity for Ca2+ (Kdapp = 0.5 mM) being too low for detecting normal intracellular levels. Instead, CIB2 displays a significantly high affinity for Mg2+ (Kdapp = 290 μM), and it is probably Mg2+ -bound under physiological conditions. At odds with the homologous protein CIB1, CIB2 forms a non-covalent dimer under conditions that mimic the physiological ones, and as such it interacts with its physiological target α7B integrin. NMR spectroscopy revealed a long-range allosteric communication between the residue E64, located at the N-terminal domain, and the metal cation binding site EF3, located at the C-terminal domain. The conservative E64D mutation breaks up such inter-domain communication resulting in the impaired ability of CIB2 to switch to its Mg2+-bound form. The ability to bind the target integrin peptide was substantially conserved for E64D CIB2, thus suggesting that the molecular defect associated with USH1J resides in its inability to sense Mg2+ and adopt the required conformation.
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Affiliation(s)
- Rosario Vallone
- Section of Biological Chemistry, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Giuditta Dal Cortivo
- Section of Biological Chemistry, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | | | - Daniele Dell'Orco
- Section of Biological Chemistry, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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