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Zheng L, Adam SA, García‐Anoveros J, Mitchell BJ, Bartles JR. Espin overexpression causes stereocilia defects and provides an anti-capping effect on actin polymerization. Cytoskeleton (Hoboken) 2022; 79:64-74. [PMID: 35844198 PMCID: PMC9796729 DOI: 10.1002/cm.21719] [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: 05/20/2022] [Revised: 07/01/2022] [Accepted: 07/12/2022] [Indexed: 01/30/2023]
Abstract
Stereocilia are actin-based projections of hair cells that are arranged in a step like array, in rows of increasing height, and that constitute the mechanosensory organelle used for the senses of hearing and balance. In order to function properly, stereocilia must attain precise sizes in different hair cell types and must coordinately form distinct rows with varying lengths. Espins are actin-bundling proteins that have a well-characterized role in stereocilia formation; loss of function mutations in Espin result in shorter stereocilia and deafness in the jerker mouse. Here we describe the generation of an Espin overexpressing transgenic mouse line that results in longer first row stereocilia and discoordination of second-row stereocilia length. Furthermore, Espin overexpression results in the misregulation of other stereocilia factors including GNAI3, GPSM2, EPS8, WHRN, and MYO15A, revealing that GNAI3 and GPSM2 are dispensable for stereocilia overgrowth. Finally, using an in vitro actin polymerization assay we show that espin provides an anti-capping function that requires both the G-actin binding WH2 domain as well as either the C-terminal F-actin binding domain or the internal xAB actin-binding domain. Our results provide a novel function for Espins at the barbed ends of actin filaments distinct from its previous known function of actin bundling that may account for their effects on stereocilia growth.
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Affiliation(s)
- Lili Zheng
- Department of Cell and Developmental BiologyNorthwestern University, Feinberg School of MedicineChicagoIllinoisUSA
| | - Stephen A. Adam
- Department of Cell and Developmental BiologyNorthwestern University, Feinberg School of MedicineChicagoIllinoisUSA
| | - Jaime García‐Anoveros
- Department of Anesthesiology Neurology and NeuroscienceNorthwestern University, Feinberg School of MedicineChicagoIllinoisUSA,Hugh Knowles Center for Clinical and Basic Science in Hearing and its DisordersNorthwestern University, Feinberg School of MedicineChicagoIllinoisUSA
| | - Brian J. Mitchell
- Department of Cell and Developmental BiologyNorthwestern University, Feinberg School of MedicineChicagoIllinoisUSA
| | - James R. Bartles
- Department of Cell and Developmental BiologyNorthwestern University, Feinberg School of MedicineChicagoIllinoisUSA,Hugh Knowles Center for Clinical and Basic Science in Hearing and its DisordersNorthwestern University, Feinberg School of MedicineChicagoIllinoisUSA
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Abstract
BACKGROUND Hearing loss (HL) is a heterogeneous condition that causes partial or complete hearing impairment. Hundreds of variants in more than 60 genes have been reported to be associated with Hereditary HL (HHL). The HHL prevalence is thought to be high in the Arab population; however, the genetic epidemiology of HHL among Arab populations is understudied. This study aimed to systematically analyze the genetic epidemiology of HHL in Arab countries. METHODS We searched four literature databases (PubMed, Scopus, Science Direct, and Web of Science) from the time of inception until January 2019 using broad search terms to capture all the reported epidemiological and genetic data related to Arab patients with HHL. FINDINGS A total of 2,600 citations were obtained; 96 studies met our inclusion criteria. Our search strategy yielded 121,276 individuals who were tested for HL over 52 years (1966-2018), of whom 8,099 were clinically diagnosed with HL and belonged to 16 Arab countries. A total of 5,394 patients and 61 families with HHL were genotyped, of whom 336 patients and 6 families carried 104 variants in 44 genes and were from 17/22 Arab countries. Of these variants, 72 (in 41 genes) were distinctive to Arab patients. Arab patients manifested distinctive clinical phenotypes. The incidence of HHL in the captured studies ranged from 1.20 to 18 per 1,000 births per year, and the prevalence was the highest in Iraq (76.3%) and the lowest in Jordan (1.5%). INTERPRETATION This is the first systematic review to capture the prevalence and spectrum of variants associated with HHL in an Arab population. There appears to be a distinctive clinical picture for Arab patients with HHL, and the range and distribution of variants among Arab patients differ from those noted in other affected ethnic groups.
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Autosomal dominant Alport syndrome due to a COL4A4 mutation with an additional ESPN variant detected by whole-exome analysis. CEN Case Rep 2019; 9:59-64. [PMID: 31677115 DOI: 10.1007/s13730-019-00429-w] [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: 07/09/2019] [Accepted: 10/20/2019] [Indexed: 10/25/2022] Open
Abstract
Alport syndrome (AS) is a rare hereditary disease that presents with chronic kidney disease and sensorineural hearing loss, and is diagnosed by its clinical features, pathological features on renal tissue, and mode of inheritance. We report a woman in her 20 s who exhibited persistent haematuria with normal renal function and sensorineural hearing loss. Her family members exhibited the same clinical findings among three generations and were suspected of having autosomal dominant AS (ADAS). Renal biopsy showed minor glomerular abnormalities on light microscopy and extensive thinning of the glomerular basement membrane on electron microscopy. Whole-exome analysis revealed a known COL4A4 (type IV collagen α4) mutation (c. 2510 G > C: p. Gly837Ala). Two pedigrees with the same variant have been reported previously, one as ADAS and the other as autosomal recessive AS. However, these two cases exhibited no sensorineural hearing loss. The analysis in the present case revealed another missense variant in ESPN (Espin), an actin-bundling protein, which is a causative gene for sensorineural hearing loss. Although the pathophysiological significance of this novel missense variant needs to be clarified, computational analysis predicted that the variant creates a new phosphorylation site for protein kinase C. Our case suggests a possible association of hereditary sensorineural hearing loss with ADAS. Whole-exome analysis should be considered to diagnose hereditary and multiple-organ disorders.
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Xiao Q, Hu X, Wei Z, Tam KY. Cytoskeleton Molecular Motors: Structures and Their Functions in Neuron. Int J Biol Sci 2016; 12:1083-92. [PMID: 27570482 PMCID: PMC4997052 DOI: 10.7150/ijbs.15633] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/28/2016] [Indexed: 12/21/2022] Open
Abstract
Cells make use of molecular motors to transport small molecules, macromolecules and cellular organelles to target region to execute biological functions, which is utmost important for polarized cells, such as neurons. In particular, cytoskeleton motors play fundamental roles in neuron polarization, extension, shape and neurotransmission. Cytoskeleton motors comprise of myosin, kinesin and cytoplasmic dynein. F-actin filaments act as myosin track, while kinesin and cytoplasmic dynein move on microtubules. Cytoskeleton motors work together to build a highly polarized and regulated system in neuronal cells via different molecular mechanisms and functional regulations. This review discusses the structures and working mechanisms of the cytoskeleton motors in neurons.
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Affiliation(s)
- Qingpin Xiao
- 1. Faculty of Health Sciences, University of Macau, Taipa, Macau, China; 2. Department of Biology, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xiaohui Hu
- 1. Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Zhiyi Wei
- 2. Department of Biology, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Kin Yip Tam
- 1. Faculty of Health Sciences, University of Macau, Taipa, Macau, China
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Oonk AMM, Huygen PLM, Kunst HPM, Kremer H, Pennings RJE. Features of autosomal recessive non-syndromic hearing impairment: a review to serve as a reference. Clin Otolaryngol 2016; 41:487-97. [PMID: 26474130 DOI: 10.1111/coa.12567] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2015] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Non-syndromic sensorineural hearing impairment is inherited in an autosomal recessive fashion in 75-85% of cases. To date, 61 genes with this type of inheritance have been identified as related to hearing impairment, and the genetic heterogeneity is accompanied by a large variety of clinical characteristics. Adequate counselling on a patient's hearing prognosis and rehabilitation is part of the diagnosis on the genetic cause of hearing impairment and, in addition, is important for the psychological well-being of the patient. TYPE OF REVIEW Traditional literature review. DATA SOURCE All articles describing clinical characteristics of the audiovestibular phenotypes of identified genes and related loci have been reviewed. CONCLUSION This review aims to serve as a summary and a reference for counselling purposes when a causative gene has been identified in a patient with a non-syndromic autosomal recessively inherited sensorineural hearing impairment.
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Affiliation(s)
- A M M Oonk
- Department of Otorhinolaryngology, Hearing & Genes, Radboud University Medical Center, Nijmegen, The Netherlands. .,Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - P L M Huygen
- Department of Otorhinolaryngology, Hearing & Genes, Radboud University Medical Center, Nijmegen, The Netherlands
| | - H P M Kunst
- Department of Otorhinolaryngology, Hearing & Genes, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - H Kremer
- Department of Otorhinolaryngology, Hearing & Genes, Radboud University Medical Center, Nijmegen, The Netherlands.,Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - R J E Pennings
- Department of Otorhinolaryngology, Hearing & Genes, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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Liu H, Li J, Raval MH, Yao N, Deng X, Lu Q, Nie S, Feng W, Wan J, Yengo CM, Liu W, Zhang M. Myosin III-mediated cross-linking and stimulation of actin bundling activity of Espin. eLife 2016; 5. [PMID: 26785147 PMCID: PMC4758956 DOI: 10.7554/elife.12856] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/18/2016] [Indexed: 11/13/2022] Open
Abstract
Class III myosins (Myo3) and actin-bundling protein Espin play critical roles in regulating the development and maintenance of stereocilia in vertebrate hair cells, and their defects cause hereditary hearing impairments. Myo3 interacts with Espin1 through its tail homology I motif (THDI), however it is not clear how Myo3 specifically acts through Espin1 to regulate the actin bundle assembly and stabilization. Here we discover that Myo3 THDI contains a pair of repeat sequences capable of independently and strongly binding to the ankyrin repeats of Espin1, revealing an unexpected Myo3-mediated cross-linking mechanism of Espin1. The structures of Myo3 in complex with Espin1 not only elucidate the mechanism of the binding, but also reveal a Myo3-induced release of Espin1 auto-inhibition mechanism. We also provide evidence that Myo3-mediated cross-linking can further promote actin fiber bundling activity of Espin1.
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Affiliation(s)
- Haiyang Liu
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Jianchao Li
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Manmeet H Raval
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, United States
| | - Ningning Yao
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Xiaoying Deng
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China
| | - Qing Lu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Si Nie
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Wei Feng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jun Wan
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China.,Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Christopher M Yengo
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, United States
| | - Wei Liu
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China.,Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Mingjie Zhang
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, China.,Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.,Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Hong Kong, China
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Bakhchane A, Charif M, Salime S, Boulouiz R, Nahili H, Roky R, Lenaers G, Barakat A. Recessive TBC1D24 Mutations Are Frequent in Moroccan Non-Syndromic Hearing Loss Pedigrees. PLoS One 2015; 10:e0138072. [PMID: 26371875 PMCID: PMC4570774 DOI: 10.1371/journal.pone.0138072] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 08/26/2015] [Indexed: 11/18/2022] Open
Abstract
Mutations in the TBC1D24 gene are responsible for four neurological presentations: infantile epileptic encephalopathy, infantile myoclonic epilepsy, DOORS (deafness, onychodystrophy, osteodystrophy, mental retardation and seizures) and NSHL (non-syndromic hearing loss). For the latter, two recessive (DFNB86) and one dominant (DFNA65) mutations have so far been identified in consanguineous Pakistani and European/Chinese families, respectively. Here we report the results of a genetic study performed on a large Moroccan cohort of deaf patients that identified three families with compound heterozygote mutations in TBC1D24. Four novel mutations were identified, among which, one c.641G>A (p.Arg214His) was present in the three families, and has a frequency of 2% in control Moroccan population with normal hearing, suggesting that it acts as an hypomorphic variant leading to restricted deafness when combined with another recessive severe mutation. Altogether, our results show that mutations in TBC1D24 gene are a frequent cause (>2%) of NSHL in Morocco, and that due to its possible compound heterozygote recessive transmission, this gene should be further considered and screened in other deaf cohorts.
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Affiliation(s)
- Amina Bakhchane
- Laboratoire de Génétique Moléculaire Humaine, Département de Recherche Scientifique, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Majida Charif
- Laboratoire de Génétique Moléculaire Humaine, Département de Recherche Scientifique, Institut Pasteur du Maroc, Casablanca, Morocco
- Institut des Neurosciences de Montpellier, U1051 de l’INSERM, Université de Montpellier, BP 74103, 34091 Montpellier cedex 05, France
- PREMMi, Mitochondrial Medicine Research Centre, Université d'Angers, CHU Bât IRIS/IBS, Rue des Capucins, 49933 Angers cedex 9, France
| | - Sara Salime
- Laboratoire de Génétique Moléculaire Humaine, Département de Recherche Scientifique, Institut Pasteur du Maroc, Casablanca, Morocco
- Institut des Neurosciences de Montpellier, U1051 de l’INSERM, Université de Montpellier, BP 74103, 34091 Montpellier cedex 05, France
| | - Redouane Boulouiz
- Laboratoire de Génétique Moléculaire Humaine, Département de Recherche Scientifique, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Halima Nahili
- Laboratoire de Génétique Moléculaire Humaine, Département de Recherche Scientifique, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Rachida Roky
- Université Hassan II Ain Chock, Laboratoire de Physiologie et génétique moléculaire, Km 8 Route d'El Jadida, B.P 5366 Maarif, Casablanca, 20100, Morocco
| | - Guy Lenaers
- Institut des Neurosciences de Montpellier, U1051 de l’INSERM, Université de Montpellier, BP 74103, 34091 Montpellier cedex 05, France
- PREMMi, Mitochondrial Medicine Research Centre, Université d'Angers, CHU Bât IRIS/IBS, Rue des Capucins, 49933 Angers cedex 9, France
| | - Abdelhamid Barakat
- Laboratoire de Génétique Moléculaire Humaine, Département de Recherche Scientifique, Institut Pasteur du Maroc, Casablanca, Morocco
- * E-mail:
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Liu Q, Chen J, Gao X, Ding J, Tang Z, Zhang C, Chen J, Li L, Chen P, Wang J. Identification of stage-specific markers during differentiation of hair cells from mouse inner ear stem cells or progenitor cells in vitro. Int J Biochem Cell Biol 2015; 60:99-111. [PMID: 25582750 DOI: 10.1016/j.biocel.2014.12.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 12/10/2014] [Accepted: 12/31/2014] [Indexed: 12/11/2022]
Abstract
The induction of inner ear hair cells from stem cells or progenitor cells in the inner ear proceeds through a committed inner ear sensory progenitor cell stage prior to hair cell differentiation. To increase the efficacy of inducing inner ear hair cell differentiation from the stem cells or progenitor cells, it is essential to identify comprehensive markers for the stem cells/progenitor cells from the inner ear, the committed inner ear sensory progenitor cells and the differentiating hair cells to optimize induction conditions. Here, we report that we efficiently isolated and expanded the stem cells or progenitor cells from postnatal mouse cochleae, and induced the generation of inner ear progenitor cells and subsequent differentiation of hair cells. We profiled the gene expression of the stem cells or progenitor cells, the inner ear progenitor cells, and hair cells using aRNA microarray analysis. The pathway and gene ontology (GO) analysis of differentially expressed genes was performed. Analysis of genes exclusively detected in one particular cellular population revealed 30, 38, and 31 genes specific for inner ear stem cells, inner ear progenitor cells, and hair cells, respectively. We further examined the expression of these genes in vivo and determined that Gdf10+Ccdc121, Tmprss9+Orm1, and Chrna9+Espnl are marker genes specific for inner ear stem cells, inner ear progenitor cells, and differentiating hair cells, respectively. The identification of these marker genes will likely help the effort to increase the efficacy of hair cell induction from the stem cells or progenitor cells.
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Affiliation(s)
- Quanwen Liu
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Jiarong Chen
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Xiangli Gao
- Laboratory of Bone Marrow, The First Hospital, Zhejiang University, Hangzhou, Zhejiang 310006, PR China
| | - Jie Ding
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Zihua Tang
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Cui Zhang
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Jianling Chen
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Liang Li
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Ping Chen
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China; Departments of Cell Biology and Otolaryngology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Jinfu Wang
- Institute of Cell and Development, College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China.
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Non-syndromic hereditary sensorineural hearing loss: review of the genes involved. The Journal of Laryngology & Otology 2014; 128:13-21. [PMID: 24423691 DOI: 10.1017/s0022215113003265] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Hereditary sensorineural hearing loss is the most frequently occurring birth defect. It has profound effects for the individual and is a substantial burden on society. Insight into disease mechanisms can help to broaden therapeutic options and considerably lower lifetime social costs. In the past few decades, the identification of genes that can cause this type of hearing loss has developed rapidly. OBJECTIVE This paper provides a concise overview of the currently known genes involved in non-syndromic hereditary hearing loss and their function in the inner ear.
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Charif M, Boulouiz R, Bakhechane A, Benrahma H, Nahili H, Eloualid A, Rouba H, Kandil M, Abidi O, Lenaers G, Barakat A. Genetic and molecular analysis of the CLDN14 gene in Moroccan family with non-syndromic hearing loss. INDIAN JOURNAL OF HUMAN GENETICS 2013; 19:331-6. [PMID: 24339547 PMCID: PMC3841559 DOI: 10.4103/0971-6866.120828] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND: Hearing loss is the most prevalent human genetic sensorineural defect. Mutations in the CLDN14 gene, encoding the tight junction claudin 14 protein expressed in the inner ear, have been shown to cause non-syndromic recessive hearing loss DFNB29. AIM: We describe a Moroccan SF7 family with non-syndromic hearing loss. We performed linkage analysis in this family and sequencing to identify the mutation causing deafness. MATERIALS AND METHODS: Genetic linkage analysis, suggested the involvement of CLDN14 and KCNE1 gene in deafness in this family. Mutation screening was performed using direct sequencing of the CLDN14 and KCNE1 coding exon gene. RESULTS: Our results show the presence of c.11C>T mutation in the CLDN14 gene. Transmission analysis of this mutation in the family showed that the three affected individuals are homozygous, whereas parents and three healthy individuals are heterozygous. This mutation induces a substitution of threonine to methionine at position 4. CONCLUSION: These data show that CLDN14 gene can be i mplicated in the development of hearing loss in SF7 family; however, the pathogenicity of c.11C>T mutation remains to be determined.
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Affiliation(s)
- Majida Charif
- Département de Recherche Scientifique, Laboratoire de Génétique Moléculaire et Humaine, Institut Pasteur, 1, Place Louis Pasteur, C.P. 20360 Casablanca, Morocco
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12
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Charif M, Bounaceur S, Abidi O, Nahili H, Rouba H, Kandil M, Boulouiz R, Barakat A. The c.242G>A mutation in LRTOMT gene is responsible for a high prevalence of deafness in the Moroccan population. Mol Biol Rep 2012; 39:11011-6. [PMID: 23053991 DOI: 10.1007/s11033-012-2003-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 10/01/2012] [Indexed: 10/27/2022]
Abstract
Congenital hearing impairment (HI) affects one in 1,000 newborns and has a genetic cause in 50 % of the cases. Autosomal recessive non-syndromic hearing impairment is responsible for 70-80 % of all hereditary cases of HI. Recently, it has been demonstrated that, mutations of LRTOMT are associated with profound nonsyndromic hearing impairment at the DFNB63 locus. The objective of this study is to evaluate the carrier frequency of c.242G>A mutation in LRTOMT gene and define the contribution of this gene in the etiology of deafness in Moroccan population. We screened 105 unrelated Moroccan families with non-syndromic HI and 120 control individuals for mutation in the exon 8 of the LRTOMT gene, by sequencing and PCR-RFLP. The Homozygous c.242G>A mutation was found in 8.75 % of the families tested and in 4.16 % of control in the heterozygous state. Our results show that after the GJB2 gene mutation in LRTOMT gene is the second cause of congenital hearing impairment in Moroccan patients. This finding should facilitate diagnosis of congenital deafness of the affected subjects in Morocco.
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Affiliation(s)
- Majida Charif
- Laboratoire de Génétique Moléculaire et Humaine, Département de Recherche Scientifique, Institut Pasteur, 1, Place Louis Pasteur, C.P 20360, Casablanca, Morocco
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Li Y, Pohl E, Boulouiz R, Schraders M, Nürnberg G, Charif M, Admiraal RJ, von Ameln S, Baessmann I, Kandil M, Veltman JA, Nürnberg P, Kubisch C, Barakat A, Kremer H, Wollnik B. Mutations in TPRN cause a progressive form of autosomal-recessive nonsyndromic hearing loss. Am J Hum Genet 2010; 86:479-84. [PMID: 20170898 DOI: 10.1016/j.ajhg.2010.02.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2010] [Revised: 02/02/2010] [Accepted: 02/04/2010] [Indexed: 10/19/2022] Open
Abstract
We performed genome-wide homozygosity mapping in a large consanguineous family from Morocco and mapped the autosomal-recessive nonsyndromic hearing loss (ARNSHL) in this family to the DFNB79 locus on chromosome 9q34. By sequencing of 62 positional candidate genes of the critical region, we identified a causative homozygous 11 bp deletion, c.42_52del, in the TPRN gene in all seven affected individuals. The deletion is located in exon 1 and results in a frameshift and premature protein truncation (p.Gly15AlafsX150). Interestingly, the deleted sequence is part of a repetitive and CG-rich motive predicted to be prone to structural aberrations during crossover formation. We identified another family with progressive ARNSHL linked to this locus, whose affected members were shown to carry a causative 1 bp deletion (c.1347delG) in exon 1 of TPRN. The function of the encoded protein, taperin, is unknown; yet, partial homology to the actin-caping protein phostensin suggests a role in actin dynamics.
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