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Le Nabec A, Blotas C, Briset A, Collobert M, Férec C, Moisan S. 3D Chromatin Organization Involving MEIS1 Factor in the cis-Regulatory Landscape of GJB2. Int J Mol Sci 2022; 23:ijms23136964. [PMID: 35805969 PMCID: PMC9266880 DOI: 10.3390/ijms23136964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/17/2022] [Accepted: 06/21/2022] [Indexed: 02/04/2023] Open
Abstract
The human genome is covered by 8% of candidate cis-regulatory elements. The identification of distal acting regulatory elements and an understanding of their action are crucial to determining their key role in gene expression. Disruptions of such regulatory elements and/or chromatin conformation are likely to play a critical role in human genetic diseases. Non-syndromic hearing loss (i.e., DFNB1) is mostly due to GJB2 (Gap Junction Beta 2) variations and DFNB1 large deletions. Although several GJB2 cis-regulatory elements (CREs) have been described, GJB2 gene regulation remains not well understood. We investigated the endogenous effect of these CREs with CRISPR (clustered regularly interspaced short palindromic repeats) disruptions and observed GJB2 expression. To decipher the GJB2 regulatory landscape, we used the 4C-seq technique and defined new chromatin contacts inside the DFNB1 locus, which permit DNA loops and long-range regulation. Moreover, through ChIP-PCR, we determined the involvement of the MEIS1 transcription factor in GJB2 expression. Taken together, the results of our study enable us to describe the 3D DFNB1 regulatory landscape.
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Affiliation(s)
- Anaïs Le Nabec
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
- Correspondence: or twitter@anaisnabec (A.L.N.); (S.M.); Tel.: +33-2-98-01-65-84 (A.L.N.); +33-2-98-01-65-67 (S.M.)
| | - Clara Blotas
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
| | - Alinéor Briset
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
| | - Mégane Collobert
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
| | - Claude Férec
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
| | - Stéphanie Moisan
- University Brest, Inserm, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.B.); (A.B.); (M.C.); (C.F.)
- Laboratoire de Génétique Moléculaire et d’Histocompatibilité, CHRU Brest, UMR 1078, F-29200 Brest, France
- Correspondence: or twitter@anaisnabec (A.L.N.); (S.M.); Tel.: +33-2-98-01-65-84 (A.L.N.); +33-2-98-01-65-67 (S.M.)
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Acharya A, Schrauwen I, Leal SM. Identification of autosomal recessive nonsyndromic hearing impairment genes through the study of consanguineous and non-consanguineous families: past, present, and future. Hum Genet 2022; 141:413-430. [PMID: 34291353 PMCID: PMC10416318 DOI: 10.1007/s00439-021-02309-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 06/24/2021] [Indexed: 10/20/2022]
Abstract
Hearing impairment (HI) is one of the most common sensory disabilities with exceptionally high genetic heterogeneity. Of genetic HI cases, 30% are syndromic and 70% are nonsyndromic. For nonsyndromic (NS) HI, 77% of the cases are due to autosomal recessive (AR) inheritance. ARNSHI is usually congenital/prelingual, severe-to-profound, affects all frequencies and is not progressive. Thus far, 73 ARNSHI genes have been identified. Populations with high rates of consanguinity have been crucial in the identification of ARNSHI genes, and 92% (67/73) of these genes were identified in consanguineous families. Recent changes in genomic technologies and analyses have allowed a shift towards ARNSHI gene discovery in outbred populations. The latter is crucial towards understanding the genetic architecture of ARNSHI in diverse and understudied populations. We present an overview of the 73 ARNSHI genes, the methods used to identify them, including next-generation sequencing which revolutionized the field, and new technologies that show great promise in advancing ARNSHI discoveries.
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Affiliation(s)
- Anushree Acharya
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Suzanne M Leal
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA.
- Department of Neurology, Columbia University Medical Center, New York, NY, USA.
- Taub Institute for Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA.
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3
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Bowles B, Ferrer A, Nishimura CJ, Pinto E Vairo F, Rey T, Leheup B, Sullivan J, Schoch K, Stong N, Agolini E, Cocciadiferro D, Williams A, Cummings A, Loddo S, Genovese S, Roadhouse C, McWalter K, Wentzensen IM, Li C, Babovic-Vuksanovic D, Lanpher BC, Dentici ML, Ankala A, Hamm JA, Dallapiccola B, Radio FC, Shashi V, Gérard B, Bloch-Zupan A, Smith RJ, Klee EW. TSPEAR variants are primarily associated with ectodermal dysplasia and tooth agenesis but not hearing loss: A novel cohort study. Am J Med Genet A 2021; 185:2417-2433. [PMID: 34042254 PMCID: PMC8361973 DOI: 10.1002/ajmg.a.62347] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 04/12/2021] [Accepted: 04/22/2021] [Indexed: 12/30/2022]
Abstract
Biallelic loss‐of‐function variants in the thrombospondin‐type laminin G domain and epilepsy‐associated repeats (TSPEAR) gene have recently been associated with ectodermal dysplasia and hearing loss. The first reports describing a TSPEAR disease association identified this gene is a cause of nonsyndromic hearing loss, but subsequent reports involving additional affected families have questioned this evidence and suggested a stronger association with ectodermal dysplasia. To clarify genotype–phenotype associations for TSPEAR variants, we characterized 13 individuals with biallelic TSPEAR variants. Individuals underwent either exome sequencing or panel‐based genetic testing. Nearly all of these newly reported individuals (11/13) have phenotypes that include tooth agenesis or ectodermal dysplasia, while three newly reported individuals have hearing loss. Of the individuals displaying hearing loss, all have additional variants in other hearing‐loss‐associated genes, specifically TMPRSS3, GJB2, and GJB6, that present competing candidates for their hearing loss phenotype. When presented alongside previous reports, the overall evidence supports the association of TSPEAR variants with ectodermal dysplasia and tooth agenesis features but creates significant doubt as to whether TSPEAR variants are a monogenic cause of hearing loss. Further functional evidence is needed to evaluate this phenotypic association.
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Affiliation(s)
- Bradley Bowles
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Alejandro Ferrer
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Carla J Nishimura
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Filippo Pinto E Vairo
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, USA
| | - Tristan Rey
- Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France.,Laboratoires de Diagnostic génétique, Pôle de Biologie, Hôpitaux Universitaires de Strasbourg, Institut de Génétique Médicale d'Alsace, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS-UMR7104, Université de Strasbourg, Illkirch, France
| | - Bruno Leheup
- Département de Médecine Infantile, CHRU de Nancy, Nancy, France
| | - Jennifer Sullivan
- Department of Pediatrics, Duke University, Durham, North Carolina, USA
| | - Kelly Schoch
- Department of Pediatrics, Duke University, Durham, North Carolina, USA
| | - Nicholas Stong
- Institute for Genomic Medicine, Columbia University, New York, New York, USA.,Brystol Myers Squibb, New York, New York, USA
| | - Emanuele Agolini
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Dario Cocciadiferro
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Abigail Williams
- Department of Pediatrics, East Tennessee Children's Hospital, Knoxville, Tennessee, USA
| | - Alex Cummings
- Department of Pediatrics, East Tennessee Children's Hospital, Knoxville, Tennessee, USA.,University of Wisconsin Hospitals and Clinics, Madison, Wisconsin, USA
| | - Sara Loddo
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Silvia Genovese
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Chelsea Roadhouse
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | | | | | | | - Chumei Li
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Dusica Babovic-Vuksanovic
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, USA
| | - Brendan C Lanpher
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, USA
| | - Maria Lisa Dentici
- Genetics and Rare Diseases Research Division, Molecular Genetics and Functional Genomics Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Arun Ankala
- EGL Genetics LLC, Tucker, Georgia, USA.,Emory University School of Medicine, Atlanta, Georgia, USA
| | - J Austin Hamm
- Department of Pediatrics, East Tennessee Children's Hospital, Knoxville, Tennessee, USA
| | - Bruno Dallapiccola
- Genetics and Rare Diseases Research Division, Molecular Genetics and Functional Genomics Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Francesca Clementina Radio
- Genetics and Rare Diseases Research Division, Molecular Genetics and Functional Genomics Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Vandana Shashi
- Department of Pediatrics, Duke University, Durham, North Carolina, USA
| | - Benedicte Gérard
- Laboratoires de Diagnostic génétique, Pôle de Biologie, Hôpitaux Universitaires de Strasbourg, Institut de Génétique Médicale d'Alsace, Strasbourg, France
| | - Agnes Bloch-Zupan
- Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France.,Centre de référence des maladies rares orales et dentaires O-Rares, Filière Santé Maladies rares TETE COU, European Reference Network CRANIO, Pôle de Médecine et Chirurgie Bucco-dentaires, Hôpital Civil, Hôpitaux Universitaires de Strasbourg (HUS), Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS-UMR7104, Université de Strasbourg, Illkirch, France
| | - Richard J Smith
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA
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Safka Brozkova D, Uhrova Meszarosova A, Lassuthova P, Varga L, Staněk D, Borecká S, Laštůvková J, Čejnová V, Rašková D, Lhota F, Gašperíková D, Seeman P. The Cause of Hereditary Hearing Loss in GJB2 Heterozygotes-A Comprehensive Study of the GJB2/DFNB1 Region. Genes (Basel) 2021; 12:genes12050684. [PMID: 34062854 PMCID: PMC8147375 DOI: 10.3390/genes12050684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 12/14/2022] Open
Abstract
Hearing loss is a genetically heterogeneous sensory defect, and the frequent causes are biallelic pathogenic variants in the GJB2 gene. However, patients carrying only one heterozygous pathogenic (monoallelic) GJB2 variant represent a long-lasting diagnostic problem. Interestingly, previous results showed that individuals with a heterozygous pathogenic GJB2 variant are two times more prevalent among those with hearing loss compared to normal-hearing individuals. This excess among patients led us to hypothesize that there could be another pathogenic variant in the GJB2 region/DFNB1 locus. A hitherto undiscovered variant could, in part, explain the cause of hearing loss in patients and would mean reclassifying them as patients with GJB2 biallelic pathogenic variants. In order to detect an unknown causal variant, we examined 28 patients using NGS with probes that continuously cover the 0.4 Mb in the DFNB1 region. An additional 49 patients were examined by WES to uncover only carriers. We did not reveal a second pathogenic variant in the DFNB1 region. However, in 19% of the WES-examined patients, the cause of hearing loss was found to be in genes other than the GJB2. We present evidence to show that a substantial number of patients are carriers of the GJB2 pathogenic variant, albeit only by chance.
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Affiliation(s)
- Dana Safka Brozkova
- Neurogenetic laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, 15006 Prague, Czech Republic; (A.U.M.); (P.L.); (D.S.); (P.S.)
- Correspondence:
| | - Anna Uhrova Meszarosova
- Neurogenetic laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, 15006 Prague, Czech Republic; (A.U.M.); (P.L.); (D.S.); (P.S.)
| | - Petra Lassuthova
- Neurogenetic laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, 15006 Prague, Czech Republic; (A.U.M.); (P.L.); (D.S.); (P.S.)
| | - Lukáš Varga
- Department of Otorhinolaryngology–Head and Neck Surgery, Faculty of Medicine and University Hospital, Comenius University, 85107 Bratislava, Slovakia;
- Diabgene Laboratory, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia; (S.B.); (D.G.)
| | - David Staněk
- Neurogenetic laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, 15006 Prague, Czech Republic; (A.U.M.); (P.L.); (D.S.); (P.S.)
| | - Silvia Borecká
- Diabgene Laboratory, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia; (S.B.); (D.G.)
| | - Jana Laštůvková
- Department of Medical Genetics, Masaryk Hospital in Usti nad Labem, Regional Health Corporation, 40011 Ústí nad Labem, Czech Republic; (J.L.); (V.Č.)
| | - Vlasta Čejnová
- Department of Medical Genetics, Masaryk Hospital in Usti nad Labem, Regional Health Corporation, 40011 Ústí nad Labem, Czech Republic; (J.L.); (V.Č.)
| | - Dagmar Rašková
- Centre for Medical Genetics and Reproductive Medicine GENNET, 17000 Prague, Czech Republic; (D.R.); (F.L.)
| | - Filip Lhota
- Centre for Medical Genetics and Reproductive Medicine GENNET, 17000 Prague, Czech Republic; (D.R.); (F.L.)
| | - Daniela Gašperíková
- Diabgene Laboratory, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia; (S.B.); (D.G.)
| | - Pavel Seeman
- Neurogenetic laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, 15006 Prague, Czech Republic; (A.U.M.); (P.L.); (D.S.); (P.S.)
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Ebrahimkhani S, Asaadi Tehrani G. Evaluation of the GJB2 and GJB6 Polymorphisms with Autosomal Recessive Nonsyndromic Hearing Loss in Iranian Population. IRANIAN JOURNAL OF OTORHINOLARYNGOLOGY 2021; 33:79-86. [PMID: 33912482 PMCID: PMC8052483 DOI: 10.22038/ijorl.2020.45196.2483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Hearing loss (HL), with more than 100 gene loci, is the most common sensorineural defects in humans. The mutations in two GJB2 and GJB6 (Gap Junction Protein Beta 2, 6) genes are responsible for nearly 50% of autosomal recessive nonsyndromic hearing loss. The aim of the present study was to evaluate polymorphisms of 111C>T (rs7329857) and 337G>T (rs7333214) in GJB2 (encoding connexin 26) and GJB6 (encoding connexin 32) genes, respectively. MATERIALS AND METHODS In this study, 32 blood samples were obtained from Iranian patients with HL defect and 32 normal blood samples were prepared. After genomic deoxyribonucleic acid extraction, genotyping in rs7333214 and rs7329857 polymorphisms was conducted using tetra-amplification refractory mutation system-polymerase chain reaction and the obtained data were analyzed. RESULTS In this study, the prevalence rates of CC, CT, and TT genotypes in GJB2 gene were reported as 84.4%, 68.7%, and 0% in the affected subjects and 0%, 15.6%, and 31.3% in the control samples, respectively, which were statistically significant (P=0.004). In relation to GJB6 gene, the prevalence rates of GG, GT, and TT genotypes were 65.2%, 78.1%, and 25% in the control subjects and 21.9%, 9.4%, and 0% in the affected samples, respectively, which were not statistically significant (P>0.05). CONCLUSION The results of this study revealed that 111C>T polymorphism in GJB2 gene was involved in the incidence of HL in the studied population and could be suggested as a prognostic factor in genetic counseling before marriage and pregnancy.
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Affiliation(s)
| | - Golnaz Asaadi Tehrani
- Department of Genetics, Zanjan Branch, Islamic Azad University, Zanjan, Iran.,Corresponding Author: Department of Genetics, Faculty of Medical and Sciences, Zanjan Branch, Islamic Azad University, Etemadeyeh, Moalem St, Zanjan, Iran. E-mail: Golnaz_ asaadi¬ @yahoo.com
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Falah M, Houshmand M, Balali M, Asghari A, Bagher Z, Alizadeh R, Farhadi M. Role of GJB2 and GJB6 in Iranian Nonsyndromic Hearing Impairment: From Molecular Analysis to Literature Reviews. Fetal Pediatr Pathol 2020; 39:1-12. [PMID: 31215297 DOI: 10.1080/15513815.2019.1627625] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background: Hearing impairment (HI) is a heterogeneous disorder. GJB2 and GJB6 genes are typically the first line of genetic screening before proceeding to any massive parallel sequencing. We evaluated the clinical utility of GJB2 and GJB6 testing in the Iranian population. Methods: GJB2 and GJB6 were sequenced. PubMed and Google Scholar were searched for Iranian publications on deletions in the DFNB1 locus. Results: We detected mutations of GJB2 in 16.5%, and no mutations of GJB6. Literature review revealed no reports of mutations of GJB6 in the Iranian population. Conclusion: This data and literature reviews indicate that GJB6 is not commonly responsible for Iranian nonsyndromic HI. Hence, the clinical utility of GJB6 genetic analysis as a first line for HI evaluation does not have the same utility as GJB2. The study is consistent with recent studies emphasizing the role of ethnicity in the selection of HI genetic testing strategy.
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Affiliation(s)
- Masoumeh Falah
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Massoud Houshmand
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran.,Department of Medical Genetics, National Institute for Genetic Engineering and Biotechnology, Tehran, Islamic Republic of Iran
| | - Maryam Balali
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Alimohamad Asghari
- Skull Base Research Center, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Zohreh Bagher
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Rafieh Alizadeh
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Mohammad Farhadi
- ENT and Head & Neck Research Center and Department, The Five Senses Institute, Hazrat Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
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Moisan S, Le Nabec A, Quillévéré A, Le Maréchal C, Férec C. Characterization of GJB2 cis-regulatory elements in the DFNB1 locus. Hum Genet 2019; 138:1275-1286. [PMID: 31586237 DOI: 10.1007/s00439-019-02068-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/29/2019] [Indexed: 11/28/2022]
Abstract
Although most disease-causing variants are within coding region of genes, it is now well established that cis-acting regulatory sequences, depending on 3D-chromatin organization, are required for temporal and spatial control of gene expression. Disruptions of such regulatory elements and/or chromatin conformation are likely to play a critical role in human genetic disease. Hence, recurrent monoallelic cases, who present the most common hereditary type of nonsyndromic hearing loss (i.e., DFNB1), carry only one identified pathogenic allele. This strongly suggests the presence of uncharacterized distal cis-acting elements in the missing allele. Here within, we study the spatial organization of a large DFNB1 locus encompassing the gap junction protein beta 2 (GJB2) gene, the most frequently mutated gene in this inherited hearing loss phenotype, with the chromosome conformation capture carbon copy technology (5C). By combining this approach with functional activity reporter assays and mapping of CCCTC-binding factor (CTCF) along the DFNB1 locus, we identify a novel set of cooperating GJB2 cis-acting elements and suggest a DFNB1 three-dimensional looping regulation model.
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Affiliation(s)
- Stéphanie Moisan
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, CHRU de Brest, Bretagne, Brest, France. .,Univ Brest, Inserm, EFS UMR 1078, GGB, 29200, Brest, France.
| | - Anaïs Le Nabec
- Univ Brest, Inserm, EFS UMR 1078, GGB, 29200, Brest, France
| | | | - Cédric Le Maréchal
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, CHRU de Brest, Bretagne, Brest, France.,Univ Brest, Inserm, EFS UMR 1078, GGB, 29200, Brest, France
| | - Claude Férec
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, CHRU de Brest, Bretagne, Brest, France. .,Univ Brest, Inserm, EFS UMR 1078, GGB, 29200, Brest, France.
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8
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Koohiyan M, Azadegan-Dehkordi F, Koohian F, Abolhasani M, Hashemzadeh-Chaleshtori M. Genetics of hereditary hearing loss in east Iran population: A systematic review of GJB2 mutations. Intractable Rare Dis Res 2019; 8:172-178. [PMID: 31523594 PMCID: PMC6743427 DOI: 10.5582/irdr.2019.01070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mutations in the GJB2 gene are the most common cause of pre-lingual hearing loss (HL) worldwide. Previous studies have shown the frequency of GJB2 mutations to be 16% in Iran, but varies among different ethnic groups. Here, we have reviewed results from previous published mutation reports to provide a comprehensive collection of data for GJB2 mutations and HL in eastern Iran. We conducted a systematic literature review of PubMed, Google Scholar, Web of Science, and Science Direct databases for articles published before March, 2019. The literature search was performed by 2 independent researchers. The primary data of these studies including the number of samples, allelic frequency, and so on were extracted. Six studies involving 812 unrelated families from four different eastern provinces were included and analyzed for the type and prevalence of GJB2 mutations. A total of 19 different genetic variants were detected. GJB2 mutations were 8.8% in the studied eastern provinces, which was lower than that reported in northern populations of Iran. Moreover, a gradient in the frequency of GJB2 mutations from north to south Iran was observed. c.35delG was the most frequent mutation, accounting for 48.5% % of the populations studied. However, this mutation was absent in the Baluchi population. This review shows that particular rare mutations are frequent in some Iranian ethnic groups, and should be considered for genetic counselling.
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Affiliation(s)
- Mahbobeh Koohiyan
- Cancer Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Fatemeh Azadegan-Dehkordi
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Farideh Koohian
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Marziye Abolhasani
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Morteza Hashemzadeh-Chaleshtori
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
- Address correspondence to:Prof. Morteza Hashezadeh-Chaleshtori, Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Rahmatieh, Shahrekord 8813833435, Iran. E-mail:
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Schrauwen I, Chakchouk I, Acharya A, Liaqat K, Irfanullah, Nickerson DA, Bamshad MJ, Shah K, Ahmad W, Leal SM. Novel digenic inheritance of PCDH15 and USH1G underlies profound non-syndromic hearing impairment. BMC MEDICAL GENETICS 2018; 19:122. [PMID: 30029624 PMCID: PMC6053831 DOI: 10.1186/s12881-018-0618-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/24/2018] [Indexed: 11/10/2022]
Abstract
BACKGROUND Digenic inheritance is the simplest model of oligenic disease. It can be observed when there is a strong epistatic interaction between two loci. For both syndromic and non-syndromic hearing impairment, several forms of digenic inheritance have been reported. METHODS We performed exome sequencing in a Pakistani family with profound non-syndromic hereditary hearing impairment to identify the genetic cause of disease. RESULTS We found that this family displays digenic inheritance for two trans heterozygous missense mutations, one in PCDH15 [p.(Arg1034His)] and another in USH1G [p.(Asp365Asn)]. Both of these genes are known to cause autosomal recessive non-syndromic hearing impairment and Usher syndrome. The protein products of PCDH15 and USH1G function together at the stereocilia tips in the hair cells and are necessary for proper mechanotransduction. Epistasis between Pcdh15 and Ush1G has been previously reported in digenic heterozygous mice. The digenic mice displayed a significant decrease in hearing compared to age-matched heterozygous animals. Until now no human examples have been reported. CONCLUSIONS The discovery of novel digenic inheritance mechanisms in hereditary hearing impairment will aid in understanding the interaction between defective proteins and further define inner ear function and its interactome.
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Affiliation(s)
- Isabelle Schrauwen
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza 700D, Houston, TX, 77030, USA
| | - Imen Chakchouk
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza 700D, Houston, TX, 77030, USA
| | - Anushree Acharya
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza 700D, Houston, TX, 77030, USA
| | - Khurram Liaqat
- Department of Biotechnology, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Irfanullah
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Michael J Bamshad
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Khadim Shah
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Wasim Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Suzanne M Leal
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza 700D, Houston, TX, 77030, USA.
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10
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Chen K, Wu X, Zong L, Jiang H. GJB3/GJB6 screening in GJB2 carriers with idiopathic hearing loss: Is it necessary? J Clin Lab Anal 2018; 32:e22592. [PMID: 29926981 DOI: 10.1002/jcla.22592] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 05/29/2018] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Genetic analysis detected excessive mono-allelic recessive GJB2 mutations in individuals with idiopathic deafness; the remaining alleles in trans/cis are underdetermined. The aim of this study was to assess the contributions of variants in GJB3 or GJB6 to non-syndromic sensorineural hearing impairment (NSHI) in Chinese patients with mono-allelic GJB2 mutations. METHODS The entire coding sequences of GJB3/GJB6, as well as deletions in GJB6, in a cohort of NSHI patients (n = 100) carrying likely pathogenic heterozygous GJB2 mutations, were tested. Targeted next generation sequencing was further performed in a multiplex family GDHY with moderate to profound NSHI. RESULTS Putatively causative GJB3 variant underlied 1% (1/100) in this cohort. In family GDHY, we identified a rare GJB3 c.250G>A mutation, as double heterozygotes with GJB2 c.109G>A and/or a novel GJB2 mutation c.638T>C predicted to be damaging in a digenic inheritance after precluding other attributable mutations from 127 deafness genes. No GJB6 mutation was found. CONCLUSIONS GJB3/GJB6 variants account for a low proportion in autosomal recessive GJB2 mutation carriers in our cohort. Environmental causes, or other NSHI relevant genes, revealed by targeted next generation sequencing or whole exome sequencing, may play major roles in triggering deafness in these patients.
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Affiliation(s)
- Kaitian Chen
- Department of Otorhinolaryngology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, China
| | - Xuan Wu
- Department of Otorhinolaryngology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, China
| | - Ling Zong
- Department of Otorhinolaryngology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Hongyan Jiang
- Department of Otorhinolaryngology, Hainan General Hospital, Haikou, China
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11
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Deltas C. Digenic inheritance and genetic modifiers. Clin Genet 2018; 93:429-438. [PMID: 28977688 DOI: 10.1111/cge.13150] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/27/2017] [Accepted: 09/28/2017] [Indexed: 12/28/2022]
Abstract
Digenic inheritance (DI) concerns pathologies with the simplest form of multigenic etiology, implicating more than 1 gene (and perhaps the environment). True DI is when biallelic or even triallelic mutations in 2 distinct genes, in cis or in trans, are necessary and sufficient to cause pathology with a defined diagnosis. In true DI, a heterozygous mutation in each of 2 genes alone is not associated with a recognizable phenotype. Well-documented diseases with true DI are so far rare and follow non-Mendelian inheritance. DI is also encountered when by serendipity, pathogenic mutations responsible for 2 distinct disease entities are co-inherited, leading to a mixed phenotype. Also, we can consider many true monogenic Mendelian conditions, which show impressively broad spectrum of phenotypes due to pseudo-DI, as a result of co-inheriting genetic modifiers (GMs). I am herewith reviewing examples of GM and embark on presenting some recent notable examples of true DI, with wider discussion of the literature. Undeniably, the advent of high throughput sequencing is bound to unravel more patients suffering with true DI conditions and elucidate many important GM, thus impacting precision medicine.
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Affiliation(s)
- C Deltas
- College of Medicine, Qatar University, Doha, Qatar.,Department of Biological Sciences, Molecular Medicine Research Center, University of Cyprus, Nicosia, Cyprus
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12
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del Castillo FJ, del Castillo I. DFNB1 Non-syndromic Hearing Impairment: Diversity of Mutations and Associated Phenotypes. Front Mol Neurosci 2017; 10:428. [PMID: 29311818 PMCID: PMC5743749 DOI: 10.3389/fnmol.2017.00428] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/07/2017] [Indexed: 02/02/2023] Open
Abstract
The inner ear is a very complex sensory organ whose development and function depend on finely balanced interactions among diverse cell types. The many different kinds of inner ear supporting cells play the essential roles of providing physical and physiological support to sensory hair cells and of maintaining cochlear homeostasis. Appropriately enough, the gene most commonly mutated among subjects with hereditary hearing impairment (HI), GJB2, encodes the connexin-26 (Cx26) gap-junction channel protein that underlies both intercellular communication among supporting cells and homeostasis of the cochlear fluids, endolymph and perilymph. GJB2 lies at the DFNB1 locus on 13q12. The specific kind of HI associated with this locus is caused by recessively-inherited mutations that inactivate the two alleles of the GJB2 gene, either in homozygous or compound heterozygous states. We describe the many diverse classes of genetic alterations that result in DFNB1 HI, such as large deletions that either destroy the GJB2 gene or remove a regulatory element essential for GJB2 expression, point mutations that interfere with promoter function or splicing, and small insertions or deletions and nucleotide substitutions that target the GJB2 coding sequence. We focus on how these alterations disrupt GJB2 and Cx26 functions and on their different effects on cochlear development and physiology. We finally discuss the diversity of clinical features of DFNB1 HI as regards severity, age of onset, inner ear malformations and vestibular dysfunction, highlighting the areas where future research should be concentrated.
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Affiliation(s)
- Francisco J. del Castillo
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Ignacio del Castillo
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
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13
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Mei L, Chen J, Zong L, Zhu Y, Liang C, Jones RO, Zhao HB. A deafness mechanism of digenic Cx26 (GJB2) and Cx30 (GJB6) mutations: Reduction of endocochlear potential by impairment of heterogeneous gap junctional function in the cochlear lateral wall. Neurobiol Dis 2017; 108:195-203. [PMID: 28823936 DOI: 10.1016/j.nbd.2017.08.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 07/12/2017] [Accepted: 08/16/2017] [Indexed: 12/19/2022] Open
Abstract
Digenic Connexin26 (Cx26, GJB2) and Cx30 (GJB6) heterozygous mutations are the second most frequent cause of recessive deafness in humans. However, the underlying deafness mechanism remains unclear. In this study, we created different double Cx26 and Cx30 heterozygous (Cx26+/-/Cx30+/-) mouse models to investigate the underlying pathological changes and deafness mechanism. We found that double Cx26+/-/Cx30+/- heterozygous mice had hearing loss. Endocochlear potential (EP), which is a driving force for hair cells producing auditory receptor current, was reduced. However, unlike Cx26 homozygous knockout (Cx26-/-) mice, the cochlea in Cx26+/-/Cx30+/- mice displayed normal development and had no apparent hair cell degeneration. Gap junctions (GJs) in the cochlea form two independent networks: the epithelial cell GJ network in the organ of Corti and the connective tissue GJ network in the cochlear lateral wall. We further found that double heterozygous deletion of Cx26 and Cx30 in the epithelial cells did not reduce EP and had normal hearing, suggesting that Cx26+/-/Cx30+/- may mainly impair gap junctional functions in the cochlear lateral wall and lead to EP reduction and hearing loss. Most of Cx26 and Cx30 in the cochlear lateral wall co-expressed in the same gap junctional plaques. Moreover, sole Cx26+/- or Cx30+/- heterozygous mice had no hearing loss. These data further suggest that digenic Cx26 and Cx30 mutations may impair heterozygous coupling of Cx26 and Cx30 in the cochlear lateral wall to reduce EP, thereby leading to hearing loss.
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Affiliation(s)
- Ling Mei
- Department of Otolaryngology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA; Department of Otolaryngology, Xinhua Hospital, Shanghai Jiao Tong University Medical School, Shanghai 200092, PR China
| | - Jin Chen
- Department of Otolaryngology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA; Department of Otolaryngology, Tongji Hospital, Huazhong University of Science & Technology, 1095 Jiefang Avenue, Wuhan 430030, PR China
| | - Liang Zong
- Department of Otolaryngology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA; Department of Otolaryngology, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853, PR China
| | - Yan Zhu
- Department of Otolaryngology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA
| | - Chun Liang
- Department of Otolaryngology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA
| | - Raleigh O Jones
- Department of Otolaryngology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA
| | - Hong-Bo Zhao
- Department of Otolaryngology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536, USA.
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14
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Bliznetz EA, Lalayants MR, Markova TG, Balanovsky OP, Balanovska EV, Skhalyakho RA, Pocheshkhova EA, Nikitina NV, Voronin SV, Kudryashova EK, Glotov OS, Polyakov AV. Update of the GJB2/DFNB1 mutation spectrum in Russia: a founder Ingush mutation del(GJB2-D13S175) is the most frequent among other large deletions. J Hum Genet 2017; 62:789-795. [PMID: 28405014 PMCID: PMC5584515 DOI: 10.1038/jhg.2017.42] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 03/05/2017] [Accepted: 03/05/2017] [Indexed: 11/09/2022]
Abstract
Although mutations in the GJB2 gene sequence make up the majority of variants causing autosomal-recessive non-syndromic hearing loss, few large deletions have been shown to contribute to DFNB1 deafness. Currently, genetic testing for DFNB1 hearing loss includes GJB2 sequencing and DFNB1 deletion analysis for two common large deletions, del(GJB6-D13S1830) and del(GJB6-D13S1854). Here, we report frequency in Russia, clinical significance and evolutionary origins of a 101 kb deletion, del(GJB2-D13S175), recently identified by us. In multiethnic cohort of 1104 unrelated hearing loss patients with biallelic mutations at the DFNB1 locus, the del(GJB2-D13S175) allele frequency of up to 0.5% (11/2208) was determined and this allele was shown to be predominantly associated with profound sensorineural hearing loss. Additionally, eight previously unpublished GJB2 mutations were described in this study. All patients carrying del(GJB2-D13S175) were of the Ingush ancestry. Among normal hearing individuals, del(GJB2-D13S175) was observed in Russian Republic of Ingushetia with a carrier rate of ~1% (2/241). Analysis of haplotypes associated with the deletion revealed a common founder in the Ingushes, with age of the deletion being ~3000 years old. Since del(GJB2-D13S175) was missed by standard methods of GJB2 analysis, del(GJB2-D13S175) detection has been added to our routine testing strategy for DFNB1 hearing loss.
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Affiliation(s)
- Elena A Bliznetz
- The Federal Agency for Scientific Organizations, Federal State Budgetary Institution, Research Centre for Medical Genetics, Moscow, Russia
| | - Maria R Lalayants
- Federal Medical and Biological Agency, Federal State-Funded Institution of Science, National Research Center for Audiology and Hearing Rehabilitation, Moscow, Russia
| | - Tatiana G Markova
- Federal Medical and Biological Agency, Federal State-Funded Institution of Science, National Research Center for Audiology and Hearing Rehabilitation, Moscow, Russia
| | - Oleg P Balanovsky
- The Federal Agency for Scientific Organizations, Federal State Budgetary Institution, Research Centre for Medical Genetics, Moscow, Russia
- The Russian Academy of Sciences, Federal State-Funded Institution of Science, Vavilov Institute of General Genetics, Moscow, Russia
| | - Elena V Balanovska
- The Federal Agency for Scientific Organizations, Federal State Budgetary Institution, Research Centre for Medical Genetics, Moscow, Russia
| | - Roza A Skhalyakho
- The Federal Agency for Scientific Organizations, Federal State Budgetary Institution, Research Centre for Medical Genetics, Moscow, Russia
- The Russian Academy of Sciences, Federal State-Funded Institution of Science, Vavilov Institute of General Genetics, Moscow, Russia
| | - Elvira A Pocheshkhova
- The Ministry of Health, Federal State-Funded Educational Institution of Higher Education, Kuban State Medical University, Krasnodar, Russia
| | - Natalya V Nikitina
- The Ministry of Health, State Budgetary Healthcare Institution, Clinical-Diagnostic Center of Mother and Child Health Protection, Yekaterinburg, Russia
| | - Sergey V Voronin
- State Autonomous Healthcare Institution, Regional Clinical Center of Specialized Medical Care, Vladivostok, Russia
| | - Elena K Kudryashova
- The Ministry of Health, State Budgetary Healthcare Institution, Leningrad Regional Clinical Hospital, Saint Petersburg, Russia
| | - Oleg S Glotov
- Federal State Budgetary Educational Institution of Higher Education, Saint Petersburg University, Saint Petersburg, Russia
| | - Alexander V Polyakov
- The Federal Agency for Scientific Organizations, Federal State Budgetary Institution, Research Centre for Medical Genetics, Moscow, Russia
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15
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Bliznetz EA, Kanivets IV, Polyakov AV. DNA copy number analysis of the DFNB1 hereditary hearing loss locus. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417050027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Lazăr C, Popp R, Al-Khzouz C, Mihuț G, Grigorescu-Sido P. GJB2 and GJB6 genes mutations in children with non-syndromic hearing loss. REV ROMANA MED LAB 2017. [DOI: 10.1515/rrlm-2017-0004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Introduction. At the moment there is not enough data in Romania about the incidence of the main genetic mutations which can cause hearing loss.
Objective. The current research aims to determine on a representative sample the prevalence of two mutations of genes GJB2 -c.35delG and p.W24X- and two mutations of genes GJB6 -del(GJB6-D13S1830), del(GJB6-D13S1854) respectively - in patients with congenital nonsyndromic sensorineural hearing loss (CNSHL).
Methods: The sample group included 179 children with CNSHL. The evaluation consist in: a.Clinical, laboratory and imagistic examination; b.ENT exam and audiological evaluation. c.Two methods (semi-nested PCR technique followed by RFLP, validated with ARMS-PCR analysis) for detection of c.35delG and pW24X mutations; d.PCR-multiplex technique for detecting del(GJB6-D13S1830) and del (GJB6-D13S1854).
Results: The audiological diagnosis was: profound hearing loss in 116 patients (64.8%), severe hearing loss in 29 children (16.2%) and moderate hearing loss in 34 patients (representing 19% of the trial patients). The prevalence for the three mutations was: 27.3 % for c.35delG, 3.6 % for p.W24X and 0.28% for del(GJB6-D13S1830). The detection of the three mutations (two on GJB2 gene and one on GJB 6 gene) has allowed to establish the genetic cause for deafness in 45 patients, representing 25.14% of the sample group. Our study is reporting the first case in Romania with a mutation of gene GJB6. Mutation del(GJB6-D13S1854) lacked in all 179 patients.
Conclusion: The prevalence data obtained in the current research are comparable to data communicated by studies from other European countries.
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Affiliation(s)
- Călin Lazăr
- Department of Paediatrics I, University of Medicine and Pharmacy „Iuliu Hațieganu” Cluj-Napoca, Romania
| | - Radu Popp
- Department of Medical Genetics, „Iuliu Hațieganu” University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Camelia Al-Khzouz
- Department of Paediatrics I, University of Medicine and Pharmacy „Iuliu Hațieganu” Cluj-Napoca, Romania
| | - Gheorghe Mihuț
- Service of Otolaryngology, Clinical Emergency Paediatric Hospital, Cluj-Napoca, Romania
| | - Paula Grigorescu-Sido
- Department of Paediatrics I, University of Medicine and Pharmacy „Iuliu Hațieganu” Cluj-Napoca, Romania
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17
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First report of prevalence c.IVS1+1G>A and del (GJB6-13S1854) mutations in Syrian families with non-syndromic sensorineural hearing loss. Int J Pediatr Otorhinolaryngol 2017; 92:82-87. [PMID: 28012540 DOI: 10.1016/j.ijporl.2016.11.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 11/13/2016] [Accepted: 11/14/2016] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Mutations in GJB2 and GJB6 genes are a frequent cause of congenital non-syndromic hearing loss (NSHL). Mutational screening has usually focused on coding region of GJB2 gene. A few studies have been conducted on the non-coding region and exon 1. c.IVS1+1G>A (a splice site mutation in GJB2 gene have been detected as disruptive mutation. Del (GJB6 D13S1830) is found in many populations, but del (GJB6 D13S1854) is reported from a few restricted countries. This study was carried out to investigate the prevalence of splice site mutation c.IVS1+1G>A and two common deletions in GJB6 gene as the genetic etiology of hearing impairment in 70 Syrian families. METHODS The frequency of the c.IVS1+1G>A mutation and two deletions were determined by PCR-RFLP and A multiplex PCR assay. RESULT Our results showed a high prevalence of IVS1+1G>A mutation (20%) and del(GJB6-D13S1854) (15.7%) in deaf families. The homozygous genotype (c.IVS1+1G>A/c.IVS1+1G>A) was observed in one family and the compound heterozygous genotypes (c.35delG/c.IVS1+1G>A) and (c.IVS1+1G>A/V153I) were observed in 7 families and one family respectively. Also, the heterozygous state (c.IVS1+1G>A/unknown) was detected in 5 families. The study of del((GJB6-D13S1854) was showed a compound heterozygous genotype del((GJB6-D13S1854)/c.IVS1+1G>A) in the same families (5 families) having heterozygous genotype of c.IVS1+1G>A mutation. Also, del(GJB6-D13S1854) is combined with c.35delG mutation in 2 families and it was observed in the heterozygous state del(GJB6-D13S1854)/unknown) in 4 families. In contrast, the del(GJB6-D13S1830) described in many population was absent in our patients. CONCLUSION Our findings indicate to significant contribution of the splice site mutation and del(GJB6-D13S1854) in our deaf families and these mutations were important causes of hearing impairment.
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18
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Kim SY, Kim AR, Kim NKD, Lee C, Kim MY, Jeon EH, Park WY, Choi BY. Unraveling of Enigmatic Hearing-Impaired GJB2 Single Heterozygotes by Massive Parallel Sequencing: DFNB1 or Not? Medicine (Baltimore) 2016; 95:e3029. [PMID: 27057829 PMCID: PMC4998745 DOI: 10.1097/md.0000000000003029] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The molecular etiology of nonsyndromic sensorineural hearing loss (SNHL) in subjects with only one detectable autosomal recessive GJB2 mutation is unclear. Here, we report GJB2 single heterozygotes with various final genetic diagnoses and suggest appropriate diagnostic strategies. A total of 160 subjects with SNHL without phenotypic markers were screened for GJB2 mutations. Single-nucleotide variants or structural variations within the DFNB1 locus or in other deafness genes were examined by Sanger sequencing, breakpoint PCR, and targeted exome sequencing (TES) of 129 deafness genes. We identified 27 subjects with two mutations and 10 subjects with only one detectable mutation in GJB2. The detection rate of the single GJB2 mutation among the 160 SNHL subjects in the present study (6.25%) was higher than 2.58% in normal hearing controls in Korean. The DFNB1 was clearly excluded as a molecular etiology in four (40%) subjects: other recessive deafness genes (N = 3) accounted for SNHL and the causative gene for the other non-DFNB1 subject (N = 1) was not identified. The etiology of additional two subjects was potentially explained by digenic etiology (N = 2) of GJB2 with MITF and GJB3, respectively. The contribution of the single GJB2 mutation in the four remaining subjects is unclear. Comprehensive diagnostic testing including TES is prerequisite for understanding GJB2 single heterozygotes.
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Affiliation(s)
- So Young Kim
- From the Department of Otorhinolaryngology-Head and Neck Surgery, CHA medical center, CHA university, Seongnam (SYK), Department of Otorhinolaryngology-Head and Neck Surgery (SYK, ARK), Seoul National University Hospital, Seoul National University College of Medicine; Samsung Genome Institue (NKDK, CL), Samsung Medical Center, Seoul, Korea; Department of Health Sciences and Technology (CL), SAIHST, Sungkyunkwan University, Seobu-ro, Jangan-gu, Suwon, Republic of Korea; Department of Otorhinolaryngology-Head and Neck Surgery (MYK, E-HJ, BYC), Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam; Samsung Genome Institute (W-YP), Samsung Medical Center; Department of Molecular Cell Biology, School of Medicine (W-YP), Sungkyunkwan University; Sensory Organ Research Institute (BYC), Seoul National University Medical Research Center, Seoul, Korea; and Wide River Institute of Immunology (BYC), Seoul National University College of Medicine, Hongcheon, Republic of Korea
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Abou Tayoun AN, Al Turki SH, Oza AM, Bowser MJ, Hernandez AL, Funke BH, Rehm HL, Amr SS. Improving hearing loss gene testing: a systematic review of gene evidence toward more efficient next-generation sequencing-based diagnostic testing and interpretation. Genet Med 2015; 18:545-53. [PMID: 26562227 DOI: 10.1038/gim.2015.141] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/27/2015] [Indexed: 12/11/2022] Open
Abstract
PURPOSE With next generation sequencing technology improvement and cost reductions, it has become technically feasible to sequence a large number of genes in one diagnostic test. This is especially relevant for diseases with large genetic and/or phenotypic heterogeneity, such as hearing loss. However, variant interpretation remains the major bottleneck. This is further exacerbated by the lack in the clinical genetics community of consensus criteria for defining the evidence necessary to include genes on targeted disease panels or in genomic reports, and the consequent risk of reporting variants in genes with no relevance to disease. METHODS We describe a systematic evidence-based approach for assessing gene-disease associations and for curating relevant genes for different disease aspects, including mode of inheritance, phenotypic severity, and mutation spectrum. RESULTS By applying this approach to clinically available hearing loss gene panels with a total of 163 genes, we show that a significant number (45%) of genes lack sufficient evidence of association with disease and thus are expected to increase uncertainty and patient anxiety, in addition to intensifying the interpretation burden. Information about all curated genes is summarized. Our retrospective analysis of 539 hearing loss cases tested by our previous OtoGenomeV2 panel demonstrates the impact of including genes with weak disease association in laboratory wet-bench and interpretation processes. CONCLUSION Our study is, to our knowledge, the first to highlight the urgent need for defining the clinical validity of gene-disease relationships for more efficient and accurate clinical testing and reporting.Genet Med 18 6, 545-553.
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Affiliation(s)
- Ahmad N Abou Tayoun
- Genetics Training Program, Harvard Medical School, Cambridge, Massachusetts, USA.,Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA.,Division of Genomic Diagnostics, The Children's Hospital of Philadelphia, The University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Saeed H Al Turki
- Genetics Training Program, Harvard Medical School, Cambridge, Massachusetts, USA
| | - Andrea M Oza
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA
| | - Mark J Bowser
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA
| | - Amy L Hernandez
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA
| | - Birgit H Funke
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Heidi L Rehm
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Sami S Amr
- Laboratory for Molecular Medicine, Partners Healthcare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Tayoun ANA, Mason-Suares H, Frisella AL, Bowser M, Duffy E, Mahanta L, Funke B, Rehm HL, Amr SS. Targeted Droplet-Digital PCR as a Tool for Novel Deletion Discovery at the DFNB1 Locus. Hum Mutat 2015; 37:119-26. [DOI: 10.1002/humu.22912] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/21/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Ahmad N. Abou Tayoun
- Harvard Medical School Genetics Training Program; Harvard; Cambridge MA
- Laboratory for Molecular Medicine; Partners Healthcare Personalized Medicine; Cambridge MA
- Division of Genomic Diagnostics; The Children's Hospital of Philadelphia; The University of Pennsylvania Perelman School of Medicine; PA
| | - Heather Mason-Suares
- Laboratory for Molecular Medicine; Partners Healthcare Personalized Medicine; Cambridge MA
- Department of Pathology; Brigham and Women's Hospital; Harvard Medical School; Boston MA
| | - Ashley L. Frisella
- Laboratory for Molecular Medicine; Partners Healthcare Personalized Medicine; Cambridge MA
| | - Mark Bowser
- Laboratory for Molecular Medicine; Partners Healthcare Personalized Medicine; Cambridge MA
| | - Elizabeth Duffy
- Laboratory for Molecular Medicine; Partners Healthcare Personalized Medicine; Cambridge MA
| | - Lisa Mahanta
- Laboratory for Molecular Medicine; Partners Healthcare Personalized Medicine; Cambridge MA
| | - Birgit Funke
- Laboratory for Molecular Medicine; Partners Healthcare Personalized Medicine; Cambridge MA
- Department of Pathology; Brigham and Women's Hospital; Harvard Medical School; Boston MA
| | - Heidi L. Rehm
- Laboratory for Molecular Medicine; Partners Healthcare Personalized Medicine; Cambridge MA
- Department of Pathology; Brigham and Women's Hospital; Harvard Medical School; Boston MA
| | - Sami S. Amr
- Laboratory for Molecular Medicine; Partners Healthcare Personalized Medicine; Cambridge MA
- Department of Pathology; Brigham and Women's Hospital; Harvard Medical School; Boston MA
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Zaidieh T, Habbal W, Monem F. Screening of GJB6 Gene Large Deletions Among Syrians with Congenital Hearing Impairment. Genet Test Mol Biomarkers 2015; 19:405-7. [PMID: 25989237 DOI: 10.1089/gtmb.2015.0019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Tarek Zaidieh
- Department of Biochemistry and Microbiology, Faculty of Pharmacy, Damascus University, Damascus, Syria
| | - Wafa Habbal
- Clinical Laboratories Department, Al-Assad Hospital, Damascus University, Damascus, Syria
| | - Fawza Monem
- Department of Biochemistry and Microbiology, Faculty of Pharmacy, Damascus University, Damascus, Syria
- Clinical Laboratories Department, Al-Assad Hospital, Damascus University, Damascus, Syria
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Amorini M, Romeo P, Bruno R, Galletti F, Di Bella C, Longo P, Briuglia S, Salpietro C, Rigoli L. Prevalence of Deafness-Associated Connexin-26 (GJB2) and Connexin-30 (GJB6) Pathogenic Alleles in a Large Patient Cohort from Eastern Sicily. Ann Hum Genet 2015; 79:341-349. [PMID: 26096904 DOI: 10.1111/ahg.12120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 03/24/2015] [Indexed: 11/28/2022]
Abstract
Mutations in the gene encoding the gap junction protein connexin 26 (GJB2) and connexin 30 (GJB6) have been shown to be a major contributor to prelingual, sensorineural, nonsyndromic deafness. The aim of this study was to characterize and establish the prevalence of GJB2 and GJB6 gene alterations in 196 patients affected by sensorineural, nonsyndromic hearing loss, from Eastern Sicily. We performed sequence analysis of GJB2 and identified sequence variants in 68 out of 196 patients (34.7%); (28 homozygous for c.35delG, 22 compound heterozygous and 11 with only one variant allele). We found 12 different allelic variants, the most prevalent being c.35delG, which was found on 89 chromosomes (65.5%), followed by other alleles with different frequencies (p.E47X, c.-23+1G>A, p.L90P, p.R184W, p.M34T, c.167delT, p.R127H, p.M163V, p.V153I, p.W24X, and p.T8M). Importantly, for the first time we present the frequency and spectrum of GJB2 mutations in NSHL patients from Eastern Sicily. No alterations were found in the GJB6 gene, confirming that alterations in this gene are uncommon in our geographic area. Note that 65.3% and 23.5% of our patients, respectively were found to be negative or carriers by GJB2 molecular screening. This emphasizes the need to broaden the genetic analysis to other genes involved in hearing loss.
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Affiliation(s)
- Maria Amorini
- Department of Paediatrics, University of Messina, Italy
| | | | - Rocco Bruno
- Department of Experimental Medical-Surgery, Specialist and Odontostomatological Science, Otorhinolaringology and Auditory Microsurgery Unit, University of Messina, Italy
| | - Francesco Galletti
- Department of Experimental Medical-Surgery, Specialist and Odontostomatological Science, Otorhinolaringology and Auditory Microsurgery Unit, University of Messina, Italy
| | | | - Patrizia Longo
- Department of Experimental Medical-Surgery, Specialist and Odontostomatological Science, Otorhinolaringology and Auditory Microsurgery Unit, University of Messina, Italy
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Haraksingh RR, Jahanbani F, Rodriguez-Paris J, Gelernter J, Nadeau KC, Oghalai JS, Schrijver I, Snyder MP. Exome sequencing and genome-wide copy number variant mapping reveal novel associations with sensorineural hereditary hearing loss. BMC Genomics 2014; 15:1155. [PMID: 25528277 PMCID: PMC4367882 DOI: 10.1186/1471-2164-15-1155] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 12/12/2014] [Indexed: 11/17/2022] Open
Abstract
Background The genetic diversity of loci and mutations underlying hereditary hearing loss is an active area of investigation. To identify loci associated with predominantly non-syndromic sensorineural hearing loss, we performed exome sequencing of families and of single probands, as well as copy number variation (CNV) mapping in a case–control cohort. Results Analysis of three distinct families revealed several candidate loci in two families and a single strong candidate gene, MYH7B, for hearing loss in one family. MYH7B encodes a Type II myosin, consistent with a role for cytoskeletal proteins in hearing. High-resolution genome-wide CNV analysis of 150 cases and 157 controls revealed deletions in genes known to be involved in hearing (e.g. GJB6, OTOA, and STRC, encoding connexin 30, otoancorin, and stereocilin, respectively), supporting CNV contributions to hearing loss phenotypes. Additionally, a novel region on chromosome 16 containing part of the PDXDC1 gene was found to be frequently deleted in hearing loss patients (OR = 3.91, 95% CI: 1.62-9.40, p = 1.45 × 10-7). Conclusions We conclude that many known as well as novel loci and distinct types of mutations not typically tested in clinical settings can contribute to the etiology of hearing loss. Our study also demonstrates the challenges of exome sequencing and genome-wide CNV mapping for direct clinical application, and illustrates the need for functional and clinical follow-up as well as curated open-access databases. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1155) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | | | - Michael P Snyder
- Department of Genetics, Stanford University School of Medicine, 300 Pasteur Dr,, M-344A, Stanford, CA 94305, USA.
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Hernández-Juárez AA, Lugo-Trampe JDJ, Campos-Acevedo LD, Lugo-Trampe A, Treviño-González JL, de-la-Cruz-Ávila I, Martínez-de-Villarreal LE. GJB2 and GJB6 mutations are an infrequent cause of autosomal-recessive nonsyndromic hearing loss in residents of Mexico. Int J Pediatr Otorhinolaryngol 2014; 78:2107-12. [PMID: 25288386 DOI: 10.1016/j.ijporl.2014.09.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 09/12/2014] [Accepted: 09/16/2014] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Mutations in the DFNB1 locus are the most common cause of autosomal-recessive nonsyndromic hearing loss (ARNSHL) worldwide. The aim of this study was to identify the most frequent mutations in patients with ARNSHL who reside in Northeastern Mexico. METHODS We determined the nucleotide sequence the coding region of GJB2 of 78 patients with ARNSHL. Polymerase chain reaction assays were used to detect the GJB2 IVS1+1G>A mutation and deletions within GJB6. RESULTS GJB2 mutations were detected in 9.6% of the alleles, and c.35delG was the most frequent. Six other less-frequent mutations were detected, including an extremely rare variant (c.645_648delTAGA), a novel mutation (c.35G>A), and one of possible Mexican origin (c.34G>T). GJB6 deletions and GJB2 IVS1+1G>A were not detected. CONCLUSIONS These data suggest that mutations in the DFNB1 locus are a rare cause of ARNSHL among the population of Northeastern Mexico. This confirms the genetic heterogeneity of this condition and indicates that further research is required to determine the other mechanisms of pathogenesis of ARNSHL in Mexicans.
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Affiliation(s)
- Aideé Alejandra Hernández-Juárez
- Departamento de Genética, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México
| | - José de Jesús Lugo-Trampe
- Departamento de Genética, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México
| | - Luis Daniel Campos-Acevedo
- Departamento de Genética, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México
| | - Angel Lugo-Trampe
- Centro Mesoamericano de Estudios en Salud Pública y Desastres, Universidad Autónoma de Chiapas (UNACH), Carretera Antiguo Aeropuerto; Pista Principal cruce con Pista Secundaria S/N, Col. Solidaridad 2000, CP 30798, Tapachula, Chis, México
| | - José Luis Treviño-González
- Departamento de Otorrinolaringología, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México
| | - Israel de-la-Cruz-Ávila
- Servicio de Audiología Pediátrica, Hospital Materno-Infantil, Aldama 460, Col. San Rafael, CP. 67190, Guadalupe, N.L., México
| | - Laura Elia Martínez-de-Villarreal
- Departamento de Genética, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León (UANL), Av. Gonzalitos s/n cruce con Av. Madero, Col. Mitras Centro CP 64460, Monterrey, N.L., México.
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Salvago P, Martines E, La Mattina E, Mucia M, Sammarco P, Sireci F, Martines F. Distribution and phenotype of GJB2 mutations in 102 Sicilian patients with congenital non syndromic sensorineural hearing loss. Int J Audiol 2014; 53:558-63. [PMID: 24793888 DOI: 10.3109/14992027.2014.905717] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To evaluate the frequency of GJB2 mutations and their correlation with phenotype in Sicilian non-syndromic sensorineural hearing loss (NSHL) patients. DESIGN Sequencing of the coding region, basal promoter, exon 1, and donor splice site of the GJB2 gene; screening for the presence of the two common GJB6 deletions. STUDY SAMPLE A cohort of 102 Sicilian NSHL patients. RESULTS Fifteen different mutations in GJB2 and seventeen different genotypes were detected. No GJB6 mutations were found. The hearing impairment was profound in the 64.72% of probands (mean PTA0.25-4 kHz of 88.82 ± 26.52 dB HL). A total of 81.37% of patients harboured at least one c.35delG allele; c.167delT and c.-23 + 1G> A were identified in 10.78% and the 9.8% of patients respectively; c.35delG homozygotes presented more severe hearing impairment (75.59% of profound hearing loss) and a higher mean PTA0.25-4 kHz (96.79 ± 21.11 dB HL) with respect to c.35delG/non-c.35delG and c.35delG/Wt patients (P < 0.05). CONCLUSIONS This work underlines the role of c.35delG, c.167delT and c.-23 + 1G> A as the most frequent causes of NSHL in Sicily. The c.35delG frequency found is similar to those reported in other populations of the Mediterranean area. The analysis of genetic and audiologic data confirmed a variability in the phenotype associated to a single genotype.
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Affiliation(s)
- Pietro Salvago
- * Dipartimento di Biomedicina Sperimentale e Neuroscienze Cliniche, (BioNeC), Sezione di Otorinolaringoiatria, Università degli Studi di Palermo , Palermo , Italy
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Bliznetz EA, Makienko ON, Okuneva EG, Markova TG, Polyakov AV. New recurrent large deletion, encompassing both GJB2 and GB6 genes, results in isolated sensorineural hearing impairment with autosomal recessive mode of inheritance. RUSS J GENET+ 2014. [DOI: 10.1134/s1022795414020045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Chan DK, Chang KW. GJB2-associated hearing loss: Systematic review of worldwide prevalence, genotype, and auditory phenotype. Laryngoscope 2013; 124:E34-53. [DOI: 10.1002/lary.24332] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2013] [Indexed: 12/17/2022]
Affiliation(s)
- Dylan K. Chan
- Department of Otolaryngology-Head and Neck Surgery; University of California; San Francisco U.S.A
| | - Kay W. Chang
- Department of Otolaryngology-Head and Neck Surgery; Stanford University School of Medicine; Stanford California U.S.A
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Manzoli GN, Abe-Sandes K, Bittles AH, da Silva DSD, Fernandes LDC, Paulon RMC, de Castro ICS, Padovani CMCA, Acosta AX. Non-syndromic hearing impairment in a multi-ethnic population of Northeastern Brazil. Int J Pediatr Otorhinolaryngol 2013; 77:1077-82. [PMID: 23684175 DOI: 10.1016/j.ijporl.2013.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Revised: 03/30/2013] [Accepted: 04/01/2013] [Indexed: 01/28/2023]
Abstract
OBJECTIVE There are many hearing impaired individuals in Monte Santo, a rural municipality in the state of Bahia, Brazil, including multiple familial cases strongly suggestive of a genetic aetiology. METHODS The present study investigated 81 subjects with hearing impairment (HI) recruited from 36 families. Mutations often associated with HI, i.e. the DFNB1 mutations c.35delG in GJB2, deletions del(GJB6-D13S1830) and del(GJB6-D13S1854), and A1555G in the mitochondrial gene MTRNR1 were initially analyzed, with additional mutations in GJB2 identified by sequencing the coding region of the gene. RESULTS Seven different mutations were present in GJB2 with mutations c.35delG and p.Arg75Gln, which are known to be pathogenic, identified in 37.0% of the subjects. Individuals homozygous for the c.35delG mutation were diagnosed in eight families, corresponding to 24.7% of unrelated individuals with nonsyndromic hearing impairment (NSHI), and an additional heterozygote for this mutation was present in a single family. Ten individuals (12.4%) in another family were heterozygous for the mutation p.Arg75Gln. CONCLUSIONS Significant heterogeneity was observed in the alleles and patterns of NSHI inheritance among the subjects studied, probably due to the extensive inter-ethnic admixture that characterizes the peoples of Brazil, together with a high prevalence of community endogamy and consanguineous marriage.
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Affiliation(s)
- Gabrielle N Manzoli
- Advanced Laboratory of Public Health/Gonçalo Moniz Research Center (CPqGM), Oswaldo Cruz Foundation (FIOCRUZ), Salvador, Bahia, Brazil
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Abstract
Digenic inheritance (DI) is the simplest form of inheritance for genetically complex diseases. By contrast with the thousands of reports that mutations in single genes cause human diseases, there are only dozens of human disease phenotypes with evidence for DI in some pedigrees. The advent of high-throughput sequencing (HTS) has made it simpler to identify monogenic disease causes and could similarly simplify proving DI because one can simultaneously find mutations in two genes in the same sample. However, through 2012, I could find only one example of human DI in which HTS was used; in that example, HTS found only the second of the two genes. To explore the gap between expectation and reality, I tried to collect all examples of human DI with a narrow definition and characterise them according to the types of evidence collected, and whether there has been replication. Two strong trends are that knowledge of candidate genes and knowledge of protein–protein interactions (PPIs) have been helpful in most published examples of human DI. By contrast, the positional method of genetic linkage analysis, has been mostly unsuccessful in identifying genes underlying human DI. Based on the empirical data, I suggest that combining HTS with growing networks of established PPIs may expedite future discoveries of human DI and strengthen the evidence for them.
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Digenic inheritance in autosomal recessive non-syndromic hearing loss cases carrying GJB2 heterozygote mutations: assessment of GJB4, GJA1, and GJC3. Int J Pediatr Otorhinolaryngol 2013; 77:189-93. [PMID: 23141803 DOI: 10.1016/j.ijporl.2012.10.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/20/2012] [Accepted: 10/22/2012] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Autosomal recessive non-syndromic hearing loss (ARNSHL) can be caused by many genes. However, mutations in the GJB2 gene, which encodes the gap-junction (GJ) protein connexin (Cx) 26, constitute a considerable proportion differing among population. Between 10 and 42 percent of patients with recessive GJB2 mutations carry only one mutant allele. Mutations in GJB4, GJA1, and GJC3 encoding Cx30.3, Cx43, and Cx29, respectively, can lead to HL. Combination of different connexins in heteromeric and heterotypic GJ assemblies is possible. This study aims to determine whether variations in any of the genes GJB4, GJA1 or GJC3 can be the second mutant allele causing the disease in the digenic mode of inheritance in the studied GJB2 heterozygous cases. METHODS We examined 34 unrelated GJB2 heterozygous ARNSHL subjects from different geographic and ethnic areas in Iran, using polymerase chain reaction (PCR) followed by direct DNA sequencing to identify any sequence variations in these genes. Restriction fragment length polymorphism (RFLP) assays were performed on 400 normal hearing individuals. RESULTS Sequence analysis of GJB4 showed five heterozygous variations including c.451C>A, c.219C>T, c.507C>G, c.155_158delTCTG and c.542C>T, with only the latter variation not being detected in any of control samples. There were three heterozygous variations including c.758C>T, c.717G>A and c.3*dupA in GJA1 in four cases. We found no variations in GJC3 gene sequence. CONCLUSION Our data suggest that GJB4 c.542C>T variant and less likely some variations of GJB4 and GJA1, but not possibly GJC3, can be assigned to ARNSHL in GJB2 heterozygous mutation carriers providing clues of the digenic pattern.
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El Bakkouri W, Loundon N, Thierry B, Nevoux J, Marlin S, Rouillon I, Garabédian EN. Cochlear implantation and congenital deafness: perceptive and lexical results in 2 genetically pediatric identified population. Otol Neurotol 2012; 33:539-44. [PMID: 22569142 DOI: 10.1097/mao.0b013e31824bae35] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To evaluate the perceptive and linguistic results in 2 predefined genetic population of children with implants. STUDY DESIGN Retrospective cohort study. SETTING Otolaryngology department of a tertiary referral hospital. PATIENTS Among 336 children with prelingual deafness who underwent implantation in our department between 1997 and 2007, 85 with GJB2 gene-related (Cx) deafness and 30 patients with Waardenburg syndrome (WaardS) were included. Mean age at implantation was 4.7 years (range, 15 mo to 16.5 yr) in the Cx group and 4.8 years (range, 16 mo to 16 yr) in the WaardS group. The mean follow-up period was 6.5 years (range, 19 mo to 12 yr) in the Cx group and 7.1 years (range, 27 mo to 13.5 yr) in the WaardS group. More than 75% of the families in both groups scored 4 and 5 when using the Mary Pat Moeller rating (p > 0.05). A psychoneurological evaluation was performed in one third of the patients in both groups. MAIN OUTCOME MEASURES Patients underwent linguistic and perceptive evaluations at 12, 24, 36, and 48 months: speech perception with closed-set and open-set words, speech production (Level 1 = vocalizations to Level 5 = complex sentences), and lexical comprehension with EVIP/GaelP (Peabody Picture Vocabulary Test) tests that ranged in 5 levels (-2 SD to +2 SD). RESULTS Score results for open-set words were 38.5%, 57.5%, 69%, and 75% in the Cx group and 30.5%, 59%, 67.5%, and 78% in the WaardS group (p > 0.05) at 12, 24, 36, and 48 months. The proportion of children in Levels 4 and 5 of speech production was 27%, 42%, 57.5%, and 58% in the Cx group and 23%, 33%, 55%, and 66% in the WaardS group (p > 0.05). Lexical result at Level -2 SD at 1 year was 90% in the Cx group and 85% in the WaardS group and that at 4 years was 70% in the Cx group and 65% in the WaardS group (p > 0.05). CONCLUSION Perceptive and linguistic evolutions for both populations were of good quality, but lexical evaluation showed residual language difficulties in both groups.
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Affiliation(s)
- Wissame El Bakkouri
- Service d'Otorhinolaryngologie et de Chirurgie Cervico-Faciale, Hôpital d'Enfants Armand-Trousseau, AP-HP, Paris, France
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Xu J, Nicholson BJ. The role of connexins in ear and skin physiology - functional insights from disease-associated mutations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:167-78. [PMID: 22796187 DOI: 10.1016/j.bbamem.2012.06.024] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 06/23/2012] [Accepted: 06/29/2012] [Indexed: 12/20/2022]
Abstract
Defects in several different connexins have been associated with several different diseases. The most common of these is deafness, where a few mutations in connexin (Cx) 26 have been found to contribute to over 50% of the incidence of non-syndromic deafness in different human populations. Other mutations in Cx26 or Cx30 have also been associated with various skin phenotypes linked to deafness (palmoplanta keratoderma, Bart-Pumphrey syndrome, Vohwinkel syndrome, keratitis-ichthyosis-deafness syndrome, etc.). The large array of disease mutants offers unique opportunities to gain insights into the underlying function of gap junction proteins and their channels in the normal and pathogenic physiologies of the cochlea and epidermis. This review focuses on those mutants where the impact on channel function has been assessed, and correlated with the disease phenotype, or organ function in knock-out mouse models. These approaches have provided evidence supporting a role of gap junctions and hemichannels in K(+) removal and recycling in the ear, as well as possible roles for nutrient passage, in the cochlea. In contrast, increases in hemichannel opening leading to increased cell death, were associated with several keratitis-ichthyosis-deafness syndrome skin disease/hearing mutants. In addition to providing clues for therapeutic strategies, these findings allow us to better understand the specific functions of connexin channels that are important for normal tissue function. This article is part of a Special Issue entitled: The communicating junctions, roles and dysfunctions.
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Affiliation(s)
- Ji Xu
- Department of Physiology, University of California, Los Angeles, CA 90095, USA
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