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Domínguez-Ruiz M, Murillo-Cuesta S, Contreras J, Cantero M, Garrido G, Martín-Bernardo B, Gómez-Rosas E, Fernández A, Del Castillo FJ, Montoliu L, Varela-Nieto I, Del Castillo I. A murine model for the del(GJB6-D13S1830) deletion recapitulating the phenotype of human DFNB1 hearing impairment: generation and functional and histopathological study. BMC Genomics 2024; 25:359. [PMID: 38605287 PMCID: PMC11007912 DOI: 10.1186/s12864-024-10289-z] [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: 02/06/2024] [Accepted: 04/07/2024] [Indexed: 04/13/2024] Open
Abstract
Inherited hearing impairment is a remarkably heterogeneous monogenic condition, involving hundreds of genes, most of them with very small (< 1%) epidemiological contributions. The exception is GJB2, the gene encoding connexin-26 and underlying DFNB1, which is the most frequent type of autosomal recessive non-syndromic hearing impairment (ARNSHI) in most populations (up to 40% of ARNSHI cases). DFNB1 is caused by different types of pathogenic variants in GJB2, but also by large deletions that keep the gene intact but remove an upstream regulatory element that is essential for its expression. Such large deletions, found in most populations, behave as complete loss-of-function variants, usually associated with a profound hearing impairment. By using CRISPR-Cas9 genetic edition, we have generated a murine model (Dfnb1em274) that reproduces the most frequent of those deletions, del(GJB6-D13S1830). Dfnb1em274 homozygous mice are viable, bypassing the embryonic lethality of the Gjb2 knockout, and present a phenotype of profound hearing loss (> 90 dB SPL) that correlates with specific structural abnormalities in the cochlea. We show that Gjb2 expression is nearly abolished and its protein product, Cx26, is nearly absent all throughout the cochlea, unlike previous conditional knockouts in which Gjb2 ablation was not obtained in all cell types. The Dfnb1em274 model recapitulates the clinical presentation of patients harbouring the del(GJB6-D13S1830) variant and thus it is a valuable tool to study the pathological mechanisms of DFNB1 and to assay therapies for this most frequent type of human ARNSHI.
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Affiliation(s)
- María Domínguez-Ruiz
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - Silvia Murillo-Cuesta
- Institute for Biomedical Research "Sols-Morreale", Spanish National Research Council-Autonomous University of Madrid, Madrid, Spain
- Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - Julio Contreras
- Institute for Biomedical Research "Sols-Morreale", Spanish National Research Council-Autonomous University of Madrid, Madrid, Spain
- Anatomy and Embryology Department, Faculty of Veterinary, Universidad Complutense de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - Marta Cantero
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - Gema Garrido
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - Belén Martín-Bernardo
- Institute for Biomedical Research "Sols-Morreale", Spanish National Research Council-Autonomous University of Madrid, Madrid, Spain
- Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - Elena Gómez-Rosas
- Servicio de Genética, Hospital Universitario Ramón y Cajal, IRYCIS, Madrid, Spain
| | - Almudena Fernández
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - 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-ISCIII), Madrid, Spain
| | - Lluís Montoliu
- Department of Molecular and Cellular Biology, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
| | - Isabel Varela-Nieto
- Institute for Biomedical Research "Sols-Morreale", Spanish National Research Council-Autonomous University of Madrid, Madrid, Spain
- Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), 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-ISCIII), Madrid, Spain.
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Kriukelis R, Gabbett MT, Beswick R, McInerney-Leo AM, Driscoll C, Liddle K. The congenital hearing phenotype in GJB2 in Queensland, Australia: V37I and mild hearing loss predominates. Eur J Hum Genet 2024:10.1038/s41431-024-01584-0. [PMID: 38486023 DOI: 10.1038/s41431-024-01584-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/12/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024] Open
Abstract
GJB2 was originally identified in severe, non-syndromic sensorineural hearing loss (SNHL), but was subsequently associated with mild and moderate SNHL. Given the increasing utilisation of genetic testing pre-conceptually, prenatally, and neonatally, it is crucial to understand genotype-phenotype correlations. This study evaluated the nature and frequency of GJB2 variants in an Australian paediatric population with varying degrees of SNHL ascertained through newborn hearing screening. Audiograms from individuals with GJB2 variants and/or a GJB6 deletion (GJB6-D13S11830) were retrospectively reviewed (n = 127). Two-thirds were biallelic (homozygous/compound heterozygous) for pathogenic/likely pathogenic variants of GJB2 and/or GJB6 (n = 80). The most frequent variant was c.109 G > A, followed by c.35delG and c.101 T > C. Compared to biallelic carriage of other GJB2 variants, c.109 G > A positive individuals (homozygous/compound heterozygous) were more likely to have mild HL at their initial and latest audiograms (p = 0.0004). Biallelic carriage of c.35delG was associated with moderately-severe or greater SNHL at both initial and latest audiograms (p = 0.007). The c.101 T > C variant presented with milder SNHL and U-shaped audiograms (p = 0.02). In this agnostically identified cohort, mild SNHL predominated in GJB2/GJB6 carriers in contrast to previous studies targeting individuals with significant loss. Consequently, c.109 G > A, associated with milder phenotypes, was the most frequent. This study provides valuable data to support prognostic confidence in genetic counselling.
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Affiliation(s)
| | - Michael T Gabbett
- Centre for Genomics and Personalised Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Rachael Beswick
- University of Queensland Centre for Children's Health Research, South Brisbane, QLD, Australia
- Healthy Hearing Program, Children's Health Queensland Hospital and Health Service, Brisbane, QLD, Australia
- School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Aideen M McInerney-Leo
- Frazer Institute, University of Queensland, Dermatology Research Centre, Brisbane, QLD, Australia
| | - Carlie Driscoll
- School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Karen Liddle
- Queensland Children's Hospital, South Brisbane, QLD, Australia.
- University of Queensland Centre for Children's Health Research, South Brisbane, QLD, Australia.
- Frazer Institute, University of Queensland, Dermatology Research Centre, Brisbane, QLD, Australia.
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3
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Wener ER, McLennan JD, Papsin BC, Cushing SL, Stavropoulos DJ, Mendoza-Londono R, Quercia N, Gordon KA. Variants in Genes Associated with Hearing Loss in Children: Prevalence in a Large Canadian Cohort. Laryngoscope 2024. [PMID: 38426810 DOI: 10.1002/lary.31373] [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: 07/20/2023] [Revised: 01/17/2024] [Accepted: 02/02/2024] [Indexed: 03/02/2024]
Abstract
OBJECTIVE The objective of this study was to assess the prevalence of genetic variants associated with hearing loss in a large cohort of children in Canada using high throughput next generation sequencing (NGS). METHODS A total of 485 children with hearing loss underwent NGS testing with an 80 gene panel of syndromic and non-syndromic variants known to be associated with hearing loss. Genetic variants were classified as pathogenic, likely pathogenic, likely benign, benign, or variants of uncertain significance (VUS), according to the American College of Medical Genetics and Genomics guidelines. RESULTS Across the 80 genes tested, 923 variants, predominantly in 28 genes, were identified in 324 children. Pathogenic variants occurred in 19/80 (23.8%) of the hearing loss related genes tested and confirmed the etiology of hearing loss in 73/485 (15.1%) of children. GJB2 was the most prevalent gene, affecting 28/73 (38.4%) children with confirmed genetic hearing loss in our cohort. Most identified variants (748/923, 81.0%, in 76/80 genes) were of uncertain significance. CONCLUSION Genetic testing using NGS identified the etiology in approximately 15% of childhood hearing loss in a Canadian cohort which is lower than what is typically reported. GJB2 was the most common genetic cause of hearing loss. VUS are commonly identified, presenting clinical challenges for counseling. LEVEL OF EVIDENCE Level 4 Laryngoscope, 2024.
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Affiliation(s)
- Emily R Wener
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jacob D McLennan
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Blake C Papsin
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sharon L Cushing
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Dimitri James Stavropoulos
- Genome Diagnostics Paediatric Laboratory Medicine, Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Roberto Mendoza-Londono
- Genome Diagnostics Paediatric Laboratory Medicine, Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nada Quercia
- Division of Clinical & Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Genetic Counselling, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Karen A Gordon
- Archie's Cochlear Implant Laboratory, Neuroscience & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada
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De Rosa MA, Bernardi MT, Kleppe S, Walz K. Hearing Loss: Genetic Testing, Current Advances and the Situation in Latin America. Genes (Basel) 2024; 15:178. [PMID: 38397168 PMCID: PMC10888486 DOI: 10.3390/genes15020178] [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: 12/27/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Congenital hearing loss is the most common birth defect, estimated to affect 2-3 in every 1000 births, with ~50-60% of those related to genetic causes. Technological advances enabled the identification of hundreds of genes related to hearing loss (HL), with important implications for patients, their families, and the community. Despite these advances, in Latin America, the population with hearing loss remains underdiagnosed, with most studies focusing on a single locus encompassing the GJB2/GJB6 genes. Here we discuss how current and emerging genetic knowledge has the potential to alter the approach to diagnosis and management of hearing loss, which is the current situation in Latin America, and the barriers that still need to be overcome.
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Affiliation(s)
- Maria Agustina De Rosa
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EHA, Argentina; (M.A.D.R.); (M.T.B.)
| | - Maria T. Bernardi
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EHA, Argentina; (M.A.D.R.); (M.T.B.)
| | - Soledad Kleppe
- Department of Clinical Pediatrics, Hospital Italiano de Buenos Aires, Instituto Universitario Hospital Italiano de Buenos Aires, Buenos Aires C1199ABB, Argentina;
| | - Katherina Walz
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EHA, Argentina; (M.A.D.R.); (M.T.B.)
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
- John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, 1501 NW 10th Avenue, BRB-418 (M-860), Miami, FL 33136, USA
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Dadhich A, Bhargava S, Samdhani S, Malhotra B, Mathur P, Rawat A, Grover M. A Descriptive Observational Study of GJB2 and GJB6 Mutations in Familial Autosomal Recessive Non-syndromic Hearing Impairment. Indian J Otolaryngol Head Neck Surg 2023; 75:3575-3580. [PMID: 37974894 PMCID: PMC10645806 DOI: 10.1007/s12070-023-03948-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/08/2023] [Indexed: 11/19/2023] Open
Abstract
Mutations in the genes, GJB2 and GJB6 play an important role in autosomal recessive, non-syndromic hearing loss. This study is aimed to detect the association of mutations in GJB2 and GJB6 genes in familial autosomal recessive non-syndromic hearing impairment cases. We included 26 families with at least two affected individuals having congenital bilateral, non-syndromic sensorineural hearing loss. Blood samples were drawn, DNA was extracted, and sent for multiplex PCR and Sanger sequencing. Of the 26 families analyzed, GJB2 mutations were detected in 9(34.6%) and GJB6 mutations were not detected in any of the families. GJB2 mutations are a major cause of congenital, non-syndromic hearing loss in this study population. This study also suggests that GJB6 mutations do not contribute to autosomal recessive non-syndromic hearing loss in the Indian population.
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Affiliation(s)
- Aakanksha Dadhich
- Department of Otorhinolaryngology and Head and Neck Surgery, Sawai Man Singh Medical College and Hospital, Jaipur, Rajasthan 302004 India
| | - Shruti Bhargava
- Department of Pathology, Sawai Man Singh Medical College and Hospital, Jaipur, Rajasthan 302004 India
| | - Sunil Samdhani
- Department of Otorhinolaryngology and Head and Neck Surgery, Sawai Man Singh Medical College and Hospital, Jaipur, Rajasthan 302004 India
| | - Bharti Malhotra
- Department of Microbiology, Sawai Man Singh Medical College and Hospital, Jaipur, Rajasthan 302004 India
| | - Priyanshu Mathur
- Department of Pediatrics, Sawai Man Singh Medical College and Hospital, Jaipur, Rajasthan 302004 India
| | - Anshu Rawat
- Department of Otorhinolaryngology and Head and Neck Surgery, Sawai Man Singh Medical College and Hospital, Jaipur, Rajasthan 302004 India
| | - Mohnish Grover
- Department of Otorhinolaryngology and Head and Neck Surgery, Sawai Man Singh Medical College and Hospital, Jaipur, Rajasthan 302004 India
- Jaipur, India
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Imizcoz T, Prieto-Matos C, Manrique-Huarte R, Calavia D, Huarte A, Pruneda PC, Ordoñez GR, Cañada-Higueras E, Patiño-García A, Alkorta-Aranburu G, Manrique Rodríguez M. Next-generation sequencing improves precision medicine in hearing loss. Front Genet 2023; 14:1264899. [PMID: 37811145 PMCID: PMC10557071 DOI: 10.3389/fgene.2023.1264899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 08/23/2023] [Indexed: 10/10/2023] Open
Abstract
Background: An early etiological diagnosis of hearing loss positively impacts children's quality of life including language and cognitive development. Even though hearing loss associates with extremely high genetic and allelic heterogeneity, several studies have proven that Next-Generation Sequencing (NGS)-based gene panel testing significantly reduces the time between onset and diagnosis. Methods: In order to assess the clinical utility of our custom NGS GHELP panel, the prevalence of pathogenic single nucleotide variants, indels or copy number variants was assessed by sequencing 171 nuclear and 8 mitochondrial genes in 155 Spanish individuals with hearing loss. Results: A genetic diagnosis of hearing loss was achieved in 34% (52/155) of the individuals (5 out of 52 were syndromic). Among the diagnosed cases, 87% (45/52) and 12% (6/52) associated with autosomal recessive and dominant inheritance patterns respectively; remarkably, 2% (1/52) associated with mitochondrial inheritance pattern. Although the most frequently mutated genes in this cohort were consistent with those described in the literature (GJB2, OTOF or MYO7A), causative variants in less frequent genes such as TMC1, FGF3 or mitCOX1 were also identified. Moreover, 5% of the diagnosed cases (3/52) were associated with pathogenic copy number variants. Conclusion: The clinical utility of NGS panels that allows identification of different types of pathogenic variants-not only single nucleotide variants/indels in both nuclear and mitochondrial genes but also copy number variants-has been demonstrated to reduce the clinical diagnostic odyssey in hearing loss. Thus, clinical implementation of genomic strategies within the regular clinical practice, and, more significantly, within the newborn screening protocols, is warranted.
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Affiliation(s)
- T. Imizcoz
- CIMA LAB Diagnostics, University of Navarra, Pamplona, Spain
| | - C. Prieto-Matos
- Department of Otorhinolaryngology, University Clinic of Navarra, Pamplona, Spain
| | - R. Manrique-Huarte
- Department of Otorhinolaryngology, University Clinic of Navarra, Pamplona, Spain
| | - D. Calavia
- Department of Otorhinolaryngology, University Clinic of Navarra, Pamplona, Spain
| | - A. Huarte
- Department of Otorhinolaryngology, University Clinic of Navarra, Pamplona, Spain
| | | | | | | | - A. Patiño-García
- CIMA LAB Diagnostics, University of Navarra, Pamplona, Spain
- Department of Pediatrics and Medical Genomics Unit, University Clinic of Navarra, Pamplona, Spain
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Wong HTC, Lukasz D, Drerup CM, Kindt KS. In vivo investigation of mitochondria in lateral line afferent neurons and hair cells. Hear Res 2023; 431:108740. [PMID: 36948126 PMCID: PMC10079644 DOI: 10.1016/j.heares.2023.108740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 02/17/2023] [Accepted: 03/12/2023] [Indexed: 03/16/2023]
Abstract
To process sensory stimuli, intense energy demands are placed on hair cells and primary afferents. Hair cells must both mechanotransduce and maintain pools of synaptic vesicles for neurotransmission. Furthermore, both hair cells and afferent neurons must continually maintain a polarized membrane to propagate sensory information. These processes are energy demanding and therefore both cell types are critically reliant on mitochondrial health and function for their activity and maintenance. Based on these demands, it is not surprising that deficits in mitochondrial health can negatively impact the auditory and vestibular systems. In this review, we reflect on how mitochondrial function and dysfunction are implicated in hair cell-mediated sensory system biology. Specifically, we focus on live imaging approaches that have been applied to study mitochondria using the zebrafish lateral-line system. We highlight the fluorescent dyes and genetically encoded biosensors that have been used to study mitochondria in lateral-line hair cells and afferent neurons. We then describe the impact this in vivo work has had on the field of mitochondrial biology as well as the relationship between mitochondria and sensory system development, function, and survival. Finally, we delineate the areas in need of further exploration. This includes in vivo analyses of mitochondrial dynamics and biogenesis, which will round out our understanding of mitochondrial biology in this sensitive sensory system.
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Affiliation(s)
- Hiu-Tung C Wong
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Daria Lukasz
- Section on Sensory Cell Development and Function, National Institute of Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Catherine M Drerup
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Katie S Kindt
- Section on Sensory Cell Development and Function, National Institute of Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
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Aboagye ET, Adadey SM, Wonkam-Tingang E, Amenga-Etego L, Awandare GA, Wonkam A. Global Distribution of Founder Variants Associated with Non-Syndromic Hearing Impairment. Genes (Basel) 2023; 14:399. [PMID: 36833326 PMCID: PMC9957346 DOI: 10.3390/genes14020399] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 01/28/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
The genetic etiology of non-syndromic hearing impairment (NSHI) is highly heterogeneous with over 124 distinct genes identified. The wide spectrum of implicated genes has challenged the implementation of molecular diagnosis with equal clinical validity in all settings. Differential frequencies of allelic variants in the most common NSHI causal gene, gap junction beta 2 (GJB2), has been described as stemming from the segregation of a founder variant and/or spontaneous germline variant hot spots. We aimed to systematically review the global distribution and provenance of founder variants associated with NSHI. The study protocol was registered on PROSPERO, the International Prospective Register of Systematic Reviews, with the registration number "CRD42020198573". Data from 52 reports, involving 27,959 study participants from 24 countries, reporting 56 founder pathogenic or likely pathogenic (P/LP) variants in 14 genes (GJB2, GJB6, GSDME, TMC1, TMIE, TMPRSS3, KCNQ4, PJVK, OTOF, EYA4, MYO15A, PDZD7, CLDN14, and CDH23), were reviewed. Varied number short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs) were used for haplotype analysis to identify the shared ancestral informative markers in a linkage disequilibrium and variants' origins, age estimates, and common ancestry computations in the reviewed reports. Asia recorded the highest number of NSHI founder variants (85.7%; 48/56), with variants in all 14 genes, followed by Europe (16.1%; 9/56). GJB2 had the highest number of ethnic-specific P/LP founder variants. This review reports on the global distribution of NSHI founder variants and relates their evolution to population migration history, bottleneck events, and demographic changes in populations linked with the early evolution of deleterious founder alleles. International migration and regional and cultural intermarriage, coupled to rapid population growth, may have contributed to re-shaping the genetic architecture and structural dynamics of populations segregating these pathogenic founder variants. We have highlighted and showed the paucity of data on hearing impairment (HI) variants in Africa, establishing unexplored opportunities in genetic traits.
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Affiliation(s)
- Elvis Twumasi Aboagye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra LG Box 54, Ghana
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Samuel Mawuli Adadey
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra LG Box 54, Ghana
| | - Edmond Wonkam-Tingang
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Lucas Amenga-Etego
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra LG Box 54, Ghana
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra LG Box 54, Ghana
| | - Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- McKusick-Nathans Institute and Department of Genetic Medicine, John Hopkins University School of Medicine, Baltimore, MD 21205, USA
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9
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Moon PK, Qian ZJ, Stevenson DA, Chang KW. Single Versus Multigene Testing for Hereditary Hearing Loss: Use and Costs in a Commercially Insured Cohort. Otolaryngol Head Neck Surg 2023; 168:1472-1476. [PMID: 36939467 DOI: 10.1002/ohn.204] [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: 04/14/2022] [Revised: 10/20/2022] [Accepted: 10/31/2022] [Indexed: 01/23/2023]
Abstract
OBJECTIVE The objectives of this study were to describe trends in single-gene GJB2/6 (connexin 26/30) and multigene hearing loss panel (HLP) testing for hereditary hearing loss using real-world evidence. STUDY DESIGN Retrospective study using insurance claims data. SETTING Optum Data Mart database from 2015 to 2020. METHODS Rates of overall and hearing-specific genetic testing and costs to insurers and patients were reported. Linear regression models were used to assess the proportion of single-gene GJB2/6 testing over time. Additional linear regression models were used to assess changes in costs over time. RESULTS From 2015 to 2020, 91,986 children received genetic testing for any indication, of which 601 (0.65%) received hearing-specific tests. The proportion of single-gene GJB2/6 testing remained similar over time (mean difference [MD]: -1.3% per year; 95% confidence interval [CI]: -4.3%, 1.7%), while multigene HLP use increased over time (MD: 4.0% per year; 95% CI: 0.4%, 7.5%). The median charge for single-gene GJB2/6 testing remained constant during the study period (MD: -$34; 95% CI: -$86, $18), while the median charge for multigene HLP decreased during the study period (MD: -$145 per year; 95% CI: -$278, -$12). CONCLUSION Compared to molecular testing for GJB2/6, HLPs are becoming more common for hereditary hearing loss. The comprehensiveness of HLP and decreasing costs provide justification for its more widespread adoption moving forward.
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Affiliation(s)
- Peter K Moon
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - Z Jason Qian
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
| | - David A Stevenson
- Department of Pediatrics-Medical Genetics, Stanford University School of Medicine, California, USA
| | - Kay W Chang
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, USA
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Silva VAR, Pauna HF, Lavinsky J, Hyppolito MA, Vianna MF, Leal M, Massuda ET, Hamerschmidt R, Bahmad F, Cal RV, Sampaio ALL, Felix F, Chone CT, Castilho AM. Task force Guideline of Brazilian Society of Otology ‒ hearing loss in children - Part I ‒ Evaluation. Braz J Otorhinolaryngol 2022; 89:159-189. [PMID: 36529647 PMCID: PMC9874360 DOI: 10.1016/j.bjorl.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES To provide an overview of the main evidence-based recommendations for the diagnosis of hearing loss in children and adolescents aged 0 to 18 years. METHODS Task force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on childhood hearing loss were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions. RESULTS The evaluation and diagnosis of hearing loss: universal newborn hearing screening, laboratory testing, congenital infections (especially cytomegalovirus), genetic testing and main syndromes, radiologic imaging studies, vestibular assessment of children with hearing loss, auditory neuropathy spectrum disorder, autism spectrum disorder, and noise-induced hearing loss. CONCLUSIONS Every child with suspected hearing loss has the right to diagnosis and appropriate treatment if necessary. This task force considers 5 essential rights: (1) Otolaryngologist consultation; (2) Speech assessment and therapy; (3) Diagnostic tests; (4) Treatment; (5) Ophthalmologist consultation.
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Affiliation(s)
- Vagner Antonio Rodrigues Silva
- Universidade Estadual de Campinas (Unicamp), Faculdade de Ciências Médicas, Departamento de Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Campinas, SP, Brazil.
| | - Henrique Furlan Pauna
- Hospital Universitário Cajuru, Departamento de Otorrinolaringologia, Curitiba, PR, Brazil
| | - Joel Lavinsky
- Universidade Federal do Rio Grande do Sul (UFRGS), Departamento de Cirurgia, Porto Alegre, RS, Brazil
| | - Miguel Angelo Hyppolito
- Universidade de São Paulo (USP), Faculdade de Medicina de Ribeirão Preto, Departamento de Oftalmologia, Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Ribeirão Preto, SP, Brazil
| | - Melissa Ferreira Vianna
- Irmandade Santa Casa de Misericórdia de São Paulo, Departamento de Otorrinolaringologia, São Paulo, SP, Brazil
| | - Mariana Leal
- Universidade Federal de Pernambuco (UFPE), Departamento de Cirurgia, Recife, PE, Brazil
| | - Eduardo Tanaka Massuda
- Universidade de São Paulo (USP), Faculdade de Medicina de Ribeirão Preto, Departamento de Oftalmologia, Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Ribeirão Preto, SP, Brazil
| | - Rogério Hamerschmidt
- Universidade Federal do Paraná (UFPR), Hospital de Clínicas, Departamento de Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Curitiba, PR, Brazil
| | - Fayez Bahmad
- Universidade de Brasília (UnB), Programa de Pós-Graduação em Ciências da Saúde, Brasília, DF, Brazil; Instituto Brasiliense de Otorrinolaringologia (IBO), Brasília, DF, Brazil
| | - Renato Valério Cal
- Centro Universitário do Estado do Pará (CESUPA), Departamento de Otorrinolaringologia, Belém, PA, Brazil
| | - André Luiz Lopes Sampaio
- Universidade de Brasília (UnB), Faculdade de Medicina, Laboratório de Ensino e Pesquisa em Otorrinolaringologia, Brasília, DF, Brazil
| | - Felippe Felix
- Universidade Federal do Rio de Janeiro (UFRJ), Hospital Universitário Clementino Fraga Filho (HUCFF), Departamento de Otorrinolaringologia, Rio de Janeiro, RJ, Brazil
| | - Carlos Takahiro Chone
- Universidade Estadual de Campinas (Unicamp), Faculdade de Ciências Médicas, Departamento de Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Campinas, SP, Brazil
| | - Arthur Menino Castilho
- Universidade Estadual de Campinas (Unicamp), Faculdade de Ciências Médicas, Departamento de Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Campinas, SP, Brazil
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11
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Jiang Y, Huang S, Zhang Y, Fang N, Liu Q, Liu Y, Bai L, Han D, Dai P. Evolutionary origin of pathogenic GJB2 alleles in China. Clin Genet 2022; 102:305-313. [PMID: 35841299 DOI: 10.1111/cge.14191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 11/28/2022]
Abstract
The frequency of the pathogenic allele of the autosomal recessive deafness gene GJB2 varies among different populations in the world, and accumulates to a sufficiently high frequency in certain population. The purpose of this study is to investigate the origin and evolution of GJB2 pathogenic alleles in Chinese deaf patients. Children with non-syndromic hearing loss, and their parents, from 295 families were recruited. Customized capture probes targeted at 943 SNPs related to GJB2 gene were designed for sequencing of genomic DNA in blood samples. Haplotypes carrying pathogenic allele were analyzed through linkage disequilibrium block building, ancestry tracing, and extended haplotype heterozygosity calculation. Two pathogenic GJB2 alleles, c.235delC (18.41%) and c.109G>A (15.57%), were observed in 867 donors. For c.235delC allele, 3 different core haplotypes with one major haplotype (97.32%) were found, and their core SNPs were 100% conserved. For c.109G>A allele, 6 different haplotypes with one major haplotype (93.28%) were found and the major c.109G>A allele evolved from a specific ancestral haplotype. Geographical origins of donors carrying GJB2 c.109G>A and c.235delC core haplotypes centered between Qinghai and Neimenggu. GJB2 c.235delC has long-range linkage disequilibrium. No positive selection signature was found for GJB2 c.235delC or c.109G>A in the studied population. In conclusion, we discovered a single origin of GJB2 c.235delC allele and multiple independent origins of GJB2 c.109G>A allele. Alternative to positive selection or multiple independent recurrent mutation event, population bottleneck effect might account for the observed high population frequency of these pathogenic alleles.
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Affiliation(s)
- Yi Jiang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Shasha Huang
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Yi Zhang
- Euler Technology, Beijing, China
| | - Nan Fang
- Beijing Scisoon Biotechnology Co., Ltd, Beijing, China
| | - Qian Liu
- Beijing Scisoon Biotechnology Co., Ltd, Beijing, China
| | - Yunchao Liu
- Beijing Scisoon Biotechnology Co., Ltd, Beijing, China
| | - Ling Bai
- Beijing Scisoon Biotechnology Co., Ltd, Beijing, China
| | - Dongyi Han
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Pu Dai
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China.,National Clinical Research Center for Otolaryngologic Diseases, Beijing, China.,Key Lab of Hearing Impairment Science of Ministry of Education, Beijing, China.,Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
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12
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Li MM, Tayoun AA, DiStefano M, Pandya A, Rehm HL, Robin NH, Schaefer AM, Yoshinaga-Itano C. Clinical evaluation and etiologic diagnosis of hearing loss: A clinical practice resource of the American College of Medical Genetics and Genomics (ACMG). Genet Med 2022; 24:1392-1406. [PMID: 35802133 DOI: 10.1016/j.gim.2022.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 03/28/2022] [Indexed: 11/26/2022] Open
Abstract
Hearing loss is a common and complex condition that can occur at any age, can be inherited or acquired, and is associated with a remarkably wide array of etiologies. The diverse causes of hearing loss, combined with the highly variable and often overlapping presentations of different forms of hearing loss, challenge the ability of traditional clinical evaluations to arrive at an etiologic diagnosis for many deaf and hard-of-hearing individuals. However, identifying the etiology of hearing loss may affect clinical management, improve prognostic accuracy, and refine genetic counseling and assessment of the likelihood of recurrence for relatives of deaf and hard-of-hearing individuals. Linguistic and cultural identities associated with being deaf or hard-of-hearing can complicate access to and the effectiveness of clinical care. These concerns can be minimized when genetic and other health care services are provided in a linguistically and culturally sensitive manner. This clinical practice resource offers information about the frequency, causes, and presentations of hearing loss and suggests approaches to the clinical and genetic evaluation of deaf and hard-of-hearing individuals aimed at identifying an etiologic diagnosis and providing informative and effective patient education and genetic counseling.
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Affiliation(s)
- Marilyn M Li
- Department of Pathology and Laboratory Medicine, Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA
| | - Ahmad Abou Tayoun
- Al Jalila Genomics Center, Al Jalila Children's Specialty Hospital, Mohammed Bin Rashid University, Dubai, United Arab Emirates
| | | | - Arti Pandya
- Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Heidi L Rehm
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA
| | - Nathaniel H Robin
- Departments of Genetics and Pediatrics, University of Alabama at Birmingham, Birmingham, AL
| | - Amanda M Schaefer
- Department of Otolaryngology-Head & Neck Surgery, Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA
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13
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Dia Y, Adadey SM, Diop JPD, Aboagye ET, Ba SA, De Kock C, Ly CAT, Oluwale OG, Sène ARG, Sarr PD, Diallo BK, Diallo RN, Wonkam A. GJB2 Is a Major Cause of Non-Syndromic Hearing Impairment in Senegal. BIOLOGY 2022; 11:795. [PMID: 35625523 PMCID: PMC9138795 DOI: 10.3390/biology11050795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 11/29/2022]
Abstract
This study aimed to investigate GJB2 (MIM: 121011) and GJB6 (MIM: 604418) variants associated with familial non-syndromic hearing impairment (HI) in Senegal. We investigated a total of 129 affected and 143 unaffected individuals from 44 multiplex families by segregating autosomal recessive non-syndromic HI, 9 sporadic HI cases of putative genetic origin, and 148 control individuals without personal or family history of HI. The DNA samples were screened for GJB2 coding-region variants and GJB6-D3S1830 deletions. The mean age at the medical diagnosis of the affected individuals was 2.93 ± 2.53 years [range: 1−15 years]. Consanguinity was present in 40 out of 53 families (75.47%). Variants in GJB2 explained HI in 34.1% (n = 15/44) of multiplex families. A bi-allelic pathogenic variant, GJB2: c.94C>T: p.(Arg32Cys) accounted for 25% (n = 11/44 families) of familial cases, of which 80% (n = 12/15) were consanguineous. Interestingly, the previously reported “Ghanaian” founder variant, GJB2: c.427C>T: p.(Arg143Trp), accounted for 4.5% (n = 2/44 families) of the families investigated. Among the normal controls, the allele frequency of GJB2: c.94C>T and GJB2: c.427C>T was estimated at 1% (2/148 ∗ 2) and 2% (4/148 ∗ 2), respectively. No GJB6-D3S1830 deletion was identified in any of the HI patients. This is the first report of a genetic investigation of HI in Senegal, and suggests that GJB2: c.94C>T: p.(Arg32Cys) and GJB2: c.427C>T: p.(Arg143Trp) should be tested in clinical practice for congenital HI in Senegal.
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Affiliation(s)
- Yacouba Dia
- Division of Human Genetics, Faculty of Medicine, Pharmacy and Odontology, University Cheikh Anta Diop (UCAD), Dakar 10700, Senegal; (Y.D.); (J.P.D.D.); (S.A.B.); (C.A.T.L.); (A.R.G.S.); (P.D.S.), (R.N.D.)
| | - Samuel Mawuli Adadey
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa; (S.M.A.); (E.T.A.); (C.D.K.); (O.G.O.)
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Legon, Accra P.O. Box LG 54, Ghana
| | - Jean Pascal Demba Diop
- Division of Human Genetics, Faculty of Medicine, Pharmacy and Odontology, University Cheikh Anta Diop (UCAD), Dakar 10700, Senegal; (Y.D.); (J.P.D.D.); (S.A.B.); (C.A.T.L.); (A.R.G.S.); (P.D.S.), (R.N.D.)
| | - Elvis Twumasi Aboagye
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa; (S.M.A.); (E.T.A.); (C.D.K.); (O.G.O.)
| | - Seydi Abdoul Ba
- Division of Human Genetics, Faculty of Medicine, Pharmacy and Odontology, University Cheikh Anta Diop (UCAD), Dakar 10700, Senegal; (Y.D.); (J.P.D.D.); (S.A.B.); (C.A.T.L.); (A.R.G.S.); (P.D.S.), (R.N.D.)
| | - Carmen De Kock
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa; (S.M.A.); (E.T.A.); (C.D.K.); (O.G.O.)
| | - Cheikh Ahmed Tidjane Ly
- Division of Human Genetics, Faculty of Medicine, Pharmacy and Odontology, University Cheikh Anta Diop (UCAD), Dakar 10700, Senegal; (Y.D.); (J.P.D.D.); (S.A.B.); (C.A.T.L.); (A.R.G.S.); (P.D.S.), (R.N.D.)
| | - Oluwafemi Gabriel Oluwale
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa; (S.M.A.); (E.T.A.); (C.D.K.); (O.G.O.)
| | - Andrea Regina Gnilane Sène
- Division of Human Genetics, Faculty of Medicine, Pharmacy and Odontology, University Cheikh Anta Diop (UCAD), Dakar 10700, Senegal; (Y.D.); (J.P.D.D.); (S.A.B.); (C.A.T.L.); (A.R.G.S.); (P.D.S.), (R.N.D.)
| | - Pierre Diaga Sarr
- Division of Human Genetics, Faculty of Medicine, Pharmacy and Odontology, University Cheikh Anta Diop (UCAD), Dakar 10700, Senegal; (Y.D.); (J.P.D.D.); (S.A.B.); (C.A.T.L.); (A.R.G.S.); (P.D.S.), (R.N.D.)
| | - Bay Karim Diallo
- Department of Oto-Rhino-Laryngology, Albert Royer Children’s Hospital, Dakar 10700, Senegal;
| | - Rokhaya Ndiaye Diallo
- Division of Human Genetics, Faculty of Medicine, Pharmacy and Odontology, University Cheikh Anta Diop (UCAD), Dakar 10700, Senegal; (Y.D.); (J.P.D.D.); (S.A.B.); (C.A.T.L.); (A.R.G.S.); (P.D.S.), (R.N.D.)
| | - Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa; (S.M.A.); (E.T.A.); (C.D.K.); (O.G.O.)
- McKusick-Nathans Institute and Department of Genetic Medicine, Johns-Hopskins University School of Medicine, Baltimore, MD 21205, USA
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Genetic etiology of non-syndromic hearing loss in Europe. Hum Genet 2022; 141:683-696. [PMID: 35044523 DOI: 10.1007/s00439-021-02425-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 12/20/2021] [Indexed: 12/17/2022]
Abstract
Hearing impairment not etiologically associated with clinical signs in other organs (non-syndromic) is genetically heterogeneous, so that over 120 genes are currently known to be involved. The frequency of mutations in each gene and the most frequent mutations vary throughout populations. Here we review the genetic etiology of non-syndromic hearing impairment (NSHI) in Europe. Over the years, epidemiological data were scarce because of the large number of involved genes, whose screening was not cost-effective until implementation of massively parallel DNA sequencing. In Europe, the most common form of autosomal recessive NSHI is DFNB1, which accounts for 11-57% of the cases. Mutations in STRC account for 16% of the recessive cases, and only a few more (MYO15A, MYO7A, LOXHD1, USH2A, TMPRSS3, CDH23, TMC1, OTOF, OTOA, SLC26A4, ADGRV1 and TECTA) have contributions higher than 2%. As regards autosomal-dominant NSHI, DFNA22 (MYO6) and DFNA8/12 (TECTA) represent the most common forms, accounting for 21% and 18% of elucidated cases, respectively. The contribution of ACTG1 and WFS1 drops to 9% in both cases, followed by POU4F3 (6.5%), MYO7A (5%), MYH14 and COL11A2 (4% each). Four additional genes contribute 2.5% each one (MITF, KCNQ4, EYA4, SOX10) and the remaining are residually represented. X-linked hearing loss and maternally-inherited NSHI have minor contributions in most countries. Further knowledge on the genetic epidemiology of NSHI in Europe needs a standardization of the experimental approaches and a stratification of the results according to clinical features, familial history and patterns of inheritance, to facilitate comparison between studies.
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15
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Predicting pathogenicity for novel hearing loss mutations based on genetic and protein structure approaches. Sci Rep 2022; 12:301. [PMID: 34997062 PMCID: PMC8741999 DOI: 10.1038/s41598-021-04081-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 12/14/2021] [Indexed: 02/04/2023] Open
Abstract
Hearing loss is a heterogeneous disorder. Identification of causative mutations is demanding due to genetic heterogeneity. In this study, we investigated the genetic cause of sensorineural hearing loss in patients with severe/profound deafness. After the exclusion of GJB2-GJB6 mutations, we performed whole exome sequencing in 32 unrelated Argentinean families. Mutations were detected in 16 known deafness genes in 20 patients: ACTG1, ADGRV1 (GPR98), CDH23, COL4A3, COL4A5, DFNA5 (GSDDE), EYA4, LARS2, LOXHD1, MITF, MYO6, MYO7A, TECTA, TMPRSS3, USH2A and WSF1. Notably, 11 variants affecting 9 different non-GJB2 genes resulted novel: c.12829C > T, p.(Arg4277*) in ADGRV1; c.337del, p.(Asp109*) and c.3352del, p.(Gly1118Alafs*7) in CDH23; c.3500G > A, p.(Gly1167Glu) in COL4A3; c.1183C > T, p.(Pro395Ser) and c.1759C > T, p.(Pro587Ser) in COL4A5; c.580 + 2 T > C in EYA4; c.1481dup, p.(Leu495Profs*31) in LARS2; c.1939 T > C, p.(Phe647Leu), in MYO6; c.733C > T, p.(Gln245*) in MYO7A and c.242C > G, p.(Ser81*) in TMPRSS3 genes. To predict the effect of these variants, novel protein modeling and protein stability analysis were employed. These results highlight the value of whole exome sequencing to identify candidate variants, as well as bioinformatic strategies to infer their pathogenicity.
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Confirmation of COL4A6 variants in X-linked nonsyndromic hearing loss and its clinical implications. Eur J Hum Genet 2022; 30:7-12. [PMID: 33840813 PMCID: PMC8738723 DOI: 10.1038/s41431-021-00881-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 03/18/2021] [Accepted: 03/25/2021] [Indexed: 01/03/2023] Open
Abstract
Hearing loss (HL) is one of the most common sensory defects, of which X-linked nonsyndromic hearing loss (NSHL) accounts for only 1-2%. While a COL4A6 variant has been reported in a single Hungarian family with NSHL associated with inner ear malformation, causative role of COL4A6 variants and their phenotypic consequences in NSHL remain elusive. Here we report two families in which we identified a male member with X-linked HL. Each has inherited a rare hemizygous COL4A6 variant from their respective mothers, NM_001287758.1: c.3272 G > C (p.Gly1091Ala) and c.951 + 1 G > C. An in vitro minigene splicing assay revealed that c.951 + 1 G > T leads to skipping of exon 15, strongly suggesting a pathogenic role for this variant in the HL phenotype. The p.Gly1091Ala variant is classified as a variant of unknown significance based on the variant interpretation guidelines. This report provides evidence for variants in the COL4A6 gene resulting in X-linked NSHL. It highlights the importance of in-depth genetic studies in all family members in addition to the proband, especially in multiplex families, to determine the precise etiology of HL.
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Adeyemo A, Faridi R, Chattaraj P, Yousaf R, Tona R, Okorie S, Bharadwaj T, Nouel-Saied LM, Acharya A, Schrauwen I, Morell RJ, Leal SM, Friedman TB, Griffith AJ, Roux I. Genomic analysis of childhood hearing loss in the Yoruba population of Nigeria. Eur J Hum Genet 2021; 30:42-52. [PMID: 34837038 PMCID: PMC8738750 DOI: 10.1038/s41431-021-00984-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 08/02/2021] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
Although variant alleles of hundreds of genes are associated with sensorineural deafness in children, the genes and alleles involved remain largely unknown in the Sub-Saharan regions of Africa. We ascertained 56 small families mainly of Yoruba ethno-lingual ancestry in or near Ibadan, Nigeria, that had at least one individual with nonsyndromic, severe-to-profound, prelingual-onset, bilateral hearing loss not attributed to nongenetic factors. We performed a combination of exome and Sanger sequencing analyses to evaluate both nuclear and mitochondrial genomes. No biallelic pathogenic variants were identified in GJB2, a common cause of deafness in many populations. Potential causative variants were identified in genes associated with nonsyndromic hearing loss (CIB2, COL11A1, ILDR1, MYO15A, TMPRSS3, and WFS1), nonsyndromic hearing loss or Usher syndrome (CDH23, MYO7A, PCDH15, and USH2A), and other syndromic forms of hearing loss (CHD7, OPA1, and SPTLC1). Several rare mitochondrial variants, including m.1555A>G, were detected in the gene MT-RNR1 but not in control Yoruba samples. Overall, 20 (33%) of 60 independent cases of hearing loss in this cohort of families were associated with likely causal variants in genes reported to underlie deafness in other populations. None of these likely causal variants were present in more than one family, most were detected as compound heterozygotes, and 77% had not been previously associated with hearing loss. These results indicate an unusually high level of genetic heterogeneity of hearing loss in Ibadan, Nigeria and point to challenges for molecular genetic screening, counseling, and early intervention in this population.
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Affiliation(s)
- Adebolajo Adeyemo
- Institute of Child Health, College of Medicine, University of Ibadan, Ibadan, Nigeria.
| | - Rabia Faridi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Parna Chattaraj
- Otolaryngology Branch, NIDCD, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Rizwan Yousaf
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Risa Tona
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Samuel Okorie
- Institute of Child Health, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Thashi Bharadwaj
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Department of Neurology, Columbia University Medical Center, 630 W 168th St, New York, NY, 10032, USA
| | - Liz M Nouel-Saied
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Department of Neurology, Columbia University Medical Center, 630 W 168th St, New York, NY, 10032, USA
| | - Anushree Acharya
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Department of Neurology, Columbia University Medical Center, 630 W 168th St, New York, NY, 10032, USA
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Department of Neurology, Columbia University Medical Center, 630 W 168th St, New York, NY, 10032, USA
| | - Robert J Morell
- Genomics and Computational Biology Core, NIDCD, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Suzanne M Leal
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, Department of Neurology, Columbia University Medical Center, 630 W 168th St, New York, NY, 10032, USA.,Taub Institute for Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 W 168th St, New York, NY, 10032, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Bethesda, MD, 20892, USA
| | - Andrew J Griffith
- Otolaryngology Branch, NIDCD, National Institutes of Health, Bethesda, MD, 20892, USA.,Department of Otolaryngology, College of Medicine, University of Tennessee Health Science Center, 910 Madison Avenue, Memphis, TN, 38163, USA
| | - Isabelle Roux
- Otolaryngology Branch, NIDCD, National Institutes of Health, Bethesda, MD, 20892, 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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Faistauer M, Lang Silva A, Félix TM, Todeschini de Souza L, Bohn R, Selaimen da Costa S, Petersen Schmidt Rosito L. Etiology of early hearing loss in Brazilian children. Braz J Otorhinolaryngol 2021; 88 Suppl 1:S33-S41. [PMID: 33839059 PMCID: PMC9734262 DOI: 10.1016/j.bjorl.2021.02.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/22/2021] [Accepted: 02/28/2021] [Indexed: 12/16/2022] Open
Abstract
INTRODUCTION Hearing loss etiology depends on the population studied as well as on the ethnicity and the socio-economic condition of the analyzed region. Etiological diagnosis contributes to the improvement of preventive measures and to the early identification of this deficiency. OBJECTIVE To identify the etiological factors of hearing loss and its prevalence in a tertiary hospital in southern Brazil, to verify the frequency of mutations in GJB2 and GJB6 genes, and to correlate the degree of hearing loss with the etiological factors of deafness. METHODS This prevalence study involved 140 children with bilateral sensorineural or mixed hearing loss. Medical history, physical examination, audiometry, and evoked auditory brainstem response were conducted. Imaging and genetic examinations were also performed. RESULTS Etiologies and their prevalence were as follows: (a) indeterminate causes, 31.4%; (b) conditions related to neonatal period, 22.1%; (c) genetic, 22.1%; (d) auditory neuropathy, 10%; (e) other factors (cortical malformation, intracranial hemorrhage, and internal ear malformations), 7.9% and (f) congenital infections, 6.4%. Within the genetic cases, ten homozygous and seven heterozygotes of the 35delG mutation were identified, besides two cases of rare variants of GJB2: p.Try172* and p.Arg184Pro. One case with homozygosis of del(GJB6-D13S1830) was found. Regarding severity of hearing loss, in 78.6% of the cases the degree of hearing loss was profound and there were no significant differences when comparing between etiologies. CONCLUSION The number of indeterminate etiologies is still high and congenital CMV infection may be a possible cause of undiagnosed etiology for hearing loss. The predominance of etiologies related to neonatal conditions and infectious causes are characteristic of developing countries. The most prevalent mutation was 35delG, the main GJB2 gene, probably because of the European influence in the genotype of our population.
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Affiliation(s)
- Marina Faistauer
- Universidade Federal do Rio Grande do Sul, Faculdade de Medicina, Porto Alegre, RS, Brazil
| | - Alice Lang Silva
- Hospital de Clínicas de Porto Alegre, Departamento de Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Porto Alegre, RS, Brazil; Universidade Federal do Rio Grande do Sul, Faculdade de Medicina, Departamento de Oftalmologia e Otorrinolaringologia, Porto Alegre, RS, Brazil.
| | - Têmis Maria Félix
- Hospital de Clínicas de Porto Alegre, Departamento de Genética, Porto Alegre, RS, Brazil
| | | | - Renata Bohn
- Universidade Federal do Rio Grande do Sul, Faculdade de Medicina, Porto Alegre, RS, Brazil
| | - Sady Selaimen da Costa
- Hospital de Clínicas de Porto Alegre, Departamento de Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Porto Alegre, RS, Brazil; Universidade Federal do Rio Grande do Sul, Faculdade de Medicina, Departamento de Oftalmologia e Otorrinolaringologia, Porto Alegre, RS, Brazil
| | - Letícia Petersen Schmidt Rosito
- Hospital de Clínicas de Porto Alegre, Departamento de Otorrinolaringologia e Cirurgia de Cabeça e Pescoço, Porto Alegre, RS, Brazil; Universidade Federal do Rio Grande do Sul, Faculdade de Medicina, Departamento de Oftalmologia e Otorrinolaringologia, Porto Alegre, RS, Brazil
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Adadey SM, Wonkam-Tingang E, Twumasi Aboagye E, Nayo-Gyan DW, Boatemaa Ansong M, Quaye O, Awandare GA, Wonkam A. Connexin Genes Variants Associated with Non-Syndromic Hearing Impairment: A Systematic Review of the Global Burden. Life (Basel) 2020; 10:life10110258. [PMID: 33126609 PMCID: PMC7693846 DOI: 10.3390/life10110258] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/18/2020] [Accepted: 10/27/2020] [Indexed: 12/21/2022] Open
Abstract
Mutations in connexins are the most common causes of hearing impairment (HI) in many populations. Our aim was to review the global burden of pathogenic and likely pathogenic (PLP) variants in connexin genes associated with HI. We conducted a systematic review of the literature based on targeted inclusion/exclusion criteria of publications from 1997 to 2020. The databases used were PubMed, Scopus, Africa-Wide Information, and Web of Science. The protocol was registered on PROSPERO, the International Prospective Register of Systematic Reviews, with the registration number “CRD42020169697”. The data extracted were analyzed using Microsoft Excel and SPSS version 25 (IBM, Armonk, New York, United States). A total of 571 independent studies were retrieved and considered for data extraction with the majority of studies (47.8% (n = 289)) done in Asia. Targeted sequencing was found to be the most common technique used in investigating connexin gene mutations. We identified seven connexin genes that were associated with HI, and GJB2 (520/571 publications) was the most studied among the seven. Excluding PLP in GJB2, GJB6, and GJA1 the other connexin gene variants (thus GJB3, GJB4, GJC3, and GJC1 variants) had conflicting association with HI. Biallelic GJB2 PLP variants were the most common and widespread variants associated with non-syndromic hearing impairment (NSHI) in different global populations but absent in most African populations. The most common GJB2 alleles found to be predominant in specific populations include; p.Gly12ValfsTer2 in Europeans, North Africans, Brazilians, and Americans; p.V37I and p.L79Cfs in Asians; p.W24X in Indians; p.L56Rfs in Americans; and the founder mutation p.R143W in Africans from Ghana, or with putative Ghanaian ancestry. The present review suggests that only GJB2 and GJB3 are recognized and validated HI genes. The findings call for an extensive investigation of the other connexin genes in many populations to elucidate their contributions to HI, in order to improve gene-disease pair curations, globally.
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Affiliation(s)
- Samuel Mawuli Adadey
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, P.O. Box LG 54, Legon GA184, Accra, Greater Accra Region, Ghana; (S.M.A.); (O.Q.); (G.A.A.)
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, P.O. Box LG 54, Legon Accra GA184, Greater Accra Region, Ghana; (E.T.A.); (M.B.A.)
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town 7925, South Africa;
| | - Edmond Wonkam-Tingang
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town 7925, South Africa;
| | - Elvis Twumasi Aboagye
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, P.O. Box LG 54, Legon Accra GA184, Greater Accra Region, Ghana; (E.T.A.); (M.B.A.)
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town 7925, South Africa;
| | - Daniel Wonder Nayo-Gyan
- Department of Applied Chemistry and Biochemistry, C. K. Tedam University of Technology and Applied Sciences, P.O. Box 24, Navrongo 00000, Upper East Region, Ghana;
| | - Maame Boatemaa Ansong
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, P.O. Box LG 54, Legon Accra GA184, Greater Accra Region, Ghana; (E.T.A.); (M.B.A.)
| | - Osbourne Quaye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, P.O. Box LG 54, Legon GA184, Accra, Greater Accra Region, Ghana; (S.M.A.); (O.Q.); (G.A.A.)
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, P.O. Box LG 54, Legon Accra GA184, Greater Accra Region, Ghana; (E.T.A.); (M.B.A.)
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, P.O. Box LG 54, Legon GA184, Accra, Greater Accra Region, Ghana; (S.M.A.); (O.Q.); (G.A.A.)
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, P.O. Box LG 54, Legon Accra GA184, Greater Accra Region, Ghana; (E.T.A.); (M.B.A.)
| | - Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, Cape Town 7925, South Africa;
- Correspondence: ; Tel.: +27-21-4066307
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Morgan A, Lenarduzzi S, Spedicati B, Cattaruzzi E, Murru FM, Pelliccione G, Mazzà D, Zollino M, Graziano C, Ambrosetti U, Seri M, Faletra F, Girotto G. Lights and Shadows in the Genetics of Syndromic and Non-Syndromic Hearing Loss in the Italian Population. Genes (Basel) 2020; 11:genes11111237. [PMID: 33105617 PMCID: PMC7690429 DOI: 10.3390/genes11111237] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/15/2020] [Accepted: 10/20/2020] [Indexed: 11/16/2022] Open
Abstract
Hearing loss (HL), both syndromic (SHL) and non-syndromic (NSHL), is the most common sensory disorder, affecting ~460 million people worldwide. More than 50% of the congenital/childhood cases are attributable to genetic causes, highlighting the importance of genetic testing in this class of disorders. Here we applied a multi-step strategy for the molecular diagnosis of HL in 125 patients, which included: (1) an accurate clinical evaluation, (2) the analysis of GJB2, GJB6, and MT-RNR1 genes, (3) the evaluation STRC-CATSPER2 and OTOA deletions via Multiplex Ligation Probe Amplification (MLPA), (4) Whole Exome Sequencing (WES) in patients negative to steps 2 and 3. Our approach led to the characterization of 50% of the NSHL cases, confirming both the relevant role of the GJB2 (20% of cases) and STRC deletions (6% of cases), and the high genetic heterogeneity of NSHL. Moreover, due to the genetic findings, 4% of apparent NSHL patients have been re-diagnosed as SHL. Finally, WES characterized 86% of SHL patients, supporting the role of already know disease-genes. Overall, our approach proved to be efficient in identifying the molecular cause of HL, providing essential information for the patients’ future management.
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Affiliation(s)
- Anna Morgan
- Institute for Maternal and Child Health–IRCCS “Burlo Garofolo”, 34137 Trieste, Italy; (S.L.); (B.S.); (E.C.); (F.M.M.); (G.P.); (D.M.); (F.F.); (G.G.)
- Correspondence:
| | - Stefania Lenarduzzi
- Institute for Maternal and Child Health–IRCCS “Burlo Garofolo”, 34137 Trieste, Italy; (S.L.); (B.S.); (E.C.); (F.M.M.); (G.P.); (D.M.); (F.F.); (G.G.)
| | - Beatrice Spedicati
- Institute for Maternal and Child Health–IRCCS “Burlo Garofolo”, 34137 Trieste, Italy; (S.L.); (B.S.); (E.C.); (F.M.M.); (G.P.); (D.M.); (F.F.); (G.G.)
- Department of Medicine, Surgery and Health Sciences, University of Trieste, 34125 Trieste, Italy
| | - Elisabetta Cattaruzzi
- Institute for Maternal and Child Health–IRCCS “Burlo Garofolo”, 34137 Trieste, Italy; (S.L.); (B.S.); (E.C.); (F.M.M.); (G.P.); (D.M.); (F.F.); (G.G.)
| | - Flora Maria Murru
- Institute for Maternal and Child Health–IRCCS “Burlo Garofolo”, 34137 Trieste, Italy; (S.L.); (B.S.); (E.C.); (F.M.M.); (G.P.); (D.M.); (F.F.); (G.G.)
| | - Giulia Pelliccione
- Institute for Maternal and Child Health–IRCCS “Burlo Garofolo”, 34137 Trieste, Italy; (S.L.); (B.S.); (E.C.); (F.M.M.); (G.P.); (D.M.); (F.F.); (G.G.)
| | - Daniela Mazzà
- Institute for Maternal and Child Health–IRCCS “Burlo Garofolo”, 34137 Trieste, Italy; (S.L.); (B.S.); (E.C.); (F.M.M.); (G.P.); (D.M.); (F.F.); (G.G.)
| | - Marcella Zollino
- Fondazione Policlinico Universitario A. Gemelli, IRCCS, UOC Genetica, 00168 Rome, Italy;
- Istituto di Medicina Genomica, Università Cattolica Sacro Cuore, 00168 Rome, Italy
| | - Claudio Graziano
- Unit of Medical Genetics, S. Orsola-Malpighi Hospital, 40138 Bologna, Italy; (C.G.); (M.S.)
| | - Umberto Ambrosetti
- Audiology and audiophonology, University of Milano/Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, 20122 Milano, Italy;
| | - Marco Seri
- Unit of Medical Genetics, S. Orsola-Malpighi Hospital, 40138 Bologna, Italy; (C.G.); (M.S.)
| | - Flavio Faletra
- Institute for Maternal and Child Health–IRCCS “Burlo Garofolo”, 34137 Trieste, Italy; (S.L.); (B.S.); (E.C.); (F.M.M.); (G.P.); (D.M.); (F.F.); (G.G.)
| | - Giorgia Girotto
- Institute for Maternal and Child Health–IRCCS “Burlo Garofolo”, 34137 Trieste, Italy; (S.L.); (B.S.); (E.C.); (F.M.M.); (G.P.); (D.M.); (F.F.); (G.G.)
- Department of Medicine, Surgery and Health Sciences, University of Trieste, 34125 Trieste, Italy
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Buonfiglio P, Bruque CD, Luce L, Giliberto F, Lotersztein V, Menazzi S, Paoli B, Elgoyhen AB, Dalamón V. GJB2 and GJB6 Genetic Variant Curation in an Argentinean Non-Syndromic Hearing-Impaired Cohort. Genes (Basel) 2020; 11:E1233. [PMID: 33096615 PMCID: PMC7589744 DOI: 10.3390/genes11101233] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/08/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
Genetic variants in GJB2 and GJB6 genes are the most frequent causes of hereditary hearing loss among several deaf populations worldwide. Molecular diagnosis enables proper genetic counseling and medical prognosis to patients. In this study, we present an update of testing results in a cohort of Argentinean non-syndromic hearing-impaired individuals. A total of 48 different sequence variants were detected in genomic DNA from patients referred to our laboratory. They were manually curated and classified based on the American College of Medical Genetics and Genomics/Association for Molecular Pathology ACMG/AMP standards and hearing-loss-gene-specific criteria of the ClinGen Hearing Loss Expert Panel. More than 50% of sequence variants were reclassified from their previous categorization in ClinVar. These results provide an accurately interpreted set of variants to be taken into account by clinicians and the scientific community, and hence, aid the precise genetic counseling to patients.
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Affiliation(s)
- Paula Buonfiglio
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas—INGEBI/CONICET, C1428ADN Ciudad Autónoma de Buenos Aires, Argentina; (P.B.); (A.B.E.)
| | - Carlos D. Bruque
- Centro Nacional de Genética Médica, ANLIS-Malbrán, C1425 Ciudad Autónoma de Buenos Aires, Argentina;
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Científicas y Técnicas—IBYME/CONICET, C1428ADN Ciudad Autónoma de Buenos Aires, Argentina
| | - Leonela Luce
- Laboratorio de Distrofinopatías, Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina; (L.L.); (F.G.)
- Instituto de Inmunología, Genética y Metabolismo—INIGEM/CONICET, Universidad de Buenos Aires, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina
| | - Florencia Giliberto
- Laboratorio de Distrofinopatías, Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina; (L.L.); (F.G.)
- Instituto de Inmunología, Genética y Metabolismo—INIGEM/CONICET, Universidad de Buenos Aires, C1113AAD Ciudad Autónoma de Buenos Aires, Argentina
| | - Vanesa Lotersztein
- Servicio de Genética, Hospital Militar Central “Dr. Cosme Argerich”, C1426 Ciudad Autónoma de Buenos Aires, Argentina;
| | - Sebastián Menazzi
- Servicio de Genética, Hospital de Clínicas “José de San Martín”, C1120AAR Ciudad Autónoma de Buenos Aires, Argentina;
| | - Bibiana Paoli
- Servicio de Otorrinolaringología Infantil, Hospital de Clínicas “José de San Martín”, C1120AAR Ciudad Autónoma de Buenos Aires, Argentina;
| | - Ana Belén Elgoyhen
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas—INGEBI/CONICET, C1428ADN Ciudad Autónoma de Buenos Aires, Argentina; (P.B.); (A.B.E.)
- Departamento de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, C1121ABG Ciudad Autónoma de Buenos Aires, Argentina
| | - Viviana Dalamón
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres”, Consejo Nacional de Investigaciones Científicas y Técnicas—INGEBI/CONICET, C1428ADN Ciudad Autónoma de Buenos Aires, Argentina; (P.B.); (A.B.E.)
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Safka Brozkova D, Poisson Marková S, Mészárosová AU, Jenčík J, Čejnová V, Čada Z, Laštůvková J, Rašková D, Seeman P. Spectrum and frequencies of non GJB2 gene mutations in Czech patients with early non-syndromic hearing loss detected by gene panel NGS and whole-exome sequencing. Clin Genet 2020; 98:548-554. [PMID: 32860223 DOI: 10.1111/cge.13839] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/24/2020] [Accepted: 08/24/2020] [Indexed: 01/17/2023]
Abstract
Non-syndromic autosomal recessive hearing loss is an extremely heterogeneous disease caused by mutations in more than 80 genes. We examined Czech patients with early/prelingual non-syndromic, presumably genetic hearing loss (NSHL) without known cause after GJB2 gene testing. Four hundred and twenty-one unrelated patients were examined for STRC gene deletions with quantitative comparative fluorescent PCR (QCF PCR), 197 unrelated patients with next-generation sequencing by custom-designed NSHL gene panels and 19 patients with whole-exome sequencing (WES). Combining all methods, we discovered the cause of the disease in 54 patients. The most frequent type of NSHL was DFNB16 (STRC), which was detected in 22 patients, almost half of the clarified patients. Other biallelic pathogenic mutations were detected in the genes: MYO15A, LOXHD1, TMPRSS3 (each gene was responsible for five clarified patients, CDH23 (four clarified patients), OTOG and OTOF (each gene was responsible for two clarified patients). Other genes (AIFM1, CABP2, DIAPH1, PTPRQ, RDX, SLC26A4, TBC1D24, TECTA, TMC1) that explained the cause of hearing impairment were further detected in only one patient for each gene. STRC gene mutations, mainly deletions remain the most frequent NSHL cause after mutations in the GJB2.
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Affiliation(s)
- Dana Safka Brozkova
- DNA Laboratory, Department of Paediatric Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Simona Poisson Marková
- DNA Laboratory, Department of Paediatric Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Anna Uhrová Mészárosová
- DNA Laboratory, Department of Paediatric Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Ján Jenčík
- DNA Laboratory, Department of Paediatric Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Vlasta Čejnová
- Department of Medical Genetics, Masaryk Hospital in Usti nad Labem, Regional Health Corporation, Usti nad Labem, Czech Republic
| | - Zdeněk Čada
- Department of Otorhinolaryngology and Head and Neck Surgery, First Faculty of Medicine, Charles University, Motol University Hospital, Prague, Czech Republic
| | - Jana Laštůvková
- Department of Medical Genetics, Masaryk Hospital in Usti nad Labem, Regional Health Corporation, Usti nad Labem, Czech Republic
| | - Dagmar Rašková
- Centre for Medical Genetics and Reproductive Medicine Gennet, Prague 7, Czech Republic
| | - Pavel Seeman
- DNA Laboratory, Department of Paediatric Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
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Božanić Urbančič N, Battelino S, Tesovnik T, Trebušak Podkrajšek K. The Importance of Early Genetic Diagnostics of Hearing Loss in Children. MEDICINA (KAUNAS, LITHUANIA) 2020; 56:E471. [PMID: 32937936 PMCID: PMC7558651 DOI: 10.3390/medicina56090471] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/30/2020] [Accepted: 09/10/2020] [Indexed: 11/28/2022]
Abstract
Hearing loss is one of the most common sensory deficits. It carries severe medical and social consequences, and therefore, universal newborn hearing screening was introduced at the beginning of this century. Affected patients can have hearing loss as a solitary deficit (non-syndromic hearing loss) or have other organs affected as well (syndromic hearing loss). In around 60% of cases, congenital hearing loss has a genetic etiology, where disease-causing variants can change any component of the hearing pathway. Genetic testing is usually performed by sequencing. Sanger sequencing enables analysis of the limited number of genes strictly preselected according to the clinical presentation and the prevalence among the hearing loss patients. In contrast, next-generation sequencing allows broad analysis of the numerous genes related to hearing loss, exome, or the whole genome. Identification of the genetic etiology is possible, and it makes the foundation for the genetic counselling in the family. Furthermore, it enables the identification of the comorbidities that may need a referral for specialty care, allows early treatment, helps with identification of candidates for cochlear implant, appropriate aversive/protective management, and is the foundation for the development of novel therapeutic options.
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Affiliation(s)
- Nina Božanić Urbančič
- Department of Otorhinolaryngology and Cervicofacial Surgery, University Medical Centre Ljubljana, Zaloska 2, 1000 Ljubljana, Slovenia;
- Department of Otorhinolaryngology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Saba Battelino
- Department of Otorhinolaryngology and Cervicofacial Surgery, University Medical Centre Ljubljana, Zaloska 2, 1000 Ljubljana, Slovenia;
- Department of Otorhinolaryngology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Tine Tesovnik
- University Children’s Hospital, University Medical Centre Ljubljana, Bohoriceva 20, 1000 Ljubljana, Slovenia; (T.T.); (K.T.P.)
| | - Katarina Trebušak Podkrajšek
- University Children’s Hospital, University Medical Centre Ljubljana, Bohoriceva 20, 1000 Ljubljana, Slovenia; (T.T.); (K.T.P.)
- Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
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Adadey SM, Esoh KK, Quaye O, Amedofu GK, Awandare GA, Wonkam A. GJB4 and GJC3 variants in non-syndromic hearing impairment in Ghana. Exp Biol Med (Maywood) 2020; 245:1355-1367. [PMID: 32524838 PMCID: PMC7441344 DOI: 10.1177/1535370220931035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 05/11/2020] [Indexed: 12/13/2022] Open
Abstract
IMPACT STATEMENT Although connexins are known to be the major genetic factors associated with HI, only a few studies have investigated GJB4 and GJC3 variants among hearing-impaired patients. This study is the first to report GJB4 and GJC3 variants from an African HI cohort. We have demonstrated that GJB4 and GJC3 genes may not contribute significantly to HI in Ghana, hence these genes should not be considered for routine clinical screening in Ghana. However, it is important to study a larger population to determine the association of GJB4 and GJC3 variants with HI.
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Affiliation(s)
- Samuel M Adadey
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra LG 54, Ghana
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | | | - Osbourne Quaye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra LG 54, Ghana
| | | | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra LG 54, Ghana
| | - Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
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Goldblat E, Rivkin D, Konstantinov V. Associations between ethnicity, place of residence, hearing status of family and habilitation of children with hearing impairment. Isr J Health Policy Res 2020; 9:36. [PMID: 32660547 PMCID: PMC7359005 DOI: 10.1186/s13584-020-00394-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/07/2020] [Indexed: 11/10/2022] Open
Abstract
Background Hearing parents tend to have a strong preference for their deaf and hard-of-hearing children to acquire adequate speech, as opposed to use of sign language. Research reports the contribution of many variables to speech acquisition by children with hearing loss (HL). Yet, little is known about the association between ethnicity, place of residence, and hearing status of family members and mode of communication of young people with HL. The purpose of the present study was to examine whether mode of communication of young people with HL is associated with ethnicity, place of residence, and hearing status of family members. Method Participants were young adults with sensory-neural severe to profound HL, either congenital or acquired prior to age 3. Only participants without additional disabilities were included. The data on participants were extracted from records of the Ministry of Labor, Social Affairs and Social Services in Israel. The data for each participant in the study included mode of communication, gender, use of assistive device, ethnicity, geographic place of residence, and presence of first-degree relatives with HL. Regarding participants with a cochlear implant (CI), age at implantation was documented as well. Results Chi-square tests revealed significant associations between mode of communication and all of the study variables. In addition, all the study variables made a significant contribution to mode of communication. Regarding ethnicity, most of the ultra-Orthodox participants used oral language, while the majority of Israeli-Arab participants used sign language. Regarding geographical place of residence, lower rates of oral language use were found in the northern and southern districts of Israel. Conclusions The findings of the present study underline the need for better monitoring of Israeli-Arab children with HL and children residing in peripheral areas in Israel and for improving access to habilitation services.
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Affiliation(s)
- Ester Goldblat
- Administration of Disabilities, Ministry of Labor, Social Affairs & Social Services, P.O.B 1260, Jerusalem, Israel.
| | - Dori Rivkin
- Family Group, Myers-JDC-Brookdale, Jerusalem, Israel
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Lalonde E, Rentas S, Lin F, Dulik MC, Skraban CM, Spinner NB. Genomic Diagnosis for Pediatric Disorders: Revolution and Evolution. Front Pediatr 2020; 8:373. [PMID: 32733828 PMCID: PMC7360789 DOI: 10.3389/fped.2020.00373] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 06/02/2020] [Indexed: 12/14/2022] Open
Abstract
Powerful, recent advances in technologies to analyze the genome have had a profound impact on the practice of medical genetics, both in the laboratory and in the clinic. Increasing utilization of genome-wide testing such as chromosomal microarray analysis and exome sequencing have lead a shift toward a "genotype-first" approach. Numerous techniques are now available to diagnose a particular syndrome or phenotype, and while traditional techniques remain efficient tools in certain situations, higher-throughput technologies have become the de facto laboratory tool for diagnosis of most conditions. However, selecting the right assay or technology is challenging, and the wrong choice may lead to prolonged time to diagnosis, or even a missed diagnosis. In this review, we will discuss current core technologies for the diagnosis of classic genetic disorders to shed light on the benefits and disadvantages of these strategies, including diagnostic efficiency, variant interpretation, and secondary findings. Finally, we review upcoming technologies posed to impart further changes in the field of genetic diagnostics as we move toward "genome-first" practice.
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Affiliation(s)
- Emilie Lalonde
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Stefan Rentas
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Fumin Lin
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Matthew C. Dulik
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Cara M. Skraban
- Division of Human Genetics, Department of Pediatrics, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
| | - Nancy B. Spinner
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, School of Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, United States
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Pandya A, O'Brien A, Kovasala M, Bademci G, Tekin M, Arnos KS. Analyses of del(GJB6-D13S1830) and del(GJB6-D13S1834) deletions in a large cohort with hearing loss: Caveats to interpretation of molecular test results in multiplex families. Mol Genet Genomic Med 2020; 8:e1171. [PMID: 32067424 PMCID: PMC7196463 DOI: 10.1002/mgg3.1171] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 01/24/2020] [Accepted: 01/30/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Mutations involving the closely linked GJB2 and GJB6 at the DFNB1 locus are a common genetic cause of profound congenital hearing loss in many populations. In some deaf GJB2 heterozygotes, a 309 kb deletion involving the GJB6 has been found to be the cause for hearing loss when inherited in trans to a GJB2 mutation. METHODS We screened 2,376 probands from a National DNA Repository of deaf individuals. RESULTS Fifty-two of 318 heterozygous probands with pathogenic GJB2 sequence variants had a GJB6 deletion. Additionally, eight probands had an isolated heterozygous GJB6 deletion that did not explain their hearing loss. In two deaf subjects, including one proband, a homozygous GJB6 deletion was the cause for their hearing loss, a rare occurrence not reported to date. CONCLUSION This study represents the largest US cohort of deaf individuals harboring GJB2 and GJB6 variants, including unique subsets of families with deaf parents. Testing additional members to clarify the phase of GJB2/GJB6 variants in multiplex families was crucial in interpreting clinical significance of the variants in the proband. It highlights the importance of determining the phase of GJB2/GJB6 variants when interpreting molecular test results especially in multiplex families with assortative mating.
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Affiliation(s)
- Arti Pandya
- Department of Pediatrics, Division of Genetics and Metabolism, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Alexander O'Brien
- Department of Pediatrics, Division of Genetics and Metabolism, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Michael Kovasala
- Department of Pediatrics, Division of Genetics and Metabolism, UNC Chapel Hill, Chapel Hill, NC, USA
| | - Guney Bademci
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA
| | - Mustafa Tekin
- Dr. John T. Macdonald Foundation Department of Human Genetics, John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA
| | - Kathleen S Arnos
- Department of Science, Technology, & Mathematics, Gallaudet University, Washington, DC, USA
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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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Yu X, Lin Y, Xu J, Che T, Li L, Yang T, Wu H. Molecular epidemiology of Chinese Han deaf patients with bi-allelic and mono-allelic GJB2 mutations. Orphanet J Rare Dis 2020; 15:29. [PMID: 31992338 PMCID: PMC6986010 DOI: 10.1186/s13023-020-1311-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 01/17/2020] [Indexed: 02/07/2023] Open
Abstract
Background Recessive mutations in GJB2 is the most common cause of genetic hearing loss worldwide. The aim of this study is to determine the spectrum and frequency of GJB2 variants in Chinese Han deaf patients and to investigate the underlying causative genes in patients with mono-allelic GJB2 mutations. Methods We analyzed the mutation screening results of GJB2 in 1852 Chinese Han probands with apparently autosomal-recessive hearing loss in our laboratory. Targeted next-generation sequencing of 139 known deafness-related genes were performed in 44 probands with mono-allelic GJB2 mutations. Results Bi-allelic GJB2 mutations was identified in 25.65% of patients, in which the c.235delC (p.L79Cfs*3) mutation is the most frequent cause for both severe-to-profound (84.93%) and mild-to-moderate hearing loss (54.05%), while the c.109G > A (p.V37I) mutation is another frequent cause for mild-to-moderate hearing loss (40.54%). In 3.89% of patients only one mutant allele can be identified in GJB2. Targeted next generation sequencing in 44 such probands revealed digenic heterozygous mutations in GJB2/GJB6 and GJB2/GJB3 as the likely pathogenic mechanism in three probands. In 13 probands, on the other hand, pathogenic mutations in other deafness-associated genes (STRC, EYA1, MITF, PCDH15, USH2A, MYO15A, CDH23, OTOF, SLC26A4, SMPX, and TIMM8A) can be identified as the independent genetic cause, suggesting that the mono-allelic GJB2 mutations in those probands is likely co-incidental. Conclusions Our results demonstrated that GJB2 should be a primary target for mutation screening in Chinese Han deaf patients, and those with mono-allelic GJB2 mutations should be further screened by next generation sequencing.
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Affiliation(s)
- Xiaoyu Yu
- Department of Otorhinolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Yun Lin
- Department of Otorhinolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Jun Xu
- Department of Otorhinolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Tuanjie Che
- Key Laboratory of Functional Genomic and Molecular Diagnosis of Gansu Province, Lanzhou, 730030, China
| | - Lin Li
- Laboratory of Precision Medicine and Translational Medicine, Suzhou Hospital Affiliated to Nanjing Medical University, Suzhou Science and Technology Town Hospital, Suzhou, 215153, China
| | - Tao Yang
- Department of Otorhinolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Hao Wu
- Department of Otorhinolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China. .,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
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Cochlear Implantation Outcome in Children with DFNB1 locus Pathogenic Variants. J Clin Med 2020; 9:jcm9010228. [PMID: 31952308 PMCID: PMC7019930 DOI: 10.3390/jcm9010228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 11/30/2022] Open
Abstract
Almost 60% of children with profound prelingual hearing loss (HL) have a genetic determinant of deafness, most frequently two DFNB1 locus (GJB2/GJB6 genes) recessive pathogenic variants. Only few studies combine HL etiology with cochlear implantation (CI) outcome. Patients with profound prelingual HL who received a cochlear implant before 24 months of age and had completed DFNB1 genetic testing were enrolled in the study (n = 196). LittlEARS questionnaire scores were used to assess auditory development. Our data show that children with DFNB1-related HL (n = 149) had good outcome from the CI (6.85, 22.24, and 28 scores at 0, 5, and 9 months post-CI, respectively). A better auditory development was achieved in patients who receive cochlear implants before 12 months of age. Children without residual hearing presented a higher rate of auditory development than children with responses in hearing aids over a wide frequency range prior to CI, but both groups reached a similar level of auditory development after 9 months post-CI. Our data shed light upon the benefits of CI in the homogenous group of patients with HL due to DFNB1 locus pathogenic variants and clearly demonstrate that very early CI is the most effective treatment method in this group of patients.
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Wu X, Zhang W, Li Y, Lin X. Structure and Function of Cochlear Gap Junctions and Implications for the Translation of Cochlear Gene Therapies. Front Cell Neurosci 2019; 13:529. [PMID: 31827424 PMCID: PMC6892400 DOI: 10.3389/fncel.2019.00529] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 11/13/2019] [Indexed: 12/23/2022] Open
Abstract
Connexins (Cxs) are ubiquitous membrane proteins that are found throughout vertebrate organs, acting as building blocks of the gap junctions (GJs) known to play vital roles in the normal function of many organs. Mutations in Cx genes (particularly GJB2, which encodes Cx26) cause approximately half of all cases of congenital hearing loss in newborns. Great progress has been made in understanding GJ function and the molecular mechanisms for the role of Cxs in the cochlea. Data reveal that multiple types of Cxs work together to ensure normal development and function of the cochlea. These findings include many aspects not proposed in the classic K+ recycling theory, such as the formation of normal cochlear morphology (e.g., the opening of the tunnel of Corti), the fine-tuning of the innervation of nerve fibers to the hair cells (HCs), the maturation of the ribbon synapses, and the initiation of the endocochlear potential (EP). New data, especially those collected from targeted modification of major Cx genes in the mouse cochlea, have demonstrated that Cx26 plays an essential role in the postnatal maturation of the cochlea. Studies also show that Cx26 and Cx30 assume very different roles in the EP generation, given that only Cx26 is required for normal hearing. This article will review our current understanding of the molecular structure, cellular distribution, and major functions of cochlear GJs. Potential implications of the knowledge of cochlear GJs on the design and implementation of translational studies of cochlear gene therapies for Cx mutations are also discussed.
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Affiliation(s)
- Xuewen Wu
- Department of Otolaryngology, Head-Neck and Surgery, Xiangya Hospital of Central South University, Changsha, China
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
| | - Wenjuan Zhang
- Department of Otolaryngology, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yihui Li
- Department of Pharmacy, Changsha Hospital of Traditional Medicine, Changsha, China
| | - Xi Lin
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
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GJB2 and GJB6 Mutations in Hereditary Recessive Non-Syndromic Hearing Impairment in Cameroon. Genes (Basel) 2019; 10:genes10110844. [PMID: 31731535 PMCID: PMC6895965 DOI: 10.3390/genes10110844] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/07/2019] [Accepted: 10/23/2019] [Indexed: 02/06/2023] Open
Abstract
This study aimed to investigate GJB2 (connexin 26) and GJB6 (connexin 30) mutations associated with familial non-syndromic childhood hearing impairment (HI) in Cameroon. We selected only families segregating HI, with at least two affected individuals and with strong evidence of non-environmental causes. DNA was extracted from peripheral blood, and the entire coding region of GJB2 was interrogated using Sanger sequencing. Multiplex PCR and Sanger sequencing were used to analyze the prevalence of the GJB6-D3S1830 deletion. A total of 93 patients, belonging to 41 families, were included in the analysis. Hearing impairment was sensorineural in 51 out of 54 (94.4%) patients. Pedigree analysis suggested autosomal recessive inheritance in 85.4% (35/41) of families. Hearing impairment was inherited in an autosomal dominant and mitochondrial mode in 12.2% (5/41) and 2.4% (1/41) of families, respectively. Most HI participants were non-syndromic (92.5%; 86/93). Four patients from two families presented with type 2 Waardenburg syndrome, and three cases of type 2 Usher syndrome were identified in one family. No GJB2 mutations were found in any of the 29 families with non-syndromic HI. Additionally, the GJB6-D3S1830 deletion was not identified in any of the HI patients. This study confirms that mutations in the GJB2 gene and the del(GJB6-D13S1830) mutation do not contribute to familial HI in Cameroon.
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Adadey SM, Manyisa N, Mnika K, de Kock C, Nembaware V, Quaye O, Amedofu GK, Awandare GA, Wonkam A. GJB2 and GJB6 Mutations in Non-Syndromic Childhood Hearing Impairment in Ghana. Front Genet 2019; 10:841. [PMID: 31620164 PMCID: PMC6759689 DOI: 10.3389/fgene.2019.00841] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 08/13/2019] [Indexed: 01/16/2023] Open
Abstract
Our study aimed to investigate GJB2 (connexin 26) and GJB6 (connexin 30) mutations associated with non-syndromic childhood hearing impairment (HI) as well as the environmental causes of HI in Ghana. Medical reports of 1,104 students attending schools for the deaf were analyzed. Families segregating HI, as well as isolated cases of HI of putative genetic origin were recruited. DNA was extracted from peripheral blood followed by Sanger sequencing of the entire coding region of GJB2. Multiplex PCR and Sanger sequencing were used to analyze the prevalence of GJB6-D3S1830 deletion. Ninety-seven families segregating HI were identified, with 235 affected individuals; and a total of 166 isolated cases of putative genetic causes, were sampled from 11 schools for the deaf in Ghana. The environmental factors, particularly meningitis, remain a major cause of HI impairment in Ghana. The male/female ratio was 1.49. Only 59.6% of the patients had their first comprehensive HI test between 6 to 11 years of age. Nearly all the participants had sensorineural HI (99.5%; n = 639). The majority had pre-lingual HI (68.3%, n = 754), of which 92.8% were congenital. Pedigree analysis suggested autosomal recessive inheritance in 96.9% of the familial cases. GJB2-R143W mutation, previously reported as founder a mutation in Ghana accounted for 25.9% (21/81) in the homozygous state in familial cases, and in 7.9% (11/140) of non-familial non-syndromic congenital HI cases, of putative genetic origin. In a control population without HI, we found a prevalent of GJB2-R143W carriers of 1.4% (2/145), in the heterozygous state. No GJB6-D3S1830 deletion was identified in any of the HI patients. GJB2-R143W mutation accounted for over a quarter of familial non-syndromic HI in Ghana and should be investigated in clinical practice. The large connexin 30 gene deletion (GJB6-D3S1830 deletion) does not account for of congenital non-syndromic HI in Ghana. There is a need to employ next generation sequencing approaches and functional genomics studies to identify the other genes involved in most families and isolated cases of HI in Ghana.
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Affiliation(s)
- Samuel M. Adadey
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Noluthando Manyisa
- Division of Human Genetics, Faculty of Health Sciences—University of Cape Town, Cape Town , South Africa
| | - Khuthala Mnika
- Division of Human Genetics, Faculty of Health Sciences—University of Cape Town, Cape Town , South Africa
| | - Carmen de Kock
- Division of Human Genetics, Faculty of Health Sciences—University of Cape Town, Cape Town , South Africa
| | - Victoria Nembaware
- Division of Human Genetics, Faculty of Health Sciences—University of Cape Town, Cape Town , South Africa
| | - Osbourne Quaye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Geoffrey K. Amedofu
- Department of Eye, Ear, Nose and Throat, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Ambroise Wonkam
- Division of Human Genetics, Faculty of Health Sciences—University of Cape Town, Cape Town , South Africa
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Raymond M, Walker E, Dave I, Dedhia K. Genetic testing for congenital non-syndromic sensorineural hearing loss. Int J Pediatr Otorhinolaryngol 2019; 124:68-75. [PMID: 31163360 DOI: 10.1016/j.ijporl.2019.05.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/25/2019] [Accepted: 05/25/2019] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Approximately 60% of congenital pediatric hearing loss is of genetic etiology. To evaluate non-syndromic sensorineural hearing loss (NSSNHL), guidelines emphasize the use of comprehensive genetic testing (CGT) with next generation sequencing (NGS), yet these tests have limited accessibility, and potential CGT results may not be well understood. Thus, our objective was to analyze genetic testing practices and results for pediatric patients with NSSNHL. METHODS This was a retrospective chart review of pediatric patients (<18 years) diagnosed with NSSNHL from 2014 to 2017 at a tertiary pediatric hospital. Demographics, clinical data, CGT results, genetic testing practices and referral patterns were recorded and descriptively analyzed. Logistic regression models identified patient characteristics associated with pathogenic variants (PV) and variants of unknown significance (VOUS). RESULTS 430 patients with congenital NSSNHL were included in the study. Genetic testing was ordered for 28% (n = 122) and resulted for 16% (n = 68). Most of the ordered tests (89%, n = 109) were the CGT panel. A majority (62%, n = 97) of the time in which genetic testing was not ordered, a referral for genetics consultation was placed. Amongst those with CGT results, a definitive genetic etiology was identified in 25% (n = 13), with less than half due to variants of GJB2/6. At least one PV was identified for 33% (n = 18), while at least one VOUS for 93% (n = 51). There were no significant differences in PV presence or number of VOUS across any characteristic except race. When compared to Caucasians, African Americans had significantly higher rates of VOUS with a rate ratio and 95% CI of 1.61 [1.11-2.34], p = 0.01, and Asians trended towards higher rates (1.96 [0.95-4.05], p = 0.06). CONCLUSIONS CGT is of high utility in the identification of relevant genetic variants and definitive genetic etiologies for pediatric patients with NSSNHL. Though guidelines recommend the early use of CGT, there are many barriers to appropriate testing and counseling, leading to low rates of CGT use at this single institution.
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Affiliation(s)
- Mallory Raymond
- Emory University School of Medicine, Department of Otolaryngology - Head and Neck Surgery, Division of Pediatric Otolaryngology, USA
| | - Elizabeth Walker
- Emory University School of Medicine, Department of Otolaryngology - Head and Neck Surgery, Division of Pediatric Otolaryngology, USA
| | - Ishaan Dave
- Emory University School of Medicine, Department of Pediatrics, USA
| | - Kavita Dedhia
- Emory University School of Medicine, Department of Otolaryngology - Head and Neck Surgery, Division of Pediatric Otolaryngology, USA.
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Talbi S, Bonnet C, Boudjenah F, Mansouri MT, Petit C, Ammar Khodja F. The spectrum of GJB2 gene mutations in Algerian families with nonsyndromic hearing loss from Sahara and Kabylie regions. Int J Pediatr Otorhinolaryngol 2019; 124:157-160. [PMID: 31200317 DOI: 10.1016/j.ijporl.2019.05.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 05/23/2019] [Accepted: 05/23/2019] [Indexed: 01/14/2023]
Abstract
INTRODUCTION DFNB1, caused by mutations of GJB2 or GJB6, is the most prevalent genetic form of nonsyndromic (i.e., isolated) congenital deafness in countries located around the Mediterranean Sea. Because some mutations are restricted to specific ethnic-geographic groups, we studied the prevalence and spectrum of GJB2/GJB6 mutations in deaf patients originating from two different Algerian regions, Kabylie and Sahara. PATIENTS AND METHODS Among 91 reportedly unrelated Algerian patients affected by prelingual deafness, 80 patients (41 from Kabylie and 39 from Sahara) were diagnosed with isolated deafness. All had profound deafness, except one patient with mild deafness. They were screened for the presence of GJB2 mutations by direct sequencing of the single coding exon of GJB2. Patients without mutations were then screened for the presence of the most frequent two deletions of GJB6: del(GJB6-D13S1854) and del(GJB6-D13S1830). RESULTS Causative mutations were found in 13 and 8 patients from Kabylie and Sahara, respectively, accounting for more than a quarter of the cohort. The c.35delG, p.Gly12Valfs*2 mutation remains the most important mutation both in Kabylie (10 patients) and Sahara (7 patients). All detected patients were homozygous for this mutation. In addition, two other mutations (c.139G > T, p.Glu47* and c.167delT, p.Leu56Argfs*26) were found homozygous in one family each, and two patients were compound heterozygotes for (c.35delG p.Gly12Valfs*2/c.139G > T, p.Glu47*). No deletion of GJB6 was detected. CONCLUSION We confirm that mutations in GJB2, mainly c.35delG, are one of the most prevalent causes of nonsyndromic congenital deafness in Algeria, whereas the del (GJB6-D13S1854) and del (GJB6-D13S1830) deletions of GJB6 contribute little, if any. Further investigation is needed to identify the cause of deafness in other patients without diagnostic.
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Affiliation(s)
- Sonia Talbi
- Equipe de Génétique, Laboratoire de Biologie Cellulaire et Moléculaire, Faculté des Sciences Biologiques, Université des Sciences et de la Technologie Houari Boumediene (USTHB), POB32 ElAlia, 16111, Bab Ezzouar, Alger, Algeria.
| | - Crystel Bonnet
- Inserm UMRS 1120, Institut de la Vision, Sorbonne Université, Paris, France
| | - Farid Boudjenah
- Service d'Otorhinolaryngologie (ORL), Hôpital de Frantz fanon, Bejaia, Algeria; Service d'Otorhinolaryngologie (ORL), Hôpital Sidi Belloua, Tizi-Ouzou, Algeria
| | | | - Christine Petit
- Inserm UMRS 1120, Institut de la Vision, Sorbonne Université, Paris, France; Institut Pasteur, Collège de France, Paris, France
| | - Fatima Ammar Khodja
- Equipe de Génétique, Laboratoire de Biologie Cellulaire et Moléculaire, Faculté des Sciences Biologiques, Université des Sciences et de la Technologie Houari Boumediene (USTHB), POB32 ElAlia, 16111, Bab Ezzouar, Alger, Algeria
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Chakchouk I, Zhang D, Zhang Z, Francioli LC, Santos-Cortez RLP, Schrauwen I, Leal SM. Disparities in discovery of pathogenic variants for autosomal recessive non-syndromic hearing impairment by ancestry. Eur J Hum Genet 2019; 27:1456-1465. [PMID: 31053783 PMCID: PMC6777454 DOI: 10.1038/s41431-019-0417-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/01/2019] [Accepted: 04/16/2019] [Indexed: 12/22/2022] Open
Abstract
Hearing impairment (HI) is characterized by extensive genetic heterogeneity. To determine the population-specific contribution of known autosomal recessive nonsyndromic (ARNS)HI genes and variants to HI etiology; pathogenic and likely pathogenic (PLP) ARNSHI variants were selected from ClinVar and the Deafness Variation Database and their frequencies were obtained from gnomAD for seven populations. ARNSHI prevalence due to PLP variants varies greatly by population ranging from 96.9 affected per 100,000 individuals for Ashkenazi Jews to 5.2 affected per 100,000 individuals for Africans/African Americans. For Europeans, Finns have the lowest prevalence due to ARNSHI PLP variants with 9.5 affected per 100,000 individuals. For East Asians, Latinos, non-Finish Europeans, and South Asians, ARNSHI prevalence due to PLP variants ranges from 17.1 to 33.7 affected per 100,000 individuals. ARNSHI variants that were previously reported in a single ancestry or family were observed in additional populations, e.g., USH1C p.(Q723*) reported in a Chinese family was the most prevalent pathogenic variant observed in gnomAD for African/African Americans. Variability between populations is due to how extensively ARNSHI has been studied, ARNSHI prevalence and ancestry specific ARNSHI variant architecture which is impacted by population history. Our study demonstrates that additional gene and variant discovery studies are necessary for all populations and particularly for individuals of African ancestry.
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Affiliation(s)
- Imen Chakchouk
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Di Zhang
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Zhihui Zhang
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Center for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA
| | - Laurent C Francioli
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
- Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA, USA
| | | | - Isabelle Schrauwen
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Center for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA
| | - Suzanne M Leal
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
- Center for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA.
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Inner Ear Connexin Channels: Roles in Development and Maintenance of Cochlear Function. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033233. [PMID: 30181354 DOI: 10.1101/cshperspect.a033233] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Connexin 26 and connexin 30 are the prevailing isoforms in the epithelial and connective tissue gap junction systems of the developing and mature cochlea. The most frequently encountered variants of the genes that encode these connexins, which are transcriptionally coregulated, determine complete loss of protein function and are the predominant cause of prelingual hereditary deafness. Reducing connexin 26 expression by Cre/loxP recombination in the inner ear of adult mice results in a decreased endocochlear potential, increased hearing thresholds, and loss of >90% of outer hair cells, indicating that this connexin is essential for maintenance of cochlear function. In the developing cochlea, connexins are necessary for intercellular calcium signaling activity. Ribbon synapses and basolateral membrane currents fail to mature in inner hair cells of mice that are born with reduced connexin expression, even though hair cells do not express any connexin. In contrast, pannexin 1, an alternative mediator of intercellular signaling, is dispensable for hearing acquisition and auditory function.
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Posukh OL, Zytsar MV, Bady-Khoo MS, Danilchenko VY, Maslova EA, Barashkov NA, Bondar AA, Morozov IV, Maximov VN, Voevoda MI. Unique Mutational Spectrum of the GJB2 Gene and its Pathogenic Contribution to Deafness in Tuvinians (Southern Siberia, Russia): A High Prevalence of Rare Variant c.516G>C (p.Trp172Cys). Genes (Basel) 2019; 10:E429. [PMID: 31195736 PMCID: PMC6627114 DOI: 10.3390/genes10060429] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 05/30/2019] [Accepted: 06/03/2019] [Indexed: 01/09/2023] Open
Abstract
Mutations in the GJB2 gene are the main cause for nonsyndromic autosomal recessive deafness 1A (DFNB1A) in many populations. GJB2 mutational spectrum and pathogenic contribution are widely varying in different populations. Significant efforts have been made worldwide to define DFNB1A molecular epidemiology, but this issue still remains open for some populations. The main aim of study is to estimate the DFNB1A prevalence and GJB2 mutational spectrum in Tuvinians-an indigenous population of the Tyva Republic (Southern Siberia, Russia). Sanger sequencing was applied to analysis of coding (exon 2) and non-coding regions of GJB2 in a cohort of Tuvinian patients with hearing impairments (n = 220) and ethnically matched controls (n = 157). Diagnosis of DFNB1A was established for 22.3% patients (28.8% of familial vs 18.6% of sporadic cases). Our results support that patients with monoallelic GJB2 mutations (8.2%) are coincidental carriers. Recessive mutations p.Trp172Cys, c.-23+1G>A, c.235delC, c.299_300delAT, p.Val37Ile and several benign variants were found in examined patients. A striking finding was a high prevalence of rare variant p.Trp172Cys (c.516G>C) in Tuvinians accounting for 62.9% of all mutant GJB2 alleles and a carrier frequency of 3.8% in controls. All obtained data provide important targeted information for genetic counseling of affected Tuvinian families and enrich current information on variability of GJB2 worldwide.
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Affiliation(s)
- Olga L Posukh
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.
- Novosibirsk State University, 630090 Novosibirsk, Russia.
| | - Marina V Zytsar
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.
| | - Marita S Bady-Khoo
- Research Institute of Medical-Social Problems and Management of the Republic of Tyva, 667000 Kyzyl, Russia.
- Perinatal Center of the Republic of Tyva, 667000 Kyzyl, Russia.
| | - Valeria Yu Danilchenko
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.
| | - Ekaterina A Maslova
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.
- Novosibirsk State University, 630090 Novosibirsk, Russia.
| | - Nikolay A Barashkov
- Yakut Scientific Centre of Complex Medical Problems, 677019 Yakutsk, Russia.
- M.K. Ammosov North-Eastern Federal University, 677027 Yakutsk, Russia.
| | - Alexander A Bondar
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.
| | - Igor V Morozov
- Novosibirsk State University, 630090 Novosibirsk, Russia.
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.
| | - Vladimir N Maximov
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.
- Novosibirsk State University, 630090 Novosibirsk, Russia.
| | - Michael I Voevoda
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia.
- Novosibirsk State University, 630090 Novosibirsk, Russia.
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Abstract
OBJECTIVE To determine the prevalence and spectrum of Connexin 26 (GJB2) mutations in pre-lingual non-syndromic hearing loss (NSHL) patients in authors' centre and to review the data of Indian patients from the literature. METHODS Sanger sequencing of entire coding region contained in single exon (Exon 2) of GJB2 gene in 15 patients of NSHL. RESULTS GJB2 mutations were found in 40% (6/15) of NSHL patients, out of which mono-allelic were 33.3% (2/6). Bi-allelic GJB2 mutations were identified in 4 of 6 patients. Most common GJB2 mutation identified was c.71G > A(p.W24X), comprising 30% of the total GJB2 mutant alleles. Six studies involving 1119 patients with NSHL were reviewed and 4 of them have reported c.71G > A(p.W24X) as the commonest mutation while 2 studies found c.35delG as the commonest. GJB2 mutations accounted for 10.9%-36% cases of NSHL. Sixteen other mutations in GJB2 gene were reported in Indian patients out of which 6 mutations other than c.71G > A(p.W24X) viz., c.35delG, c.1A > G(p.M1V), c.127G > A(p.V43 M), c.204C > G(p.Y86X), c.231G > A(p.W77X) and c.439G > A(p.E147K) were identified in the present study. CONCLUSIONS Connexin 26 (GJB2) mutations are responsible for 19.4% of NSHL in Indian population. The c.71G > A(W24X) and c.35delG were the most prevalent GJB2 mutations accounting for 72.2% (234 of 324 total mutated alleles from 7 studies) and 15.4% (50 of 324 total mutated alleles from 7 studies) respectively. Thus, screening of these two common mutations in GJB2 gene by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) would greatly help in providing easy genetic diagnosis and help in genetic counseling of the families with NSHL.
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Abe S, Nishio S, Yokota Y, Moteki H, Kumakawa K, Usami S. Diagnostic pitfalls for GJB2-related hearing loss: A novel deletion detected by Array-CGH analysis in a Japanese patient with congenital profound hearing loss. Clin Case Rep 2018; 6:2111-2116. [PMID: 30455902 PMCID: PMC6230644 DOI: 10.1002/ccr3.1800] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/05/2018] [Accepted: 08/12/2018] [Indexed: 11/10/2022] Open
Abstract
Here, we report a novel deletion (copy number variation: CNV) in the GJB2 gene observed in a Japanese hearing loss patient. The deleted segment started in the middle of the GJB2 gene, but the GJB6 gene remained intact. This partial deletion in the GJB2 gene highlights the need for further improvements in GJB2 screening.
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Affiliation(s)
- Satoko Abe
- Department of OtorhinolaryngologyToranomon HospitalTokyoJapan
| | - Shin‐ya Nishio
- Department of OtolaryngologyShinshu University School of MedicineNaganoJapan
- Department of Hearing Implant SciencesShinshu University School of MedicineNaganoJapan
| | - Yoh Yokota
- Department of OtolaryngologyShinshu University School of MedicineNaganoJapan
| | - Hideaki Moteki
- Department of OtolaryngologyShinshu University School of MedicineNaganoJapan
- Department of Hearing Implant SciencesShinshu University School of MedicineNaganoJapan
| | - Kozo Kumakawa
- Department of OtorhinolaryngologyToranomon HospitalTokyoJapan
| | - Shin‐ichi Usami
- Department of OtolaryngologyShinshu University School of MedicineNaganoJapan
- Department of Hearing Implant SciencesShinshu University School of MedicineNaganoJapan
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Wang L, Kempton JB, Brigande JV. Gene Therapy in Mouse Models of Deafness and Balance Dysfunction. Front Mol Neurosci 2018; 11:300. [PMID: 30210291 PMCID: PMC6123355 DOI: 10.3389/fnmol.2018.00300] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 08/06/2018] [Indexed: 12/16/2022] Open
Abstract
Therapeutic strategies to restore hearing and balance in mouse models of inner ear disease aim to rescue sensory function by gene replacement, augmentation, knock down or knock out. Modalities to achieve therapeutic effects have utilized virus-mediated transfer of wild type genes and small interfering ribonucleic acids; systemic and focal administration of antisense oligonucleotides (ASO) and designer small molecules; and lipid-mediated transfer of Cas 9 ribonucleoprotein (RNP) complexes. This work has established that gene or drug administration to the structurally and functionally immature, early neonatal mouse inner ear prior to hearing onset is a prerequisite for the most robust therapeutic responses. These observations may have significant implications for translating mouse inner ear gene therapies to patients. The human fetus hears by gestational week 19, suggesting that a corollary window of therapeutic efficacy closes early in the second trimester of pregnancy. We hypothesize that fetal therapeutics deployed prior to hearing onset may be the most effective approach to preemptively manage genetic mutations that cause deafness and vestibular dysfunction. We assert that gene therapy studies in higher vertebrate model systems with fetal hearing onset and a comparable acoustic range and sensitivity to that of humans are an essential step to safely and effectively translate murine gene therapies to the clinic.
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Affiliation(s)
- Lingyan Wang
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, United States
| | - J Beth Kempton
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, United States
| | - John V Brigande
- Oregon Hearing Research Center, Department of Otolaryngology, Oregon Health & Science University, Portland, OR, United States
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Pawlak-Osiñska K, Linkowska K, Grzybowski T. Genes important for otoneurological diagnostic purposes - current status and future prospects. ACTA ACUST UNITED AC 2018; 38:242-250. [PMID: 29984802 DOI: 10.14639/0392-100x-1692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/12/2017] [Indexed: 11/23/2022]
Abstract
SUMMARY This review focuses on the current knowledge of the genes responsible for non-syndromic hearing loss that can be useful for otoneurological diagnostic purposes. From among a large number of genes that have been associated with non-syndromic hearing impairment, we selected several best-known genes, including the COCH gene, GJB2, GJB6 and SLC26A4, and we describe their role and effects of mutations and prevalence of mutations in various populations. Next, we focus on genes associated with tinnitus. Important areas for further research include assessment of genes potentially involved in pathophysiology of tinnitus and vertigo, which have traditionally been considered as being of otological aetiology, while advances in neuroimaging techniques have increasingly shifted studies toward neurological correlations.
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Affiliation(s)
- K Pawlak-Osiñska
- Department of Otolaryngology and Oncology Collegium Medicum in Bydgoszcz Nicolaus Copernicus University, Skłodowskiej-Curie 9, Bydgoszcz, Poland
| | - K Linkowska
- Department of Forensic Medicine Division of Molecular and Forensic Genetics Collegium Medicum in Bydgoszcz Nicolaus Copernicus University, Skłodowskiej-Curie 9, Bydgoszcz, Poland
| | - T Grzybowski
- Department of Forensic Medicine Division of Molecular and Forensic Genetics Collegium Medicum in Bydgoszcz Nicolaus Copernicus University, Skłodowskiej-Curie 9, Bydgoszcz, Poland
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STRC Deletion is a Frequent Cause of Slight to Moderate Congenital Hearing Impairment in the Czech Republic. Otol Neurotol 2018; 38:e393-e400. [PMID: 28984810 DOI: 10.1097/mao.0000000000001571] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE This study aimed to clarify the molecular epidemiology of hearing loss by identifying the responsible genes in patients without GJB2 mutations. STUDY DESIGN Prospective genetic study. SETTING Tertiary referral hospital. PATIENTS Fifty one patients with bilateral sensorineural hearing loss, 20 men, and 31 women, mean age 24.9 years, range 3 to 64 years, from 49 families. GJB2 and deltaGJB6-D13S1830 mutations were excluded previously. INTERVENTION Diagnostic. Sixty-nine genes reported to be causative of hearing loss were analyzed. Sequence capture technology, next-generation sequencing, and multiplex ligation-dependent probe amplification (MLPA) were used. Coverage of STRC was screened in Integrative Genomics Viewer software. MAIN OUTCOME MEASURE Identification of causal pathogenic mutations in genes related to deafness. RESULTS Five families (10%) had recessive STRC deletions or mutations. Five unrelated patients (10%) had recessive mutations in TMPRSS3, USH2A, PCDH15, LOXHD1, and MYO15A. Three families (6%) had autosomal dominant mutations in MYO6A, KCNQ4, and SIX1. One family (2%) had an X-linked POU3F4 mutation. Thus, we identified the cause of hearing loss in 28% of the families studied. CONCLUSIONS Following GJB2, STRC was the second most frequently mutated gene in patients from the Czech Republic with hearing loss. To decrease the cost of testing, we recommend STRC deletion screening with MLPA before next-generation sequencing. The existence of a pseudogene and polymorphic STRC regions can lead to false-positive or false-negative results when copy number variation analysis is based on next-generation sequencing data.
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Plevova P, Tvrda P, Paprskarova M, Turska P, Kantorova B, Mrazkova E, Zapletalova J. Genetic Aetiology of Nonsyndromic Hearing Loss in Moravia-Silesia. MEDICINA-LITHUANIA 2018; 54:medicina54020028. [PMID: 30344259 PMCID: PMC6037260 DOI: 10.3390/medicina54020028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND OBJECTIVE Hearing loss is the most common sensory deficit in humans. The aim of this study was to clarify the genetic aetiology of nonsyndromic hearing loss in the Moravian-Silesian population of the Czech Republic. PATIENTS AND METHODS This study included 200 patients (93 males, 107 females, mean age 16.9 years, ranging from 4 months to 62 years) with nonsyndromic sensorineural hearing loss. We screened all patients for mutations in GJB2 and the large deletion del(GJB6-D13S1830). We performed further screening for additional genes (SERPINB6, TMIE, COCH, ESPN, ACTG1, KCNQ4, and GJB3) with Sanger sequencing on a subset of patients that were negative for GJB2 mutations. RESULTS We detected biallelic GJB2 mutations in 44 patients (22%). Among these patients, 63.6%, 9.1% and 2.3% exhibited homozygous c.35delG, p.Trp24*, and p.Met34Thr mutations, respectively. The remaining 25% of these patients exhibited compound heterozygous c.35delG, c.-23+1G>A, p.Trp24*, p.Val37Ile, p.Met34Thr, p.Leu90Pro, c.235delC, c.313_326del14, p.Ser139Asn, and p.Gly147Leu mutations. We found a monoallelic GJB2 mutation in 12 patients (6.6%). We found no pathogenic mutations in the other tested genes. Conclusions: One fifth of our cohort had deafness related to GJB2 mutations. The del(GJB6-D13S1830), SERPINB6, TMIE, COCH, ESPN, ACTG1, GJB3, and KCNQ4 mutations were infrequently associated with deafness in the Moravian-Silesian population. Therefore, we suggest that del(GJB6-D13S1830) testing should be performed only when patients with deafness carry the monoallelic GJB2 mutation.
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Affiliation(s)
- Pavlina Plevova
- Department of Medical Genetics, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava, Czech Republic.
| | - Petra Tvrda
- Department of Medical Genetics, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava, Czech Republic.
| | - Martina Paprskarova
- Department of Medical Genetics, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava, Czech Republic.
| | - Petra Turska
- Department of Medical Genetics, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava, Czech Republic.
| | - Barbara Kantorova
- Department of Medical Genetics, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava, Czech Republic.
| | - Eva Mrazkova
- Department of Epidemiology and Public Health, Faculty of Medicine, University of Ostrava, Syllabova 19, 703 00 Ostrava, Zábřeh, Czech Republic.
- Department of Otorhinolaryngology, Hospital of Havířov, Dělnická 1132/24, 736 01 Havířov, Czech Republic.
| | - Jana Zapletalova
- Department of Medical Biophysics, Faculty of Medicine and Dentistry, Palacky University Olomouc, Hnevotinska 3, 775 15 Olomouc, Czech Republic.
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Caroça C, de Matos TM, Ribeiro D, Lourenço V, Martins T, Campelo P, Fialho G, Silva SN, Paço J, Caria H. Genetic Basis of Nonsyndromic Sensorineural Hearing Loss in the Sub-Saharan African Island Population of São Tomé and Príncipe: The Role of the DFNB1 Locus? OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2018; 20:449-55. [PMID: 27501294 DOI: 10.1089/omi.2016.0067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hearing loss (HL) is a common condition with both genetic and environmental causes, and it greatly impacts global health. The prevalence of HL is reportedly higher in developing countries such as the Sub-Saharan African island of São Tomé and Príncipe, where the deaf community is estimated to be less than 1% of the population. We investigated the role of the DFNB1 locus (GJB2 and GJB6 genes) in the etiology of nonsyndromic sensorineural hearing loss (NSSHL) in São Tomé and Príncipe. A sample of 316 individuals, comprising 136 NSSHL patients (92 bilateral, 44 unilateral) and 180 controls, underwent a clinical and audiological examination. Sequencing of the GJB2 coding region and testing for the (GJB6-D13S1830) and del(GJB6-D13S1854) GJB6 deletions were performed. A total of 311 out of 316 individuals were successfully analyzed regarding the GJB2 and GJB6 genetic variations, respectively. The frequency of the GJB2 coding mutations in patients and controls was low. Some of those coding mutations are the most commonly found in Eurasian and Mediterranean populations and have also been identified in Portugal. None of the GJB6 deletions was present. The presence of certain coding variants in São Tomé and Príncipe suggests a non-Sub-Saharan genetic influx and supports the previously reported genetic influx from European (mainly Portuguese) ancestors. In summary, DFNB1 locus does not appear to be a major contributor to NSSHL in São Tomé and Príncipe. However, the presence of both pathogenic and likely pathogenic mutations in GJB2 suggests that GJB2-related NSSHL might still occur in this population, warranting further research on GJB2 testing in NSSHL cases.
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Affiliation(s)
- Cristina Caroça
- 1 Otolaryngology Department, Nova Medical School/Faculty of Medical Sciences , Universidade Nova de Lisboa, Lisboa, Portugal .,2 Hospital CUF Infante Santo , Otolaryngology Department, Hospital CUF Infante Santo, Lisboa, Portugal
| | - Tiago Morim de Matos
- 3 Deafness Research Group, Biomedicine and Translational Research, BioISI, Faculty of Sciences, University of Lisbon , Lisbon, Portugal
| | - Diogo Ribeiro
- 2 Hospital CUF Infante Santo , Otolaryngology Department, Hospital CUF Infante Santo, Lisboa, Portugal
| | - Vera Lourenço
- 2 Hospital CUF Infante Santo , Otolaryngology Department, Hospital CUF Infante Santo, Lisboa, Portugal
| | - Tânia Martins
- 2 Hospital CUF Infante Santo , Otolaryngology Department, Hospital CUF Infante Santo, Lisboa, Portugal
| | - Paula Campelo
- 2 Hospital CUF Infante Santo , Otolaryngology Department, Hospital CUF Infante Santo, Lisboa, Portugal
| | - Graça Fialho
- 3 Deafness Research Group, Biomedicine and Translational Research, BioISI, Faculty of Sciences, University of Lisbon , Lisbon, Portugal
| | - Susana Nunes Silva
- 4 Centre for Toxicogenomics and Human Health (ToxOmics), NOVA Medical School , Faculty of Medical Sciences, Universidade Nova de Lisboa, Lisboa, Portugal
| | - João Paço
- 1 Otolaryngology Department, Nova Medical School/Faculty of Medical Sciences , Universidade Nova de Lisboa, Lisboa, Portugal .,2 Hospital CUF Infante Santo , Otolaryngology Department, Hospital CUF Infante Santo, Lisboa, Portugal
| | - Helena Caria
- 3 Deafness Research Group, Biomedicine and Translational Research, BioISI, Faculty of Sciences, University of Lisbon , Lisbon, Portugal .,5 School of Health, Polytechnic Institute of Setubal , Setubal, Portugal
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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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Leclère JC, Le Gac MS, Le Maréchal C, Ferec C, Marianowski R. GJB2 mutations: Genotypic and phenotypic correlation in a cohort of 690 hearing-impaired patients, toward a new mutation? Int J Pediatr Otorhinolaryngol 2017; 102:80-85. [PMID: 29106882 DOI: 10.1016/j.ijporl.2017.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 09/10/2017] [Accepted: 09/11/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVES To analyze the clinical features of hearing impairment and to search for correlations with the genotype in patients with GJB2 mutations. DESIGN Case series. SETTING Collaborative study in referral centers, institutional practice. PATIENTS A total of 690 hearing-impaired patients were genotypically and phenotypically described. The mutations of GJB2 and GJB6 were studied. Heterozygous patients were searched for another mutation by microsatellite approach. MAIN OUTCOME MEASURES Prevalence of GJB2 mutations, microsatellite approach, hearing-impairment. RESULTS In 498 patients (72,17% of the cohort), no mutation was found. Homozygotous patients were 59 (8,55%), with 51 for c.35delG, 6 for p.M34T and 2 for GJB6. Compound heterozygous were 64 (9,28%) with 56 c.35delG-others mutations. Genotypes with biallelic non sense mutations had a high risk of severe to profound hearing impairment. It was frequently milder in compound heterozygotes than in c.35delG homozygotes. Heterozygous patients were 69 (10%) with 21 c.35delG, 20 p.M34T and 28 others mutations. We selected patients with a complete historical medical file (clinical and audiometric data). Then, we performed a microsatellite approach (multiplex PCR of short DNA fragments) to localize a new pathologic allele. Seventeen heterozygous patients were studied. Six patients (35%) showed the same haplotype. They were compound heterozygous bearing a new pathologic allele. CONCLUSION Genotype may affect deafness severity, but environmental and other genetic factors may also modulate the severity and evolution of GJB2-GJB6 deafness. A new haplotype for GJB2 is described but the exact mutation remains unknown.
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Affiliation(s)
- Jean-Christophe Leclère
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital CHU Brest, France
| | - Marie-Suzanne Le Gac
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital CHU Brest, France
| | | | - Claude Ferec
- Genetic Department, University Hospital CHU Brest, France
| | - Rémi Marianowski
- Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital CHU Brest, France.
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Parzefall T, Frohne A, Koenighofer M, Kirchnawy A, Streubel B, Schoefer C, Frei K, Lucas T. Whole-exome sequencing to identify the cause of congenital sensorineural hearing loss in carriers of a heterozygous GJB2 mutation. Eur Arch Otorhinolaryngol 2017; 274:3619-3625. [PMID: 28821934 PMCID: PMC5591807 DOI: 10.1007/s00405-017-4699-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 08/02/2017] [Indexed: 12/01/2022]
Abstract
Bi-allelic variations in the gap junction protein beta-2 (GJB2) gene cause up to 50% of cases of newborn hearing loss. Heterozygous pathogenic GJB2 variations are also fivefold overrepresented in idiopathic patient groups compared to the normal-hearing population. Whether hearing loss in this group is due to unidentified additional variations within GJB2 or variations in other deafness genes is unknown in most cases. Whole-exome sequencing offers an effective approach in the search for causative variations in patients with Mendelian diseases. In this prospective genetic cohort study, we initially investigated a family of Turkish origin suffering from congenital autosomal recessive hearing loss. An index patient and his normal-hearing father, both bearing a single heterozygous pathogenic c.262G>T (p.Ala88Ser) GJB2 transversion as well as the normal-hearing mother were investigated by means of whole-exome sequencing. Subsequently the genetic screening was extended to a hearing-impaired cohort of 24 families of Turkish origin. A homozygous missense c.5492G>T transversion (p.Gly1831Val) in the Myosin 15a gene, previously linked to deafness, was identified as causative in the index family. This very rare variant is not listed in any population in the Genome Aggregation Database. Subsequent screening of index patients from additional families of Turkish origin with recessive hearing loss identified the c.5492G>T variation in an additional family. Whole-exome sequencing may effectively identify the causes of idiopathic hearing loss in patients bearing heterozygous GJB2 variations.
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Affiliation(s)
- Thomas Parzefall
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Alexandra Frohne
- Department for Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Martin Koenighofer
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Andreas Kirchnawy
- Department for Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Berthold Streubel
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Christian Schoefer
- Department for Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Klemens Frei
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria. .,Department of Otorhinolaryngology, Head and Neck Surgery, Vienna General Hospital (AKH), Waehringer Guertel 18-20, 1090, Vienna, Austria.
| | - Trevor Lucas
- Department for Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
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Alkowari MK, Vozzi D, Bhagat S, Krishnamoorthy N, Morgan A, Hayder Y, Logendra B, Najjar N, Gandin I, Gasparini P, Badii R, Girotto G, Abdulhadi K. Targeted sequencing identifies novel variants involved in autosomal recessive hereditary hearing loss in Qatari families. Mutat Res 2017; 800-802:29-36. [PMID: 28501645 DOI: 10.1016/j.mrfmmm.2017.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/11/2017] [Accepted: 05/03/2017] [Indexed: 06/07/2023]
Abstract
Hereditary hearing loss is characterized by a very high genetic heterogeneity. In the Qatari population the role of GJB2, the worldwide HHL major player, seems to be quite limited compared to Caucasian populations. In this study we analysed 18 Qatari families affected by non-syndromic hearing loss using a targeted sequencing approach that allowed us to analyse 81 genes simultaneously. Thanks to this approach, 50% of these families (9 out of 18) resulted positive for the presence of likely causative alleles in 6 different genes: CDH23, MYO6, GJB6, OTOF, TMC1 and OTOA. In particular, 4 novel alleles were detected while the remaining ones were already described to be associated to HHL in other ethnic groups. Molecular modelling has been used to further investigate the role of novel alleles identified in CDH23 and TMC1 genes demonstrating their crucial role in Ca2+ binding and therefore possible functional role in proteins. Present study showed that an accurate molecular diagnosis based on next generation sequencing technologies might largely improve molecular diagnostics outcome leading to benefits for both genetic counseling and definition of recurrence risk.
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Affiliation(s)
- Moza K Alkowari
- Division of Experimental Genetics, Sidra Medical and Research Centre, Doha, Qatar
| | - Diego Vozzi
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | | | - Navaneethakrishnan Krishnamoorthy
- Division of Experimental Genetics, Sidra Medical and Research Centre, Doha, Qatar; Heart Science Centre, National Heart and Lung Institute, Imperial College London, United Kingdom
| | - Anna Morgan
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy; Medical Sciences, Chirurgical and Health Department, University of Trieste, Trieste, Italy
| | | | | | | | - Ilaria Gandin
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Paolo Gasparini
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy; Medical Sciences, Chirurgical and Health Department, University of Trieste, Trieste, Italy
| | - Ramin Badii
- Molecular Genetics Laboratory, HMC, Doha, Qatar
| | - Giorgia Girotto
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy; Medical Sciences, Chirurgical and Health Department, University of Trieste, Trieste, Italy.
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