Genetic Basis of Hearing Loss (original) (raw)
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The Genetic Basis of Hearing Loss: Recent Advances and Future Prospects
International Journal of Head and Neck Surgery
Hearing loss (HL) is a common and complex condition that can occur at any age, be inherited or acquired, and is associated with a wide number of etiologies. HL is the most common sensory deficit in newborn children. In developed countries, genetic causes are considered the most frequent etiology of HL, and are estimated to account for 75% of the causes of HL. Current estimates suggest 1% of human genes (200-250 genes) are associated with genetic HL, and to date, more than 80 genes with over 1000 mutations and 140 loci have been identified associated with non-syndromic HL. The Online Mendelian Inheritance in Man reports more than 400 syndromes with HL. Syndromic and non-syndromic HL can be caused by different mutations within the same gene. Establishing the genetic cause of HL in prelingual children facilitates the medical course of action, rehabilitation choices and long term care in children. Patients with HL of undiagnosed etiology should be evaluated by a clinical geneticist and consider genetic testing as a part of their multidisciplinary evaluation.
Research of genetic bases of hereditary non-syndromic hearing loss
Turk pediatri arsivi, 2017
Hearing loss is the most common sensory disorder that affects approximately one per 1000 live births. With this project, we aimed to identify gene variants that were common causes of hearing loss in Turkey to contribute to the planning of genetic screening programs for hearing loss, as well as to improve genetic counseling to affected families. Twenty-one families with at least two affected individuals and parental consanguinity who presented with non-syndromic severe-to-profound sensorineural hearing loss were included in this study. We first screened for mutations in GJB2 and mitochondrial DNA 12S RNA genes. Subsequently, we genotyped the TMIE c.250C>T and SNP markers flanking the SLC26A4, MYO7A, MYO15A, OTOF, CDH23, TMIE, TECTA, PCDH15, TMC1, TMPRSS3, TMHS genes in the remaining twelve families without mutations in GJB2. Screening for mutations in GJB2 gene showed c.[35delG];[35delG] mutation in four families, c.[35delG];[507C>A] mutation in two families, c.[35delG];[-23+1G...
Yi chuan = Hereditas / Zhongguo yi chuan xue hui bian ji, 2014
More than 50% cases with hearing loss are caused by genetic defects. With the development of genomics technology, molecular genetics of hearing loss has become a cutting-edge field under investigation in otology. The next generation sequencing has provided a new model originated from sequencing data to genetic disease study, and has made a revolutionary change in the strategy of gene identification for genetic diseases. Due to the application of next generation sequencing technology, gene identification of hearing loss has been accelerated in recent years, and moreover, the new technology and strategy were explored to clinical application. In this review, we briefly introduce the current situation of hereditary hearing loss research, and the application and perspective of next generation sequencing in this field.
Hearing loss: A review on molecular genetics and epidemiologic aspects
2017
Background and aims: Hearing loss (HL) happens due to the genetic or environmental causes or both. Risk factors include congenital infections and congenital deformities of auricle and ear duct. The present study was performed to briefly explain the genetics, molecular biology and epidemiology of HL in Middle East especially in Iran. Methods: An intense an comprehensive literature search was prformed through heading journals in the field. All data was organized using Mendeley software and incorporated to the text as required. Results: While the etiology of 25% of HL cases remains indistinct, it is estimated that at least 50% of pre lingual HL cases have a genetic cause. About 70% of genetic HL cases are non Syndromic (NSHL) without anomaly, whereas the remaining 30% are Syndromic. Autosomal recessive non-syndromic hearing loss forms (ARNSHL) are the severest forms of congenital HL with defect in cochlea. In addition to X-linked (DFNX), autosomal dominant (DFNA), autosomal recessive (...
The Laryngoscope, 2009
Significant hearing loss (≥ 25 decibels) is prevalent in the adult population (15-20%) and affects approximately 50% of individuals 80 years of age or older1. It is estimated that 15% of inherited hearing impairment is accounted for by autosomal dominant non-syndromic forms of hearing loss (ADNSHL). To date, 57 loci for autosomal dominant deafness have been mapped to chromosomal regions, and 23 causally-related genes have been identified at these loci (http://webh01.ua.ac.be/hhh/; May 8 th , 2009)2. In most cases the hearing loss is sensorineural (SNHL) and non-syndromic.
Role of Genetic Factors in the Causation of Non-Syndromic Hearing Loss (NSHL) in Indian Population
Hearing loss affects about 70 million people worldwide, which can be inherited as either syndromic or non-syndromic forms. Approximately 50% of all childhood deafness is caused due to gene defects. The Non-syndromic hearing loss (NSHL) is extremely heterogenous trait inherited as autosomal recessive, autosomal dominant and X-linked and also due to mitochondrial mutations. In the present review genes causing non-syndromic hearing loss (NSHL) are classified based on their molecular function. GJB2 is most prominent deafness causing gene among the different populations including India, followed by other genes. The recent technological advances in target-enrichment methods and next generation sequencing has overcome the barriers possessed by the earlier methods and laid the path for comprehensive analysis of all the known genes causing non-syndromic hearing loss. The review mainly emphases on the genes causing non-syndromic hearing loss in Indian population and their molecular function. Identifying the genes responsible for hearing loss enables otolaryngologists, geneticist to apply molecular diagnosis by offering genetic testing which helps in prevention of the condition of non-syndromic hearing loss, proper diagnosis, Arch Clin Biomed Res 2020; 4 (6): 775-793
First-Line Molecular Genetic Evaluation of Autosomal Recessive Non-Syndromic Hearing Loss
Turkish Archives of Otorhinolaryngology, 2019
Objective: The aim of this study is to in vestigate the efficiency of a first-line molecular genet ic evaluation approach, in children with deafness. Methods: Patients who were found to have sensorineural hearing loss by age-appropriate audiological tests were selected for the molecular genetic evaluation. The molecular genetic evaluation was carried out with GJB2 gene sequence analysis and mtDNA m.1555A>G mutation Restriction Fragment Length Polymorphism (RFLP) analysis. Additionally, in a small group of patients, hearing loss Multiplex Ligation-dependent Probe Amplification (MLPA) analysis was done out to identify the possible role of copy number changes. Results: In this Turkish cohort, which included 104 index patients and 78 relatives, 33 (31.7%) had Pathogenic/Likely Pathogenic variants. One or more GJB2 sequence variants were identified in 46 (44.1%) of the 104 index patients. The homozygous c.35delG mutation by itself explained the etiology in 24% of our ARSNHL group. In one (5%) of the 20 patients of MLPA group, a hemizygous deletion in POU3F4 gene was detected. Conclusion: In our Turkish cohort, we applied a first-line molecular genetic evaluation approach using GJB2 gene sequence analysis and mtDNA m.1555A>G RFLP analysis. This approach revealed the genetic etiology of 44.1% of our index patients. Additionaly, the results of hearing loss MLPA analysis revealed the limited role of copy number changes in this patient group. Furthermore, with a detailed genotype-phenotype association workup, 2 rare cases of Deafness with Palmoplantar Hyperkeratosis and Keratitis-Ichthyosis-Deafness syndrome were reported.
Novel Trends in the Molecular Genetics of Hearing Loss
Journal of Hearing Science
Genetically determined hearing loss is a highly heterogeneous disorder, and to date the analysis of its causes has been conducted selectively, covering only individual genes. Breakthroughs associated with current technological advances have contributed to a rapid development in the molecular genetics of hearing loss. Here we review a number of novel and important achievements in the field: application of next-generation sequencing, novel genes, and trends in molecular therapies for hearing loss. Current achievements in the molecular genetics of hearing loss are discussed in the context of previously published results and data from our own studies.