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Ford CL, Riggs WJ, Quigley T, Keifer OP, Whitton JP, Valayannopoulos V. The natural history, clinical outcomes, and genotype-phenotype relationship of otoferlin-related hearing loss: a systematic, quantitative literature review. Hum Genet 2023; 142:1429-1449. [PMID: 37679651 PMCID: PMC10511631 DOI: 10.1007/s00439-023-02595-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/09/2023] [Indexed: 09/09/2023]
Abstract
Congenital hearing loss affects one in 500 newborns. Sequence variations in OTOF, which encodes the calcium-binding protein otoferlin, are responsible for 1-8% of congenital, nonsyndromic hearing loss and are the leading cause of auditory neuropathy spectrum disorders. The natural history of otoferlin-related hearing loss, the relationship between OTOF genotype and hearing loss phenotype, and the outcomes of clinical practices in patients with this genetic disorder are incompletely understood because most analyses have reported on small numbers of cases with homogeneous OTOF genotypes. Here, we present the first systematic, quantitative literature review of otoferlin-related hearing loss, which analyzes patient-specific data from 422 individuals across 61 publications. While most patients display a typical phenotype of severe-to-profound hearing loss with prelingual onset, 10-15% of patients display atypical phenotypes, including mild-to-moderate, progressive, and temperature-sensitive hearing loss. Patients' phenotypic presentations appear to depend on their specific genotypes. For example, non-truncating variants located in and immediately downstream of the C2E calcium-binding domain are more likely to produce atypical phenotypes. Additionally, the prevalence of certain sequence variants and their associated phenotypes varies between populations due to evolutionary founder effects. Our analyses also suggest otoacoustic emissions are less common in older patients and those with two truncating OTOF variants. Critically, our review has implications for the application and limitations of clinical practices, including newborn hearing screenings, hearing aid trials, cochlear implants, and upcoming gene therapy clinical trials. We conclude by discussing the limitations of available research and recommendations for future studies on this genetic cause of hearing loss.
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Yuan L, Yu X, Xiao H, Deng S, Xia H, Xu H, Yang Y, Deng H. Identification of novel compound heterozygous variants in the DNAH1 gene of a Chinese family with left-right asymmetry disorder. Front Mol Biosci 2023; 10:1190162. [PMID: 37457836 PMCID: PMC10345202 DOI: 10.3389/fmolb.2023.1190162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023] Open
Abstract
Most internal organs in humans and other vertebrates exhibit striking left-right asymmetry in position and structure. Variation of normal organ positioning results in left-right asymmetry disorders and presents as internal organ reversal or randomization. Up to date, at least 82 genes have been identified as the causative genetic factors of left-right asymmetry disorders. This study sought to discover potential pathogenic variants responsible for left-right asymmetry disorder present in a Han-Chinese family using whole exome sequencing combined with Sanger sequencing. Novel compound heterozygous variants, c.5690A>G (p.Asn1897Ser) and c.7759G>A (p.Val2587Met), in the dynein axonemal heavy chain 1 gene (DNAH1), were found in the proband and absent in unaffected family members. Conservation analysis has shown that the variants affect evolutionarily conserved residues, which may impact the tertiary structure of the DNAH1 protein. The novel compound heterozygous variants may potentially bear responsibility for left-right asymmetry disorder, which results from a perturbation of left-right axis coordination at the earliest embryonic development stages. This study broadens the variant spectrum of left-right asymmetry disorders and may be helpful for genetic counseling and healthcare management for the diagnosed individual, and promotes a greater understanding of the pathophysiology.
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Affiliation(s)
- Lamei Yuan
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
- Disease Genome Research Center, Central South University, Changsha, China
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Xuehui Yu
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Heng Xiao
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Sheng Deng
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China
| | - Hong Xia
- Department of Emergency, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hongbo Xu
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Yan Yang
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hao Deng
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
- Disease Genome Research Center, Central South University, Changsha, China
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
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Bitarafan F, Seyedena SY, Mahmoudi M, Garshasbi M. Identification of novel variants in Iranian consanguineous pedigrees with nonsyndromic hearing loss by next-generation sequencing. J Clin Lab Anal 2020; 34:e23544. [PMID: 32864763 PMCID: PMC7755797 DOI: 10.1002/jcla.23544] [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: 04/12/2020] [Revised: 07/24/2020] [Accepted: 07/29/2020] [Indexed: 12/17/2022] Open
Abstract
Background The extremely high genetic heterogeneity of hearing loss due to diverse group of genes encoding proteins required for development, function, and maintenance of the complex auditory system makes the genetic diagnosis of this disease challenging. Up to now, 121 different genes have been identified for nonsyndromic hearing loss (NSHL), of which 76 genes are responsible for the most common forms of NSHL, autosomal recessive nonsyndromic hearing loss (ARNSHL). Methods After excluding mutations in the most common ARNSHL gene, GJB2, by Sanger sequencing, genetic screening for a panel of genes responsible for hereditary hearing impairment performed in 9 individuals with ARNSHL from unrelated Iranian consanguineous pedigrees. Results One compound heterozygote and eight homozygote variants, of which five are novel, were identified: CDH23:p.(Glu1970Lys), and p.(Ala1072Asp), GIPC3:p.(Asn82Ser), and (p.Thr41Lys), MYO7A:p.[Phe456Phe]; p.[Met708Val], and p.(Gly163Arg), TECTA:p.(Leu17Leufs*19), OTOF:c.1392+1G>A, and TRIOBP:p.(Arg1068*). Sanger sequencing confirmed the segregation of the variants with the disease in each family. Conclusion Finding more variants and expanding the spectrum of hearing impairment mutations can increase the diagnostic value of molecular testing in the screening of patients and can improve counseling to minimize the risk of having affected children for at risk couples.
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Affiliation(s)
- Fatemeh Bitarafan
- Department of Biology, Faculty of Biological Sciences, Islamic Azad University, North Tehran Branch, Tehran, Iran
| | - Seyed Yousef Seyedena
- Department of Biology, Faculty of Biological Sciences, Islamic Azad University, North Tehran Branch, Tehran, Iran
| | - Mahdi Mahmoudi
- Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Teheran, Iran
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