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Justin Margret J, Jayasankaran C, Amritkumar P, Azaiez H, Srisailapathy CRS. Unraveling the Genetic Basis of Combined Deafness and Male Infertility Phenotypes through High-Throughput Sequencing in a Unique Cohort from South India. ADVANCED GENETICS (HOBOKEN, N.J.) 2024; 5:2300206. [PMID: 38884051 PMCID: PMC11170077 DOI: 10.1002/ggn2.202300206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 03/15/2024] [Indexed: 06/18/2024]
Abstract
The co-occurrence of sensorineural hearing loss and male infertility has been reported in several instances, suggesting potential shared genetic underpinnings. One such example is the contiguous gene deletion of CATSPER2 and STRC genes, previously associated with deafness-infertility syndrome (DIS) in males. Fifteen males with both hearing loss and infertility from southern India after exclusion for the DIS contiguous gene deletion and the FOXI1 gene mutations are subjected to exome sequencing. This resolves the genetic etiology in four probands for both the phenotypes; In the remaining 11 probands, two each conclusively accounted for deafness and male infertility etiologies. Genetic heterogeneity is well reflected in both phenotypes. Four recessive (TRIOBP, SLC26A4, GJB2, COL4A3) and one dominant (SOX10) for the deafness; six recessive genes (LRGUK, DNAH9, ARMC4, DNAH2, RSPH6A, and ACE) for male infertility can be conclusively ascribed. LRGUK and RSPH6A genes are implicated earlier only in mice models, while the ARMC4 gene is implicated in chronic destructive airway diseases due to primary ciliary dyskinesia. This study would be the first to document the role of these genes in the male infertility phenotype in humans. The result suggests that deafness and infertility are independent events and do not segregate together among the probands.
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Affiliation(s)
- Jeffrey Justin Margret
- Department of Genetics Dr. ALM Post Graduate Institute of Basic Medical Sciences University of Madras Taramani Campus Chennai 600 113 India
- Department of Pediatrics Louisiana State University Health Sciences Center Shreveport LA 71103 USA
| | - Chandru Jayasankaran
- Department of Genetics Dr. ALM Post Graduate Institute of Basic Medical Sciences University of Madras Taramani Campus Chennai 600 113 India
- Department of Personalized Health Care Roche Products India Pvt., Ltd. Bengaluru Karnataka 560 025 India
| | - Pavithra Amritkumar
- Department of Genetics Dr. ALM Post Graduate Institute of Basic Medical Sciences University of Madras Taramani Campus Chennai 600 113 India
- Meenakshi Academy of Higher Education and Research (MAHER) Chennai 600 078 India
| | - Hela Azaiez
- Department of Otolaryngology Carver College of Medicine University of Iowa Iowa City Iowa 52242 USA
| | - C R Srikumari Srisailapathy
- Department of Genetics Dr. ALM Post Graduate Institute of Basic Medical Sciences University of Madras Taramani Campus Chennai 600 113 India
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Danilchenko VY, Zytsar MV, Maslova EA, Posukh OL. Selection of Diagnostically Significant Regions of the SLC26A4 Gene Involved in Hearing Loss. Int J Mol Sci 2022; 23:ijms232113453. [PMID: 36362242 PMCID: PMC9655724 DOI: 10.3390/ijms232113453] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/23/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022] Open
Abstract
Screening pathogenic variants in the SLC26A4 gene is an important part of molecular genetic testing for hearing loss (HL) since they are one of the common causes of hereditary HL in many populations. However, a large size of the SLC26A4 gene (20 coding exons) predetermines the difficulties of its complete mutational analysis, especially in large samples of patients. In addition, the regional or ethno-specific prevalence of SLC26A4 pathogenic variants has not yet been fully elucidated, except variants c.919-2A>G and c.2168A>G (p.His723Arg), which have been proven to be most common in Asian populations. We explored the distribution of currently known pathogenic and likely pathogenic (PLP) variants across the SLC26A4 gene sequence presented in the Deafness Variation Database for the selection of potential diagnostically important parts of this gene. As a result of this bioinformatic analysis, we found that molecular testing ten SLC26A4 exons (4, 6, 10, 11, 13−17 and 19) with flanking intronic regions can provide a diagnostic rate of 61.9% for all PLP variants in the SLC26A4 gene. The primary sequencing of these SLC26A4 regions may be applied as an initial effective diagnostic testing in samples of patients of unknown ethnicity or as a subsequent step after the targeted testing of already-known ethno- or region-specific pathogenic SLC26A4 variants.
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Affiliation(s)
- Valeriia Yu. Danilchenko
- 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
| | - 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
| | - 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
- Correspondence:
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Nakano A, Arimoto Y, Mutai H, Nara K, Inoue S, Matsunaga T. Clinical and genetic analysis of children with hearing loss and bilateral enlarged vestibular aqueducts. Int J Pediatr Otorhinolaryngol 2022; 152:110975. [PMID: 34801268 DOI: 10.1016/j.ijporl.2021.110975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 08/28/2021] [Accepted: 11/08/2021] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To evaluate the clinical and genetic features of children with hearing loss associated with one of the most common malformations of the inner ear: bilateral enlargement of vestibular aqueducts (EVA). METHODS Clinical and genetic features were investigated in 28 children with hearing loss diagnosed with bilateral EVA by computed tomography from January 2008 to September 2019. RESULTS Fourteen subjects had undergone newborn hearing screening (NHS). Nine subjects (64.3%) were referred in both ears, 4 subjects (28.6%) were referred in one ear, and one subject (7.1%) passed in both ears. Nineteen of 26 subjects (73.1%) who were followed for more than 3 years had hearing fluctuations, while 17 (65.4%) had hearing loss progression. Eleven of 28 subjects (39.2%) had vertigo attacks. Pathogenic variants were identified in two alleles of the SLC26A4 gene in 24 of 27 subjects (88.9%) by sequencing of all exons and flanking introns, leading to genetic diagnosis of Pendred syndrome/DFNB4. Our results indicate that genetic screening for specific SLC26A4 variants using a commercial clinical laboratory test in Japan would have achieved genetic diagnoses in 13 of the 27 subjects (54.2%). Although there was no statistically significance in the frequency of hearing fluctuation or progression depending on the presence or absence of the gene variant, mean hearing level was severe in subjects with two pathogenic variants in SLC26A4 gene. The most common variant detected in our subjects was p.His723Arg (13 alleles, 27.1%), followed by c. 919-2A > G (four alleles, 8.3%). Two novel variants were detected in this study: c.1544+1G > T and c.1614+5G > A. CONCLUSIONS Our data suggest that some subjects may present with bilateral EVA that cannot be detected by NHS. We estimated that genetic diagnosis for SLC264 gene would not have been made in almost half subjects with the commercial genetic screening approach used in the present study in Japan. Although there were some limitations in this study, the subjects with pathogenic variants in two alleles of the SLC26A4 gene could have more severe hearing loss.
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Affiliation(s)
- Atsuko Nakano
- Division of Otorhinolaryngology, Chiba Children's Hospital, 579-1 Heta-cho, Chiba-shi, Chiba, 266-0007, Japan.
| | - Yukiko Arimoto
- Division of Otorhinolaryngology, Chiba Children's Hospital, 579-1 Heta-cho, Chiba-shi, Chiba, 266-0007, Japan
| | - Hideki Mutai
- Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo, 152-8902, Japan
| | - Kiyomitsu Nara
- Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo, 152-8902, Japan
| | - Satomi Inoue
- Medical Genetics Center, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo, 152-8902, Japan
| | - Tatsuo Matsunaga
- Division of Hearing and Balance Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo, 152-8902, Japan; Medical Genetics Center, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro-ku, Tokyo, 152-8902, Japan
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Tian Y, Xu H, Liu D, Zhang J, Yang Z, Zhang S, Liu H, Li R, Tian Y, Zeng B, Li T, Lin Q, Wang H, Li X, Lu W, Shi Y, Zhang Y, Zhang H, Jiang C, Xu Y, Chen B, Liu J, Tang W. Increased diagnosis of enlarged vestibular aqueduct by multiplex PCR enrichment and next-generation sequencing of the SLC26A4 gene. Mol Genet Genomic Med 2021; 9:e1734. [PMID: 34170635 PMCID: PMC8404235 DOI: 10.1002/mgg3.1734] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/30/2021] [Accepted: 05/24/2021] [Indexed: 12/11/2022] Open
Abstract
Background The enlarged vestibular aqueduct (EVA) is the commonest malformation of inner ear accompanied by sensorineural hearing loss in children. Three genes SLC26A4, FOXI1, and KCNJ10 have been associated with EVA, among them SLC26A4 being the most common. Yet, hotspot mutation screening can only diagnose a small number of patients. Methods Thus, in this study, we designed a new molecular diagnosis panel for EVA based on multiplex PCR enrichment and next‐generation sequencing of the exon and flanking regions of SLC26A4. A total of 112 hearing loss families with EVA were enrolled and the pathogenicity of the rare variants detected was interpreted according to the American College of Medical Genetics and Genomics (ACMG) guidelines. Results Our results showed that 107/112 (95.54%) families carried SLC26A4 biallelic mutations, 4/112 (3.57%) carried monoallelic variants, and 1/112 (0.89%) had none variant, resulting in a diagnostic rate of 95.54%. A total of 49 different variants were detected in those patients and we classified 30 rare variants as pathogenic/likely pathogenic, of which 13 were not included in the Clinvar database. Conclusion Our diagnostic panel has an increased diagnostic yield with less cost, and the curated list of pathogenic variants in the SLC26A4 gene can be directly used to aid the genetic counseling to patients.
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Affiliation(s)
- Yongan Tian
- BGI College, Zhengzhou University, Zhengzhou, China.,Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China.,Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Hongen Xu
- The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Danhua Liu
- The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Juanli Zhang
- Henan Province Medical Instrument Testing Institute, Zhengzhou, China
| | | | - Sen Zhang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Huanfei Liu
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | - Ruijun Li
- Precision Medicine Center, Academy of Medical Science, Zhengzhou University, Zhengzhou, China
| | | | - Beiping Zeng
- BGI College, Zhengzhou University, Zhengzhou, China.,Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Tong Li
- BGI College, Zhengzhou University, Zhengzhou, China.,Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Qianyu Lin
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Haili Wang
- National Health Commission Key Laboratory of Birth Defects Prevention, Henan Key Laboratory of Population Defects Prevention, Zhengzhou, China
| | - Xiaohua Li
- Department of Otology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Wei Lu
- Department of Otology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ying Shi
- The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yan Zhang
- The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hui Zhang
- The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Chang Jiang
- Department of Otology, Henan Provincial People's Hospital, Zhengzhou, China
| | - Ying Xu
- Zhengzhou Children's Hospital, Zhengzhou, China
| | - Bei Chen
- Department of Otology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jun Liu
- Department of Otology, Henan Provincial People's Hospital, Zhengzhou, China
| | - Wenxue Tang
- The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Zhou C, Zou X, Peng C, Gao G, Guo Z. A novel genotyping technique for discriminating LVAS-associated high-frequency variants in SLC26A4 gene. AMB Express 2020; 10:166. [PMID: 32930899 PMCID: PMC7492351 DOI: 10.1186/s13568-020-01102-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 09/08/2020] [Indexed: 11/10/2022] Open
Abstract
An increasing number of biological and epidemiological evidence suggests that c.919-2A > G and c.2168A > G variants of solute carrier family 26, member 4 (SLC26A4) gene play a critical role in the development of large vestibular aqueduct syndrome (LVAS). In this study, we developed a rapid genotyping method for discriminating LVAS-associated high-frequency variants in SLC26A4 gene. The genotyping technique consists of 3' terminal exonuclease-resistant phosphorothioate-modified allele specific primer extension mediated by exo+ polymerase. In PCR amplification by Pfu polymerase, allelic specific primers perfectly matching wild type allele were extended while no specific products were yielded from primers targeting variant allele. Similarly, allelic specific primers perfectly matching variant allele were extended and no specific products were observed from primers targeting wild type allele. The clinical application of 3' terminal phosphorothioate-modified allele specific primer extension mediated by Pfu polymerase identified both homozygous for SLC26A4 gene c.919-2A > G variant in two patients clinically diagnosed as LVAS by temporal bone CT scan. The genetic results from this method are consistent with that of DNA sequencing. The data suggest that exo+ polymerase-mediated 3' terminal phosphorothioate-modified primer extension is reliable in the identification of SLC26A4 gene high-frequency variant prior to high-resolution CT scan. The method is extremely suitable for quickly molecular etiologic screening and early diagnosis and aggressive prevention therapy of LVAS.
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Affiliation(s)
- Chen Zhou
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang, Hunan, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, Hunan, China
| | - Xiangman Zou
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang, Hunan, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, Hunan, China
| | - Cuiying Peng
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, Hunan, China
| | - Guoqiang Gao
- The Second Affiliated Hospital, University of South China, Hengyang, Hunan, China
| | - Zifen Guo
- Institute of Pharmacy and Pharmacology, University of South China, Hengyang, Hunan, China. .,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, Hunan, China.
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Genetic analysis of SLC26A4 gene (pendrin) related deafness among a cohort of assortative mating families from southern India. Eur Arch Otorhinolaryngol 2020; 277:3021-3035. [DOI: 10.1007/s00405-020-06026-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 04/27/2020] [Indexed: 10/24/2022]
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Extrusion pump ABCC1 was first linked with nonsyndromic hearing loss in humans by stepwise genetic analysis. Genet Med 2019; 21:2744-2754. [PMID: 31273342 DOI: 10.1038/s41436-019-0594-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 06/17/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To determine the genetic etiology of deafness in a family (HN-SD01) with autosomal dominant nonsyndromic hearing loss (NSHL). METHODS Stepwise genetic analysis was performed on family HN-SD01, including hotspot variant screening, exome sequencing, virtual hearing loss gene panel, and genome-wide linkage analysis. Targeted region sequencing was used to screen ABCC1 in additional cases. Cochlear expression of Abcc1 was evaluated by messenger RNA (mRNA) and protein levels. Computational prediction, immunofluorescence, real-time quantitative polymerase chain reaction, and flow cytometry were conducted to uncover functional consequences of candidate variants. RESULTS Stepwise genetic analysis identified a heterozygous missense variant, ABCC1:c.1769A>G (p.Asn590Ser), cosegregating with phenotype in HN-SD01. Screening of ABCC1 in an additional 217 cases identified candidate pathogenic variants c.692G>A (p.Gly231Asp) in a sporadic case and c.887A>T (p.Glu296Val) in a familial proband. Abcc1 expressed in stria vascularis and auditory nerve of mouse cochlea. Immunofluorescence showed p.Asn590Ser distributed in cytomembrane and cytoplasm, while wild type was shown only in cytomembrane. Besides, it generated unstable mRNA and decreased efflux capacity of ABCC1. CONCLUSION Stepwise genetic analysis is efficient to analyze the genetic etiology of NSHL. Variants in ABCC1 are linked with NSHL and suggest an important role of extruding pumps in maintaining cochlea function.
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Sex-specific enlarged vestibular aqueduct morphology and audiometry. Am J Otolaryngol 2019; 40:473-477. [PMID: 31060752 DOI: 10.1016/j.amjoto.2019.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 03/16/2019] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Enlargement of the vestibular aqueduct (EVA) is one of the most common congenital malformations in pediatric patients presenting with sensorineural or mixed hearing loss. The relationship between vestibular aqueduct (VA) morphology and hearing loss across sex is not well characterized. This study assesses VA morphology and frequency-specific hearing thresholds with sex as the primary predictor of interest. MATERIALS AND METHODS A retrospective, longitudinal, and repeated-measures study was used. 47 patients at an academic tertiary care center with hearing loss and a record of CT scan of the internal auditory canal were candidates, and included upon meeting EVA criteria after confirmatory measurements of vestibular aqueduct midpoint and operculum widths. Audiometric measures included pure-tone average and frequency-specific thresholds. RESULTS Of the 47 patients (23 female and 24 male), 79 total ears were affected by EVA; the median age at diagnosis was 6.60 years. After comparing morphological measurements between sexes, ears from female patients were observed to have a greater average operculum width (3.25 vs. 2.70 mm for males, p = 0.006) and a greater average VA midpoint width (2.80 vs. 1.90 mm for males, p = 0.004). After adjusting for morphology, male patients' ears had pure-tone average thresholds 17.6 dB greater than female patients' ears (95% CI, 3.8 to 31.3 dB). CONCLUSIONS Though females seem to have greater enlargement of the vestibular aqueduct, this difference does not extend to hearing loss. Therefore, our results indicate that criteria for EVA diagnoses may benefit from re-evaluation. Further exploration into morphological and audiometric discrepancies across sex may help inform both clinician and patient expectations.
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Targeted Next-Generation Sequencing Facilitates Genetic Diagnosis and Provides Novel Pathogenetic Insights into Deafness with Enlarged Vestibular Aqueduct. J Mol Diagn 2018; 21:138-148. [PMID: 30268946 DOI: 10.1016/j.jmoldx.2018.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 08/13/2018] [Accepted: 08/30/2018] [Indexed: 12/24/2022] Open
Abstract
Enlarged vestibular aqueduct (EVA) is an inner-ear malformation associated with sensorineural hearing impairment. Most EVAs are associated with Pendred syndrome and nonsyndromic autosomal recessive deafness-4 (DFNB4), two autosomal-recessive disorders caused by mutations in SLC26A4. However, many EVA patients cannot have a confirmed diagnosis by screening common SLC26A4 mutations, constituting an enigma in genetic diagnosis. To enable comprehensive genetic examination and explore the etiologies of EVA, we designed a next-generation sequencing panel targeting the entire length of 3 Pendred syndrome/DFNB4 genes (SLC26A4, FOXI1, and KCNJ10) and exons of 10 other genes related to EVA and performed genetic testing in 50 EVA families without confirmative results on screening for SLC26A4 hotspots (c.919-2A>G and p.H723R). Bi-allelic SLC26A4 mutations were identified in 34 families and EYA1 mutations in two families, yielding a diagnostic rate of 72% (36 of 50). In addition, two variants were identified in KCNJ10 and FOXI1, but findings did not support the previous hypothesis that mutations in these two genes are probable contributors to EVA through recessive inheritance or digenic inheritance with SLC26A4. Of note, a large SLC26A4 deletion was confirmed in one step using our panel. These results show the utility of a next-generation sequencing-based panel to address EVA families by identifying various types of gene mutations with satisfactory diagnostic yields and provide novel insights into the pathogenesis of EVA.
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A New Genetic Diagnostic for Enlarged Vestibular Aqueduct Based on Next-Generation Sequencing. PLoS One 2016; 11:e0168508. [PMID: 27997596 PMCID: PMC5173027 DOI: 10.1371/journal.pone.0168508] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 12/01/2016] [Indexed: 12/12/2022] Open
Abstract
Enlarged vestibular aqueduct (EVA) is one of the most common congenital inner ear malformations and accounts for 1–12% of sensorineural deafness in children and adolescents. Multiple genetic defects contribute to EVA; therefore, early molecular diagnosis is critical for EVA patients to ensure that the most effective treatment strategies are employed. This study explored a new genetic diagnosis method for EVA and applied it to clinic diagnoses of EVA patients. Using next-generation sequencing technology, we set up a multiple polymerase chain reaction enrichment system for target regions of EVA pathogenic genes (SLC26A4, FOXI1, and KCNJ10). Forty-six EVA samples were sequenced by this system. Variants were detected in 87.0% (40/46) of cases, including three novel variants (SLC26A4 c.923_929del, c.1002-8C>G, and FOXI1 c.519C>A). Biallelic potential pathogenic variants were detected in 27/46 patient samples, leading to a purported diagnostic rate of 59%. All results were verified by Sanger sequencing. Our target region capture system was validated to amplify and measure SLC26A4, FOXI1, and KCNJ10 in one reaction system. The result supplemented the mutation spectrum of EVA. Thus, this strategy is an economic, rapid, accurate, and reliable method with many useful applications in the clinical diagnosis of EVA patients.
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Mapping pathogenic mutations suggests an innovative structural model for the pendrin (SLC26A4) transmembrane domain. Biochimie 2016; 132:109-120. [PMID: 27771369 DOI: 10.1016/j.biochi.2016.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/03/2016] [Indexed: 12/16/2022]
Abstract
Human pendrin (SLC26A4) is an anion transporter mostly expressed in the inner ear, thyroid and kidney. SLC26A4 gene mutations are associated with a broad phenotypic spectrum, including Pendred Syndrome and non-syndromic hearing loss with enlarged vestibular aqueduct (ns-EVA). No experimental structure of pendrin is currently available, making phenotype-genotype correlations difficult as predictions of transmembrane (TM) segments vary in number. Here, we propose a novel three-dimensional (3D) pendrin transmembrane domain model based on the SLC26Dg transporter. The resulting 14 TM topology was found to include two non-canonical transmembrane segments crucial for pendrin activity. Mutation mapping of 147 clinically validated pathological mutations shows that most affect two previously undescribed TM regions.
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Sagong B, Baek JI, Lee KY, Kim UK. A Novel Frameshift Mutation of SLC26A4 in a Korean Family With Nonsyndromic Hearing Loss and Enlarged Vestibular Aqueduct. Clin Exp Otorhinolaryngol 2016; 10:50-55. [PMID: 27384033 PMCID: PMC5327591 DOI: 10.21053/ceo.2016.00430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/22/2016] [Accepted: 05/26/2016] [Indexed: 11/23/2022] Open
Abstract
Objectives We aimed to identify the causative mutation for siblings in a Korean family with nonsyndromic hearing loss (HL) and enlarged vestibular aqueduct (EVA). The siblings were a 19-year-old female with bilateral profound HL and an 11-year-old male with bilateral moderately severe HL. Methods We extracted genomic DNA from blood samples of the siblings with HL, their parents, and 100 controls. We performed mutation analysis for SLC26A4 using direct sequencing. Results The two siblings were compound heterozygotes with the novel mutation p.I713LfsX8 and the previously described mutation p.H723R. Their parents had heterozygous mono-allelic mutations. Father had p.I713LfsX8 mutation as heterozygous, and mother had p.H723R mutation as heterozygous. However, novel mutation p.I713LfsX8 was not detected in 100 unrelated controls. Conclusion Both mutations identified in this study were located in the sulfate transporter and anti-sigma factor antagonist domain, the core region for membrane targeting of SulP/SLC26 anion transporters, which strongly suggests that failure in membrane trafficking by SLC26A4 is a direct cause of HL in this family. Our study could therefore provide a foundation for further investigations elucidating the SLC26A4-related mechanisms of HL.
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Affiliation(s)
- Borum Sagong
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, Korea
| | - Jeong-In Baek
- Department of Aroma Applied Industry, College of Herbal Bio-Industry, Daegu Haany University, Gyeongsan, Korea
| | - Kyu-Yup Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Kyungpook National University School of Medicine, Daegu, Korea
| | - Un-Kyung Kim
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, Korea.,School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Korea
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Mutation Analysis of the Common Deafness Genes in Patients with Nonsyndromic Hearing Loss in Linyi by SNPscan Assay. BIOMED RESEARCH INTERNATIONAL 2016; 2016:1302914. [PMID: 27247933 PMCID: PMC4876198 DOI: 10.1155/2016/1302914] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/06/2016] [Accepted: 04/17/2016] [Indexed: 11/26/2022]
Abstract
Hearing loss is a common sensory disorder, and at least 50% of cases are due to a genetic etiology. Although hundreds of genes have been reported to be associated with nonsyndromic hearing loss, GJB2, SLC26A4, and mtDNA12SrRNA are the major contributors. However, the mutation spectrum of these common deafness genes varies among different ethnic groups. The present work summarized mutations in these three genes and their prevalence in 339 patients with nonsyndromic hearing loss at three different special education schools and one children's hospital in Linyi, China. A new multiplex genetic screening system “SNPscan assay” was employed to detect a total of 115 mutations of the above three genes. Finally, 48.67% of the patients were identified with hereditary hearing loss caused by mutations in GJB2, SLC26A4, and mtDNA12SrRNA. The carrying rate of mutations in the three genes was 37.76%, 19.75%, and 4.72%, respectively. This mutation profile in our study is distinct from other parts of China, with high mutation rate of GJB2 suggesting a unique mutation spectrum in this area.
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Genetics of vestibular disorders: pathophysiological insights. J Neurol 2016; 263 Suppl 1:S45-53. [PMID: 27083884 PMCID: PMC4833787 DOI: 10.1007/s00415-015-7988-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 11/01/2015] [Accepted: 11/29/2015] [Indexed: 01/09/2023]
Abstract
The two most common vestibular disorders are motion sickness and vestibular migraine, affecting 30 and 1–2 % of the population respectively. Both are related to migraine and show a familial trend. Bilateral vestibular hypofunction is a rare condition, and some of patients also present cerebellar ataxia and neuropathy. We present recent advances in the genetics of vestibular disorders with familial aggregation. The clinical heterogeneity observed in different relatives of the same families suggests a variable penetrance and the interaction of several genes in each family. Some Mendelian sensorineural hearing loss also exhibits vestibular dysfunction, including DFNA9, DFNA11, DFNA15 and DFNA28. However, the most relevant finding during the past years is the familial clustering observed in Meniere’s disease. By using whole exome sequencing and combining bioinformatics tools, novel variants in DTNA and FAM136A genes have been identified in familial Meniere’s disease, and this genomic strategy will facilitate the discovery of the genetic basis of familial vestibular disorders.
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Pang X, Chai Y, He L, Chen P, Wang X, Li L, Jia H, Wu H, Yang T. A 7666-bp genomic deletion is frequent in Chinese Han deaf patients with non-syndromic enlarged vestibular aqueduct but without bi-allelic SLC26A4 mutations. Int J Pediatr Otorhinolaryngol 2015; 79:2248-52. [PMID: 26549381 DOI: 10.1016/j.ijporl.2015.10.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 10/12/2015] [Accepted: 10/13/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To investigate the genetic cause of the patients with non-syndromic enlarged vestibular aqueduct (EVA) but without bi-allelic SLC26A4 mutations. METHODS Presence of a homozygous genomic deletion was detected in a Chinese Han deaf patient (D1467-1) who failed to amplify the first three exons of SLC26A4. The breakpoints of the deletion were fine-mapped and revealed by PCR amplification and sequencing. This deletion was subsequently screened in 22 Chinese Han EVA probands with mono-allelic SLC26A4 mutations. The possible founder effect of the newly identified genomic deletion was evaluated by haplotype analysis. RESULTS A homozygous c.-2071_307+3801del7666 deletion of SLC26A4 was identified in patient D1467-1. This novel genomic deletion was subsequently identified in 18% (4/22) of the Chinese Han EVA probands with mono-allelic SLC26A4 mutations. Haplotype analysis showed that this genomic deletion is likely a founder mutation in Chinese Hans. CONCLUSION Our results suggested that the cryptic c.-2071_307+3801del7666 deletion of SLC26A4 is relatively frequent in Chinese Han non-syndromic EVA patients without bi-allelic SLC26A4 mutations. Screening of this genomic deletion should be incorporated into the routine DNA testing of SLC26A4 in Chinese Hans.
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Affiliation(s)
- Xiuhong Pang
- Department of Otorhinolaryngology-Head and Neck Surgery, Taizhou People's Hospital, Jiangsu Province, China; Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Yongchuan Chai
- Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital of Soochow University, Suzhou, China; Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Longxia He
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Penghui Chen
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Xiaowen Wang
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Lei Li
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Huan Jia
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Hao Wu
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
| | - Tao Yang
- Department of Otolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
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Jiang Y, Huang S, Deng T, Wu L, Chen J, Kang D, Xu X, Li R, Han D, Dai P. Mutation Spectrum of Common Deafness-Causing Genes in Patients with Non-Syndromic Deafness in the Xiamen Area, China. PLoS One 2015; 10:e0135088. [PMID: 26252218 PMCID: PMC4529078 DOI: 10.1371/journal.pone.0135088] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/16/2015] [Indexed: 11/19/2022] Open
Abstract
In China, approximately 30,000 babies are born with hearing impairment each year. However, the molecular factors causing congenital hearing impairment in the Xiamen area of Fujian province have not been evaluated. To provide accurate genetic testing and counseling in the Xiamen area, we investigated the molecular etiology of non-syndromic deafness in a deaf population from Xiamen. Unrelated students with hearing impairment (n = 155) who attended Xiamen Special Education School in Fujian Province were recruited for this study. Three common deafness-related genes, GJB2, SLC26A4, and mtDNA12SrRNA, were analyzed using all-exon sequencing. GJB2 mutations were detected in 27.1% (42/155) of the entire cohort. The non-syndromic hearing loss (NSHL) hotspot mutations c.109G>A (p.V37I) and c.235delC were found in this population, whereas the Caucasian hotspot mutation c.35delG was not. The allelic frequency of the c.109G>A mutation was 9.03% (28/310), slightly higher than that of c.235delC (8.39%, 26/310), which is the most common GJB2 mutation in most areas of China. The allelic frequency of the c.109G>A mutation was significantly higher in this Xiamen's deaf population than that in previously reported cohorts (P = 0.00). The SLC26A4 mutations were found in 16.77% (26/155) of this cohort. The most common pathogenic allele was c.IVS7-2A>G (6.13%, 19/310), and the second most common was the c.1079C>T (p.A360V) mutation (1.94%, 6/310) which has rarely been reported as a hotspot mutation in other studies. The mutation rate of mtDNA12SrRNA in this group was 3.87% (6/155), all being the m.A1555G mutation. These findings show the specificity of the common deaf gene-mutation spectrum in this area. According to this study, there were specific hotspot mutations in Xiamen deaf patients. Comprehensive sequencing analysis of the three common deaf genes can help portray the mutation spectrum and develop optimal testing strategies for deaf patients in this area.
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Affiliation(s)
- Yi Jiang
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
- Fujian Medical University ShengLi clinical college, Fujian Provincial Hospital, Fuzhou, P. R. China
| | - Shasha Huang
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
| | - Tao Deng
- Beijing Capital Bio Independent Clinical Laboratory, Beijing, P. R. China
| | - Lihua Wu
- Fujian Medical University ShengLi clinical college, Fujian Provincial Hospital, Fuzhou, P. R. China
| | - Juan Chen
- Fujian Medical University ShengLi clinical college, Fujian Provincial Hospital, Fuzhou, P. R. China
| | - Dongyang Kang
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
| | - Xiufeng Xu
- Beijing Capital Bio Independent Clinical Laboratory, Beijing, P. R. China
| | - Ruiyu Li
- Fujian Medical University ShengLi clinical college, Fujian Provincial Hospital, Fuzhou, P. R. China
- * E-mail: (PD); (DYH); (RYL)
| | - Dongyi Han
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
- * E-mail: (PD); (DYH); (RYL)
| | - Pu Dai
- Department of Otolaryngology, Head and Neck Surgery, PLA General Hospital, Beijing, P. R. China
- * E-mail: (PD); (DYH); (RYL)
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Li H, Wang B, Liu D, Wang T, Li Q, Wang W, Li H. SNPscan as a high-performance screening tool for mutation hotspots of hearing loss-associated genes. Genomics 2015; 106:83-7. [DOI: 10.1016/j.ygeno.2015.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 05/15/2015] [Accepted: 05/17/2015] [Indexed: 11/16/2022]
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Dai ZY, Sun BC, Huang SS, Yuan YY, Zhu YH, Su Y, Dai P. Correlation analysis of phenotype and genotype of GJB2 in patients with non-syndromic hearing loss in China. Gene 2015; 570:272-6. [PMID: 26095810 DOI: 10.1016/j.gene.2015.06.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 06/11/2015] [Accepted: 06/12/2015] [Indexed: 11/18/2022]
Abstract
BACKGROUND Disease-associated mutations in GJB2 gene are one of the major reasons that can cause non-syndromic sensorineural hearing loss (NSHL). GJB2 gene deafness has various clinical phenotypes. This study aims to analyze characteristics and relationships of clinical phenotypes through analyzing 1481 NSHL cases and 190 GJB2 deafness patients (with dual gene mutations). PATIENTS AND METHODS All the patients diagnosed as deaf disease molecular diagnostics were obtained from the people's liberation army general hospital from March 2007 to March 2011. The accession number of GJB2 was NM_004004 in GenBank, and sequence alignment and annotation were performed using GeneTool software. RESULTS In NSHL patients, mutated allele frequency in GJB2 was 20.57%, and the preponderant type was c.235delC (11.84%) followed by c.109G>A (3.75%). Mutation rate of double allelic gene was 16.18%, including 8.43% of homozygous mutation rate and 7.75% of recombination heterozygosis mutation. Moreover, auditory threshold of GJB2 biallelic marker was associated with ages of onset, while no significant correlation was detected with disease time and whether the inner ear malformation. Similar clinical phenotype could be detected between patients with c.109G>A dual gene mutation and dual gene mutation. However, in the aspect of hearing impairment, the phenomenon of pathopoiesia caused by mutation of c.109G>A was poorer than the other mutations, and even near those patients without pathogenic mutations. CONCLUSION Our study further shows the definite relationship of clinical phenotype and genotype in GJB2 gene correlated deafness, and these results can provide basis for revealing pathogenesis, gene diagnosis and consult of deafness. The level of evidence in the study is level 4 (case series).
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Affiliation(s)
- Zhi-Yao Dai
- Department of Otolaryngology, The First Affiliated Hospital of PLA General Hospital, Beijing 100048, China
| | - Bao-Chun Sun
- Department of Otolaryngology, The First Affiliated Hospital of PLA General Hospital, Beijing 100048, China
| | - Sha-Sha Huang
- Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China
| | - Yong-Yi Yuan
- Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China
| | - Yu-Hua Zhu
- Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China
| | - Yu Su
- Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China
| | - Pu Dai
- Department of Otolaryngology, Head & Neck Surgery, Chinese PLA General Hospital, Beijing 100853, China.
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Government-funded universal newborn hearing screening and genetic analyses of deafness predisposing genes in Taiwan. Int J Pediatr Otorhinolaryngol 2015; 79:584-90. [PMID: 25724631 DOI: 10.1016/j.ijporl.2015.01.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/09/2015] [Accepted: 01/31/2015] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the association of eight connexin genes (GJB2, GJB4, GJA1P1, GJB6, GJB3, GJA1, GJB1, and GJC3) and the SLC26A4 gene with congenital hearing impairment among infants in a universal newborn hearing screening program. METHOD From September 2009 to October 2013, the consecutive neonates born in all six branches of Taipei City Hospital were enrolled. Infants who failed the newborn hearing screening and were diagnosed with hearing impairment underwent the genetic analyses. RESULT 15,404 neonates were born at Taipei City Hospital, and 15,345 neonates underwent newborn hearing screening. Among them, 32 infants were diagnosed with unilateral or bilateral hearing impairment. 26 of them underwent analyses of the connexin genes and the SLC26A4 gene. Of the connexin genes, two infants carried a GJB3 mutation (heterozygous c.580G>A and heterozygous c.520G>A, respectively). Only one infant carried a GJB2 mutation (homozygous c.235delC). One infant carried a GJA1P1 mutation (heterozygous c.929delC) and another carried a GJB4 mutation (heterozygous c.302G>A). Additionally, one infant carried a GJA1P1 novel variant (heterozygous c.1081C>T). Another infant carried a GJA1 novel variant (heterozygous c.1-33C>G). Of the SLC26A4 gene, one infant carried heterozygous c.919-2A>G mutation and a novel variant (heterozygous c.164+1G>C), and high-resolution computed tomography (HRCT) of the temporal bone revealed bilateral enlarged vestibular aqueducts. One infant carried heterozygous c.919-2A>G mutation and no inner ear anomalies were demonstrated by HRCT of the temporal bone. Another infant carried a novel variant (heterozygous c.818C>T). CONCLUSION These results provide a genetic profile of the connexin genes and SLC26A4 gene among infants with hearing impairment detected by a universal newborn hearing screening program in Taiwan. Further studies and long-term follow up of this cohort are warranted to determine the pathogenicity of each variants and the long-term hearing consequence.
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Pique LM, Brennan ML, Davidson CJ, Schaefer F, Greinwald J, Schrijver I. Mutation analysis of the SLC26A4, FOXI1 and KCNJ10 genes in individuals with congenital hearing loss. PeerJ 2014; 2:e384. [PMID: 24860705 PMCID: PMC4017815 DOI: 10.7717/peerj.384] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 04/25/2014] [Indexed: 01/05/2023] Open
Abstract
Pendred syndrome (PDS) and DFNB4 comprise a phenotypic spectrum of sensorineural hearing loss disorders that typically result from biallelic mutations of the SLC26A4 gene. Although PDS and DFNB4 are recessively inherited, sequencing of the coding regions and splice sites of SLC26A4 in individuals suspected to be affected with these conditions often fails to identify two mutations. We investigated the potential contribution of large SLC26A4 deletions and duplications to sensorineural hearing loss (SNHL) by screening 107 probands with one known SLC26A4 mutation by Multiplex Ligation-dependent Probe Amplification (MLPA). A heterozygous deletion, spanning exons 4-6, was detected in only one individual, accounting for approximately 1% of the missing mutations in our cohort. This low frequency is consistent with previously published MLPA results. We also examined the potential involvement of digenic inheritance in PDS/DFNB4 by sequencing the coding regions of FOXI1 and KCNJ10. Of the 29 probands who were sequenced, three carried nonsynonymous variants including one novel sequence change in FOXI1 and two polymorphisms in KCNJ10. We performed a review of prior studies and, in conjunction with our current data, conclude that the frequency of FOXI1 (1.4%) and KCNJ10 (3.6%) variants in PDS/DFNB4 individuals is low. Our results, in combination with previously published reports, indicate that large SLC26A4 deletions and duplications as well as mutations of FOXI1 and KCNJ10 play limited roles in the pathogenesis of SNHL and suggest that other genetic factors likely contribute to the phenotype.
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Affiliation(s)
- Lynn M Pique
- Department of Pathology, Stanford University Medical Center , Stanford, CA , USA
| | - Marie-Luise Brennan
- Department of Pediatrics, Stanford University Medical Center , Stanford, CA , USA
| | | | - Frederick Schaefer
- Molecular Genetics, Center for Genetic Testing at Saint Francis Hospital , Tulsa, OK , USA
| | - John Greinwald
- Divisions of Human Genetics and Otolaryngology, Cincinnati Children's Hospital Medical Center , Cincinnati, OH , USA
| | - Iris Schrijver
- Department of Pathology, Stanford University Medical Center , Stanford, CA , USA ; Department of Pediatrics, Stanford University Medical Center , Stanford, CA , USA
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Song MH, Shin JW, Park HJ, Lee KA, Kim Y, Kim UK, Jeon JH, Choi JY. Intrafamilial phenotypic variability in families with biallelic SLC26A4 mutations. Laryngoscope 2013; 124:E194-202. [PMID: 24338212 DOI: 10.1002/lary.24504] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 09/26/2013] [Accepted: 10/30/2013] [Indexed: 11/05/2022]
Abstract
OBJECTIVES/HYPOTHESIS Enlarged vestibular aqueduct (EVA) and hearing loss are known to be caused by SLC26A4 mutations, but large phenotypic variability exists among patients with biallelic SLC26A4 mutations. Intrafamilial phenotypic variability was analyzed in multiplex EVA families carrying biallelic SLC26A4 mutations to identify the contribution of SLC26A4 mutations and other genetic or environmental factors influencing the clinical manifestations. STUDY DESIGN Retrospective case series. METHODS Eleven multiplex Korean families with EVA and hearing loss that carry biallelic mutations of the SLC26A4 gene were included. Genetic analysis for SLC26A4 and other genes including FOXI1, FOXI1-DBD, and KCNJ10 was performed. The auditory and other phenotypes were compared among siblings with the same SLC26A4 mutations. RESULTS The difference in the auditory phenotypes was identified between siblings in approximately half of the EVA families. Families with SLC26A4 mutations other than H723R homozygous mutations demonstrated more phenotypic variability, especially in those carrying IVS7-2A>G splice site mutation. Cochlear malformation was a consistent finding among siblings with the same SLC26A4 mutations. No mutation was identified in the FOXI1, FOXI1-DBD, and KCNJ10 genes in the tested families. CONCLUSIONS The possibility of variability concerning auditory phenotype should be considered even within family members carrying the same SLC26A4 mutations when providing genetic counseling to multiplex EVA families. Mutations in the currently known genes associated with EVA other than SLC26A4 were not found to be responsible for the intrafamilial phenotypic variability. Modifier genes or environmental factors other than the currently known genes seem to play a role in the phenotypic expressions of EVA patients.
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Affiliation(s)
- Mee Hyun Song
- Department of Otorhinolaryngology, Kwandong University College of Medicine, Myongji Hospital, Goyang, South Korea
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Huang CJ, Lei TH, Chang WL, Tu TY, Shiao AS, Chiu CY, Jap TS. A Novel mutation in the SLC26A4 gene in a Chinese family with Pendred syndrome. Int J Pediatr Otorhinolaryngol 2013; 77:1495-9. [PMID: 23838540 DOI: 10.1016/j.ijporl.2013.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/15/2013] [Accepted: 06/18/2013] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To investigate the mutations in the SLC26A4 gene in a Chinese patient with Pendred syndrome. METHODS The diagnosis of Pendred syndrome was confirmed by the family history, pure tone audiogram, perchlorate discharge test (PDT), and computed tomography (CT) of the temporal bone. DNA extraction, PCR and DNA sequencing were performed according to standard procedures. Mutations in the SLC26A4 gene were compared with 100 unrelated subjects to exclude common polymorphism. Splice-site mutation was further confirmed by restriction enzyme length polymorphism (RFLP) with the specifically designed primers. RESULTS The proband presented with typical features of bilateral sensorineural deafness since childhood and goiter development in the early adulthood. Thyroid studies disclosed euthyroidism with elevated thyroglobulin, but negative for PDT. Marked enlargement of bilateral vestibular aqueduct (>1.5 mm) was found by CT of the temporal bone. A novel SLC26A4 splice-site mutation c.1263+1G>A (IVS10+1G>A) was identified in compound heterozygosity with the missense mutation c.1079C>T (p.A360V) in the proband. Both mutations were not found in the 100 unrelated Chinese. CONCLUSIONS Our results support previous findings that Pendred syndrome can be caused by compound heterozygous mutation in the SLC26A4 gene, in which IVS10+1G>A is a novel pathogenic mutation.
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MESH Headings
- Asian People/genetics
- Case-Control Studies
- China
- DNA Mutational Analysis
- Female
- Genetic Predisposition to Disease
- Goiter, Nodular/diagnosis
- Goiter, Nodular/ethnology
- Goiter, Nodular/genetics
- Hearing Loss, Sensorineural/diagnosis
- Hearing Loss, Sensorineural/ethnology
- Hearing Loss, Sensorineural/genetics
- Heterozygote
- Humans
- Male
- Membrane Transport Proteins/genetics
- Mutation, Missense/genetics
- Pedigree
- Perchlorates
- Polymorphism, Genetic
- Polymorphism, Restriction Fragment Length
- Reference Values
- Sequence Analysis, DNA
- Sulfate Transporters
- Tomography, X-Ray Computed
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Affiliation(s)
- Chun-Jui Huang
- Division of Endocrinology & Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
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Yao G, Li S, Chen D, Wang H, Zhang J, Feng Z, Guo L, Yang Z, Yang S, Sun C, Zhang X, Ma D. Compound heterozygous mutations of SLC26A4 in 4 Chinese families with enlarged vestibular aqueduct. Int J Pediatr Otorhinolaryngol 2013; 77:544-9. [PMID: 23385134 DOI: 10.1016/j.ijporl.2013.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 01/04/2013] [Accepted: 01/05/2013] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Enlarged vestibular aqueduct is the most common inner ear malformation in individuals with sensorineural hearing loss. Mutations in SLC26A4 can cause non-syndromic EVA. To date, more than 170 SLC26A4 mutations have been described. The aim of the present study was to detect and report genetic causes of four unrelated Chinese families with hearing loss. METHODS We evaluated 4 families presenting bilateral enlarged vestibular aqueducts and describe the clinical and molecular characteristics of 5 patients. RESULTS The SLC26A4 gene was sequenced in 23 members of these 4 Chinese families with EVA, and the patients were found to carry 4 compound heterozygous mutations, p.G197R and p.S391R, IVS7-2A>G, p.I188T and c.1746 del G, p.V659L and p.T410M, and p.T94I and p.G197R, none of which have been reported previously. CONCLUSIONS These results emphasize the necessity of considering the complete DNA sequencing of the SLC26A4 gene in molecular diagnosis of deafness, especially when phenotypes such as congenital, invariable, and progressive hearing loss with EVA are present.
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Affiliation(s)
- Gendong Yao
- Central Hospital of Handan, 056001 Hebei, China.
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Wei X, Sun Y, Xie J, Shi Q, Qu N, Yang G, Cai J, Yang Y, Liang Y, Wang W, Yi X. Next-generation sequencing identifies a novel compound heterozygous mutation in MYO7A in a Chinese patient with Usher Syndrome 1B. Clin Chim Acta 2012; 413:1866-71. [PMID: 22898263 DOI: 10.1016/j.cca.2012.07.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 07/27/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Targeted enrichment and next-generation sequencing (NGS) have been employed for detection of genetic diseases. The purpose of this study was to validate the accuracy and sensitivity of our method for comprehensive mutation detection of hereditary hearing loss, and identify inherited mutations involved in human deafness accurately and economically. METHODS To make genetic diagnosis of hereditary hearing loss simple and timesaving, we designed a 0.60 MB array-based chip containing 69 nuclear genes and mitochondrial genome responsible for human deafness and conducted NGS toward ten patients with five known mutations and a Chinese family with hearing loss (never genetically investigated). RESULTS Ten patients with five known mutations were sequenced using next-generation sequencing to validate the sensitivity of the method. We identified four known mutations in two nuclear deafness causing genes (GJB2 and SLC26A4), one in mitochondrial DNA. We then performed this method to analyze the variants in a Chinese family with hearing loss and identified compound heterozygosity for two novel mutations in gene MYO7A. CONCLUSIONS The compound heterozygosity identified in gene MYO7A causes Usher Syndrome 1B with severe phenotypes. The results support that the combination of enrichment of targeted genes and next-generation sequencing is a valuable molecular diagnostic tool for hereditary deafness and suitable for clinical application.
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Chen K, Wang X, Sun L, Jiang H. Screening of SLC26A4, FOXI1, KCNJ10, and GJB2 in bilateral deafness patients with inner ear malformation. Otolaryngol Head Neck Surg 2012; 146:972-8. [PMID: 22412181 DOI: 10.1177/0194599812439670] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Bilateral nonsyndromic sensorineural hearing loss associated with inner ear malformation is closely related to genetics. SLC26A4 is considered to be the major involved gene. Recently, FOXI1 and KCNJ10 mutations have been linked to enlarged vestibular aqueducts and GJB2 mutations linked to temporal bone malformation. The authors aimed to investigate the mutation spectrums of these genes in Chinese patients with bilateral hearing impairment associated with inner ear malformation. STUDY DESIGN Cross-sectional study. SETTING Affiliated hospital of the university. SUBJECTS AND METHODS The authors analyzed the GJB2, SLC26A4, FOXI1, and KCNJ10 gene sequences in 43 patients presenting with bilateral hearing impairment associated with inner ear malformation using pyrosequencing and direct DNA sequencing. RESULTS In total, 74.4% (32/43) of patients carried at least 1 of 14 pathogenic SLC26A4 mutations, including 6 novel mutations and 4 polymorphisms. Patients with enlarged vestibular aqueducts had a higher rate of SLC26A4 mutation than Mondini dysplasia patients. No FOXI1 or KCNJ10 potential pathogenic mutation was present, and GJB2 biallelic pathogenic mutations were uncommon (2.3%; 1/43). No significant correlation was observed between the genotype and phenotype of SLC26A4 mutations. CONCLUSION SLC26A4 accounts for 74.4% of inner ear malformations in our cohort, whereas FOXI1, KCNJ10, and GJB2 mutations are not common. Other possible genes or external factors may contribute to this multibranch abnormality.
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Affiliation(s)
- Kaitian Chen
- Department of Otorhinolaryngology, the First Affiliated Hospital, Sun Yat-Sen University and Institute of Otorhinolaryngology, Sun Yat-sen University, Guangzhou, PR China
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Genetic diagnosis and cochlear implantation for patients with nonsyndromic hearing loss and enlarged vestibular aqueduct. The Journal of Laryngology & Otology 2012; 126:349-55. [DOI: 10.1017/s002221511100346x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractObjective:To review the genotype and cochlear implantation outcome of patients with nonsyndromic hearing loss and enlarged vestibular aqueduct.Methods:Twenty-one Chinese children with nonsyndromic hearing loss and enlarged vestibular aqueduct underwent genetic examination. A DNA microarray was used to screen for the IVS7-2A>G and H723R mutations. Any DNA samples with one or none of the two mutant alleles were sequenced to detect other mutations in the SLC26A4 and FOXI1 genes.Results:Twelve SLC26A4 mutations were detected, including three novel mutations. The most common mutations detected were IVS7-2A>G and H723R. Twelve patients received cochlear implants, and subsequently demonstrated excellent speech perception.Conclusion:Three novel mutations were detected in Chinese patients with nonsyndromic hearing loss and enlarged vestibular aqueduct. The SLC26A4 mutation spectrum in the Chinese population is similar to that in other East Asian populations. Cochlear implantation is a safe and effective treatment in patients with enlarged vestibular aqueduct.
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Huang S, Han D, Yuan Y, Wang G, Kang D, Zhang X, Yan X, Meng X, Dong M, Dai P. Extremely discrepant mutation spectrum of SLC26A4 between Chinese patients with isolated Mondini deformity and enlarged vestibular aqueduct. J Transl Med 2011; 9:167. [PMID: 21961810 PMCID: PMC3204245 DOI: 10.1186/1479-5876-9-167] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 09/30/2011] [Indexed: 11/16/2022] Open
Abstract
Background Mutations in SLC26A4 cause Pendred syndrome (hearing loss with goiter) or DFNB4 (non-syndromic hearing loss with inner ear malformation, such as enlarged vestibular aqueduct or Mondini deformity). The relationship between mutations in SLC26A4 and Mondini deformity without enlarged vestibular aqueduct has not been studied in any Chinese deaf population. The purpose of this study was to assess whether mutations in the SLC26A4 gene cause Mondini deformity without an enlarged vestibular aqueduct (isolated Mondini deformity) in a Chinese population. Methods In total, 144 patients with sensorineural hearing loss were included and subjected to high-resolution temporal bone CT. Among them, 28 patients with isolated Mondini dysplasia (MD group), 50 patients with enlarged vestibular aqueduct with Mondini dysplasia (EVA with MD group), 50 patients with enlarged vestibular aqueduct without Mondini dysplasia (EVA group), and 16 patients with other types of inner ear malformations (IEM group) were identified. The coding exons of SLC26A4 were analyzed in all subjects. Results DNA sequence analysis of SLC26A4 was performed in all 144 patients. In the different groups, the detection rate of the SLC26A4 mutation differed. In the isolated MD group, only one single allelic mutation in SLC26A4 was found in one patient (1/28, 3.6%). In the EVA with MD group, biallelic and monoallelic SLC26A4 mutations were identified in 46 patients (46/50, 92.0%) and three patients (3/50, 6.0%), respectively. Also, in the EVA group, biallelic and monoallelic SLC26A4 mutations were identified in 46 patients (46/50, 92.0%) and three patients (3/50, 6.0%), respectively. These percentages were identical to those in the EVA plus MD group. Only two patients carried monoallelic mutations of the SLC26A4 gene in the IEM group (2/16, 12.5%). There were significant differences in the frequency of SLC26A4 mutation among the groups (P < 0.001). The detection rate of SLC26A4 mutation in the isolated MD group was significantly lower than in the EVA group (with or without MD; P < 0.001), and there was no significant difference in the detection rate of SLC26A4 between the MD group and IEM group (P > 0.5). Conclusion Although mutations in the SLC26A4 gene were frequently found in Chinese EVA patients with and without MD, there was no evidence to show a relationship between isolated MD and the SLC26A4 gene in the Chinese population examined. Hearing impairment in patients with isolated MD may be caused by factors other than mutations in the SLC26A4 gene.
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Affiliation(s)
- Shasha Huang
- Department of Otolaryngology, PLA General Hospital, Beijing, People's Republic of China
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Ji YB, Han DY, Lan L, Wang DY, Zong L, Zhao FF, Liu Q, Benedict-Alderfer C, Zheng QY, Wang QJ. Molecular epidemiological analysis of mitochondrial DNA12SrRNA A1555G, GJB2, and SLC26A4 mutations in sporadic outpatients with nonsyndromic sensorineural hearing loss in China. Acta Otolaryngol 2011; 131:124-9. [PMID: 21162657 DOI: 10.3109/00016489.2010.483479] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION GJB2 mutation was frequent in sporadic outpatients and its mutation frequency was significant higher in the prelingual group than in the postlingual group, whereas the mutation of mtDNA A1555G and SLC26A4 was very rare in Chinese sporadic outpatients with nonsyndromic sensorineural hearing loss (NSHL). Standard and comprehensive inclusion and grouping criteria are necessary for epidemiological studies of deafness-related gene mutations. OBJECTIVES This study aimed to examine the mutations of the three common deafness genes GJB2, SLC26A4, and mtDNA A1555G in Chinese sporadic outpatients with NSHL and to discuss the factors that influence the detection accuracy of mutation frequencies. METHODS A total of 473 sporadic NSHL patients without any type of inner ear malformation, including both prelingual and postlingual groups were enrolled in this study. Three genes of mtDNA A1555G, GJB2, and SLC26A4 were screened for mutation in our study cohort. A chi-square test was performed to compare mutation frequencies between prelingual and postlingual groups. RESULTS The mutation frequencies of MtDNA A1555G, GJB2, and SLC26A4 were 1.63%, 13.63%, and 0%, respectively, in our study cohort. The mutational hot spot of GJB2 was c.235delC, whose allele frequency was 12.68% in sporadic outpatients. Mutation frequency of GJB2 in the prelingual group was significantly higher than in the postlingual group (p < 0.05).
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Affiliation(s)
- Yu-bin Ji
- Department of Otolaryngology/Head and Neck Surgery, Chinese PLA Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China
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Mahdieh N, Rabbani B, Wiley S, Akbari MT, Zeinali S. Genetic causes of nonsyndromic hearing loss in Iran in comparison with other populations. J Hum Genet 2010; 55:639-48. [PMID: 20739942 DOI: 10.1038/jhg.2010.96] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Identification of two novel mutations, c.232T>C and c.2006A>T, in SLC26A4 in a Chinese family associated with enlarged vestibular aqueduct. Int J Pediatr Otorhinolaryngol 2010; 74:831-5. [PMID: 20483489 DOI: 10.1016/j.ijporl.2010.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2010] [Revised: 04/04/2010] [Accepted: 04/10/2010] [Indexed: 11/22/2022]
Abstract
It is known that enlarged vestibular aqueduct syndrome is closely related to the SLC26A4 mutation. Up to date, more than 200 of SLC26A4 mutations have been described, and novel mutations are being continually identified in different countries and ethnic groups. In this study, two novel variations were identified in a Chinese family associated with enlarged vestibular aqueduct. The two novel substitutions, c.232T>C and c.2006A>T, were detected in exon 3 and exon 17 of the pendrin encoding gene, respectively. The T/C transversion at 232 nucleotide caused p.Y78H mutation while the A/T transversion at 2006 nucleotide caused p.D669V mutation.
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Choi BY, Stewart AK, Nishimura KK, Cha WJ, Seong MW, Park SS, Kim SW, Chun YS, Chung JW, Park SN, Chang SO, Kim CS, Alper SL, Griffith AJ, Oh SH. Efficient molecular genetic diagnosis of enlarged vestibular aqueducts in East Asians. Genet Test Mol Biomarkers 2010; 13:679-87. [PMID: 19645628 DOI: 10.1089/gtmb.2009.0054] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
CONTEXT Enlargement of the vestibular aqueduct (EVA) is a commonly detected inner ear anomaly related to hearing loss and often associated with mutations of SLC26A4 encoding pendrin, a transmembrane exchanger of Cl(-), I(-), and HCO(3)(-). Here we describe the phenotypes of 27 Korean EVA subjects and their SLC26A4 genotypes determined by bidirectional nucleotide sequencing. RESULTS The detected variants include two novel missense substitutions (p.V138L and p.P542R). We characterized the ability of p.V138L and p.P542R pendrin products to traffic to the plasma membrane in COS-7 cells and to transport Cl(-), I(-), and HCO(3)(-) in Xenopus oocytes. The results indicate that p.P542R is a benign polymorphic variant, whereas p.V138L is a pathogenic mutation. Since this and other studies of East Asian EVA cohorts show that the majority of SLC26A4 mutations affect either or both of two amplicons (exons 7-8 and 19), we developed a hierarchical protocol that integrates direct sequencing with denaturing high-performance liquid chromatography analyses for detection of SLC26A4 mutations in these populations. We validated the cost efficiency of the integrated protocol by a simulated screen of published East Asian EVA cohorts with known SLC26A4 genotypes. CONCLUSIONS Our study further defines the spectrum of SLC26A4 mutations among East Asians and demonstrates a rapid and efficient protocol for their detection.
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Affiliation(s)
- Byung Yoon Choi
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul, Korea
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Reyes S, Wang G, Ouyang X, Han B, Du LL, Yuan HJ, Yan D, Dai P, Liu XZ. Mutation analysis of SLC26A4 in mainland Chinese patients with enlarged vestibular aqueduct. Otolaryngol Head Neck Surg 2009; 141:502-8. [PMID: 19786220 DOI: 10.1016/j.otohns.2009.07.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 07/07/2009] [Accepted: 07/09/2009] [Indexed: 11/28/2022]
Abstract
OBJECTIVE We have characterized the spectrum of SLC26A4 mutations and clinical features in a population of mainland Chinese patients with nonsyndromic sensorineural hearing loss (SNHL) and enlarged vestibular aqueduct (EVA). STUDY DESIGN Cross-sectional clinical genetic study. SETTING Tertiary care outpatient otolaryngology clinic. METHODS A total of 32 subjects identified with bilateral EVA using high-resolution CT were screened for mutations in SLC26A4 by denaturing high-performance liquid chromatography and direct sequencing methods. RESULTS A total of 13 different mutations were identified in the SLC26A4 gene, five of which are novel. A total of 88 percent of the patients harbored biallelic mutations, 11 patients were homozygotes, and 17 were compound heterozygotes. Four patients were found to carry a single SLC26A4 mutation. The IVS7-2A>G mutation was the most frequent, accounting for 60 percent of the mutant alleles. We have not found any correlations between the type of SLC26A4 mutations and the type, degree, and progression of hearing loss. There are significant proportions of patients with asymmetric (26%), progressive (32%), or fluctuating hearing loss (21%). CONCLUSION Our data confirm the high prevalence of SLC26A4 mutations in Chinese patients with SNHL and EVA. We could not establish any relationship between genotype and phenotype. However, the high incidence of asymmetric, progressive, and fluctuating hearing loss found in the current study indicates that patients with those features should be routinely screened for SLC26A4 mutation in addition to diagnosis of EVA using CT or MRI.
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Affiliation(s)
- Samuel Reyes
- Department of Otolaryngology, University of Miami, Miami, FL 33136, USA
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Dai P, Stewart AK, Chebib F, Hsu A, Rozenfeld J, Huang D, Kang D, Lip V, Fang H, Shao H, Liu X, Yu F, Yuan H, Kenna M, Miller DT, Shen Y, Yang W, Zelikovic I, Platt OS, Han D, Alper SL, Wu BL. Distinct and novel SLC26A4/Pendrin mutations in Chinese and U.S. patients with nonsyndromic hearing loss. Physiol Genomics 2009; 38:281-90. [PMID: 19509082 DOI: 10.1152/physiolgenomics.00047.2009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mutations of the human SLC26A4/PDS gene constitute the most common cause of syndromic and nonsyndromic hearing loss. Definition of the SLC26A4 mutation spectrum among different populations with sensorineural hearing loss is important for development of optimal genetic screening services for congenital hearing impairment. We screened for SLC26A4 mutations among Chinese and U.S. subjects with hearing loss, using denaturing HPLC (DHPLC) and direct DNA sequencing. Fifty-two of 55 Chinese subjects with deafness accompanied by enlargement of the vestibular aqueduct (EVA) exhibited at least one mutant SLC26A4 allele, whereas SLC26A4 mutations were found in only 2 of 116 deaf Chinese patients without EVA. The spectrum of SLC26A4 mutations differed among Chinese and U.S. subjects and included 10 previously unreported SLC26A4 variants: 4 in the Chinese population (p.E303Q, p.X329, p.X467, p.X573) and 6 in the U.S. population (p.V250A, p.D266N, p.F354S, p.D697A, p.K715N, p.E737D). Among the seven novel in-frame missense mutations, five encoded SLC26A4 proteins with substantially reduced Cl(-)/anion exchange activity as expressed and measured in Xenopus oocytes, but four of these were sufficiently active to allow study of anion selectivity. The only mutant polypeptide exhibiting complete loss of anion exchange function, p.E303Q, was expressed at or near the oocyte surface at near-wild-type levels. Two variants, p.F354S and p.E737D, displayed selective reduction in relative rate of Cl(-)/HCO(3)(-) exchange compared with similarly measured rates of Cl(-)/Cl(-) and Cl(-)/I(-) exchange. Our data show that mutation analysis of the SLC26A4 gene is of high diagnostic yield among subjects with deafness and bilateral EVA in both China and the U.S. However, the pathogenicity of monoallelic SLC26A4 gene variants in patients with hearing loss remains unclear in many instances.
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Affiliation(s)
- Pu Dai
- Department of Otorhinolaryngology Head and Neck Surgery and Genetic Testing Center for Deafness, PLA General Hospital, Beijing, People's Republic of China
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Choi BY, Stewart AK, Madeo AC, Pryor SP, Lenhard S, Kittles R, Eisenman D, Kim HJ, Niparko J, Thomsen J, Arnos KS, Nance WE, King KA, Zalewski CK, Brewer CC, Shawker T, Reynolds JC, Butman JA, Karniski LP, Alper SL, Griffith AJ. Hypo-functional SLC26A4 variants associated with nonsyndromic hearing loss and enlargement of the vestibular aqueduct: genotype-phenotype correlation or coincidental polymorphisms? Hum Mutat 2009; 30:599-608. [PMID: 19204907 PMCID: PMC2663020 DOI: 10.1002/humu.20884] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Hearing loss with enlargement of the vestibular aqueduct (EVA) can be associated with mutations of the SLC26A4 gene encoding pendrin, a transmembrane Cl(-)/I(-)/HCO(3)(-) exchanger. Pendrin's critical transport substrates are thought to be I(-) in the thyroid gland and HCO(3)(-) in the inner ear. We previously reported that bi-allelic SLC26A4 mutations are associated with Pendred syndromic EVA whereas one or zero mutant alleles are associated with nonsyndromic EVA. One study proposed a correlation of nonsyndromic EVA with SLC26A4 alleles encoding pendrin with residual transport activity. Here we describe the phenotypes and SLC26A4 genotypes of 47 EVA patients ascertained since our first report of 39 patients. We sought to determine the pathogenic potential of each variant in our full cohort of 86 patients. We evaluated the trafficking of 11 missense pendrin products expressed in COS-7 cells. Products that targeted to the plasma membrane were expressed in Xenopus oocytes for measurement of anion exchange activity. p.F335L, p.C565Y, p.L597S, p.M775T, and p.R776C had Cl(-)/I(-) and Cl(-)/HCO(3)(-) exchange rate constants that ranged from 13 to 93% of wild type values. p.F335L, p.L597S, p.M775T and p.R776C are typically found as mono-allelic variants in nonsyndromic EVA. The high normal control carrier rate for p.L597S indicates it is a coincidentally detected nonpathogenic variant in this context. We observed moderate differential effects of hypo-functional variants upon exchange of HCO(3)(-) versus I(-) but their magnitude does not support a causal association with nonsyndromic EVA. However, these alleles could be pathogenic in trans configuration with a mutant allele in Pendred syndrome.
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Affiliation(s)
- Byung Yoon Choi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland 20850, USA
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Ouyang XM, Yan D, Yuan HJ, Pu D, Du LL, Han DY, Liu XZ. The genetic bases for non-syndromic hearing loss among Chinese. J Hum Genet 2009; 54:131-40. [PMID: 19197336 DOI: 10.1038/jhg.2009.4] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Deafness is an etiologically heterogeneous trait with many known genetic, environmental causes or a combination thereof. The identification of more than 120 independent genes for deafness has provided profound new insights into the pathophysiology of hearing. However, recent findings indicate that a large proportion of both syndromic and non-syndromic forms of deafness in the Chinese population are caused by defects in a small number of genes. Studies of the genetic epidemiology and molecular genetic features revealed that there is a clear relevance of genes causing deafness in Chinese deaf patients as well as a unique spectrum of common and rare deafness gene mutations in the Chinese population. This review is focused on the genetic aspects of non-syndromic and mitochondrial deafness, in which unique molecular genetic features of hearing impairment have been identified in the Chinese population. The current China population is approximately 1.3 billion. It is estimated that 30,000 infants are born with congenital sensorineural hearing loss each year. Better understanding of the genetic causes of deafness in the Chinese population is important for accurate genetics counseling and early diagnosis for timely intervention and treatment options.
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Affiliation(s)
- Xiao Mei Ouyang
- Department of Otolaryngology, University of Miami, Miami, FL 33136, USA
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Pera A, Villamar M, Viñuela A, Gandía M, Medà C, Moreno F, Hernández-Chico C. A mutational analysis of the SLC26A4 gene in Spanish hearing-impaired families provides new insights into the genetic causes of Pendred syndrome and DFNB4 hearing loss. Eur J Hum Genet 2008; 16:888-96. [PMID: 18285825 DOI: 10.1038/ejhg.2008.30] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Pendred syndrome (PS) and DFNB4, a non-syndromic sensorineural hearing loss with enlargement of the vestibular aqueduct (EVA), are caused by mutations in the SLC26A4 gene. Both disorders are recessive, and yet only one mutated SLC26A4 allele, or no mutations, are identified in many cases. Here we present the genetic characterization of 105 Spanish patients from 47 families with PS or non-syndromic EVA and 20 families with recessive non-syndromic hearing loss, which segregated with the DFNB4 locus. In this cohort, two causative SLC26A4 mutations could be characterized in 18 families (27%), whereas a single mutated allele was found in a patient with unilateral hearing loss and EVA in the same ear. In all, 24 different causative mutations were identified, including eight novel mutations. The novel p.Q514K variant was the most prevalent mutation in SLC26A4, accounting for 17% (6/36) of the mutated alleles identified in this study, deriving from a founder effect. We also characterized a novel multiexon 14 kb deletion spanning from intron 3 to intron 6 (g.8091T_22145Cdel). This study also revealed the first case of a de novo recessive mutation p.Q413P causing PS that arose in the proband's paternal allele, the maternal one carrying the p.L445W. The relevance of our results for genetic diagnosis of PS and non-syndromic EVA hearing loss is discussed.
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Affiliation(s)
- Alejandra Pera
- Unidad de Genética Molecular, Hospital Ramón y Cajal, Madrid, Spain
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Guo YF, Guo YF, Liu XW, Guan J, Han MK, Wang DY, Zhao YL, Rao SQ, Wang QJ. GJB2, SLC26A4 and mitochondrial DNA A1555G mutations in prelingual deafness in Northern Chinese subjects. Acta Otolaryngol 2008; 128:297-303. [PMID: 18274916 DOI: 10.1080/00016480701767382] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
CONCLUSION This genetic epidemiological study demonstrated that 26.65% of the prelingual deafness in Northern Chinese patients can be detected at younger ages by genetic testing of three common hearing loss genes (GJB2, SLC26A4 and mtDNA A1555G), and thus, early intervention measures could be undertaken to help them in language acquisition. OBJECTIVES The GJB2, SLC26A4 and mtDNA A1555G mutations are the prevalent causes of prelingual deafness worldwide. Numerous studies have revealed that the forms and frequencies of the mutations in the three genes are largely dependent on the ethnic or geographic origins. Hence, this study aimed to characterize the mutation profiles of the three genes in prelingual deafness in Northern Chinese patients. SUBECTS AND METHODS: An investigation of 514 patients with prelingual deafness and 117 controls with normal hearing was conducted. Bidirectional sequencing (or enzyme digestion) was applied to identify sequence variations. RESULTS This study revealed that 26.65% patients had two mutated alleles (homozygote or compound heterozygote) of GJB2 (9.14%) or SLC26A4 (8.95%) and/or an mtDNA A1555G (8.56%) mutation. In detail, 19.26% patients carried GJB2 mutations including 10.12% single mutant carriers. 235delC was the most common type, making up 69.18% of all mutants for GJB2. The mutant carrier rate for SLC26A4 was 15.2%, including 6.23% single mutant carriers. The two most common types (IVS7-2A > G and H723R) accounted for 51.61% and 33.06% mutations, respectively. Forty-five patients had mtDNA A1555G, giving a frequency of 8.75%. In the control group with normal hearing, 2.56%, 1.71% and 0% of the subjects carried a single mutant for GJB2, SLC26A4 and mtDNA A1555G, respectively.
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Lezirovitz K, Pardono E, de Mello Auricchio MTB, de Carvalho E Silva FL, Lopes JJ, Abreu-Silva RS, Romanos J, Batissoco AC, Mingroni-Netto RC. Unexpected genetic heterogeneity in a large consanguineous Brazilian pedigree presenting deafness. Eur J Hum Genet 2007; 16:89-96. [PMID: 17851452 DOI: 10.1038/sj.ejhg.5201917] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Nonsyndromic autosomal recessive deafness accounts for 80% of hereditary deafness. To date, 52 loci responsible for autosomal recessive deafness have been mapped and 24 genes identified. Here, we report a large inbred Brazilian pedigree with 26 subjects affected by prelingual deafness. Given the extensive consanguinity found in this pedigree, the most probable pattern of inheritance is autosomal recessive. However, our linkage and mutational analysis revealed, instead of an expected homozygous mutation in a single gene, two different mutant alleles and a possible third undetected mutant allele in the MYO15A gene (DFNB3 locus), as well as evidence for other causes for deafness in the same pedigree. Among the 26 affected subjects, 15 were homozygous for the novel c.10573delA mutation in the MYO15A gene, 5 were compound heterozygous for the mutation c.10573delA and the novel deletion c.9957_9960delTGAC and one inherited only a single c.10573delA mutant allele, while the other one could not be identified. Given the extensive consanguinity of the pedigree, there might be at least one more deafness locus segregating to explain the condition in some of the subjects whose deafness is not clearly associated with MYO15A mutations, although overlooked environmental causes could not be ruled out. Our findings illustrate a high level of etiological heterogeneity for deafness in the family and highlight some of the pitfalls of genetic analysis of large genes in extended pedigrees, when homozygosity for a single mutant allele is expected.
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Affiliation(s)
- Karina Lezirovitz
- Centro de Estudos do Genoma Humano, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
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