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Chattaraj P, Munjal T, Honda K, Rendtorff ND, Ratay JS, Muskett JA, Risso DS, Roux I, Gertz EM, Schäffer AA, Friedman TB, Morell RJ, Tranebjærg L, Griffith AJ. A common SLC26A4-linked haplotype underlying non-syndromic hearing loss with enlargement of the vestibular aqueduct. J Med Genet 2017; 54:665-673. [PMID: 28780564 PMCID: PMC5880640 DOI: 10.1136/jmedgenet-2017-104721] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/23/2017] [Accepted: 05/29/2017] [Indexed: 12/26/2022]
Abstract
BACKGROUND Enlargement of the vestibular aqueduct (EVA) is the most common radiological abnormality in children with sensorineural hearing loss. Mutations in coding regions and splice sites of the SLC26A4 gene are often detected in Caucasians with EVA. Approximately one-fourth of patients with EVA have two mutant alleles (M2), one-fourth have one mutant allele (M1) and one-half have no mutant alleles (M0). The M2 genotype is correlated with a more severe phenotype. METHODS We performed genotype-haplotype analysis and massively parallel sequencing of the SLC26A4 region in patients with M1 EVA and their families. RESULTS We identified a shared novel haplotype, termed CEVA (Caucasian EVA), composed of 12 uncommon variants upstream of SLC26A4. The presence of the CEVA haplotype on seven of ten 'mutation-negative' chromosomes in a National Institutes of Health M1 EVA discovery cohort and six of six mutation-negative chromosomes in a Danish M1 EVA replication cohort is higher than the observed prevalence of 28 of 1006 Caucasian control chromosomes (p<0.0001 for each EVA cohort). The corresponding heterozygous carrier rate is 28/503 (5.6%). The prevalence of CEVA (11 of 126) is also increased among M0 EVA chromosomes (p=0.0042). CONCLUSIONS The CEVA haplotype causally contributes to most cases of Caucasian M1 EVA and, possibly, some cases of M0 EVA. The CEVA haplotype of SLC26A4 defines the most common allele associated with hereditary hearing loss in Caucasians. The diagnostic yield and prognostic utility of sequence analysis of SLC26A4 exons and splice sites will be markedly increased by addition of testing for the CEVA haplotype.
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Affiliation(s)
- Parna Chattaraj
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), Bethesda, Maryland, USA
| | - Tina Munjal
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), Bethesda, Maryland, USA
| | - Keiji Honda
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), Bethesda, Maryland, USA
| | - Nanna D Rendtorff
- Institute of Clinical Medicine, University of Copenhagen, The Panum Institute, Copenhagen, Denmark
- Department of Otorhinolaryngology, Head & Neck Surgery and Audiology, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Genetics, Rigshospitalet/The Kennedy Center, Glostrup, Denmark
| | - Jessica S Ratay
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), Bethesda, Maryland, USA
| | - Julie A Muskett
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), Bethesda, Maryland, USA
| | - Davide S Risso
- Laboratory of Communication Disorders, NIDCD, Bethesda, Maryland, USA
| | - Isabelle Roux
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), Bethesda, Maryland, USA
| | - E Michael Gertz
- Computational Biology Branch, National Center for Biotechnology Information, Bethesda, Maryland, USA
| | - Alejandro A Schäffer
- Computational Biology Branch, National Center for Biotechnology Information, Bethesda, Maryland, USA
| | | | - Robert J Morell
- Genomics and Computational Biology Core, NIDCD, Bethesda, Maryland, USA
| | - Lisbeth Tranebjærg
- Institute of Clinical Medicine, University of Copenhagen, The Panum Institute, Copenhagen, Denmark
- Department of Otorhinolaryngology, Head & Neck Surgery and Audiology, Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Genetics, Rigshospitalet/The Kennedy Center, Glostrup, Denmark
| | - Andrew J Griffith
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders (NIDCD), Bethesda, Maryland, USA
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Rehman AU, Friedman TB, Griffith AJ. Unresolved questions regarding human hereditary deafness. Oral Dis 2017; 23:551-558. [PMID: 27259978 PMCID: PMC5136515 DOI: 10.1111/odi.12516] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 05/27/2016] [Accepted: 05/30/2016] [Indexed: 01/18/2023]
Abstract
Human hearing loss is a common neurosensory disorder about which many basic research and clinically relevant questions are unresolved. This review on hereditary deafness focuses on three examples considered at first glance to be uncomplicated, however, upon inspection, are enigmatic and ripe for future research efforts. The three examples of clinical and genetic complexities are drawn from studies of (i) Pendred syndrome/DFNB4 (PDS, OMIM 274600), (ii) Perrault syndrome (deafness and infertility) due to mutations of CLPP (PRTLS3, OMIM 614129), and (iii) the unexplained extensive clinical variability associated with TBC1D24 mutations. At present, it is unknown how different mutations of TBC1D24 cause non-syndromic deafness (DFNB86, OMIM 614617), epilepsy (OMIM 605021), epilepsy with deafness, or DOORS syndrome (OMIM 220500) that is characterized by deafness, onychodystrophy (alteration of toenail or fingernail morphology), osteodystrophy (defective development of bone), mental retardation, and seizures. A comprehensive understanding of the multifaceted roles of each gene associated with human deafness is expected to provide future opportunities for restoration as well as preservation of normal hearing.
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Affiliation(s)
- A U Rehman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - T B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - A J Griffith
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
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Ito T, Muskett J, Chattaraj P, Choi BY, Lee KY, Zalewski CK, King KA, Li X, Wangemann P, Shawker T, Brewer CC, Alper SL, Griffith AJ. SLC26A4 mutation testing for hearing loss associated with enlargement of the vestibular aqueduct. World J Otorhinolaryngol 2013; 3:26-34. [PMID: 25960948 PMCID: PMC4423814 DOI: 10.5319/wjo.v3.i2.26] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/05/2013] [Accepted: 06/13/2013] [Indexed: 02/06/2023] Open
Abstract
Pendred syndrome (PS) is characterized by autosomal recessive inheritance of goiter associated with a defect of iodide organification, hearing loss, enlargement of the vestibular aqueduct (EVA), and mutations of the SLC26A4 gene. However, not all EVA patients have PS or SLC26A4 mutations. Two mutant alleles of SLC26A4 are detected in 1/4 of North American or European EVA populations, one mutant allele is detected in another 1/4 of patient populations, and no mutations are detected in the other 1/2. The presence of two mutant alleles of SLC26A4 is associated with abnormal iodide organification, increased thyroid gland volume, increased severity of hearing loss, and bilateral EVA. The presence of a single mutant allele of SLC26A4 is associated with normal iodide organification, normal thyroid gland volume, less severe hearing loss and either bilateral or unilateral EVA. When other underlying correlations are accounted for, the presence of a cochlear malformation or the size of EVA does not have an effect on hearing thresholds. This is consistent with observations of an Slc26a4 mutant mouse model of EVA in which hearing loss is independent of endolymphatic hydrops or inner ear malformations. Segregation analyses of EVA in families suggest that the patients carrying one mutant allele of SLC26A4 have a second, undetected mutant allele of SLC26A4, and the probability of a sibling having EVA is consistent with its segregation as an autosomal recessive trait. Patients without any mutations are an etiologically heterogeneous group in which siblings have a lower probability of having EVA. SLC26A4 mutation testing can provide prognostic information to guide clinical surveillance and management, as well as the probability of EVA affecting a sibling.
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Ito T, Choi BY, King KA, Zalewski CK, Muskett J, Chattaraj P, Shawker T, Reynolds JC, Butman JA, Brewer CC, Wangemann P, Alper SL, Griffith AJ. SLC26A4 genotypes and phenotypes associated with enlargement of the vestibular aqueduct. Cell Physiol Biochem 2011; 28:545-52. [PMID: 22116369 DOI: 10.1159/000335119] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2011] [Indexed: 11/19/2022] Open
Abstract
Enlargement of the vestibular aqueduct (EVA) is the most common inner ear anomaly detected in ears of children with sensorineural hearing loss. Pendred syndrome (PS) is an autosomal recessive disorder characterized by bilateral sensorineural hearing loss with EVA and an iodine organification defect that can lead to thyroid goiter. Pendred syndrome is caused by mutations of the SLC26A4 gene. SLC26A4 mutations may also be identified in some patients with nonsyndromic EVA (NSEVA). The presence of two mutant alleles of SLC26A4 is correlated with bilateral EVA and Pendred syndrome, whereas unilateral EVA and NSEVA are correlated with one (M1) or zero (M0) mutant alleles of SLC26A4. Thyroid gland enlargement (goiter) appears to be primarily dependent on the presence of two mutant alleles of SLC26A4 in pediatric patients, but not in older patients. In M1 families, EVA may be associated with a second, undetected SLC26A4 mutation or epigenetic modifications. In M0 families, there is probably etiologic heterogeneity that includes causes other than, or in addition to, monogenic inheritance.
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Affiliation(s)
- Taku Ito
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland 20850-3320, USA
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Griffith AJ, Wangemann P. Hearing loss associated with enlargement of the vestibular aqueduct: mechanistic insights from clinical phenotypes, genotypes, and mouse models. Hear Res 2011; 281:11-7. [PMID: 21669267 PMCID: PMC3183377 DOI: 10.1016/j.heares.2011.05.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/05/2011] [Accepted: 05/06/2011] [Indexed: 02/08/2023]
Abstract
Enlargement of the vestibular aqueduct (EVA) is one of the most common inner ear malformations associated with sensorineural hearing loss in children. The delayed onset and progressive nature of this phenotype offer a window of opportunity to prevent or retard progression of hearing loss. EVA is not the direct cause of hearing loss in these patients, but rather is a radiologic marker for some underlying pathogenetic defect. Mutations of the SLC26A4 gene are a common cause of EVA. Studies of an Slc26a4 knockout mouse demonstrate that acidification and enlargement of the scala media are early events in the pathogenesis of deafness. The enlargement is driven by fluid secretion in the vestibular labyrinth and a failure of fluid absorption in the embryonic endolymphatic sac. Elucidating the mechanism of hearing loss may offer clues to potential therapeutic strategies.
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Affiliation(s)
- Andrew J Griffith
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, 5 Research Court, Rockville, Maryland 20850-3320, USA.
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