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Arai H, Noguchi A, Shina K, Otaka S, Takahashi I, Kosaki K, Takahashi T. A child with branchio-oto-renal spectrum disorder carrying an SIX1 variant. Pediatr Int 2023; 65:e15638. [PMID: 37795857 DOI: 10.1111/ped.15638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 10/06/2023]
Affiliation(s)
- Hirokazu Arai
- Department of Neonatology, Akita Red Cross Hospital, Akita, Japan
| | - Atsuko Noguchi
- Department of Pediatrics, Akita University Graduate School of Medicine, Akita, Japan
| | - Kazuhiro Shina
- Department of Otorhinolaryngology, Akita University Graduate School of Medicine, Akita, Japan
| | - Shin Otaka
- Department of Pediatrics, Akita University Graduate School of Medicine, Akita, Japan
| | - Ikuko Takahashi
- Department of Pediatrics, Akita University Graduate School of Medicine, Akita, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Tsutomu Takahashi
- Department of Pediatrics, Akita University Graduate School of Medicine, Akita, Japan
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Brotto D, Sorrentino F, Cenedese R, Avato I, Bovo R, Trevisi P, Manara R. Genetics of Inner Ear Malformations: A Review. Audiol Res 2021; 11:524-536. [PMID: 34698066 PMCID: PMC8544219 DOI: 10.3390/audiolres11040047] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/04/2021] [Accepted: 10/08/2021] [Indexed: 12/02/2022] Open
Abstract
Inner ear malformations are present in 20% of patients with sensorineural hearing loss. Although the first descriptions date to the 18th century, in recent years the knowledge about these conditions has experienced terrific improvement. Currently, most of these conditions have a rehabilitative option. Much less is known about the etiology of these anomalies. In particular, the evolution of genetics has provided new data about the possible relationship between inner ear malformations and genetic anomalies. In addition, in syndromic condition, the well-known presence of sensorineural hearing loss can now be attributed to the presence of an inner ear anomaly. In some cases, the presence of these abnormalities should be considered as a characteristic feature of the syndrome. The present paper aims to summarize the available knowledge about the possible relationships between inner ear malformations and genetic mutations.
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Affiliation(s)
- Davide Brotto
- Section of Otorhinolaryngology—Head and Neck Surgery, Department of Neurosciences, University of Padua, 35128 Padua, Italy; (F.S.); (R.C.); (R.B.); (P.T.)
- Correspondence:
| | - Flavia Sorrentino
- Section of Otorhinolaryngology—Head and Neck Surgery, Department of Neurosciences, University of Padua, 35128 Padua, Italy; (F.S.); (R.C.); (R.B.); (P.T.)
| | - Roberta Cenedese
- Section of Otorhinolaryngology—Head and Neck Surgery, Department of Neurosciences, University of Padua, 35128 Padua, Italy; (F.S.); (R.C.); (R.B.); (P.T.)
| | - Irene Avato
- Department of Diagnostic, Paediatric, Clinical and Surgical Science, University of Pavia, 35128 Pavia, Italy;
| | - Roberto Bovo
- Section of Otorhinolaryngology—Head and Neck Surgery, Department of Neurosciences, University of Padua, 35128 Padua, Italy; (F.S.); (R.C.); (R.B.); (P.T.)
| | - Patrizia Trevisi
- Section of Otorhinolaryngology—Head and Neck Surgery, Department of Neurosciences, University of Padua, 35128 Padua, Italy; (F.S.); (R.C.); (R.B.); (P.T.)
| | - Renzo Manara
- Neuroradiology Unit, Department of Neurosciences, University of Padua, 35128 Padua, Italy;
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Peusner KD, Bell NM, Hirsch JC, Beraneck M, Popratiloff A. Understanding the Pathophysiology of Congenital Vestibular Disorders: Current Challenges and Future Directions. Front Neurol 2021; 12:708395. [PMID: 34589045 PMCID: PMC8475631 DOI: 10.3389/fneur.2021.708395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/13/2021] [Indexed: 12/13/2022] Open
Abstract
In congenital vestibular disorders (CVDs), children develop an abnormal inner ear before birth and face postnatal challenges to maintain posture, balance, walking, eye-hand coordination, eye tracking, or reading. Only limited information on inner ear pathology is acquired from clinical imaging of the temporal bone or studying histological slides of the temporal bone. A more comprehensive and precise assessment and determination of the underlying mechanisms necessitate analyses of the disorders at the cellular level, which can be achieved using animal models. Two main criteria for a suitable animal model are first, a pathology that mirrors the human disorder, and second, a reproducible experimental outcome leading to statistical power. With over 40 genes that affect inner ear development, the phenotypic abnormalities resulting from congenital vestibular disorders (CVDs) are highly variable. Nonetheless, there is a large subset of CVDs that form a common phenotype of a sac-like inner ear with the semicircular canals missing or dysplastic, and discrete abnormalities in the vestibular sensory organs. We have focused the review on this subset, but to advance research on CVDs we have added other CVDs not forming a sac-like inner ear. We have included examples of animal models used to study these CVDs. Presently, little is known about the central pathology resulting from CVDs at the cellular level in the central vestibular neural network, except for preliminary studies on a chick model that show significant loss of second-order, vestibular reflex projection neurons.
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Affiliation(s)
- Kenna D Peusner
- Department of Neurology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - Nina M Bell
- Department of Neurology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - June C Hirsch
- Department of Neurology, The George Washington University School of Medicine and Health Sciences, Washington, DC, United States
| | - Mathieu Beraneck
- Université de Paris, Integrative Neuroscience and Cognition Center, CNRS UMR 8002, Paris, France
| | - Anastas Popratiloff
- The George Washington University Nanofabrication and Imaging Center, Washington, DC, United States
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Abstract
OBJECTIVE A small subset of children with congenital hearing loss have abnormal cochleovestibular nerves (i.e., absent, aplastic, or deficient cochlear nerves), with largely unknown etiology. Our objective was to investigate the underlying pathways and identify novel genetic variants responsible for cochleovestibular malformations and nerve abnormalities. It is our hypothesis that several cochleovestibular nerve abnormalities might share common causative pathways. DESIGN We used a family-based exome sequencing approach to study 12 children with known rare inner ear and/or cochleovestibular nerve malformations. RESULTS Our results highlight a diverse molecular etiology and suggest that genes important in the developing otic vesicle and cranial neural crest, e.g., MASP1, GREB1L, SIX1, TAF1, are likely to underlie inner ear and/or cochleovestibular nerve malformations. CONCLUSIONS We show that several cochleovestibular nerve malformations are neurocristopathies, which is consistent with the fact that cochleovestibular nerve development is based on otic placode-derived neurons in close association with neural crest-derived glia cells. In addition, we suggest potential genetic markers for more severely affected phenotypes, which may help prognosticate individual cochlear implantation outcomes. Developing better strategies for identifying which children with abnormal nerves will benefit from a cochlear implantation is crucial, as outcomes are usually far less robust and extremely variable in this population, and current neuroimaging and electrophysiologic parameters cannot accurately predict outcomes. Identification of a suitable treatment early will reduce the use of multiple interventions during the time-sensitive period for language development.
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Identification of Novel Candidate Genes and Variants for Hearing Loss and Temporal Bone Anomalies. Genes (Basel) 2021; 12:genes12040566. [PMID: 33924653 PMCID: PMC8069784 DOI: 10.3390/genes12040566] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/01/2021] [Accepted: 04/08/2021] [Indexed: 01/09/2023] Open
Abstract
Background: Hearing loss remains an important global health problem that is potentially addressed through early identification of a genetic etiology, which helps to predict outcomes of hearing rehabilitation such as cochlear implantation and also to mitigate the long-term effects of comorbidities. The identification of variants for hearing loss and detailed descriptions of clinical phenotypes in patients from various populations are needed to improve the utility of clinical genetic screening for hearing loss. Methods: Clinical and exome data from 15 children with hearing loss were reviewed. Standard tools for annotating variants were used and rare, putatively deleterious variants were selected from the exome data. Results: In 15 children, 21 rare damaging variants in 17 genes were identified, including: 14 known hearing loss or neurodevelopmental genes, 11 of which had novel variants; and three candidate genes IST1, CBLN3 and GDPD5, two of which were identified in children with both hearing loss and enlarged vestibular aqueducts. Patients with variants within IST1 and MYO18B had poorer outcomes after cochlear implantation. Conclusion: Our findings highlight the importance of identifying novel variants and genes in ethnic groups that are understudied for hearing loss.
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Kari E, Llaci L, Go JL, Naymik M, Knowles JA, Leal SM, Rangasamy S, Huentelman MJ, Friedman RA, Schrauwen I. A de novo SIX1 variant in a patient with a rare nonsyndromic cochleovestibular nerve abnormality, cochlear hypoplasia, and bilateral sensorineural hearing loss. Mol Genet Genomic Med 2019; 7:e995. [PMID: 31595699 PMCID: PMC6900394 DOI: 10.1002/mgg3.995] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/29/2019] [Accepted: 09/03/2019] [Indexed: 01/06/2023] Open
Abstract
Background Childhood hearing impairment affects language and cognitive development. Profound congenital sensorineural hearing impairment can be due to an abnormal cochleovestibular nerve (CVN) and cochleovestibular malformations, however, the etiology of these conditions remains unclear. Methods We used a trio‐based exome sequencing approach to unravel the underlying molecular etiology of a child with a rare nonsyndromic CVN abnormality and cochlear hypoplasia. Clinical and imaging data were also reviewed. Results We identified a de novo missense variant [p(Asn174Tyr)] in the DNA‐binding Homeodomain of SIX1, a gene which previously has been associated with autosomal dominant hearing loss (ADHL) and branchio‐oto‐renal or Branchio‐otic syndrome, a condition not seen in this patient. Conclusions SIX1 has an important function in otic vesicle patterning during embryogenesis, and mice show several abnormalities to their inner ear including loss of inner ear innervation. Previous reports on patients with SIX1 variants lack imaging data and nonsyndromic AD cases were reported to have no inner ear malformations. In conclusion, we show that a de novo variant in SIX1 in a patient with sensorineural hearing loss leads to cochleovestibular malformations and abnormalities of the CVN, without any other abnormalities. Without proper interventions, severe to profound hearing loss is devastating to both education and social integration. Choosing the correct intervention can be challenging and a molecular diagnosis may adjust intervention and improve outcomes, especially for rare cases.
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Affiliation(s)
- Elina Kari
- Division of Otolaryngology, Head and Neck Surgery, Department of Surgery, University of California, San Diego, La Jolla, CA, USA
| | - Lorida Llaci
- Neurogenomics Division and Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - John L Go
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Marcus Naymik
- Neurogenomics Division and Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - James A Knowles
- Department of Cell Biology - MSC 5, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Suzanne M Leal
- Center for Statistical Genetics, Molecular and Human Genetics Department, Baylor College of Medicine, Houston, TX, USA
| | - Sampath Rangasamy
- Neurogenomics Division and Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Matthew J Huentelman
- Neurogenomics Division and Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Rick A Friedman
- Division of Otolaryngology, Head and Neck Surgery, Department of Surgery, University of California, San Diego, La Jolla, CA, USA
| | - Isabelle Schrauwen
- Neurogenomics Division and Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ, USA.,Center for Statistical Genetics, Molecular and Human Genetics Department, Baylor College of Medicine, Houston, TX, USA
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