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Esteve-Garcia A, Cobos E, Sau C, Padró-Miquel A, Català-Mora J, Barberán-Martínez P, Millán JM, García-García G, Aguilera C. Deciphering complexity: TULP1 variants linked to an atypical retinal dystrophy phenotype. Front Genet 2024; 15:1352063. [PMID: 38450199 PMCID: PMC10915255 DOI: 10.3389/fgene.2024.1352063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/29/2024] [Indexed: 03/08/2024] Open
Abstract
Introduction: TULP1 exemplifies the remarkable clinical and genetic heterogeneity observed in inherited retinal dystrophies. Our research describes the clinical and molecular characteristics of a patient manifesting an atypical retinal dystrophy pattern, marked by the identification of both a previously unreported and a rarely encountered TULP1 variant. Methods: Whole-exome sequencing was performed to identify potential causative variants. The pathogenicity of the identified TULP1 variants was evaluated through in silico predictors and a minigene splice assay, specifically designed to assess the effect of the unreported TULP1 variant. Results: We identified two TULP1 gene variants in a patient exhibiting unusual and symmetrical alterations in both retinas, characterized by an increase in autofluorescence along the distribution of retinal vessels. These variants included a known rare missense variant, c.1376T>C, and a novel splice site variant, c.822G>T. For the latter variant (c.822G>T), we conducted a minigene splice assay that demonstrated the incorporation of a premature stop codon. This finding suggests a likely activation of the nonsense-mediated mRNA decay mechanism, ultimately resulting in the absence of protein production from this allele. Segregation analysis confirmed that these variants were in trans. Discussion: Our data support that individuals with biallelic TULP1 variants may present with a unique pattern of macular degeneration and periarteriolar vascular pigmentation. This study highlights the importance of further clinical and molecular characterization of TULP1 variants to elucidate genotype-phenotype correlations in the context of inherited retinal dystrophies.
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Affiliation(s)
- Anna Esteve-Garcia
- Department of Clinical Genetics, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Estefania Cobos
- Department of Ophthalmology, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Cristina Sau
- Department of Clinical Genetics, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Ariadna Padró-Miquel
- Genetics Laboratory, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Jaume Català-Mora
- Department of Ophthalmology, SJD Barcelona Children’s Hospital, Barcelona, Spain
| | - Pilar Barberán-Martínez
- Molecular, Cellular, and Genomic Biomedicine Group, Valencia, Spain
- Joint Unit CIPF-IIS La Fe Molecular, Cellular and Genomic Biomedicine, Valencia, Spain
| | - José M. Millán
- Molecular, Cellular, and Genomic Biomedicine Group, Valencia, Spain
- Joint Unit CIPF-IIS La Fe Molecular, Cellular and Genomic Biomedicine, Valencia, Spain
- Center for Rare Diseases (CIBERER), Madrid, Spain
- University and Polytechnic La Fe Hospital of Valencia, Valencia, Spain
| | - Gema García-García
- Molecular, Cellular, and Genomic Biomedicine Group, Valencia, Spain
- Joint Unit CIPF-IIS La Fe Molecular, Cellular and Genomic Biomedicine, Valencia, Spain
- Center for Rare Diseases (CIBERER), Madrid, Spain
| | - Cinthia Aguilera
- Genetics Laboratory, Bellvitge University Hospital, Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
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Warren B, Eberl D. What can insects teach us about hearing loss? J Physiol 2024; 602:297-316. [PMID: 38128023 DOI: 10.1113/jp281281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Over the last three decades, insects have been utilized to provide a deep and fundamental understanding of many human diseases and disorders. Here, we present arguments for insects as models to understand general principles underlying hearing loss. Despite ∼600 million years since the last common ancestor of vertebrates and invertebrates, we share an overwhelming degree of genetic homology particularly with respect to auditory organ development and maintenance. Despite the anatomical differences between human and insect auditory organs, both share physiological principles of operation. We explain why these observations are expected and highlight areas in hearing loss research in which insects can provide insight. We start by briefly introducing the evolutionary journey of auditory organs, the reasons for using insect auditory organs for hearing loss research, and the tools and approaches available in insects. Then, the first half of the review focuses on auditory development and auditory disorders with a genetic cause. The second half analyses the physiological and genetic consequences of ageing and short- and long-term changes as a result of noise exposure. We finish with complex age and noise interactions in auditory systems. In this review, we present some of the evidence and arguments to support the use of insects to study mechanisms and potential treatments for hearing loss in humans. Obviously, insects cannot fully substitute for all aspects of human auditory function and loss of function, although there are many important questions that can be addressed in an animal model for which there are important ethical, practical and experimental advantages.
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Affiliation(s)
- Ben Warren
- Neurogenetics Group, College of Life Sciences, University of Leicester, Leicester, UK
| | - Daniel Eberl
- Department of Biology, University of Iowa, Iowa City, IA, USA
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Parra-Perez AM, Lopez-Escamez JA. Types of Inheritance and Genes Associated with Familial Meniere Disease. J Assoc Res Otolaryngol 2023:10.1007/s10162-023-00896-0. [PMID: 37022572 DOI: 10.1007/s10162-023-00896-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/15/2023] [Indexed: 04/07/2023] Open
Abstract
Meniere disease (MD) is a rare disorder of the inner ear defined by sensorineural hearing loss (SNHL) associated with episodes of vertigo and tinnitus. The phenotype is variable, and it may be associated with other comorbidities such as migraine, respiratory allergies, and several autoimmune disorders. The condition has a significant heritability according to epidemiological and familial segregation studies. Familial MD is found in 10% of cases, the most frequently found genes being OTOG, MYO7A, and TECTA, previously associated with autosomal dominant and recessive non-syndromic SNHL. These findings suggest a new hypothesis where proteins involved in the extracellular structures in the apical surface of sensory epithelia (otolithic and tectorial membranes) and proteins in the stereocilia links would be key elements in the pathophysiology of MD. The ionic homeostasis of the otolithic and tectorial membranes could be critical to suppress the innate motility of individual hair cell bundles. Initially, focal detachment of these extracellular membranes may cause random depolarization of hair cells and will explain changes in tinnitus loudness or trigger vertigo attacks in early stages of MD. With the progression of the disease, a larger detachment will lead to an otolithic membrane herniation into the horizontal semicircular canal with dissociation in caloric and head impulse responses. Familial MD shows different types of inheritance, including autosomal dominant and compound recessive patterns and implementation of genetic testing will improve our understanding of the genetic structure of MD.
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Affiliation(s)
- Alberto M Parra-Perez
- Meniere's Disease Neuroscience Research Program, Faculty of Medicine & Health, School of Medical Sciences, The Kolling Institute, University of Sydney, 10 Westbourne St, St Leonards NSW 2064, Sydney, NSW, Australia
- Otology and Neurotology Group CTS495, Department of Genomic Medicine, GENYO - Centre for Genomics and Oncological Research - Pfizer, University of Granada, PTS, Junta de Andalucía, Granada, Spain
- Division of Otolaryngology, Department of Surgery, Instituto de Investigación Biosanitaria, Ibs.GRANADA, Universidad de Granada, Granada, Spain
- Sensorineural Pathology Programme, Centro de Investigación Biomédica en Red en Enfermedades Raras, CIBERER, Madrid, Spain
| | - Jose A Lopez-Escamez
- Meniere's Disease Neuroscience Research Program, Faculty of Medicine & Health, School of Medical Sciences, The Kolling Institute, University of Sydney, 10 Westbourne St, St Leonards NSW 2064, Sydney, NSW, Australia.
- Otology and Neurotology Group CTS495, Department of Genomic Medicine, GENYO - Centre for Genomics and Oncological Research - Pfizer, University of Granada, PTS, Junta de Andalucía, Granada, Spain.
- Division of Otolaryngology, Department of Surgery, Instituto de Investigación Biosanitaria, Ibs.GRANADA, Universidad de Granada, Granada, Spain.
- Sensorineural Pathology Programme, Centro de Investigación Biomédica en Red en Enfermedades Raras, CIBERER, Madrid, Spain.
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Lindner LA, Derstroff D, Oliver D, Reimann K. Distribution of ciliary adaptor proteins tubby and TULP3 in the organ of Corti. Front Neurosci 2023; 17:1162937. [PMID: 37144094 PMCID: PMC10151737 DOI: 10.3389/fnins.2023.1162937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/28/2023] [Indexed: 05/06/2023] Open
Abstract
Tubby-like proteins are membrane-associated adaptors that mediate directional trafficking into primary cilia. In inner ear sensory epithelia, cilia-including the hair cell's kinocilium-play important roles as organizers of polarity, tissue architecture and cellular function. However, auditory dysfunction in tubby mutant mice was recently found to be related to a non-ciliary function of tubby, the organization of a protein complex in sensory hair bundles of auditory outer hair cells (OHCs). Targeting of signaling components into cilia in the cochlea might therefore rather rely on closely related tubby-like proteins (TULPs). In this study, we compared cellular and subcellular localization of tubby and TULP3 in the mouse inner ear sensory organs. Immunofluorescence microscopy confirmed the previously reported highly selective localization of tubby in the stereocilia tips of OHCs and revealed a previously unnoticed transient localization to kinocilia during early postnatal development. TULP3 was detected in the organ of Corti and vestibular sensory epithelium, where it displayed a complex spatiotemporal pattern. TULP3 localized to kinocilia of cochlear and vestibular hair cells in early postnatal development but disappeared subsequently before the onset of hearing. This pattern suggested a role in targeting ciliary components into kinocilia, possibly related to the developmental processes that shape the sensory epithelia. Concurrent with loss from kinocilia, pronounced TULP3 immunolabeling progressively appeared at microtubule bundles in non-sensory Pillar (PCs) and Deiters cells (DC). This subcellular localization may indicate a novel function of TULP proteins associated with the formation or regulation of microtubule-based cellular structures.
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Affiliation(s)
- Laura A. Lindner
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Marburg, Philipps-University Marburg, Marburg, Germany
| | - Dennis Derstroff
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Marburg, Philipps-University Marburg, Marburg, Germany
| | - Dominik Oliver
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps-University Marburg, Marburg, Germany
| | - Katrin Reimann
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Marburg, Philipps-University Marburg, Marburg, Germany
- *Correspondence: Katrin Reimann,
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