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Smirnov V, Grunewald O, Muller J, Zeitz C, Obermaier CD, Devos A, Pelletier V, Bocquet B, Andrieu C, Bacquet JL, Lebredonchel E, Mohand-Saïd S, Defoort-Dhellemmes S, Sahel JA, Dollfus H, Zanlonghi X, Audo I, Meunier I, Boulanger-Scemama E, Dhaenens CM. Novel TTLL5 Variants Associated with Cone-Rod Dystrophy and Early-Onset Severe Retinal Dystrophy. Int J Mol Sci 2021; 22:ijms22126410. [PMID: 34203883 PMCID: PMC8232641 DOI: 10.3390/ijms22126410] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 01/05/2023] Open
Abstract
Variants of the TTLL5 gene, which encodes tubulin tyrosine ligase-like family member five, are a rare cause of cone dystrophy (COD) or cone-rod dystrophy (CORD). To date, only a few TTLL5 patients have been clinically and genetically described. In this study, we report five patients harbouring biallelic variants of TTLL5. Four adult patients presented either COD or CORD with onset in the late teenage years. The youngest patient had a phenotype of early onset severe retinal dystrophy (EOSRD). Genetic analysis was performed by targeted next generation sequencing of gene panels and assessment of copy number variants (CNV). We identified eight variants, of which six were novel, including two large multiexon deletions in patients with COD or CORD, while the EOSRD patient harboured the novel homozygous p.(Trp640*) variant and three distinct USH2A variants, which might explain the observed rod involvement. Our study highlights the role of TTLL5 in COD/CORD and the importance of large deletions. These findings suggest that COD or CORD patients lacking variants in known genes may harbour CNVs to be discovered in TTLL5, previously undetected by classical sequencing methods. In addition, variable phenotypes in TTLL5-associated patients might be due to the presence of additional gene defects.
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Affiliation(s)
- Vasily Smirnov
- Université de Lille, Faculté de Médecine, 59037 Lille, France;
- CHU Lille, Service d’Exploration Fonctionnelle de la Vision et de Neuro-Ophtalmologie, Hôpital Salengro, 59037 Lille, France;
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
| | - Olivier Grunewald
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, 59045 Lille, France;
| | - Jean Muller
- Laboratoire de Génétique Médicale, Institut de Génétique Médicale d’Alsace (IGMA), INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg UMRS_1112, 67000 Strasbourg, France;
- Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Institut de Génétique Médicale d’Alsace (IGMA), 67000 Strasbourg, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
| | - Carolin D. Obermaier
- Praxis für Humangenetik Tuebingen & Center for Genomics and Transcriptomics, CeGaT GmbH, 72076 Tuebingen, Germany;
| | - Aurore Devos
- Univ. Lille, CHU Lille, Service de Toxicologie et Génopathies, 59037 Lille, France; (A.D.); (E.L.)
| | - Valérie Pelletier
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (V.P.); (J.-L.B.); (H.D.)
| | - Béatrice Bocquet
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, 34295 Montpellier, France; (B.B.); (I.M.)
- Institute for Neurosciences of Montpellier (INM), INSERM, University of Montpellier, INSERM, 34295 Montpellier, France
| | - Camille Andrieu
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012 Paris, France;
| | - Jean-Louis Bacquet
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (V.P.); (J.-L.B.); (H.D.)
| | - Elodie Lebredonchel
- Univ. Lille, CHU Lille, Service de Toxicologie et Génopathies, 59037 Lille, France; (A.D.); (E.L.)
| | - Saddek Mohand-Saïd
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012 Paris, France;
| | - Sabine Defoort-Dhellemmes
- CHU Lille, Service d’Exploration Fonctionnelle de la Vision et de Neuro-Ophtalmologie, Hôpital Salengro, 59037 Lille, France;
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012 Paris, France;
- Fondation Ophtalmologique Adolphe de Rothschild, 75019 Paris, France;
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Hélène Dollfus
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (V.P.); (J.-L.B.); (H.D.)
| | | | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012 Paris, France;
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, 34295 Montpellier, France; (B.B.); (I.M.)
- Institute for Neurosciences of Montpellier (INM), INSERM, University of Montpellier, INSERM, 34295 Montpellier, France
| | | | - Claire-Marie Dhaenens
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, 59045 Lille, France;
- Correspondence: ; Tel.: +33-320-444-953
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