1
|
Vázquez-Domínguez I, Anido AA, Duijkers L, Hoppenbrouwers T, Hoogendoorn ADM, Koster C, Collin RWJ, Garanto A. Efficacy, biodistribution and safety comparison of chemically modified antisense oligonucleotides in the retina. Nucleic Acids Res 2024:gkae686. [PMID: 39119918 DOI: 10.1093/nar/gkae686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 06/25/2024] [Accepted: 07/26/2024] [Indexed: 08/10/2024] Open
Abstract
Antisense oligonucleotides (AONs) are a versatile tool for treating inherited retinal diseases. However, little is known about how different chemical modifications of AONs can affect their biodistribution, toxicity, and uptake in the retina. Here, we addressed this question by comparing splice-switching AONs with three different chemical modifications commonly used in a clinical setting (2'O-methyl-phosphorothioate (2-OMe/PS), 2'O-methoxyethyl-phosphoriate (2-MOE/PS), and phosphorodiamidite morpholino oligomers (PMO)). These AONs targeted genes exclusively expressed in certain types of retinal cells. Overall, studies in vitro and in vivo in C57BL/6J wild-type mouse retinas showed that 2-OMe/PS and 2-MOE/PS AONs have comparable efficacy and safety profiles. In contrast, octa-guanidine-dendrimer-conjugated in vivo PMO-oligonucleotides (ivPMO) caused toxicity. This was evidenced by externally visible ocular phenotypes in 88.5% of all ivPMO-treated animals, accompanied by severe alterations at the morphological level. However, delivery of unmodified PMO-AONs did not cause any toxicity, although it clearly reduced the efficacy. We conducted the first systematic comparison of different chemical modifications of AONs in the retina. Our results showed that the same AON sequence with different chemical modifications displayed different splicing modulation efficacies, suggesting the 2'MOE/PS modification as the most efficacious in these conditions. Thereby, our work provides important insights for future clinical applications.
Collapse
Affiliation(s)
| | - Alejandro Allo Anido
- Radboud university medical center, Department of Human Genetics, Nijmegen, The Netherlands
| | - Lonneke Duijkers
- Radboud university medical center, Department of Human Genetics, Nijmegen, The Netherlands
| | - Tamara Hoppenbrouwers
- Radboud university medical center, Department of Human Genetics, Nijmegen, The Netherlands
| | - Anita D M Hoogendoorn
- Radboud university medical center, Amalia Children's Hospital, Department of Pediatrics, Nijmegen, The Netherlands
| | - Céline Koster
- Departments of Human Genetics and Ophthalmology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Rob W J Collin
- Radboud university medical center, Department of Human Genetics, Nijmegen, The Netherlands
| | - Alejandro Garanto
- Radboud university medical center, Department of Human Genetics, Nijmegen, The Netherlands
- Radboud university medical center, Amalia Children's Hospital, Department of Pediatrics, Nijmegen, The Netherlands
| |
Collapse
|
2
|
Majander A, Sankila EM, Falck A, Vasara LK, Seitsonen S, Kulmala M, Haavisto AK, Avela K, Turunen JA. Natural history and biomarkers of retinal dystrophy caused by the biallelic TULP1 variant c.148delG. Acta Ophthalmol 2023; 101:215-221. [PMID: 36128853 DOI: 10.1111/aos.15252] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 08/19/2022] [Accepted: 09/03/2022] [Indexed: 11/27/2022]
Abstract
PURPOSE To report clinical features and potential disease markers of inherited retinal dystrophy (IRD) caused by the biallelic c.148delG variant in the tubby-like protein 1 (TULP1) gene. METHODS A retrospective observational study of 16 IRD patients carrying a homozygous pathogenic TULP1 c.148delG variant. Clinical data including fundus spectral-domain optical coherence tomography (SD-OCT) were assessed. A meta-analysis of visual acuity of previously reported other pathogenic TULP1 variants was performed for reference. RESULTS The biallelic TULP1 variant c.148delG was associated with infantile and early childhood onset IRD. Retinal ophthalmoscopy was primarily normal converting to peripheral pigmentary retinopathy and maculopathy characterized by progressive extra-foveal loss of the ellipsoid zone (EZ), the outer plexiform layer (OPL), and the outer nuclear layer (ONL) bands in the SD-OCT images. The horizontal width of the foveal EZ showed significant regression with the best-corrected visual acuity (BCVA) of the eye (p < 0.0001, R2 = 0.541, F = 26.0), the age of the patient (p < 0.0001, R2 = 0.433, F = 16.8), and mild correlation with the foveal OPL-ONL thickness (p = 0.014, R2 = 0.245, F = 7.2). Modelling of the BCVA data suggested a mean annual loss of logMAR 0.027. The level of visual loss was similar to that previously reported in patients carrying other truncating TULP1 variants. CONCLUSIONS This study describes the progression of TULP1 IRD suggesting a potential time window for therapeutic interventions. The width of the foveal EZ and the thickness of the foveal OPL-ONL layers could serve as biomarkers of the disease stage.
Collapse
Affiliation(s)
- Anna Majander
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Eeva-Marja Sankila
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Aura Falck
- Department of Ophthalmology, PEDEGO Research Unit and Medical Research Center, University of Oulu and Oulu University Hospital, Oulu, Finland
| | - Laura Kristiina Vasara
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Sanna Seitsonen
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Maarit Kulmala
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Anna-Kaisa Haavisto
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Kristiina Avela
- Department of Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Joni A Turunen
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Eye Genetics Group, Folkhälsan Research Center, Helsinki, Finland
| |
Collapse
|
3
|
Panneman DM, Hitti-Malin RJ, Holtes LK, de Bruijn SE, Reurink J, Boonen EGM, Khan MI, Ali M, Andréasson S, De Baere E, Banfi S, Bauwens M, Ben-Yosef T, Bocquet B, De Bruyne M, de la Cerda B, Coppieters F, Farinelli P, Guignard T, Inglehearn CF, Karali M, Kjellström U, Koenekoop R, de Koning B, Leroy BP, McKibbin M, Meunier I, Nikopoulos K, Nishiguchi KM, Poulter JA, Rivolta C, Rodríguez de la Rúa E, Saunders P, Simonelli F, Tatour Y, Testa F, Thiadens AAHJ, Toomes C, Tracewska AM, Tran HV, Ushida H, Vaclavik V, Verhoeven VJM, van de Vorst M, Gilissen C, Hoischen A, Cremers FPM, Roosing S. Cost-effective sequence analysis of 113 genes in 1,192 probands with retinitis pigmentosa and Leber congenital amaurosis. Front Cell Dev Biol 2023; 11:1112270. [PMID: 36819107 PMCID: PMC9936074 DOI: 10.3389/fcell.2023.1112270] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/20/2023] [Indexed: 02/05/2023] Open
Abstract
Introduction: Retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA) are two groups of inherited retinal diseases (IRDs) where the rod photoreceptors degenerate followed by the cone photoreceptors of the retina. A genetic diagnosis for IRDs is challenging since >280 genes are associated with these conditions. While whole exome sequencing (WES) is commonly used by diagnostic facilities, the costs and required infrastructure prevent its global applicability. Previous studies have shown the cost-effectiveness of sequence analysis using single molecule Molecular Inversion Probes (smMIPs) in a cohort of patients diagnosed with Stargardt disease and other maculopathies. Methods: Here, we introduce a smMIPs panel that targets the exons and splice sites of all currently known genes associated with RP and LCA, the entire RPE65 gene, known causative deep-intronic variants leading to pseudo-exons, and part of the RP17 region associated with autosomal dominant RP, by using a total of 16,812 smMIPs. The RP-LCA smMIPs panel was used to screen 1,192 probands from an international cohort of predominantly RP and LCA cases. Results and discussion: After genetic analysis, a diagnostic yield of 56% was obtained which is on par with results from WES analysis. The effectiveness and the reduced costs compared to WES renders the RP-LCA smMIPs panel a competitive approach to provide IRD patients with a genetic diagnosis, especially in countries with restricted access to genetic testing.
Collapse
Affiliation(s)
- Daan M. Panneman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands,*Correspondence: Daan M. Panneman,
| | - Rebekkah J. Hitti-Malin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Lara K. Holtes
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Suzanne E. de Bruijn
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Janine Reurink
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Erica G. M. Boonen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Muhammad Imran Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Manir Ali
- Division of Molecular Medicine, Leeds Institute of Medical Research, St. James’s University Hospital, University of Leeds, Leeds, United Kingdom
| | - Sten Andréasson
- Department of Ophthalmology and Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
| | - Elfride De Baere
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy,Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, Naples, Italy
| | - Miriam Bauwens
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Tamar Ben-Yosef
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Béatrice Bocquet
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, Montpellier, France,Institute for Neurosciences of Montpellier (INM), L’Institut National de la Santé et de la Recherche Médicale, University of Montpellier, L’Institut National de la Santé et de la Recherche Médicale, Montpellier, France
| | - Marieke De Bruyne
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Berta de la Cerda
- Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Seville, Spain
| | - Frauke Coppieters
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium,Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium,Department of Pharmaceutics, Ghent University, Ghent, Belgium
| | - Pietro Farinelli
- Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, Lausanne, Switzerland
| | - Thomas Guignard
- Chromosomal Genetics Unit, University Hospital of Montpellier, Montpellier, France
| | - Chris F. Inglehearn
- Division of Molecular Medicine, Leeds Institute of Medical Research, St. James’s University Hospital, University of Leeds, Leeds, United Kingdom
| | - Marianthi Karali
- Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, Naples, Italy,Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Ulrika Kjellström
- Department of Ophthalmology and Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
| | - Robert Koenekoop
- McGill University Health Center (MUHC) Research Institute, Montreal, QC, Canada,Departments of Paediatric Surgery, Human Genetics, and Adult Ophthalmology, McGill University Health Center, Montreal, QC, Canada
| | - Bart de Koning
- Department of Clinical Genetics, Maastricht University Medical Center+ (MUMC+), Maastricht, Netherlands
| | - Bart P. Leroy
- Department of Ophthalmology, Ghent University Hospital, Ghent, Belgium,Department of Head & Skin, Ghent University, Ghent, Belgium,Division of Ophthalmology & Center for Cellular & Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA, United States,Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Martin McKibbin
- Division of Molecular Medicine, Leeds Institute of Medical Research, St. James’s University Hospital, University of Leeds, Leeds, United Kingdom,Department of Ophthalmology, St. James’s University Hospital, Leeds, United Kingdom
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, Montpellier, France,Institute for Neurosciences of Montpellier (INM), L’Institut National de la Santé et de la Recherche Médicale, University of Montpellier, L’Institut National de la Santé et de la Recherche Médicale, Montpellier, France
| | | | - Koji M. Nishiguchi
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - James A. Poulter
- Division of Molecular Medicine, Leeds Institute of Medical Research, St. James’s University Hospital, University of Leeds, Leeds, United Kingdom
| | - Carlo Rivolta
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland,Department of Ophthalmology, University of Basel, Basel, Switzerland,Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Enrique Rodríguez de la Rúa
- Department of Ophthalmology, Retics Patologia Ocular, OFTARED, Instituto de Salud Carlos III, University Hospital Virgen Macarena, Madrid, Spain
| | | | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Yasmin Tatour
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
| | | | - Carmel Toomes
- Division of Molecular Medicine, Leeds Institute of Medical Research, St. James’s University Hospital, University of Leeds, Leeds, United Kingdom
| | - Anna M. Tracewska
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Hoai Viet Tran
- Oculogenetic Unit, University Eye Hospital Jules Gonin, Geneva, Switzerland
| | - Hiroaki Ushida
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Veronika Vaclavik
- Oculogenetic Unit, University Eye Hospital Jules Gonin, Geneva, Switzerland
| | - Virginie J. M. Verhoeven
- Department of Ophthalmology, Erasmus, Rotterdam, Netherlands,Department of Clinical Genetics, Erasmus, Rotterdam, Netherlands
| | - Maartje van de Vorst
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands,Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Alexander Hoischen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands,Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands,Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| |
Collapse
|
4
|
Viering DH, Hureaux M, Neveling K, Latta F, Kwint M, Blanchard A, Konrad M, Bindels RJ, Schlingmann KP, Vargas-Poussou R, de Baaij JH. Long-Read Sequencing Identifies Novel Pathogenic Intronic Variants in Gitelman Syndrome. J Am Soc Nephrol 2023; 34:333-345. [PMID: 36302598 PMCID: PMC10103101 DOI: 10.1681/asn.2022050627] [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: 05/30/2022] [Accepted: 10/17/2022] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Gitelman syndrome is a salt-losing tubulopathy characterized by hypokalemic alkalosis and hypomagnesemia. It is caused by homozygous recessive or compound heterozygous pathogenic variants in SLC12A3 , which encodes the Na + -Cl - cotransporter (NCC). In up to 10% of patients with Gitelman syndrome, current genetic techniques detect only one specific pathogenic variant. This study aimed to identify a second pathogenic variant in introns, splice sites, or promoters to increase the diagnostic yield. METHODS Long-read sequencing of SLC12A3 was performed in 67 DNA samples from individuals with suspected Gitelman syndrome in whom a single likely pathogenic or pathogenic variant was previously detected. In addition, we sequenced DNA samples from 28 individuals with one variant of uncertain significance or no candidate variant. Midigene splice assays assessed the pathogenicity of novel intronic variants. RESULTS A second likely pathogenic/pathogenic variant was identified in 45 (67%) patients. Those with two likely pathogenic/pathogenic variants had a more severe electrolyte phenotype than other patients. Of the 45 patients, 16 had intronic variants outside of canonic splice sites (nine variants, mostly deep intronic, six novel), whereas 29 patients had an exonic variant or canonic splice site variant. Midigene splice assays of the previously known c.1670-191C>T variant and intronic candidate variants demonstrated aberrant splicing patterns. CONCLUSION Intronic pathogenic variants explain an important part of the missing heritability in Gitelman syndrome. Long-read sequencing should be considered in diagnostic workflows for Gitelman syndrome.
Collapse
Affiliation(s)
- Daan H.H.M. Viering
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marguerite Hureaux
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Department of Genetics, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Paris CardioVascular Research Center, Institut National de la Santé et de Recherche Médicale (INSERM) U970, Paris City University, Paris, France
| | - Kornelia Neveling
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Femke Latta
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Michael Kwint
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anne Blanchard
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Clinical Investigations Center, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, University of Paris, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Martin Konrad
- Department of General Pediatrics, University Children’s Hospital, Münster, Germany
| | - René J.M. Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Rosa Vargas-Poussou
- Reference Center for Hereditary Kidney and Childhood Diseases (Maladies Rénales Héréditaires de l’Enfant et de l’Adulte, MARHEA), Paris, France
- Department of Genetics, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
- Clinical Investigations Center, Hôpital Européen Georges-Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Jeroen H.F. de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| |
Collapse
|
5
|
Bodenbender JP, Marino V, Bethge L, Stingl K, Haack TB, Biskup S, Kohl S, Kühlewein L, Dell’Orco D, Weisschuh N. Biallelic Variants in TULP1 Are Associated with Heterogeneous Phenotypes of Retinal Dystrophy. Int J Mol Sci 2023; 24:ijms24032709. [PMID: 36769033 PMCID: PMC9916573 DOI: 10.3390/ijms24032709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/24/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Biallelic pathogenic variants in TULP1 are mostly associated with severe rod-driven inherited retinal degeneration. In this study, we analyzed clinical heterogeneity in 17 patients and characterized the underlying biallelic variants in TULP1. All patients underwent thorough ophthalmological examinations. Minigene assays and structural analyses were performed to assess the consequences of splice variants and missense variants. Three patients were diagnosed with Leber congenital amaurosis, nine with early onset retinitis pigmentosa, two with retinitis pigmentosa with an onset in adulthood, one with cone dystrophy, and two with cone-rod dystrophy. Seventeen different alleles were identified, namely eight missense variants, six nonsense variants, one in-frame deletion variant, and two splice site variants. For the latter two, minigene assays revealed aberrant transcripts containing frameshifts and premature termination codons. Structural analysis and molecular modeling suggested different degrees of structural destabilization for the missense variants. In conclusion, we report the largest cohort of patients with TULP1-associated IRD published to date. Most of the patients exhibited rod-driven disease, yet a fraction of the patients exhibited cone-driven disease. Our data support the hypothesis that TULP1 variants do not fold properly and thus trigger unfolded protein response, resulting in photoreceptor death.
Collapse
Affiliation(s)
- Jan-Philipp Bodenbender
- Department for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany
- Correspondence: (J.-P.B.); (N.W.)
| | - Valerio Marino
- Section of Biological Chemistry, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37124 Verona, Italy
| | - Leon Bethge
- Department for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Katarina Stingl
- Department for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Tobias B. Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tübingen, Germany
- Centre for Rare Diseases, University of Tübingen, 72076 Tübingen, Germany
| | - Saskia Biskup
- Praxis für Humangenetik, 72076 Tübingen, Germany
- CeGaT GmbH, 72076 Tübingen, Germany
| | - Susanne Kohl
- Department for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
| | - Laura Kühlewein
- Department for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany
| | - Daniele Dell’Orco
- Section of Biological Chemistry, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37124 Verona, Italy
| | - Nicole Weisschuh
- Department for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
- Correspondence: (J.-P.B.); (N.W.)
| |
Collapse
|
6
|
Xu W, Xu M, Yin Q, Liu C, Cao Q, Deng Y, Liu S, He G. A novel homozygous TUB mutation associated with autosomal recessive retinitis pigmentosa in a consanguineous Chinese family. BMC Med Genomics 2023; 16:9. [PMID: 36650547 PMCID: PMC9847046 DOI: 10.1186/s12920-023-01430-0] [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: 09/22/2022] [Accepted: 01/04/2023] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Retinitis pigmentosa (RP) is the most common type of inherited retinopathy. At least 69 genes for RP have been identified. A significant proportion of RP, however, remains genetically unsolved. In this study, the genetic basis of a Chinese consanguineous family with presumed autosomal recessive retinitis pigmentosa (arRP) was investigated. METHODS Overall ophthalmic examinations, including funduscopy, decimal best-corrected visual acuity, axial length and electroretinography (ERG) were performed for the family. Genomic DNA from peripheral blood of the proband was subjected to whole exome sequencing. In silico predictions, structural modelling, and minigene assays were conducted to evaluate the pathogenicity of the variant. RESULTS A novel homozygous variant (NM_003320.4: c.1379A > G) in the TUB gene was identified as a candidate pathogenic variant in this parental consanguineous pedigree. This variant co-segregated with the disease in this pedigree and was absent in 118 ethnically matched healthy controls. It's an extremely rare variant that is neither deposited in population databases (1000 Genomes, ExAC, GnomAD, or Exome Variant Server) nor reported in the literature. Phylogenetic analysis indicated that the Asn residue at codon 460 of TUB is highly conserved across diverse species from tropicalis to humans. It was also completely conserved among the TUB, TULP1, TULP2, and TULP3 family proteins. Multiple bioinformatic algorithms predicted that this variant was deleterious. CONCLUSIONS A novel missense variant in TUB was identified, which was probably the pathogenic basis for arRP in this consanguineous family. This is the first report of a homozygous missense variant in TUB for RP.
Collapse
Affiliation(s)
- Wei Xu
- grid.477407.70000 0004 1806 9292Central Laboratory, Hunan Provincial People’s Hospital (the First Affiliated Hospital of Hunan Normal University), Changsha, 410000 China
| | - Ming Xu
- grid.464229.f0000 0004 1765 8757School of Medicine, Changsha Medical University, Changsha, 410219 China
| | - Qinqin Yin
- grid.477407.70000 0004 1806 9292Department of Ophthalmology, Hunan Provincial People’s Hospital (the First Affiliated Hospital of Hunan Normal University), Changsha, 410000 China
| | - Chuangyi Liu
- grid.477407.70000 0004 1806 9292Department of Ophthalmology, Hunan Provincial People’s Hospital (the First Affiliated Hospital of Hunan Normal University), Changsha, 410000 China
| | - Qiuxiang Cao
- grid.411427.50000 0001 0089 3695School of Life Sciences, Hunan Normal University, Changsha, 410081 China
| | - Yun Deng
- grid.411427.50000 0001 0089 3695School of Life Sciences, Hunan Normal University, Changsha, 410081 China
| | - Sulai Liu
- grid.477407.70000 0004 1806 9292Central Laboratory, Hunan Provincial People’s Hospital (the First Affiliated Hospital of Hunan Normal University), Changsha, 410000 China
| | - Guiyun He
- Department of Ophthalmology, Hunan Provincial People's Hospital (the First Affiliated Hospital of Hunan Normal University), Changsha, 410000, China.
| |
Collapse
|
7
|
Tulp1 deficiency causes early-onset retinal degeneration through affecting ciliogenesis and activating ferroptosis in zebrafish. Cell Death Dis 2022; 13:962. [PMID: 36396940 PMCID: PMC9672332 DOI: 10.1038/s41419-022-05372-w] [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: 05/13/2022] [Revised: 10/22/2022] [Accepted: 10/24/2022] [Indexed: 11/19/2022]
Abstract
Mutations in TUB-like protein 1 (TULP1) are associated with severe early-onset retinal degeneration in humans. However, the pathogenesis remains largely unknown. There are two homologous genes of TULP1 in zebrafish, namely tulp1a and tulp1b. Here, we generated the single knockout (tulp1a-/- and tulp1b-/-) and double knockout (tulp1-dKO) models in zebrafish. Knockout of tulp1a resulted in the mislocalization of UV cone opsins and the degeneration of UV cones specifically, while knockout of tulp1b resulted in mislocalization of rod opsins and rod-cone degeneration. In the tulp1-dKO zebrafish, mislocalization of opsins was present in all types of photoreceptors, and severe degeneration was observed at a very early age, mimicking the clinical manifestations of TULP1 patients. Photoreceptor cilium length was significantly reduced in the tulp1-dKO retinas. RNA-seq analysis showed that the expression of tektin2 (tekt2), a ciliary and flagellar microtubule structural component, was downregulated in the tulp1-dKO zebrafish. Dual-luciferase reporter assay suggested that Tulp1a and Tulp1b transcriptionally activate the promoter of tekt2. In addition, ferroptosis might be activated in the tulp1-dKO zebrafish, as suggested by the up-regulation of genes related to the ferroptosis pathway, the shrinkage of mitochondria, reduction or disappearance of mitochondria cristae, and the iron and lipid droplet deposition in the retina of tulp1-dKO zebrafish. In conclusion, our study establishes an appropriate zebrafish model for TULP1-associated retinal degeneration and proposes that loss of TULP1 causes defects in cilia structure and opsin trafficking through the downregulation of tekt2, which further increases the death of photoreceptors via ferroptosis. These findings offer insight into the pathogenesis and clinical treatment of early-onset retinal degeneration.
Collapse
|
8
|
Vázquez-Domínguez I, Li CHZ, Fadaie Z, Haer-Wigman L, Cremers FPM, Garanto A, Hoyng CB, Roosing S. Identification of a Complex Allele in IMPG2 as a Cause of Adult-Onset Vitelliform Macular Dystrophy. Invest Ophthalmol Vis Sci 2022; 63:27. [PMID: 35608844 PMCID: PMC9150824 DOI: 10.1167/iovs.63.5.27] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Purpose Inherited retinal diseases are a group of clinically and genetically heterogeneous disorders with approximately 270 genes involved. IMPG2 is associated with adult-onset vitelliform macular dystrophy. Here, we investigated two unrelated patients with vitelliform macular dystrophy to identify the underlying genetic cause. Methods Whole-exome sequencing identified a putative causal complex allele consisting of c.3023-15T>A and c.3023G>A (p.(Gly1008Asp)) in IMPG2 in both individuals. To assess its effect, in vitro splice assays in HEK293T and further characterization in patient-derived photoreceptor precursor cells (PPCs) were conducted. Results The results of the midigene splice assays in HEK293T showed that the complex allele causes a variety of splicing defects ranging from a small deletion to (multiple-)exon skipping. This finding was further validated using patient-derived PPCs that showed a significant increase of out-of-frame transcripts lacking one or multiple exons compared to control-derived PPCs. Overall, control PPCs consistently showed low levels of aberrantly spliced IMPG2 transcripts that were highly elevated in patient-derived PPCs. These differences were even more obvious upon inhibition of nonsense-mediated decay with cycloheximide. Conclusions We report a heterozygous complex allele in IMPG2 causative for adult-onset vitelliform macular dystrophy in two unrelated individuals with mild visual loss and bilateral vitelliform lesions. The predicted causal missense mutation c.3023G>A, located in the consensus splice acceptor site, enhances the splicing effect of the upstream variant c.3023-15T>A, leading to the generation of aberrant transcripts that decrease the full-length IMPG2 levels. These results suggest a haploinsufficiency mechanism of action and highlight the complementarity of using different models to functionally assesses splicing defects.
Collapse
Affiliation(s)
- Irene Vázquez-Domínguez
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Catherina H Z Li
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Zeinab Fadaie
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Lonneke Haer-Wigman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Alejandro Garanto
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Pediatrics, Amalia Children's Hospital and Radboud Institute of Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, the Netherlands
| | - Carel B Hoyng
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| |
Collapse
|
9
|
Clinical and Genetic Re-Evaluation of Inherited Retinal Degeneration Pedigrees following Initial Negative Findings on Panel-Based Next Generation Sequencing. Int J Mol Sci 2022; 23:ijms23020995. [PMID: 35055178 PMCID: PMC8780304 DOI: 10.3390/ijms23020995] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/03/2022] [Accepted: 01/12/2022] [Indexed: 02/06/2023] Open
Abstract
Although rare, inherited retinal degenerations (IRDs) are the most common reason for blind registration in the working age population. They are highly genetically heterogeneous (>300 known genetic loci), and confirmation of a molecular diagnosis is a prerequisite for many therapeutic clinical trials and approved treatments. First-tier genetic testing of IRDs with panel-based next-generation sequencing (pNGS) has a diagnostic yield of ≈70-80%, leaving the remaining more challenging cases to be resolved by second-tier testing methods. This study describes the phenotypic reassessment of patients with a negative result from first-tier pNGS and the rationale, outcomes, and cost of second-tier genetic testing approaches. Removing non-IRD cases from consideration and utilizing case-appropriate second-tier genetic testing techniques, we genetically resolved 56% of previously unresolved pedigrees, bringing the overall resolve rate to 92% (388/423). At present, pNGS remains the most cost-effective first-tier approach for the molecular assessment of diverse IRD populations Second-tier genetic testing should be guided by clinical (i.e., reassessment, multimodal imaging, electrophysiology), and genetic (i.e., single alleles in autosomal recessive disease) indications to achieve a genetic diagnosis in the most cost-effective manner.
Collapse
|
10
|
Fadaie Z, Whelan L, Ben-Yosef T, Dockery A, Corradi Z, Gilissen C, Haer-Wigman L, Corominas J, Astuti GDN, de Rooij L, van den Born LI, Klaver CCW, Hoyng CB, Wynne N, Duignan ES, Kenna PF, Cremers FPM, Farrar GJ, Roosing S. Whole genome sequencing and in vitro splice assays reveal genetic causes for inherited retinal diseases. NPJ Genom Med 2021; 6:97. [PMID: 34795310 PMCID: PMC8602293 DOI: 10.1038/s41525-021-00261-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 10/21/2021] [Indexed: 01/08/2023] Open
Abstract
Inherited retinal diseases (IRDs) are a major cause of visual impairment. These clinically heterogeneous disorders are caused by pathogenic variants in more than 270 genes. As 30-40% of cases remain genetically unexplained following conventional genetic testing, we aimed to obtain a genetic diagnosis in an IRD cohort in which the genetic cause was not found using whole-exome sequencing or targeted capture sequencing. We performed whole-genome sequencing (WGS) to identify causative variants in 100 unresolved cases. After initial prioritization, we performed an in-depth interrogation of all noncoding and structural variants in genes when one candidate variant was detected. In addition, functional analysis of putative splice-altering variants was performed using in vitro splice assays. We identified the genetic cause of the disease in 24 patients. Causative coding variants were observed in genes such as ATXN7, CEP78, EYS, FAM161A, and HGSNAT. Gene disrupting structural variants were also detected in ATXN7, PRPF31, and RPGRIP1. In 14 monoallelic cases, we prioritized candidate noncanonical splice sites or deep-intronic variants that were predicted to disrupt the splicing process based on in silico analyses. Of these, seven cases were resolved as they carried pathogenic splice defects. WGS is a powerful tool to identify causative variants residing outside coding regions or heterozygous structural variants. This approach was most efficient in cases with a distinct clinical diagnosis. In addition, in vitro splice assays provide important evidence of the pathogenicity of rare variants.
Collapse
Affiliation(s)
- Zeinab Fadaie
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Laura Whelan
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Tamar Ben-Yosef
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Adrian Dockery
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Zelia Corradi
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lonneke Haer-Wigman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jordi Corominas
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Galuh D N Astuti
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Division of Human Genetics, Center for Biomedical Research (CEBIOR), Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - Laura de Rooij
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Caroline C W Klaver
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Carel B Hoyng
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Niamh Wynne
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - Emma S Duignan
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - Paul F Kenna
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - G Jane Farrar
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
| |
Collapse
|
11
|
Next-Generation Sequencing Applications for Inherited Retinal Diseases. Int J Mol Sci 2021; 22:ijms22115684. [PMID: 34073611 PMCID: PMC8198572 DOI: 10.3390/ijms22115684] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal diseases (IRDs) represent a collection of phenotypically and genetically diverse conditions. IRDs phenotype(s) can be isolated to the eye or can involve multiple tissues. These conditions are associated with diverse forms of inheritance, and variants within the same gene often can be associated with multiple distinct phenotypes. Such aspects of the IRDs highlight the difficulty met when establishing a genetic diagnosis in patients. Here we provide an overview of cutting-edge next-generation sequencing techniques and strategies currently in use to maximise the effectivity of IRD gene screening. These techniques have helped researchers globally to find elusive causes of IRDs, including copy number variants, structural variants, new IRD genes and deep intronic variants, among others. Resolving a genetic diagnosis with thorough testing enables a more accurate diagnosis and more informed prognosis and should also provide information on inheritance patterns which may be of particular interest to patients of a child-bearing age. Given that IRDs are heritable conditions, genetic counselling may be offered to help inform family planning, carrier testing and prenatal screening. Additionally, a verified genetic diagnosis may enable access to appropriate clinical trials or approved medications that may be available for the condition.
Collapse
|
12
|
Truty R, Ouyang K, Rojahn S, Garcia S, Colavin A, Hamlington B, Freivogel M, Nussbaum RL, Nykamp K, Aradhya S. Spectrum of splicing variants in disease genes and the ability of RNA analysis to reduce uncertainty in clinical interpretation. Am J Hum Genet 2021; 108:696-708. [PMID: 33743207 PMCID: PMC8059334 DOI: 10.1016/j.ajhg.2021.03.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/02/2021] [Indexed: 12/20/2022] Open
Abstract
The complexities of gene expression pose challenges for the clinical interpretation of splicing variants. To better understand splicing variants and their contribution to hereditary disease, we evaluated their prevalence, clinical classifications, and associations with diseases, inheritance, and functional characteristics in a 689,321-person clinical cohort and two large public datasets. In the clinical cohort, splicing variants represented 13% of all variants classified as pathogenic (P), likely pathogenic (LP), or variants of uncertain significance (VUSs). Most splicing variants were outside essential splice sites and were classified as VUSs. Among all individuals tested, 5.4% had a splicing VUS. If RNA analysis were to contribute supporting evidence to variant interpretation, we estimated that splicing VUSs would be reclassified in 1.7% of individuals in our cohort. This would result in a clinically significant result (i.e., P/LP) in 0.1% of individuals overall because most reclassifications would change VUSs to likely benign. In ClinVar, splicing VUSs were 4.8% of reported variants and could benefit from RNA analysis. In the Genome Aggregation Database (gnomAD), splicing variants comprised 9.4% of variants in protein-coding genes; most were rare, precluding unambiguous classification as benign. Splicing variants were depleted in genes associated with dominant inheritance and haploinsufficiency, although some genes had rare variants at essential splice sites or had common splicing variants that were most likely compatible with normal gene function. Overall, we describe the contribution of splicing variants to hereditary disease, the potential utility of RNA analysis for reclassifying splicing VUSs, and how natural variation may confound clinical interpretation of splicing variants.
Collapse
Affiliation(s)
| | - Karen Ouyang
- Invitae, 1400 16th St, San Francisco, CA 94103, USA
| | - Susan Rojahn
- Invitae, 1400 16th St, San Francisco, CA 94103, USA
| | - Sarah Garcia
- Invitae, 1400 16th St, San Francisco, CA 94103, USA
| | | | | | | | | | - Keith Nykamp
- Invitae, 1400 16th St, San Francisco, CA 94103, USA
| | | |
Collapse
|
13
|
Whelan L, Dockery A, Wynne N, Zhu J, Stephenson K, Silvestri G, Turner J, O’Byrne JJ, Carrigan M, Humphries P, Keegan D, Kenna PF, Farrar GJ. Findings from a Genotyping Study of Over 1000 People with Inherited Retinal Disorders in Ireland. Genes (Basel) 2020; 11:E105. [PMID: 31963381 PMCID: PMC7016747 DOI: 10.3390/genes11010105] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 12/13/2019] [Accepted: 01/13/2020] [Indexed: 12/15/2022] Open
Abstract
The Irish national registry for inherited retinal degenerations (Target 5000) is a clinical and scientific program to identify individuals in Ireland with inherited retinal disorders and to attempt to ascertain the genetic cause underlying the disease pathology. Potential participants first undergo a clinical assessment, which includes clinical history and analysis with multimodal retinal imaging, electrophysiology, and visual field testing. If suitable for recruitment, a sample is taken and used for genetic analysis. Genetic analysis is conducted by use of a retinal gene panel target capture sequencing approach. With over 1000 participants from 710 pedigrees now screened, there is a positive candidate variant detection rate of approximately 70% (495/710). Where an autosomal recessive inheritance pattern is observed, an additional 9% (64/710) of probands have tested positive for a single candidate variant. Many novel variants have also been detected as part of this endeavor. The target capture approach is an economic and effective means of screening patients with inherited retinal disorders. Despite the advances in sequencing technology and the ever-decreasing associated processing costs, target capture remains an attractive option as the data produced is easily processed, analyzed, and stored compared to more comprehensive methods. However, with decreasing costs of whole genome and whole exome sequencing, the focus will likely move towards these methods for more comprehensive data generation.
Collapse
Affiliation(s)
- Laura Whelan
- The School of Genetics & Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (A.D.); (M.C.); (P.H.); (P.F.K.); (G.J.F.)
| | - Adrian Dockery
- The School of Genetics & Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (A.D.); (M.C.); (P.H.); (P.F.K.); (G.J.F.)
| | - Niamh Wynne
- The Research Foundation, Royal Victoria Eye and Ear Hospital, D02 XK51 Dublin, Ireland;
| | - Julia Zhu
- Clinical Genetics Centre for Ophthalmology, The Mater Misericordiae University Hospital, D07 R2WY Dublin, Ireland; (J.Z.); (K.S.); (J.T.); (J.J.O.); (D.K.)
| | - Kirk Stephenson
- Clinical Genetics Centre for Ophthalmology, The Mater Misericordiae University Hospital, D07 R2WY Dublin, Ireland; (J.Z.); (K.S.); (J.T.); (J.J.O.); (D.K.)
| | - Giuliana Silvestri
- Department of Ophthalmology, The Royal Victoria Hospital, Belfast BT12 6BA, Northern Ireland, UK;
- Centre for Experimental Medicine, Queen’s University Belfast, Belfast BT7 1NN, Northern Ireland, UK
| | - Jacqueline Turner
- Clinical Genetics Centre for Ophthalmology, The Mater Misericordiae University Hospital, D07 R2WY Dublin, Ireland; (J.Z.); (K.S.); (J.T.); (J.J.O.); (D.K.)
| | - James J. O’Byrne
- Clinical Genetics Centre for Ophthalmology, The Mater Misericordiae University Hospital, D07 R2WY Dublin, Ireland; (J.Z.); (K.S.); (J.T.); (J.J.O.); (D.K.)
| | - Matthew Carrigan
- The School of Genetics & Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (A.D.); (M.C.); (P.H.); (P.F.K.); (G.J.F.)
| | - Peter Humphries
- The School of Genetics & Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (A.D.); (M.C.); (P.H.); (P.F.K.); (G.J.F.)
| | - David Keegan
- Clinical Genetics Centre for Ophthalmology, The Mater Misericordiae University Hospital, D07 R2WY Dublin, Ireland; (J.Z.); (K.S.); (J.T.); (J.J.O.); (D.K.)
| | - Paul F. Kenna
- The School of Genetics & Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (A.D.); (M.C.); (P.H.); (P.F.K.); (G.J.F.)
- The Research Foundation, Royal Victoria Eye and Ear Hospital, D02 XK51 Dublin, Ireland;
| | - G. Jane Farrar
- The School of Genetics & Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (A.D.); (M.C.); (P.H.); (P.F.K.); (G.J.F.)
| |
Collapse
|
14
|
Verbakel SK, Fadaie Z, Klevering BJ, van Genderen MM, Feenstra I, Cremers FPM, Hoyng CB, Roosing S. The identification of a RNA splice variant in TULP1 in two siblings with early-onset photoreceptor dystrophy. Mol Genet Genomic Med 2019; 7:e660. [PMID: 30950243 PMCID: PMC6565574 DOI: 10.1002/mgg3.660] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 02/21/2019] [Accepted: 03/04/2019] [Indexed: 12/23/2022] Open
Abstract
Background Early‐onset photoreceptor dystrophies are a major cause of irreversible visual impairment in children and young adults. This clinically heterogeneous group of disorders can be caused by mutations in many genes. Nevertheless, to date, 30%–40% of cases remain genetically unexplained. In view of expanding therapeutic options, it is essential to obtain a molecular diagnosis in these patients as well. In this study, we aimed to identify the genetic cause in two siblings with genetically unexplained retinal disease. Methods Whole exome sequencing was performed to identify the causative variants in two siblings in whom a single pathogenic variant in TULP1 was found previously. Patients were clinically evaluated, including assessment of the medical history, slit‐lamp biomicroscopy, and ophthalmoscopy. In addition, a functional analysis of the putative splice variant in TULP1 was performed using a midigene assay. Results Clinical assessment showed a typical early‐onset photoreceptor dystrophy in both the patients. Whole exome sequencing identified two pathogenic variants in TULP1, a c.1445G>A (p.(Arg482Gln)) missense mutation and an intronic c.718+23G>A variant. Segregation analysis confirmed that both siblings were compound heterozygous for the TULP1 c.718+23G>A and c.1445G>A variants, while the unaffected parents were heterozygous. The midigene assay for the c.718+23G>A variant confirmed an elongation of exon 7 leading to a frameshift. Conclusion Here, we report the first near‐exon RNA splice variant that is not present in a consensus splice site sequence in TULP1, which was found in a compound heterozygous manner with a previously described pathogenic TULP1 variant in two patients with an early‐onset photoreceptor dystrophy. We provide proof of pathogenicity for this splice variant by performing an in vitro midigene splice assay, and highlight the importance of analysis of noncoding regions beyond the noncanonical splice sites in patients with inherited retinal diseases.
Collapse
Affiliation(s)
- Sanne K Verbakel
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Zeinab Fadaie
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - B Jeroen Klevering
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maria M van Genderen
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands.,Department of Ophthalmology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ilse Feenstra
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| |
Collapse
|