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Khan AO. Usher syndrome in the United Arab Emirates. Ophthalmic Genet 2024:1-5. [PMID: 39016003 DOI: 10.1080/13816810.2024.2374866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 06/26/2024] [Indexed: 07/18/2024]
Abstract
PURPOSE Usher syndrome, a common form of syndromic inherited retinal dystrophy in the Arabian Gulf, has not been molecularly defined in the United Arab Emirates. The current study addresses this gap in knowledge. METHODS A retrospective case series of Emirati patients referred to the Ocular Genetics Clinic of Cleveland Clinic Abu Dhabi who (1) were clinically diagnosed with Usher syndrome and underwent genetic testing (whole exome sequencing, 2019 to 2023, inclusive) and (2) were identified to have biallelic pathogenic variants in Usher syndrome genes during the same time period. RESULTS Ten probands (thirteen patients) were identified-seven probands (nine patients) with clinically diagnosed Usher syndrome and three additional probands (four patients) with biallelic homozygous USH2A variants. Among the seven probands initially diagnosed with Usher syndrome, six had different homozygous variants (three in MYO7A, one in ADGRV1, and one in CLRN1), one had dual diagnoses rather than Usher syndrome (i.e. separate cause for retinal dystrophy and deafness), and one had no identifiable genetic cause. Regarding the three additional probands identified with homozygous USH2A variants, all three had retinitis pigmentosa only rather than Usher syndrome and all three had different variants. DISCUSSION Clinically diagnosed Usher syndrome was genetically heterogenous without evidence for founder effect in this Emirati cohort. MYO7A was the most common associated gene. Dual diagnosis rather than single cause can mimic Usher syndrome. Homozygous USH2A variants were not identified as a cause for Usher syndrome in this cohort but were a recurrent cause for retinitis pigmentosa without hearing impairment and without founder effect.
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Affiliation(s)
- Arif O Khan
- Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, UAE
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of CWRU, Cleveland, Ohio, USA
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2
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Marafi D. Founder mutations and rare disease in the Arab world. Dis Model Mech 2024; 17:dmm050715. [PMID: 38922202 PMCID: PMC11225585 DOI: 10.1242/dmm.050715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024] Open
Abstract
Founder mutations are disease-causing variants that occur frequently in geographically or culturally isolated groups whose shared ancestor(s) carried the pathogenic variant. While some disease alleles may vanish from the genetic pool due to natural selection, variants with weaker effects may survive for a long time, thereby enhancing the prevalence of some rare diseases. These are predominantly autosomal recessive diseases but can also be autosomal dominant traits with late-onset or mild phenotypes. Cultural practices, such as endogamy and consanguinity, in these isolated groups lead to higher prevalence of such rare diseases compared to the rest of the population and worldwide. In this Perspective, we define population isolates and the underlying genetic mechanisms for accumulating founder mutations. We also discuss the current and potential scientific, clinical and public-health implications of studying founder mutations in population isolates around the world, with a particular focus on the Arab population.
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Affiliation(s)
- Dana Marafi
- Department of Pediatrics, College of Medicine, Kuwait University, P.O. Box 24923, 13110 Safat, Kuwait
- Section of Child Neurology, Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya 52700, Kuwait
- Kuwait Medical Genetics Centre, Ministry of Health, Sulaibikhat 80901, Kuwait
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3
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Nabavizadeh N, Bressin A, Shboul M, Moreno Traspas R, Chia PH, Bonnard C, Szenker‐Ravi E, Sarıbaş B, Beillard E, Altunoglu U, Hojati Z, Drutman S, Freier S, El‐Khateeb M, Fathallah R, Casanova J, Soror W, Arafat A, Escande‐Beillard N, Mayer A, Reversade B. A progeroid syndrome caused by a deep intronic variant in TAPT1 is revealed by RNA/SI-NET sequencing. EMBO Mol Med 2023; 15:e16478. [PMID: 36652330 PMCID: PMC9906387 DOI: 10.15252/emmm.202216478] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 01/19/2023] Open
Abstract
Exome sequencing has introduced a paradigm shift for the identification of germline variations responsible for Mendelian diseases. However, non-coding regions, which make up 98% of the genome, cannot be captured. The lack of functional annotation for intronic and intergenic variants makes RNA-seq a powerful companion diagnostic. Here, we illustrate this point by identifying six patients with a recessive Osteogenesis Imperfecta (OI) and neonatal progeria syndrome. By integrating homozygosity mapping and RNA-seq, we delineated a deep intronic TAPT1 mutation (c.1237-52 G>A) that segregated with the disease. Using SI-NET-seq, we document that TAPT1's nascent transcription was not affected in patients' fibroblasts, indicating instead that this variant leads to an alteration of pre-mRNA processing. Predicted to serve as an alternative splicing branchpoint, this mutation enhances TAPT1 exon 12 skipping, creating a protein-null allele. Additionally, our study reveals dysregulation of pathways involved in collagen and extracellular matrix biology in disease-relevant cells. Overall, our work highlights the power of transcriptomic approaches in deciphering the repercussions of non-coding variants, as well as in illuminating the molecular mechanisms of human diseases.
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Affiliation(s)
- Nasrinsadat Nabavizadeh
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
- Division of Genetics, Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and TechnologyUniversity of IsfahanIsfahanIran
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
| | | | - Mohammad Shboul
- Department of Medical Laboratory SciencesJordan University of Science and TechnologyIrbidJordan
| | - Ricardo Moreno Traspas
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
| | - Poh Hui Chia
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
| | - Carine Bonnard
- Model Development, A*STAR Skin Research Labs (A*SRL)Singapore CitySingapore
| | - Emmanuelle Szenker‐Ravi
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
| | - Burak Sarıbaş
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
| | | | - Umut Altunoglu
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
| | - Zohreh Hojati
- Division of Genetics, Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and TechnologyUniversity of IsfahanIsfahanIran
| | - Scott Drutman
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller BranchRockefeller UniversityNew YorkNYUSA
| | - Susanne Freier
- Max Planck Institute for Molecular GeneticsBerlinGermany
| | | | - Rajaa Fathallah
- National Center for Diabetes, Endocrinology and GeneticsAmmanJordan
| | - Jean‐Laurent Casanova
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller BranchRockefeller UniversityNew YorkNYUSA
- Laboratory of Human Genetics of Infectious Diseases, Necker BranchINSERM U1163, Necker Hospital for Sick ChildrenParisFrance
- Imagine InstituteUniversity of ParisParisFrance
- Howard Hughes Medical InstituteNew YorkNYUSA
- Pediatric Hematology and Immunology UnitNecker Hospital for Sick ChildrenParisFrance
| | - Wesam Soror
- National Center for Diabetes, Endocrinology and GeneticsAmmanJordan
| | - Alaa Arafat
- National Center for Diabetes, Endocrinology and GeneticsAmmanJordan
| | - Nathalie Escande‐Beillard
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
- Institute of Molecular and Cell Biology, A*STARSingapore CitySingapore
| | - Andreas Mayer
- Max Planck Institute for Molecular GeneticsBerlinGermany
| | - Bruno Reversade
- Laboratory of Human Genetics & TherapeuticsGenome Institute of Singapore, A*STARSingapore CitySingapore
- Medical Genetics DepartmentKoç University School of MedicineIstanbulTurkey
- Institute of Molecular and Cell Biology, A*STARSingapore CitySingapore
- Department of PaediatricsNational University of SingaporeSingapore CitySingapore
- Smart‐Health Initiative, BESE, KAUSTThuwalKingdom of Saudi Arabia
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4
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Towards a Cure for HARS Disease. Genes (Basel) 2023; 14:genes14020254. [PMID: 36833180 PMCID: PMC9956352 DOI: 10.3390/genes14020254] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/20/2023] Open
Abstract
Histidyl-tRNA synthetase (HARS) ligates histidine to its cognate transfer RNA (tRNAHis). Mutations in HARS cause the human genetic disorders Usher syndrome type 3B (USH3B) and Charcot-Marie-Tooth syndrome type 2W (CMT2W). Treatment for these diseases remains symptomatic, and no disease specific treatments are currently available. Mutations in HARS can lead to destabilization of the enzyme, reduced aminoacylation, and decreased histidine incorporation into the proteome. Other mutations lead to a toxic gain-of-function and mistranslation of non-cognate amino acids in response to histidine codons, which can be rescued by histidine supplementation in vitro. We discuss recent advances in characterizing HARS mutations and potential applications of amino acid and tRNA therapy for future gene and allele specific therapy.
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5
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Robillard KN, de Vrieze E, van Wijk E, Lentz JJ. Altering gene expression using antisense oligonucleotide therapy for hearing loss. Hear Res 2022; 426:108523. [PMID: 35649738 DOI: 10.1016/j.heares.2022.108523] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 04/20/2022] [Accepted: 05/14/2022] [Indexed: 12/12/2022]
Abstract
Hearing loss affects more than 430 million people, worldwide, and is the third most common chronic physical condition in the United States and Europe (GBD Hearing Loss Collaborators, 2021; NIOSH, 2021; WHO, 2021). The loss of hearing significantly impacts motor and cognitive development, communication, education, employment, and overall quality of life. The inner ear houses the sensory organs for both hearing and balance and provides an accessible target for therapeutic delivery. Antisense oligonucleotides (ASOs) use various mechanisms to manipulate gene expression and can be tailor-made to treat disorders with defined genetic targets. In this review, we discuss the preclinical advancements within the field of the highly promising ASO-based therapies for hereditary hearing loss disorders. Particular focus is on ASO mechanisms of action, preclinical studies on ASO treatments of hearing loss, timing of therapeutic intervention, and delivery routes to the inner ear.
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Affiliation(s)
| | - Erik de Vrieze
- Department of Otorhinolaryngology, RUMC, Geert Grooteplein 10, Route 855, GA, Nijmegen 6525, the Netherlands; Donders Institute for Brain, Cognition, and Behavior, RUMC, Nijmegen, NL
| | - Erwin van Wijk
- Department of Otorhinolaryngology, RUMC, Geert Grooteplein 10, Route 855, GA, Nijmegen 6525, the Netherlands; Donders Institute for Brain, Cognition, and Behavior, RUMC, Nijmegen, NL.
| | - Jennifer J Lentz
- Neuroscience Center of Excellence, LSUHSC, New Orleans, LA, USA; Department of Otorhinolaryngology, LSUHSC, 2020 Gravier Street, Lions Building, Room 795, New Orleans, LA, USA.
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Daich Varela M, Bellingham J, Motta F, Jurkute N, Ellingford JM, Quinodoz M, Oprych K, Niblock M, Janeschitz-Kriegl L, Kaminska K, Cancellieri F, Scholl HPN, Lenassi E, Schiff E, Knight H, Black G, Rivolta C, Cheetham ME, Michaelides M, Mahroo OA, Moore AT, Webster AR, Arno G. Multidisciplinary team directed analysis of whole genome sequencing reveals pathogenic non-coding variants in molecularly undiagnosed inherited retinal dystrophies. Hum Mol Genet 2022; 32:595-607. [PMID: 36084042 PMCID: PMC9896476 DOI: 10.1093/hmg/ddac227] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/23/2022] [Accepted: 09/04/2022] [Indexed: 02/07/2023] Open
Abstract
The purpose of this paper is to identify likely pathogenic non-coding variants in inherited retinal dystrophy (IRD) genes, using genome sequencing (GS). Patients with IRD were recruited to the study and underwent comprehensive ophthalmological evaluation and GS. The results of GS were investigated through virtual gene panel analysis, and plausible pathogenic variants and clinical phenotype evaluated by the multidisciplinary team (MDT) discussion. For unsolved patients in whom a specific gene was suspected to harbor a missed pathogenic variant, targeted re-analysis of non-coding regions was performed on GS data. Candidate variants were functionally tested by messenger RNA analysis, minigene or luciferase reporter assays. Previously unreported, likely pathogenic, non-coding variants in 7 genes (PRPF31, NDP, IFT140, CRB1, USH2A, BBS10 and GUCY2D), were identified in 11 patients. These were shown to lead to mis-splicing (PRPF31, IFT140, CRB1 and USH2A) or altered transcription levels (BBS10 and GUCY2D). MDT-led, phenotype-driven, non-coding variant re-analysis of GS is effective in identifying the missing causative alleles.
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Affiliation(s)
- Malena Daich Varela
- UCL Institute of Ophthalmology, London EC1V 9EL, UK,Moorfields Eye Hospital, London EC1V 2PD, UK
| | | | - Fabiana Motta
- UCL Institute of Ophthalmology, London EC1V 9EL, UK,Department of Ophthalmology, Universidade Federal de Sao Paulo, Sao Paulo 04021001, Brazil
| | - Neringa Jurkute
- UCL Institute of Ophthalmology, London EC1V 9EL, UK,Moorfields Eye Hospital, London EC1V 2PD, UK
| | - Jamie M Ellingford
- North West Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, St Mary’s Hospital, Manchester M13 9WL, UK,Division of Evolution and Genomic Sciences, Neuroscience and Mental Health Domain, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Mathieu Quinodoz
- Institute of Molecular and Clinical Ophthalmology Basel, Basel 4031, Switzerland,Department of Ophthalmology, University of Basel, Basel 4031, Switzerland,Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | | | | | - Lucas Janeschitz-Kriegl
- Institute of Molecular and Clinical Ophthalmology Basel, Basel 4031, Switzerland,Department of Ophthalmology, University of Basel, Basel 4031, Switzerland
| | - Karolina Kaminska
- Institute of Molecular and Clinical Ophthalmology Basel, Basel 4031, Switzerland,Department of Ophthalmology, University of Basel, Basel 4031, Switzerland
| | - Francesca Cancellieri
- Institute of Molecular and Clinical Ophthalmology Basel, Basel 4031, Switzerland,Department of Ophthalmology, University of Basel, Basel 4031, Switzerland
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology Basel, Basel 4031, Switzerland,Department of Ophthalmology, University of Basel, Basel 4031, Switzerland
| | - Eva Lenassi
- North West Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, St Mary’s Hospital, Manchester M13 9WL, UK,Division of Evolution and Genomic Sciences, Neuroscience and Mental Health Domain, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | | | | | - Graeme Black
- North West Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, St Mary’s Hospital, Manchester M13 9WL, UK,Division of Evolution and Genomic Sciences, Neuroscience and Mental Health Domain, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Carlo Rivolta
- Institute of Molecular and Clinical Ophthalmology Basel, Basel 4031, Switzerland,Department of Ophthalmology, University of Basel, Basel 4031, Switzerland,Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | | | - Michel Michaelides
- UCL Institute of Ophthalmology, London EC1V 9EL, UK,Moorfields Eye Hospital, London EC1V 2PD, UK
| | - Omar A Mahroo
- UCL Institute of Ophthalmology, London EC1V 9EL, UK,Moorfields Eye Hospital, London EC1V 2PD, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, London EC1V 9EL, UK,Moorfields Eye Hospital, London EC1V 2PD, UK,University of California, San Francisco, CA 94607, USA
| | - Andrew R Webster
- UCL Institute of Ophthalmology, London EC1V 9EL, UK,Moorfields Eye Hospital, London EC1V 2PD, UK
| | - Gavin Arno
- To whom correspondence should be addressed at: UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1 9EL, UK. Tel: +44 2076086971;
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Avraham KB, Khalaily L, Noy Y, Kamal L, Koffler-Brill T, Taiber S. The noncoding genome and hearing loss. Hum Genet 2022; 141:323-333. [PMID: 34491412 DOI: 10.1007/s00439-021-02359-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/29/2021] [Indexed: 12/16/2022]
Abstract
The age of sequencing has provided unprecedented insights into the human genome. The coding region of the genome comprises nearly 20,000 genes, of which approximately 4000 are associated with human disease. Beyond the protein-coding genome, which accounts for only 3% of the genome, lies a vast pool of regulatory elements in the form of promoters, enhancers, RNA species, and other intricate elements. These features undoubtably influence human health and disease, and as a result, a great deal of effort is currently being invested in deciphering their identity and mechanism. While a paucity of material has caused a lag in identifying these elements in the inner ear, the emergence of technologies for dealing with a minimal number of cells now has the field working overtime to catch up. Studies on microRNAs (miRNAs), long non-coding RNAs (lncRNAs), methylation, histone modifications, and more are ongoing. A number of microRNAs and other noncoding elements are known to be associated with hearing impairment and there is promise that regulatory elements will serve as future tools and targets of therapeutics and diagnostics. This review covers the current state of the field and considers future directions for the noncoding genome and implications for hearing loss.
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Affiliation(s)
- Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel.
| | - Lama Khalaily
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Yael Noy
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Lara Kamal
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Tal Koffler-Brill
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Shahar Taiber
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, 6997801, Tel Aviv, Israel
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The genetic and phenotypic landscapes of Usher syndrome: from disease mechanisms to a new classification. Hum Genet 2022; 141:709-735. [PMID: 35353227 PMCID: PMC9034986 DOI: 10.1007/s00439-022-02448-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/04/2022] [Indexed: 12/16/2022]
Abstract
Usher syndrome (USH) is the most common cause of deaf–blindness in humans, with a prevalence of about 1/10,000 (~ 400,000 people worldwide). Cochlear implants are currently used to reduce the burden of hearing loss in severe-to-profoundly deaf patients, but many promising treatments including gene, cell, and drug therapies to restore the native function of the inner ear and retinal sensory cells are under investigation. The traditional clinical classification of Usher syndrome defines three major subtypes—USH1, 2 and 3—according to hearing loss severity and onset, the presence or absence of vestibular dysfunction, and age at onset of retinitis pigmentosa. Pathogenic variants of nine USH genes have been initially reported: MYO7A, USH1C, PCDH15, CDH23, and USH1G for USH1, USH2A, ADGRV1, and WHRN for USH2, and CLRN1 for USH3. Based on the co-occurrence of hearing and vision deficits, the list of USH genes has been extended to few other genes, but with limited supporting information. A consensus on combined criteria for Usher syndrome is crucial for the development of accurate diagnosis and to improve patient management. In recent years, a wealth of information has been obtained concerning the properties of the Usher proteins, related molecular networks, potential genotype–phenotype correlations, and the pathogenic mechanisms underlying the impairment or loss of hearing, balance and vision. The advent of precision medicine calls for a clear and more precise diagnosis of Usher syndrome, exploiting all the existing data to develop a combined clinical/genetic/network/functional classification for Usher syndrome.
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Usher syndrome IIIA: a review of the disorder and preclinical research advances in therapeutic approaches. Hum Genet 2022; 141:759-783. [PMID: 35320418 DOI: 10.1007/s00439-022-02446-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/03/2022] [Indexed: 12/27/2022]
Abstract
Usher syndrome (USH) is an autosomal recessive disorder characterized by sensorineural hearing loss, progressive pigmentary retinopathy, and vestibular dysfunction. The degree and onset of hearing loss vary among subtypes I, II, and III, while blindness often occurs in the second to fourth decades of life. Usher type III (USH3), characterized by postlingual progressive sensorineural hearing loss, varying levels of vestibular dysfunction, and varying degrees of visual impairment, typically manifests in the first to second decades of life. While USH3 is rare, it is highly prevalent in certain populations. RP61, USH3, and USH3A symbolize the same disorder, with the latter symbol used more frequently in recent literature. This review focuses on the clinical features, epidemiology, molecular genetics, treatment, and research advances for sensory deficits in USH3A.
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Yadegari H, Jamil MA, Marquardt N, Oldenburg J. A Homozygous Deep Intronic Variant Causes Von Willebrand Factor Deficiency and Lack of Endothelial-Specific Secretory Organelles, Weibel-Palade Bodies. Int J Mol Sci 2022; 23:ijms23063095. [PMID: 35328514 PMCID: PMC8950443 DOI: 10.3390/ijms23063095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/26/2022] [Accepted: 03/01/2022] [Indexed: 11/16/2022] Open
Abstract
A type 3 von Willebrand disease (VWD) index patient (IP) remains mutation-negative after completion of the conventional diagnostic analysis, including multiplex ligation-dependent probe amplification and sequencing of the promoter, exons, and flanking intronic regions of the VWF gene (VWF). In this study, we intended to elucidate causative mutation through next-generation sequencing (NGS) of the whole VWF (including complete intronic region), mRNA analysis, and study of the patient-derived endothelial colony-forming cells (ECFCs). The NGS revealed a variant in the intronic region of VWF (997 + 118 T > G in intron 8), for the first time. The bioinformatics assessments (e.g., SpliceAl) predicted this variant creates a new donor splice site (ss), which could outcompete the consensus 5′ donor ss at exon/intron 8. This would lead to an aberrant mRNA that contains a premature stop codon, targeting it to nonsense-mediated mRNA decay. The subsequent quantitative real-time PCR confirmed the virtual absence of VWF mRNA in IP ECFCs. Additionally, the IP ECFCs demonstrated a considerable reduction in VWF secretion (~6% of healthy donors), and they were devoid of endothelial-specific secretory organelles, Weibel−Palade bodies. Our findings underline the potential of NGS in conjunction with RNA analysis and patient-derived cell studies for genetic diagnosis of mutation-negative type 3 VWD patients.
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Affiliation(s)
- Hamideh Yadegari
- Correspondence: (H.Y.); (J.O.); Tel.: +49-228-287-10532 (H.Y.); +49-228-287-15175 (J.O.)
| | | | | | - Johannes Oldenburg
- Correspondence: (H.Y.); (J.O.); Tel.: +49-228-287-10532 (H.Y.); +49-228-287-15175 (J.O.)
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11
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Keegan NP, Wilton SD, Fletcher S. Analysis of Pathogenic Pseudoexons Reveals Novel Mechanisms Driving Cryptic Splicing. Front Genet 2022; 12:806946. [PMID: 35140743 PMCID: PMC8819188 DOI: 10.3389/fgene.2021.806946] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/09/2021] [Indexed: 12/16/2022] Open
Abstract
Understanding pre-mRNA splicing is crucial to accurately diagnosing and treating genetic diseases. However, mutations that alter splicing can exert highly diverse effects. Of all the known types of splicing mutations, perhaps the rarest and most difficult to predict are those that activate pseudoexons, sometimes also called cryptic exons. Unlike other splicing mutations that either destroy or redirect existing splice events, pseudoexon mutations appear to create entirely new exons within introns. Since exon definition in vertebrates requires coordinated arrangements of numerous RNA motifs, one might expect that pseudoexons would only arise when rearrangements of intronic DNA create novel exons by chance. Surprisingly, although such mutations do occur, a far more common cause of pseudoexons is deep-intronic single nucleotide variants, raising the question of why these latent exon-like tracts near the mutation sites have not already been purged from the genome by the evolutionary advantage of more efficient splicing. Possible answers may lie in deep intronic splicing processes such as recursive splicing or poison exon splicing. Because these processes utilize intronic motifs that benignly engage with the spliceosome, the regions involved may be more susceptible to exonization than other intronic regions would be. We speculated that a comprehensive study of reported pseudoexons might detect alignments with known deep intronic splice sites and could also permit the characterisation of novel pseudoexon categories. In this report, we present and analyse a catalogue of over 400 published pseudoexon splice events. In addition to confirming prior observations of the most common pseudoexon mutation types, the size of this catalogue also enabled us to suggest new categories for some of the rarer types of pseudoexon mutation. By comparing our catalogue against published datasets of non-canonical splice events, we also found that 15.7% of pseudoexons exhibit some splicing activity at one or both of their splice sites in non-mutant cells. Importantly, this included seven examples of experimentally confirmed recursive splice sites, confirming for the first time a long-suspected link between these two splicing phenomena. These findings have the potential to improve the fidelity of genetic diagnostics and reveal new targets for splice-modulating therapies.
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Affiliation(s)
- Niall P. Keegan
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
- *Correspondence: Niall P. Keegan,
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
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12
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Genetic etiology of hereditary hearing loss in the Gulf Cooperation Council countries. Hum Genet 2021; 141:595-605. [PMID: 34338889 DOI: 10.1007/s00439-021-02323-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 07/19/2021] [Indexed: 10/20/2022]
Abstract
The past 30 years have seen an exponential growth concerning the identification of genes and variants responsible for hereditary hearing loss (HL) worldwide. This has led to a huge gain in our understanding of molecular mechanisms of hearing and deafness, which improved diagnosis for populations with hereditary HL. Many communities around the world, especially in the Middle East and North Africa, have a high prevalence of consanguineous marriages. Congenital monogenic conditions, such as recessive HL, are more common in these populations due to high consanguinity rates. Many studies have shown that high rates of consanguinity, endogamy, and first cousin marriages were observed in the six countries of the Gulf Cooperation Council (GCC). The intent of this study is to investigate the etiology of HL in the GCC region. A deep literature review of genes and variants responsible for HL in this region revealed 89 recessive DNA pathogenic variants reported in 138 cases/familial cases. A total of 21 genes responsible for non-syndromic hearing loss (NSHL) and 17 genes associated with syndromic hearing loss (SHL) were reported in cases from the GCC region. Out of 156 reported affected cases, 112 showed HL only, and 44 showed HL associated with other clinical manifestations. This data suggests that in the GCC region 72% of HL forms are non-syndromic and 28% are syndromic. For individuals with NSHL, 66% of variants were detected in four genes (GJB2, OTOF, TMC1 and CDH23), with a predominance of variants located in the GJB2 gene (37.5%). However, among SHL, Usher syndrome was the more frequent as it has been observed in 41% of the reported syndromic GCC cases. Finally, our analysis showed that HL genetics testing and research in the GCC region took advantage of the next generation sequencing (NGS)-based techniques, as approximately 58% of reported variants were identified using this technology.
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Ajiro M, Awaya T, Kim YJ, Iida K, Denawa M, Tanaka N, Kurosawa R, Matsushima S, Shibata S, Sakamoto T, Studer R, Krainer AR, Hagiwara M. Therapeutic manipulation of IKBKAP mis-splicing with a small molecule to cure familial dysautonomia. Nat Commun 2021; 12:4507. [PMID: 34301951 PMCID: PMC8302731 DOI: 10.1038/s41467-021-24705-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 06/21/2021] [Indexed: 01/10/2023] Open
Abstract
Approximately half of genetic disease-associated mutations cause aberrant splicing. However, a widely applicable therapeutic strategy to splicing diseases is yet to be developed. Here, we analyze the mechanism whereby IKBKAP-familial dysautonomia (FD) exon 20 inclusion is specifically promoted by a small molecule splice modulator, RECTAS, even though IKBKAP-FD exon 20 has a suboptimal 5' splice site due to the IVS20 + 6 T > C mutation. Knockdown experiments reveal that exon 20 inclusion is suppressed in the absence of serine/arginine-rich splicing factor 6 (SRSF6) binding to an intronic splicing enhancer in intron 20. We show that RECTAS directly interacts with CDC-like kinases (CLKs) and enhances SRSF6 phosphorylation. Consistently, exon 20 splicing is bidirectionally manipulated by targeting cellular CLK activity with RECTAS versus CLK inhibitors. The therapeutic potential of RECTAS is validated in multiple FD disease models. Our study indicates that small synthetic molecules affecting phosphorylation state of SRSFs is available as a new therapeutic modality for mechanism-oriented precision medicine of splicing diseases.
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Affiliation(s)
- Masahiko Ajiro
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tomonari Awaya
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Young Jin Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Kei Iida
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masatsugu Denawa
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Nobuo Tanaka
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ryo Kurosawa
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shingo Matsushima
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Saiko Shibata
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tetsunori Sakamoto
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Rolenz Studer
- Center for Stem Cell Biology, Sloan Kettering Institute, New York, NY, USA
| | | | - Masatoshi Hagiwara
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan. .,Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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14
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Fuster-García C, García-Bohórquez B, Rodríguez-Muñoz A, Aller E, Jaijo T, Millán JM, García-García G. Usher Syndrome: Genetics of a Human Ciliopathy. Int J Mol Sci 2021; 22:6723. [PMID: 34201633 PMCID: PMC8268283 DOI: 10.3390/ijms22136723] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/21/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive syndromic ciliopathy characterized by sensorineural hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. There are three clinical types depending on the severity and age of onset of the symptoms; in addition, ten genes are reported to be causative of USH, and six more related to the disease. These genes encode proteins of a diverse nature, which interact and form a dynamic protein network called the "Usher interactome". In the organ of Corti, the USH proteins are essential for the correct development and maintenance of the structure and cohesion of the stereocilia. In the retina, the USH protein network is principally located in the periciliary region of the photoreceptors, and plays an important role in the maintenance of the periciliary structure and the trafficking of molecules between the inner and the outer segments of photoreceptors. Even though some genes are clearly involved in the syndrome, others are controversial. Moreover, expression of some USH genes has been detected in other tissues, which could explain their involvement in additional mild comorbidities. In this paper, we review the genetics of Usher syndrome and the spectrum of mutations in USH genes. The aim is to identify possible mutation associations with the disease and provide an updated genotype-phenotype correlation.
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Affiliation(s)
- Carla Fuster-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Belén García-Bohórquez
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Ana Rodríguez-Muñoz
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Elena Aller
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Teresa Jaijo
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - José M. Millán
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Gema García-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
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15
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Splicing mutations in inherited retinal diseases. Prog Retin Eye Res 2021. [DOI: 10.1016/j.preteyeres.2020.100874
expr 921883647 + 833887994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
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16
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Shibata S, Ajiro M, Hagiwara M. Mechanism-Based Personalized Medicine for Cystic Fibrosis by Suppressing Pseudo Exon Inclusion. Cell Chem Biol 2020; 27:1472-1482.e6. [DOI: 10.1016/j.chembiol.2020.08.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/29/2020] [Accepted: 08/20/2020] [Indexed: 12/14/2022]
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17
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Joynt AT, Evans TA, Pellicore MJ, Davis-Marcisak EF, Aksit MA, Eastman AC, Patel SU, Paul KC, Osorio DL, Bowling AD, Cotton CU, Raraigh KS, West NE, Merlo CA, Cutting GR, Sharma N. Evaluation of both exonic and intronic variants for effects on RNA splicing allows for accurate assessment of the effectiveness of precision therapies. PLoS Genet 2020; 16:e1009100. [PMID: 33085659 PMCID: PMC7605713 DOI: 10.1371/journal.pgen.1009100] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 11/02/2020] [Accepted: 09/08/2020] [Indexed: 12/21/2022] Open
Abstract
Elucidating the functional consequence of molecular defects underlying genetic diseases enables appropriate design of therapeutic options. Treatment of cystic fibrosis (CF) is an exemplar of this paradigm as the development of CFTR modulator therapies has allowed for targeted and effective treatment of individuals harboring specific genetic variants. However, the mechanism of these drugs limits effectiveness to particular classes of variants that allow production of CFTR protein. Thus, assessment of the molecular mechanism of individual variants is imperative for proper assignment of these precision therapies. This is particularly important when considering variants that affect pre-mRNA splicing, thus limiting success of the existing protein-targeted therapies. Variants affecting splicing can occur throughout exons and introns and the complexity of the process of splicing lends itself to a variety of outcomes, both at the RNA and protein levels, further complicating assessment of disease liability and modulator response. To investigate the scope of this challenge, we evaluated splicing and downstream effects of 52 naturally occurring CFTR variants (exonic = 15, intronic = 37). Expression of constructs containing select CFTR intronic sequences and complete CFTR exonic sequences in cell line models allowed for assessment of RNA and protein-level effects on an allele by allele basis. Characterization of primary nasal epithelial cells obtained from individuals harboring splice variants corroborated in vitro data. Notably, we identified exonic variants that result in complete missplicing and thus a lack of modulator response (e.g. c.2908G>A, c.523A>G), as well as intronic variants that respond to modulators due to the presence of residual normally spliced transcript (e.g. c.4242+2T>C, c.3717+40A>G). Overall, our data reveals diverse molecular outcomes amongst both exonic and intronic variants emphasizing the need to delineate RNA, protein, and functional effects of each variant in order to accurately assign precision therapies. Genetic variants that impact pre-mRNA splicing are a common cause of genetic disease and have varying downstream molecular consequences. As a result, precision therapies that function at the protein level are not always effective for these variants and thus careful assessment is necessary. Here we evaluate RNA-level effects of 52 variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and show that study of splicing and its consequences allows for more accurate assignment of precision therapies.
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Affiliation(s)
- Anya T. Joynt
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Taylor A. Evans
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Matthew J. Pellicore
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Emily F. Davis-Marcisak
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Melis A. Aksit
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alice C. Eastman
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shivani U. Patel
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Kathleen C. Paul
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Derek L. Osorio
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alyssa D. Bowling
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Calvin U. Cotton
- Departments of Pediatrics, Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Karen S. Raraigh
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Natalie E. West
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Christian A. Merlo
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Garry R. Cutting
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (GRC); (NS)
| | - Neeraj Sharma
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (GRC); (NS)
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18
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Riedmayr LM, Böhm S, Biel M, Becirovic E. Enigmatic rhodopsin mutation creates an exceptionally strong splice acceptor site. Hum Mol Genet 2020; 29:295-304. [PMID: 31816042 DOI: 10.1093/hmg/ddz291] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/28/2019] [Accepted: 12/02/2019] [Indexed: 01/16/2023] Open
Abstract
The c.620 T > G mutation in rhodopsin found in the first mapped autosomal dominant retinitis pigmentosa (adRP) locus is associated with severe, early-onset RP. Intriguingly, another mutation affecting the same nucleotide (c.620 T > A) is related to a mild, late-onset RP. Assuming that both mutations are missense mutations (Met207Arg and Met207Lys) hampering the ligand-binding pocket, previous work addressed how they might differentially impair rhodopsin function. Here, we investigated the impact of both mutations at the mRNA and protein level in HEK293 cells and in the mouse retina. We show that, in contrast to c.620 T > A, c.620 T > G is a splicing mutation, which generates an exceptionally strong splice acceptor site (SAS) resulting in a 90 bp in-frame deletion and protein mislocalization in vitro and in vivo. Moreover, we identified the core element underlying the c.620 T > G SAS strength. Finally, we demonstrate that the c.620 T > G SAS is very flexible in branch point choice, which might explain its remarkable performance. Based on these results, we suggest that (i) point mutations should be routinely tested for mRNA splicing to avoid dispensable analysis of mutations on protein level, which do not naturally exist. (ii) Puzzling disease courses of mutations in other genes might also correlate with their effects on mRNA splicing. (iii) Flexibility in branch point choice might be another factor influencing the SAS strength. (iv) The core splice element identified in this study could be useful for biotechnological applications requiring effective SAS.
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Affiliation(s)
- Lisa M Riedmayr
- Center for Integrated Protein Science Munich (CIPSM), 81377 Munich, Germany.,Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Sybille Böhm
- Center for Integrated Protein Science Munich (CIPSM), 81377 Munich, Germany.,Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich (CIPSM), 81377 Munich, Germany.,Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Elvir Becirovic
- Center for Integrated Protein Science Munich (CIPSM), 81377 Munich, Germany.,Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
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19
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Bolz HJ. Usher syndrome: diagnostic approach, differential diagnoses and proposal of an updated function-based genetic classification. MED GENET-BERLIN 2020. [DOI: 10.1515/medgen-2020-2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abstract
Usher syndrome (USH) manifests with congenital and apparently isolated hearing loss, followed by retinal degeneration in later life. Therefore, and because of its high prevalence in the congenitally hearing-impaired population, USH is one of the most relevant deafness syndromes. Next-generation sequencing (NGS)-based testing can now provide most analyzed USH patients with a molecular diagnosis, based on mutations in 11 genes. Given the availability of several excellent articles on the clinical and biochemical basis of USH, this short review focuses on critical assessment of new genes announced as USH genes, clinical and genetic differential diagnoses and therapeutic developments. Because obsolete loci, disproved USH genes and the inclusion of genes whose mutations cause similar phenotypes have increasingly blurred genetic classification, a revision based on phenotype restricted to genes related to the Usher protein complex is proposed.
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Affiliation(s)
- Hanno J. Bolz
- Senckenberg Centre for Human Genetics , Weismüllerstr. 50 , Frankfurt am Main , Germany
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20
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Walter MA, Rezaie T, Hufnagel RB, Arno G. Ocular genetics in the genomics age. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:860-868. [PMID: 32896097 DOI: 10.1002/ajmg.c.31844] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 12/29/2022]
Abstract
Current genetic screening methods for inherited eye diseases are concentrated on the coding exons of known disease genes (gene panels, clinical exome). These tests have a variable and often limited diagnostic rate depending on the clinical presentation, size of the gene panel and our understanding of the inheritance of the disorder (with examples described in this issue). There are numerous possible explanations for the missing heritability of these cases including undetected variants within the relevant gene (intronic, up/down-stream and structural variants), variants harbored in genes outside the targeted panel, intergenic variants, variants undetectable by the applied technology, complex/non-Mendelian inheritance, and nongenetic phenocopies. In this article we further explore and review methods to investigate these sources of missing heritability.
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Affiliation(s)
- Michael A Walter
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Tayebeh Rezaie
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, Maryland, USA
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Gavin Arno
- University College London Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
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21
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Panagiotopoulos AL, Karguth N, Pavlou M, Böhm S, Gasparoni G, Walter J, Graf A, Blum H, Biel M, Riedmayr LM, Becirovic E. Antisense Oligonucleotide- and CRISPR-Cas9-Mediated Rescue of mRNA Splicing for a Deep Intronic CLRN1 Mutation. MOLECULAR THERAPY. NUCLEIC ACIDS 2020; 21:1050-1061. [PMID: 32841912 PMCID: PMC7452116 DOI: 10.1016/j.omtn.2020.07.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/23/2020] [Accepted: 07/27/2020] [Indexed: 12/26/2022]
Abstract
Mutations in CLRN1 cause Usher syndrome (USH) type III (USH3A), a disease characterized by progressive hearing impairment, retinitis pigmentosa, and vestibular dysfunction. Due to the lack of appropriate disease models, no efficient therapy for retinitis pigmentosa in USH patients exists so far. In addition, given the yet undefined functional role and expression of the different CLRN1 splice isoforms in the retina, non-causative therapies such as gene supplementation are unsuitable at this stage. In this study, we focused on the recently identified deep intronic c.254-649T>G CLRN1 splicing mutation and aimed to establish two causative treatment approaches: CRISPR-Cas9-mediated excision of the mutated intronic region and antisense oligonucleotide (AON)-mediated correction of mRNA splicing. The therapeutic potential of these approaches was validated in different cell types transiently or stably expressing CLRN1 minigenes. Both approaches led to substantial correction of the splice defect. Surprisingly, however, no synergistic effect was detected when combining both methods. Finally, the injection of naked AONs into mice expressing the mutant CLRN1 minigene in the retina also led to a significant splice rescue. We propose that both AONs and CRISPR-Cas9 are suitable strategies to initiate advanced preclinical studies for treatment of USH3A patients.
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Affiliation(s)
- Anna-Lena Panagiotopoulos
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Nina Karguth
- Center for Integrated Protein Science Munich CIPSM, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Marina Pavlou
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany; Department of Ophthalmology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sybille Böhm
- Center for Integrated Protein Science Munich CIPSM, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Gilles Gasparoni
- Department of Genetics, Saarland University, Saarbrücken, Germany
| | - Jörn Walter
- Department of Genetics, Saarland University, Saarbrücken, Germany
| | - Alexander Graf
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Helmut Blum
- Gene Center Munich, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich CIPSM, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Lisa Maria Riedmayr
- Center for Integrated Protein Science Munich CIPSM, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany.
| | - Elvir Becirovic
- Center for Integrated Protein Science Munich CIPSM, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany.
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22
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Xue K, MacLaren RE. Antisense oligonucleotide therapeutics in clinical trials for the treatment of inherited retinal diseases. Expert Opin Investig Drugs 2020; 29:1163-1170. [PMID: 32741234 DOI: 10.1080/13543784.2020.1804853] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Antisense oligonucleotides (ASOs) represent a class of drugs which can be rationally designed to complement the coding or non-coding regions of target RNA transcripts. They could modulate pre-messenger RNA splicing, induce mRNA knockdown, or block translation of disease-causing genes, thereby slowing disease progression. The pharmacokinetics of intravitreal delivery may enable ASOs to be effective in the treatment of inherited retinal diseases. AREAS COVERED We review the current status of clinical trials of ASO therapies for inherited retinal diseases, which have demonstrated safety, viable durability, and early efficacy. Future applications are discussed in the context of alternative genetic approaches, including gene augmentation and gene editing. EXPERT OPINION Early efficacy data suggest that the splicing-modulating ASO, sepofarsen, is a promising treatment for Leber congenital amaurosis associated with the common c.2991+1655A>G mutation in CEP290. However, potential variability in clinical response to ASO-mediated correction of splicing defect on one allele in patients who are compound heterozygotes needs to be assessed. ASOs hold great therapeutic potential for numerous other inherited retinal diseases with common deep-intronic and dominant gain-of-function mutations. These would complement viral vector-mediated gene augmentation which is generally limited by the size of the transgene and to the treatment of recessive diseases.
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Affiliation(s)
- Kanmin Xue
- Wellcome Trust Clinical Research Career Development Fellow, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford & Honorary Consultant Vitreoretinal Surgeon, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust , Oxford, UK
| | - Robert E MacLaren
- Professor of Ophthalmology, Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford & Honorary Consultant Vitreoretinal Surgeon, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust , Oxford, UK
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23
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Di Scipio M, Tavares E, Deshmukh S, Audo I, Green-Sanderson K, Zubak Y, Zine-Eddine F, Pearson A, Vig A, Tang CY, Mollica A, Karas J, Tumber A, Yu CW, Billingsley G, Wilson MD, Zeitz C, Héon E, Vincent A. Phenotype Driven Analysis of Whole Genome Sequencing Identifies Deep Intronic Variants that Cause Retinal Dystrophies by Aberrant Exonization. Invest Ophthalmol Vis Sci 2020; 61:36. [PMID: 32881472 PMCID: PMC7443117 DOI: 10.1167/iovs.61.10.36] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/16/2020] [Indexed: 02/07/2023] Open
Abstract
Purpose To demonstrate the effectiveness of combining retinal phenotyping and focused variant filtering from genome sequencing (GS) in identifying deep intronic disease causing variants in inherited retinal dystrophies. Methods Affected members from three pedigrees with classical enhanced S-cone syndrome (ESCS; Pedigree 1), congenital stationary night blindness (CSNB; Pedigree 2), and achromatopsia (ACHM; Pedigree 3), respectively, underwent detailed ophthalmologic evaluation, optical coherence tomography, and electroretinography. The probands underwent panel-based genetic testing followed by GS analysis. Minigene constructs (NR2E3, GPR179 and CNGB3) and patient-derived cDNA experiments (NR2E3 and GPR179) were performed to assess the functional effect of the deep intronic variants. Results The electrophysiological findings confirmed the clinical diagnosis of ESCS, CSNB, and ACHM in the respective pedigrees. Panel-based testing revealed heterozygous pathogenic variants in NR2E3 (NM_014249.3; c.119-2A>C; Pedigree 1) and CNGB3 (NM_019098.4; c.1148delC/p.Thr383Ilefs*13; Pedigree 3). The GS revealed heterozygous deep intronic variants in Pedigrees 1 (NR2E3; c.1100+1124G>A) and 3 (CNGB3; c.852+4751A>T), and a homozygous GPR179 variant in Pedigree 2 (NM_001004334.3; c.903+343G>A). The identified variants segregated with the phenotype in all pedigrees. All deep intronic variants were predicted to generate a splice acceptor gain causing aberrant exonization in NR2E3 [89 base pairs (bp)], GPR179 (197 bp), and CNGB3 (73 bp); splicing defects were validated through patient-derived cDNA experiments and/or minigene constructs and rescued by antisense oligonucleotide treatment. Conclusions Deep intronic mutations contribute to missing heritability in retinal dystrophies. Combining results from phenotype-directed gene panel testing, GS, and in silico splice prediction tools can help identify these difficult-to-detect pathogenic deep intronic variants.
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Affiliation(s)
- Matteo Di Scipio
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Erika Tavares
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Shriya Deshmukh
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- CHNO des Quinze-Vingts, INSERM-DGOS CIC1423, Paris, France
- University College London Institute of Ophthalmology, London, United Kingdom
| | - Kit Green-Sanderson
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Yuliya Zubak
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Fayçal Zine-Eddine
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Alexander Pearson
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Anjali Vig
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Chen Yu Tang
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Antonio Mollica
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Jonathan Karas
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada
| | - Caberry W. Yu
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Gail Billingsley
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Michael D. Wilson
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Elise Héon
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - Ajoy Vincent
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
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24
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Splicing mutations in inherited retinal diseases. Prog Retin Eye Res 2020; 80:100874. [PMID: 32553897 DOI: 10.1016/j.preteyeres.2020.100874] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 05/30/2020] [Accepted: 05/31/2020] [Indexed: 12/15/2022]
Abstract
Mutations which induce aberrant transcript splicing represent a distinct class of disease-causing genetic variants in retinal disease genes. Such mutations may either weaken or erase regular splice sites or create novel splice sites which alter exon recognition. While mutations affecting the canonical GU-AG dinucleotides at the splice donor and splice acceptor site are highly predictive to cause a splicing defect, other variants in the vicinity of the canonical splice sites or those affecting additional cis-acting regulatory sequences within exons or introns are much more difficult to assess or even to recognize and require additional experimental validation. Splicing mutations are unique in that the actual outcome for the transcript (e.g. exon skipping, pseudoexon inclusion, intron retention) and the encoded protein can be quite different depending on the individual mutation. In this article, we present an overview on the current knowledge about and impact of splicing mutations in inherited retinal diseases. We introduce the most common sub-classes of splicing mutations including examples from our own work and others and discuss current strategies for the identification and validation of splicing mutations, as well as therapeutic approaches, open questions, and future perspectives in this field of research.
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25
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Cassini TA, Duncan L, Rives LC, Newman JH, Phillips JA, Koziura ME, Brault J, Hamid R, Cogan J. Whole genome sequencing reveals novel IGHMBP2 variant leading to unique cryptic splice-site and Charcot-Marie-Tooth phenotype with early onset symptoms. Mol Genet Genomic Med 2019; 7:e00676. [PMID: 31020813 PMCID: PMC6565564 DOI: 10.1002/mgg3.676] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 02/24/2019] [Accepted: 03/06/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Rare variants (RV) in immunoglobulin mu-binding protein 2 (IGHMBP2) [OMIM 600502] can cause an autosomal recessive type of Charcot-Marie-Tooth (CMT) disease [OMIM 616155], an inherited peripheral neuropathy. Over 40 different genes are associated with CMT, with different possible inheritance patterns. METHODS AND RESULTS An 11-year-old female with motor delays was found to have distal atrophy, weakness, and areflexia without bulbar or sensory findings. Her clinical evaluation was unrevealing. Whole exome sequencing (WES) revealed a maternally inherited IGHMBP2 RV (c.1730T>C) predicted to be pathogenic, but no variant on the other allele was identified. Deletion and duplication analysis was negative. She was referred to the Undiagnosed Disease Network (UDN) for further evaluation. Whole genome sequencing (WGS) confirmed the previously identified IGHMBP2 RV and identified a paternally inherited non-coding IGHMBP2 RV. This was predicted to activate a cryptic splice site perturbing IGHMBP2 splicing. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis was consistent with activation of the cryptic splice site. The abnormal transcript was shown to undergo nonsense-mediated decay (NMD), resulting in halpoinsufficiency. CONCLUSION This case demonstrates the deficiencies of WES and traditional molecular analyses and highlights the advantages of utilization of WGS and functional studies.
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Affiliation(s)
- Thomas A Cassini
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.,Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Laura Duncan
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lynette C Rives
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - John H Newman
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - John A Phillips
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Mary E Koziura
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jennifer Brault
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Rizwan Hamid
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Joy Cogan
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
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26
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Abstract
Antisense oligonucleotides (ASOs) have shown potential as therapeutic molecules for the treatment of inner ear dysfunction. The peripheral sensory organs responsible for both hearing and equilibrium are housed within the inner ear. Hearing loss and vestibular balance problems affect a large portion of the population and limited treatment options exist. Targeting ASOs to the inner ear as a therapeutic strategy has unique pharmacokinetic and drug delivery opportunities and challenges. Here, we review ASO technology, delivery, disease targets, and other key considerations for development of this therapeutic approach.
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Affiliation(s)
- Michelle L Hastings
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Science and Medicine, North Chicago, IL, 60064, USA.
| | - Timothy A Jones
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, 304 Barkley Memorial Center, Lincoln, NE, 68583, USA
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27
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Understanding human DNA variants affecting pre-mRNA splicing in the NGS era. ADVANCES IN GENETICS 2019; 103:39-90. [PMID: 30904096 DOI: 10.1016/bs.adgen.2018.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Pre-mRNA splicing, an essential step in eukaryotic gene expression, relies on recognition of short sequences on the primary transcript intron ends and takes place along transcription by RNA polymerase II. Exonic and intronic auxiliary elements may modify the strength of exon definition and intron recognition. Splicing DNA variants (SV) have been associated with human genetic diseases at canonical intron sites, as well as exonic substitutions putatively classified as nonsense, missense or synonymous variants. Their effects on mRNA may be modulated by cryptic splice sites associated to the SV allele, comprehending exon skipping or shortening, and partial or complete intron retention. As splicing mRNA outputs result from combinatorial effects of both intrinsic and extrinsic factors, in vitro functional assays supported by computational analyses are recommended to assist SV pathogenicity assessment for human Mendelian inheritance diseases. The increasing use of next-generating sequencing (NGS) targeting full genomic gene sequence has raised awareness of the relevance of deep intronic SV in genetic diseases and inclusion of pseudo-exons into mRNA. Finally, we take advantage of recent advances in sequencing and computational technologies to analyze alternative splicing in cancer. We explore the Catalog of Somatic Mutations in Cancer (COSMIC) to describe the proportion of splice-site mutations in cis and trans regulatory elements. Genomic data from large cohorts of different cancer types are increasingly available, in addition to repositories of normal and somatic genetic variations. These are likely to bring new insights to understanding the genetic control of alternative splicing by mapping splicing quantitative trait loci in tumors.
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28
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McDermott JH, Molina-Ramírez LP, Bruce IA, Mahaveer A, Turner M, Miele G, Body R, Mahood R, Ulph F, MacLeod R, Harvey K, Booth N, Demain LAM, Wilson P, Black GC, Morton CC, Newman WG. Diagnosing and Preventing Hearing Loss in the Genomic Age. Trends Hear 2019; 23:2331216519878983. [PMID: 31621509 PMCID: PMC6798159 DOI: 10.1177/2331216519878983] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 06/20/2019] [Accepted: 09/06/2019] [Indexed: 12/14/2022] Open
Abstract
Over the past two decades, significant technological advances have facilitated the identification of hundreds of genes associated with hearing loss. Variants in many of these genes result in severe congenital hearing loss with profound implications for the affected individual and their family. This review collates these advances, summarizing the current state of genomic knowledge in childhood hearing loss. We consider how current and emerging genetic technologies have the potential to alter our approach to the management and diagnosis of hearing loss. We review approaches being taken to ensure that these discoveries are used in clinical practice to detect genetic hearing loss as soon as possible to reduce unnecessary investigations, provide information about reproductive risks, and facilitate regular follow-up and early treatment. We also highlight how rapid sequencing technology has the potential to identify children susceptible to antibiotic-induced hearing loss and how this adverse reaction can be avoided.
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Affiliation(s)
- John H. McDermott
- Manchester Centre for Genomic Medicine,
St Mary’s Hospital, Manchester University NHS Foundation Trust, UK
- Division of Evolution and Genomic
Sciences, School of Biological Sciences,
University
of Manchester, UK
| | - Leslie P Molina-Ramírez
- Manchester Centre for Genomic Medicine,
St Mary’s Hospital, Manchester University NHS Foundation Trust, UK
- Division of Evolution and Genomic
Sciences, School of Biological Sciences,
University
of Manchester, UK
| | - Iain A Bruce
- Hearing Health Theme, Manchester NIHR
Biomedical Research Centre, UK
- Manchester Centre for Audiology and
Deafness, School of Health Sciences,
University
of Manchester, UK
- Division of Infection, Immunity and
Respiratory Medicine, School of Biological Sciences,
University
of Manchester, UK
- Royal Manchester Children's Hospital,
Manchester University NHS Foundation Trust, UK
| | - Ajit Mahaveer
- Newborn Intensive Care Unit, Manchester
University NHS Foundation Trust, UK
| | - Mark Turner
- Newborn Intensive Care Unit, Liverpool
Women’s Hospital, UK
| | - Gino Miele
- Genedrive Diagnostics Ltd, Manchester,
UK
| | - Richard Body
- Emergency Department, Manchester
University NHS Foundation Trust, UK
- Division of Cardiovascular Sciences,
University
of Manchester, UK
| | - Rachel Mahood
- Manchester Centre for Genomic Medicine,
St Mary’s Hospital, Manchester University NHS Foundation Trust, UK
- Division of Evolution and Genomic
Sciences, School of Biological Sciences,
University
of Manchester, UK
| | - Fiona Ulph
- Division of Psychology & Mental
Health, School of Health Sciences, Faculty of Biology, Medicine and Health,
Manchester Academic Health Science Centre,
University
of Manchester, UK
| | - Rhona MacLeod
- Manchester Centre for Genomic Medicine,
St Mary’s Hospital, Manchester University NHS Foundation Trust, UK
| | - Karen Harvey
- Newborn Intensive Care Unit, Liverpool
Women’s Hospital, UK
| | - Nicola Booth
- Newborn Intensive Care Unit, Manchester
University NHS Foundation Trust, UK
| | - Leigh A. M. Demain
- Manchester Centre for Genomic Medicine,
St Mary’s Hospital, Manchester University NHS Foundation Trust, UK
- Division of Evolution and Genomic
Sciences, School of Biological Sciences,
University
of Manchester, UK
| | - Paul Wilson
- Alliance Manchester Business School,
University
of Manchester, UK
| | - Graeme C. Black
- Manchester Centre for Genomic Medicine,
St Mary’s Hospital, Manchester University NHS Foundation Trust, UK
- Division of Evolution and Genomic
Sciences, School of Biological Sciences,
University
of Manchester, UK
| | - Cynthia C. Morton
- Hearing Health Theme, Manchester NIHR
Biomedical Research Centre, UK
- Manchester Centre for Audiology and
Deafness, School of Health Sciences,
University
of Manchester, UK
- Broad
Institute of MIT and Harvard, Cambridge, MA,
USA
- Harvard
Medical School, Boston, MA, USA
- Department of Obstetrics and
Gynaecology, Brigham & Women’s Hospital, Boston, MA, USA
- Department of Pathology, Brigham &
Women’s Hospital, Boston, MA, USA
| | - William G Newman
- Manchester Centre for Genomic Medicine,
St Mary’s Hospital, Manchester University NHS Foundation Trust, UK
- Division of Evolution and Genomic
Sciences, School of Biological Sciences,
University
of Manchester, UK
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29
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Boisson B, Honda Y, Ajiro M, Bustamante J, Bendavid M, Gennery AR, Kawasaki Y, Ichishima J, Osawa M, Nihira H, Shiba T, Tanaka T, Chrabieh M, Bigio B, Hur H, Itan Y, Liang Y, Okada S, Izawa K, Nishikomori R, Ohara O, Heike T, Abel L, Puel A, Saito MK, Casanova JL, Hagiwara M, Yasumi T. Rescue of recurrent deep intronic mutation underlying cell type-dependent quantitative NEMO deficiency. J Clin Invest 2018; 129:583-597. [PMID: 30422821 DOI: 10.1172/jci124011] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/08/2018] [Indexed: 12/20/2022] Open
Abstract
X-linked dominant incontinentia pigmenti (IP) and X-linked recessive anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID) are caused by loss-of-function and hypomorphic IKBKG (also known as NEMO) mutations, respectively. We describe a European mother with mild IP and a Japanese mother without IP, whose 3 boys with EDA-ID died from ID. We identify the same private variant in an intron of IKBKG, IVS4+866 C>T, which was inherited from and occurred de novo in the European mother and Japanese mother, respectively. This mutation creates a new splicing donor site, giving rise to a 44-nucleotide pseudoexon (PE) generating a frameshift. Its leakiness accounts for NF-κB activation being impaired but not abolished in the boys' cells. However, aberrant splicing rates differ between cell types, with WT NEMO mRNA and protein levels ranging from barely detectable in leukocytes to residual amounts in induced pluripotent stem cell-derived (iPSC-derived) macrophages, and higher levels in fibroblasts and iPSC-derived neuronal precursor cells. Finally, SRSF6 binds to the PE, facilitating its inclusion. Moreover, SRSF6 knockdown or CLK inhibition restores WT NEMO expression and function in mutant cells. A recurrent deep intronic splicing mutation in IKBKG underlies a purely quantitative NEMO defect in males that is most severe in leukocytes and can be rescued by the inhibition of SRSF6 or CLK.
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Affiliation(s)
- Bertrand Boisson
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, New York, USA.,Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Imagine Institute, Paris, France
| | - Yoshitaka Honda
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masahiko Ajiro
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Jacinta Bustamante
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, New York, USA.,Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Imagine Institute, Paris, France.,Center for the Study of Primary Immunodeficiencies, Necker Hospital for Sick Children, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Matthieu Bendavid
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, New York, USA
| | - Andrew R Gennery
- Institute of Cellular Medicine, Newcastle University and Great North Children's Hospital, Newcastle upon Tyne, United Kingdom
| | - Yuri Kawasaki
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Jose Ichishima
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Mitsujiro Osawa
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Hiroshi Nihira
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takeshi Shiba
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takayuki Tanaka
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Maya Chrabieh
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Imagine Institute, Paris, France
| | - Benedetta Bigio
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, New York, USA
| | - Hong Hur
- Center for Clinical and Translational Science, The Rockefeller University, New York, New York, USA
| | - Yuval Itan
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, New York, USA.,The Charles Bronfman Institute for Personalized Medicine, and.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yupu Liang
- Center for Clinical and Translational Science, The Rockefeller University, New York, New York, USA
| | - Satoshi Okada
- Department of Pediatrics, Graduate School of Biomedical & Health Sciences, Hiroshima University, Japan
| | - Kazushi Izawa
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ryuta Nishikomori
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Osamu Ohara
- Laboratory for Integrative Genomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan.,Kazusa DNA Research Institute, Kisarazu, Japan
| | - Toshio Heike
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Hyogo Prefectural Amagasaki General Medical Center, Amagasaki, Japan
| | - Laurent Abel
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, New York, USA.,Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Imagine Institute, Paris, France
| | - Anne Puel
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, New York, USA.,Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Imagine Institute, Paris, France
| | - Megumu K Saito
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Jean-Laurent Casanova
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, The Rockefeller University, New York, New York, USA.,Laboratory of Human Genetics of Infectious Diseases, Necker Branch, INSERM U1163, Necker Hospital for Sick Children, Paris, France.,Paris Descartes University, Imagine Institute, Paris, France.,Pediatric Hematology-Immunology Unit, Necker Hospital for Sick Children, AP-HP, Paris, France.,Howard Hughes Medical Institute (HHMI), New York, New York, USA
| | - Masatoshi Hagiwara
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takahiro Yasumi
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
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30
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Fuster-García C, García-García G, Jaijo T, Fornés N, Ayuso C, Fernández-Burriel M, Sánchez-De la Morena A, Aller E, Millán JM. High-throughput sequencing for the molecular diagnosis of Usher syndrome reveals 42 novel mutations and consolidates CEP250 as Usher-like disease causative. Sci Rep 2018; 8:17113. [PMID: 30459346 PMCID: PMC6244211 DOI: 10.1038/s41598-018-35085-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/17/2018] [Indexed: 01/09/2023] Open
Abstract
Usher syndrome is a rare disorder causing retinitis pigmentosa, together with sensorineural hearing loss. Due to the phenotypic and genetic heterogeneity of this disease, the best method to screen the causative mutations is by high-throughput sequencing. In this study, we tested a semiconductor chip based sequencing approach with 77 unrelated patients, as a molecular diagnosis routine. In addition, Multiplex Ligation-dependent Probe Amplification and microarray-based Comparative Genomic Hybridization techniques were applied to detect large rearrangements, and minigene assays were performed to confirm the mRNA processing aberrations caused by splice-site mutations. The designed panel included all the USH causative genes (MYO7A, USH1C, CDH23, PCDH15, USH1G, CIB2, USH2A, ADGRV1, WHRN and CLRN1) as well as four uncertainly associated genes (HARS, PDZD7, CEP250 and C2orf71). The outcome showed an overall mutation detection ratio of 82.8% and allowed the identification of 42 novel putatively pathogenic mutations. Furthermore, we detected two novel nonsense mutations in CEP250 in a patient with a disease mimicking Usher syndrome that associates visual impairment due to cone-rod dystrophy and progressive hearing loss. Therefore, this approach proved reliable results for the molecular diagnosis of the disease and also allowed the consolidation of the CEP250 gene as disease causative for an Usher-like phenotype.
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Affiliation(s)
- Carla Fuster-García
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Gema García-García
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain.
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain.
| | - Teresa Jaijo
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
- Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Neus Fornés
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
| | - Carmen Ayuso
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
- Servicio de Genética, Fundación Jiménez Díaz, University Hospital, Instituto de Investigación Sanitaria Fundación Jiménez Díaz IIS-FJD, UAM, Madrid, Spain
| | | | | | - Elena Aller
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
- Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - José M Millán
- Grupo de Investigación en Biomedicina Molecular, Celular y Genómica, Instituto de Investigación Sanitaria La Fe (IIS La Fe), Valencia, Spain
- CIBER de Enfermedades Raras (CIBERER), Madrid, Spain
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31
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Patel N, Alkuraya H, Alzahrani SS, Nowailaty SR, Seidahmed MZ, Alhemidan A, Ben-Omran T, Ghazi NG, Al-Aqeel A, Al-Owain M, Alzaidan HI, Faqeih E, Kurdi W, Rahbeeni Z, Ibrahim N, Abdulwahab F, Hashem M, Shaheen R, Abouelhoda M, Monies D, Khan AO, Aldahmesh MA, Alkuraya FS. Mutations in known disease genes account for the majority of autosomal recessive retinal dystrophies. Clin Genet 2018; 94:554-563. [PMID: 30054919 DOI: 10.1111/cge.13426] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 01/01/2023]
Abstract
Retinal dystrophies (RDs) are hereditary blinding eye conditions that are highly variable in their clinical presentation. The remarkable genetic heterogeneity that characterizes RD was a major challenge in establishing the molecular diagnosis in these patients until the recent advent of next-generation sequencing. It remains unclear, however, what percentage of autosomal recessive RD remain undiagnosed when all established RD genes are sequenced. We enrolled 75 families in which RD segregates in an apparently autosomal recessive manner. We show that the yield of a multigene panel that contains known RD genes is 67.5%. The higher yield (82.3%) when whole exome sequencing was implemented instead was often due to hits in genes that were not included in the original design of the panel. We also show the value of homozygosity mapping even during the era of exome sequencing in uncovering cryptic mutations. In total, we describe 45 unique likely deleterious variants (of which 18 are novel including one deep intronic and one genomic deletion mutation). Our study suggests that the genetic heterogeneity of autosomal recessive RD is approaching saturation and that any new RD genes will probably account for only a minor role in the mutation burden.
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Affiliation(s)
- N Patel
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H Alkuraya
- Global Eye Care, Specialized Medical Center Hospital, Riyadh, Saudi Arabia
| | - S S Alzahrani
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - S R Nowailaty
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - M Z Seidahmed
- Pediatric Department, Security Forces Hospital, Riyadh, Saudi Arabia
| | - A Alhemidan
- Department of Ophthalmology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - T Ben-Omran
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - N G Ghazi
- Department of Ophthalmology, Lebanese American University, Lebanese American University Medical Center Rizk Hospital, Beirut, Lebanon
| | - A Al-Aqeel
- Department of Pediatric, Prince Sultan Medical Military City, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - M Al-Owain
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H I Alzaidan
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - E Faqeih
- Section of Medical Genetics, Department of Pediatric Subspecialties, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - W Kurdi
- Department of Obstetrics and Gynecology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Z Rahbeeni
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - N Ibrahim
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - F Abdulwahab
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - M Hashem
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - R Shaheen
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - M Abouelhoda
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Saudi Human Genome Project, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - D Monies
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Saudi Human Genome Project, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - A O Khan
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western University, Cleveland, Ohio
| | - M A Aldahmesh
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Saudi Human Genome Project, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
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Riedmayr LM, Böhm S, Michalakis S, Becirovic E. Construction and Cloning of Minigenes for in vivo Analysis of Potential Splice Mutations. Bio Protoc 2018; 8:e2760. [PMID: 34179284 DOI: 10.21769/bioprotoc.2760] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 02/22/2018] [Accepted: 02/26/2018] [Indexed: 11/02/2022] Open
Abstract
Disease-associated mutations influencing mRNA splicing are referred to as splice mutations. The majority of splice mutations are found on exon-intron boundaries defining canonical donor and acceptor splice sites. However, mutations in the coding region (exonic mutations) can also affect mRNA splicing. Exact knowledge of the disease mechanism of splice mutations is essential for developing optimal treatment strategies. Given the large number of disease-associated mutations thus far identified, there is an unmet need for methods to systematically analyze the effects of pathogenic mutations on mRNA splicing. As splicing can vary between cell types, splice mutations need to be tested under native conditions if possible. A commonly used tool for the analysis of mRNA splicing is the construction of minigenes carrying exonic and intronic sequences. Here, we describe a protocol for the design and cloning of minigenes into recombinant adeno-associated virus (rAAV) vectors for gene delivery and investigation of mRNA splicing in a native context. This protocol was developed for minigene-based analysis of mRNA splicing in retinal cells, however, in principle it is applicable to any cell type, which can be transduced with rAAV vectors.
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Affiliation(s)
- Lisa Maria Riedmayr
- Center for Integrated Protein Science Munich CIPSM, München, Germany.,Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany
| | - Sybille Böhm
- Center for Integrated Protein Science Munich CIPSM, München, Germany.,Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich CIPSM, München, Germany.,Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany
| | - Elvir Becirovic
- Center for Integrated Protein Science Munich CIPSM, München, Germany.,Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany
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Neuhaus C, Eisenberger T, Decker C, Nagl S, Blank C, Pfister M, Kennerknecht I, Müller-Hofstede C, Charbel Issa P, Heller R, Beck B, Rüther K, Mitter D, Rohrschneider K, Steinhauer U, Korbmacher HM, Huhle D, Elsayed SM, Taha HM, Baig SM, Stöhr H, Preising M, Markus S, Moeller F, Lorenz B, Nagel-Wolfrum K, Khan AO, Bolz HJ. Next-generation sequencing reveals the mutational landscape of clinically diagnosed Usher syndrome: copy number variations, phenocopies, a predominant target for translational read-through, and PEX26 mutated in Heimler syndrome. Mol Genet Genomic Med 2017; 5:531-552. [PMID: 28944237 PMCID: PMC5606877 DOI: 10.1002/mgg3.312] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/06/2017] [Accepted: 06/09/2017] [Indexed: 12/23/2022] Open
Abstract
Background Combined retinal degeneration and sensorineural hearing impairment is mostly due to autosomal recessive Usher syndrome (USH1: congenital deafness, early retinitis pigmentosa (RP); USH2: progressive hearing impairment, RP). Methods Sanger sequencing and NGS of 112 genes (Usher syndrome, nonsyndromic deafness, overlapping conditions), MLPA, and array‐CGH were conducted in 138 patients clinically diagnosed with Usher syndrome. Results A molecular diagnosis was achieved in 97% of both USH1 and USH2 patients, with biallelic mutations in 97% (USH1) and 90% (USH2), respectively. Quantitative readout reliably detected CNVs (confirmed by MLPA or array‐CGH), qualifying targeted NGS as one tool for detecting point mutations and CNVs. CNVs accounted for 10% of identified USH2A alleles, often in trans to seemingly monoallelic point mutations. We demonstrate PTC124‐induced read‐through of the common p.Trp3955* nonsense mutation (13% of detected USH2A alleles), a potential therapy target. Usher gene mutations were found in most patients with atypical Usher syndrome, but the diagnosis was adjusted in case of double homozygosity for mutations in OTOA and NR2E3, genes implicated in isolated deafness and RP. Two patients with additional enamel dysplasia had biallelic PEX26 mutations, for the first time linking this gene to Heimler syndrome. Conclusion Targeted NGS not restricted to Usher genes proved beneficial in uncovering conditions mimicking Usher syndrome.
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Affiliation(s)
| | | | | | - Sandra Nagl
- Bioscientia Center for Human GeneticsIngelheimGermany
| | | | - Markus Pfister
- HNO-Praxis SarnenSarnenSwitzerland.,Molecular Genetics, THRCDepartment of OtolaryngologyUniversity of TübingenTübingenGermany
| | - Ingo Kennerknecht
- Institute of Human GeneticsWestfälische Wilhelms-UniversitätMünsterGermany
| | | | - Peter Charbel Issa
- Department of OphthalmologyUniversity of BonnBonnGermany.,Center for Rare Diseases Bonn (ZSEB)University of BonnBonnGermany.,Oxford Eye HospitalUniversity of OxfordOxfordUK
| | - Raoul Heller
- Institute of Human GeneticsUniversity Hospital of CologneCologneGermany
| | - Bodo Beck
- Institute of Human GeneticsUniversity Hospital of CologneCologneGermany
| | | | - Diana Mitter
- Institute of Human GeneticsUniversity of Leipzig Hospitals and ClinicsLeipzigGermany
| | | | | | - Heike M Korbmacher
- Department of OrthodonticsGiessen and Marburg University Hospital, Marburg CampusMarburgGermany
| | | | - Solaf M Elsayed
- Medical Genetics CenterCairoEgypt.,Children's HospitalAin Shams UniversityCairoEgypt
| | | | - Shahid M Baig
- Human Molecular Genetics LaboratoryHealth Biotechnology DivisionNational Institute for Biotechnology and Genetic Engineering (NIBGE)FaisalabadPakistan
| | - Heidi Stöhr
- Department of Human GeneticsUniversity Medical Center RegensburgRegensburgGermany
| | - Markus Preising
- Department of OphthalmologyJustus-Liebig-University GiessenGiessenGermany
| | | | - Fabian Moeller
- Department of Cell and Matrix BiologyInstitute of Zoology, Johannes GutenbergUniversity of MainzMainzGermany
| | - Birgit Lorenz
- Department of OphthalmologyJustus-Liebig-University GiessenGiessenGermany
| | - Kerstin Nagel-Wolfrum
- Department of Cell and Matrix BiologyInstitute of Zoology, Johannes GutenbergUniversity of MainzMainzGermany
| | - Arif O Khan
- Division of Pediatric OphthalmologyKing Khaled Eye Specialist HospitalRiyadhSaudi Arabia.,Eye InstituteCleveland ClinicAbu DhabiUAE
| | - Hanno J Bolz
- Bioscientia Center for Human GeneticsIngelheimGermany.,Institute of Human GeneticsUniversity Hospital of CologneCologneGermany
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