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Ammous-Boukhris N, Abdelmaksoud-Dammak R, Ben Ayed-Guerfali D, Guidara S, Jallouli O, Kamoun H, Charfi Triki C, Mokdad-Gargouri R. Case report: Compound heterozygous variants detected by next-generation sequencing in a Tunisian child with ataxia-telangiectasia. Front Neurol 2024; 15:1344018. [PMID: 38882696 PMCID: PMC11178103 DOI: 10.3389/fneur.2024.1344018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 05/08/2024] [Indexed: 06/18/2024] Open
Abstract
Ataxia-telangiectasia (A-T) is an autosomal recessive primary immunodeficiency disorder (PID) caused by biallelic mutations occurring in the serine/threonine protein kinase (ATM) gene. The major role of nuclear ATM is the coordination of cell signaling pathways in response to DNA double-strand breaks, oxidative stress, and cell cycle checkpoints. Defects in ATM functions lead to A-T syndrome with phenotypic heterogeneity. Our study reports the case of a Tunisian girl with A-T syndrome carrying a compound heterozygous mutation c.[3894dupT]; p.(Ala1299Cysfs3;rs587781823), with a splice acceptor variant: c.[5763-2A>C;rs876659489] in the ATM gene that was identified by next-generation sequencing (NGS). Further genetic analysis of the family showed that the mother carried the c.[5763-2A>C] splice acceptor variant, while the father harbored the c.[3894dupT] variant in the heterozygous state. Molecular analysis provides the opportunity for accurate diagnosis and timely management in A-T patients with chronic progressive disease, especially infections and the risk of malignancies. This study characterizes for the first time the identification of compound heterozygous ATM pathogenic variants by NGS in a Tunisian A-T patient. Our study outlines the importance of molecular genetic testing for A-T patients, which is required for earlier detection and reducing the burden of disease in the future, using the patients' families.
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Affiliation(s)
- Nihel Ammous-Boukhris
- Laboratory of Eukaryotes' Molecular Biotechnology, Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Rania Abdelmaksoud-Dammak
- Laboratory of Eukaryotes' Molecular Biotechnology, Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Dorra Ben Ayed-Guerfali
- Laboratory of Eukaryotes' Molecular Biotechnology, Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Souhir Guidara
- Department of Human Genetics, Hedi Chaker Hospital, Sfax, Tunisia
| | - Olfa Jallouli
- Department of NeuroPediatry, Hedi Chaker Hospital, Sfax, Tunisia
| | - Hassen Kamoun
- Department of Human Genetics, Hedi Chaker Hospital, Sfax, Tunisia
| | | | - Raja Mokdad-Gargouri
- Laboratory of Eukaryotes' Molecular Biotechnology, Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
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Kuhn K, Lederman HM, McGrath-Morrow SA. Ataxia-telangiectasia clinical trial landscape and the obstacles to overcome. Expert Opin Investig Drugs 2023; 32:693-704. [PMID: 37622329 PMCID: PMC10530584 DOI: 10.1080/13543784.2023.2249399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 07/28/2023] [Accepted: 08/15/2023] [Indexed: 08/26/2023]
Abstract
INTRODUCTION Ataxia telangiectasia (A-T) is a life-limiting autosomal recessive disease characterized by cerebellar degeneration, ocular telangiectasias, and sinopulmonary disease. Since there is no cure for A-T, the standard of care is primarily supportive. AREAS COVERED We review clinical trials available in PubMed from 1990 to 2023 focused on lessening A-T disease burden. These approaches include genetic interventions, such as antisense oligonucleotides, designed to ameliorate disease progression in patients with select mutations. These approaches also include pharmacologic treatments that target oxidative stress, inflammation, and mitochondrial exhaustion, to attenuate neurological progression in A-T. Finally, we discuss the use of biological immunotherapies for the treatment of malignancies and granulomatous disease, along with other supportive therapies being used for the treatment of pulmonary disease and metabolic syndrome. EXPERT OPINION Barriers to successful genetic and pharmacologic interventions in A-T include the need for personalized treatment approaches based on patient-specific ATM mutations and phenotypes, lack of an animal model for the neurologic phenotype, and extreme rarity of disease making large-scale randomized trials difficult to perform. Ongoing efforts are needed to diagnose patients earlier, discover more effective therapies, and include more individuals in clinical trials, with the goal to lessen disease burden and to find a cure for patients with A-T.
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Affiliation(s)
- Katrina Kuhn
- Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States of America
| | - Howard M. Lederman
- Johns Hopkins University Division of Pediatric Allergy and Immunology and School of Medicine, Johns Hopkins University, Baltimore, MD, United States of America
| | - Sharon A. McGrath-Morrow
- Children’s Hospital of Philadelphia Division of Pulmonary Medicine and Sleep and Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
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Leite Rocha D, Ashton-Prolla P, Rosset C. Reviewing the occurrence of large genomic rearrangements in patients with inherited cancer predisposing syndromes: importance of a comprehensive molecular diagnosis. Expert Rev Mol Diagn 2022; 22:319-346. [PMID: 35234551 DOI: 10.1080/14737159.2022.2049247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Hereditary cancer predisposition syndromes are caused by germline pathogenic or likely pathogenic variants in cancer predisposition genes (CPG). The majority of pathogenic variants in CPGs are point mutations, but large gene rearrangements (LGRs) are present in several CPGs. LGRs can be much more difficult to characterize and perhaps they may have been neglected in molecular diagnoses. AREAS COVERED We aimed to evaluate the frequencies of germline LGRs in studies conducted in different populations worldwide through a qualitative systematic review based on an online literature research in PubMed. Two reviewers independently extracted data from published studies between 2009 and 2020. In total, 126 studies from 37 countries and 5 continents were included in the analysis. The number of studies in different continents ranged from 3 to 48 and for several countries there was an absolute lack of information. Asia and Europe represented most of the studies, and LGR frequencies varied from 3.04 to 15.06% in different continents. MLPA was one of the methods of choice in most studies (93%). EXPERT OPINION The LGR frequencies found in this review reinforce the need for comprehensive molecular testing regardless of the population of origin and should be considered by genetic counseling providers.
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Affiliation(s)
- Débora Leite Rocha
- Laboratório de Medicina Genômica, Serviço de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, CEP: 90035-930, Porto Alegre, Rio Grande do Sul, Brazil
| | - Patrícia Ashton-Prolla
- Laboratório de Medicina Genômica, Serviço de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, CEP: 90035-930, Porto Alegre, Rio Grande do Sul, Brazil.,Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil. Av. Bento Gonçalves, 9500 - Prédio 43312 M, CEP: 91501-970, Caixa Postal 1505, Porto Alegre, Rio Grande do Sul, Brazil.,Serviço de Genética Médica, HCPA, Rio Grande do Sul, Brazil. Rua Ramiro Barcelos, 2350, CEP: 90035-930, Porto Alegre, Rio Grande do Sul, Brazil
| | - Clévia Rosset
- Laboratório de Medicina Genômica, Serviço de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Rua Ramiro Barcelos, 2350, CEP: 90035-930, Porto Alegre, Rio Grande do Sul, Brazil
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Maroilley T, Wright NAM, Diao C, MacLaren L, Pfeffer G, Sarna JR, Billie Au PY, Tarailo-Graovac M. Case Report: Biallelic Loss of Function ATM due to Pathogenic Synonymous and Novel Deep Intronic Variant c.1803-270T > G Identified by Genome Sequencing in a Child With Ataxia–Telangiectasia. Front Genet 2022; 13:815210. [PMID: 35145552 PMCID: PMC8822238 DOI: 10.3389/fgene.2022.815210] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/03/2022] [Indexed: 11/26/2022] Open
Abstract
Ataxia–telangiectasia (AT) is a complex neurodegenerative disease with an increased risk for bone marrow failure and malignancy. AT is caused by biallelic loss of function variants in ATM, which encodes a phosphatidylinositol 3-kinase that responds to DNA damage. Herein, we report a child with progressive ataxia, chorea, and genome instability, highly suggestive of AT. The clinical ataxia gene panel identified a maternal heterozygous synonymous variant (NM_000051.3: c.2250G > A), previously described to result in exon 14 skipping. Subsequently, trio genome sequencing led to the identification of a novel deep intronic variant [NG_009830.1(NM_000051.3): c.1803-270T > G] inherited from the father. Transcript analyses revealed that c.1803-270T > G results in aberrant inclusion of 56 base pairs of intron 11. In silico tests predicted a premature stop codon as a consequence, suggesting non-functional ATM; and DNA repair analyses confirmed functional loss of ATM. Our findings highlight the power of genome sequencing, considering deep intronic variants in undiagnosed rare disease patients.
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Affiliation(s)
- Tatiana Maroilley
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Nicola A. M. Wright
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- Section of Pediatric Hematology-Immunology, Department of Pediatrics, Alberta Children’s Hospital, University of Calgary, Calgary, AB, Canada
| | - Catherine Diao
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Linda MacLaren
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Gerald Pfeffer
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Justyna R. Sarna
- Department of Clinical Neurosciences and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Ping Yee Billie Au
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- *Correspondence: Ping Yee Billie Au, ; Maja Tarailo-Graovac,
| | - Maja Tarailo-Graovac
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB, Canada
- *Correspondence: Ping Yee Billie Au, ; Maja Tarailo-Graovac,
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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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Six Novel ATM Gene Variants in Sri Lankan Patients with Ataxia Telangiectasia. Case Rep Genet 2020; 2020:6630300. [PMID: 33376610 PMCID: PMC7744220 DOI: 10.1155/2020/6630300] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/25/2020] [Accepted: 11/28/2020] [Indexed: 11/17/2022] Open
Abstract
Introduction Ataxia telangiectasia is a rare genetic condition with an estimated prevalence of 1 in 40,000-100,000 live births. This condition predominantly affects the nervous and immune systems. It is characterized by progressive ataxia beginning from early childhood. The neurological deficit associated with this condition affects one's balance, coordination, walking, and speech and can be accompanied by chorea, myoclonus, and neuropathy. They may also have ocular telangiectasias and high levels of blood alpha-fetoprotein (AFP). The ataxia telangiectasia mutated gene (ATM) is associated with this condition and codes for the ATM protein which is a phosphatidylinositol 3-kinase. This gene occupies 150 kb on chromosome 11q22-23 and contains 66 exons encoding a 13 kb transcript. ATM is a relatively large protein with a molecular weight of 350 kDa and 3,056 amino acids. Methods Four patients of Sri Lankan origin presenting with features suggestive of ataxia telangiectasia were referred to our genetics center for specialized genetic counseling and testing. Whole-exome sequencing followed by Sanger sequencing was used to confirm the candidate variants. Protein modeling and genotype to phenotype correlation was performed in the identified variants. Results We observed 6 novel ATM gene variants in four patients with ataxia telangiectasia. The identified variants are as follows: homozygous c.7397C > A (p.Ala2466Glu) and c.510_511delGT (p.Tyr171fs) and compound heterozygous c.5347_5350delGAAA (p.Glu1783fs), c.8137A > T (p.Arg2713 ∗ ) and c.1163A > C (p.Lys388Thr), and c.5227A > C (p.Thr1743Pro). Variant analysis was followed by modeling of the native and altered protein structures. Conclusion We report novel ATM gene variants that have implications on the molecular diagnosis of ataxia telangiectasia.
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7
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Li Y, Salo-Mullen E, Varghese A, Trottier M, Stadler ZK, Zhang L. Insertion of an Alu-like element in MLH1 intron 7 as a novel cause of Lynch syndrome. Mol Genet Genomic Med 2020; 8:e1523. [PMID: 33058565 PMCID: PMC7767547 DOI: 10.1002/mgg3.1523] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/13/2020] [Accepted: 08/30/2020] [Indexed: 12/16/2022] Open
Abstract
Background Lynch Syndrome (LS) is caused by germline mutations in the DNA mismatch repair (MMR) genes with mutations in MLH1 accounting for ~40% of LS‐related alterations. Methods MSK‐IMPACT analysis was performed on peripheral blood from a patient with early‐ onset colorectal cancer. Subsequently PCR and sequencing was performed to characterize the insertion. Immunohistochemistry for MMR genes and MLH1 promoter methylation were analyzed on patient's tumor. Results MSK‐IMPACT germline testing revealed an insertion into c.588+8_588+9 of MLH1 intron 7. The insertion was further characterized as an AluSx‐like element with ~115 bp in length. Functional studies demonstrated that the AluSx‐like element led to complete disruption of mRNA splicing and probably resulted in transcriptional termination at the poly (A) region of the AluSx‐like insertion. Conclusions The insertion of a truncated AluSx like element into MLH1 intron 7 results in aberrant splicing and transcription, thereby causing Lynch syndrome. This study confirms that retrotransposon insertions may be an important mechanism for cancer predisposition.
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Affiliation(s)
- Yirong Li
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Erin Salo-Mullen
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Anna Varghese
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Magan Trottier
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Zsofia K Stadler
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Liying Zhang
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, USA
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Jaudon F, Baldassari S, Musante I, Thalhammer A, Zara F, Cingolani LA. Targeting Alternative Splicing as a Potential Therapy for Episodic Ataxia Type 2. Biomedicines 2020; 8:E332. [PMID: 32899500 PMCID: PMC7555146 DOI: 10.3390/biomedicines8090332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 12/26/2022] Open
Abstract
Episodic ataxia type 2 (EA2) is an autosomal dominant neurological disorder characterized by paroxysmal attacks of ataxia, vertigo, and nausea that usually last hours to days. It is caused by loss-of-function mutations in CACNA1A, the gene encoding the pore-forming α1 subunit of P/Q-type voltage-gated Ca2+ channels. Although pharmacological treatments, such as acetazolamide and 4-aminopyridine, exist for EA2, they do not reduce or control the symptoms in all patients. CACNA1A is heavily spliced and some of the identified EA2 mutations are predicted to disrupt selective isoforms of this gene. Modulating splicing of CACNA1A may therefore represent a promising new strategy to develop improved EA2 therapies. Because RNA splicing is dysregulated in many other genetic diseases, several tools, such as antisense oligonucleotides, trans-splicing, and CRISPR-based strategies, have been developed for medical purposes. Here, we review splicing-based strategies used for genetic disorders, including those for Duchenne muscular dystrophy, spinal muscular dystrophy, and frontotemporal dementia with Parkinsonism linked to chromosome 17, and discuss their potential applicability to EA2.
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Affiliation(s)
- Fanny Jaudon
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy;
| | - Simona Baldassari
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (S.B.); (I.M.); (F.Z.)
| | - Ilaria Musante
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (S.B.); (I.M.); (F.Z.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, 16126 Genoa, Italy
| | - Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), 16132 Genoa, Italy;
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Federico Zara
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy; (S.B.); (I.M.); (F.Z.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, 16126 Genoa, Italy
| | - Lorenzo A. Cingolani
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy;
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), 16132 Genoa, Italy;
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Beißel C, Grosse S, Krebber H. Dbp5/DDX19 between Translational Readthrough and Nonsense Mediated Decay. Int J Mol Sci 2020; 21:ijms21031085. [PMID: 32041247 PMCID: PMC7037193 DOI: 10.3390/ijms21031085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 01/31/2020] [Accepted: 02/02/2020] [Indexed: 01/21/2023] Open
Abstract
The DEAD-box protein Dbp5 (human DDX19) remodels RNA-protein complexes. Dbp5 functions in ribonucleoprotein export and translation termination. Termination occurs, when the ribosome has reached a stop codon through the Dbp5 mediated delivery of the eukaryotic termination factor eRF1. eRF1 contacts eRF3 upon dissociation of Dbp5, resulting in polypeptide chain release and subsequent ribosomal subunit splitting. Mutations in DBP5 lead to stop codon readthrough, because the eRF1 and eRF3 interaction is not controlled and occurs prematurely. This identifies Dbp5/DDX19 as a possible potent drug target for nonsense suppression therapy. Neurodegenerative diseases and cancer are caused in many cases by the loss of a gene product, because its mRNA contained a premature termination codon (PTC) and is thus eliminated through the nonsense mediated decay (NMD) pathway, which is described in the second half of this review. We discuss translation termination and NMD in the light of Dbp5/DDX19 and subsequently speculate on reducing Dbp5/DDX19 activity to allow readthrough of the PTC and production of a full-length protein to detract the RNA from NMD as a possible treatment for diseases.
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Tarrasó G, Real-Martinez A, Parés M, Romero-Cortadellas L, Puigros L, Moya L, de Luna N, Brull A, Martín MA, Arenas J, Lucia A, Andreu AL, Barquinero J, Vissing J, Krag TO, Pinós T. Absence of p.R50X Pygm read-through in McArdle disease cellular models. Dis Model Mech 2020; 13:dmm.043281. [PMID: 31848135 PMCID: PMC6994938 DOI: 10.1242/dmm.043281] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 12/05/2019] [Indexed: 12/13/2022] Open
Abstract
McArdle disease is an autosomal recessive disorder caused by the absence of muscle glycogen phosphorylase, which leads to blocked muscle glycogen breakdown. We used three different cellular models to evaluate the efficiency of different read-through agents (including amlexanox, Ataluren, RTC13 and G418) in McArdle disease. The first model consisted of HeLa cells transfected with two different GFP-PYGM constructs presenting the Pygm p.R50X mutation (GFP-PYGM p.R50X and PYGM Ex1-GFP p.R50X). The second cellular model was based on the creation of HEK293T cell lines stably expressing the PYGM Ex1-GFP p.R50X construct. As these plasmids encode murine Pygm cDNA without any intron sequence, their transfection in cells would allow for analysis of the efficacy of read-through agents with no concomitant nonsense-mediated decay interference. The third model consisted of skeletal muscle cultures derived from the McArdle mouse model (knock-in for the p.R50X mutation in the Pygm gene). We found no evidence of read-through at detectable levels in any of the models evaluated. We performed a literature search and compared the premature termination codon context sequences with reported positive and negative read-through induction, identifying a potential role for nucleotide positions −9, −8, −3, −2, +13 and +14 (the first nucleotide of the stop codon is assigned as +1). The Pygm p.R50X mutation presents TGA as a stop codon, G nucleotides at positions −1 and −9, and a C nucleotide at −3, which potentially generate a good context for read-through induction, counteracted by the presence of C at −2 and its absence at +4. Summary: Here, we evaluated the efficiency of different read-through agents in McArdle disease cell culture models, revealing that read-through compounds do not restore full-length muscle glycogen phosphorylase.
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Affiliation(s)
- Guillermo Tarrasó
- Mitochondrial and Neuromuscular Disorders Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Alberto Real-Martinez
- Mitochondrial and Neuromuscular Disorders Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Marta Parés
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Lídia Romero-Cortadellas
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Laura Puigros
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Laura Moya
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - Noemí de Luna
- Laboratori de Malalties Neuromusculars, Institut de Recerca Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona 08041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Astrid Brull
- Sorbonne Université, INSERM UMRS_974, Center of Research in Myology, 75013 Paris, France
| | - Miguel Angel Martín
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Joaquin Arenas
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Alejandro Lucia
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), Madrid 28041, Spain.,Faculty of Sport Sciences, European University, Madrid 28670, Spain
| | - Antoni L Andreu
- Mitochondrial and Neuromuscular Disorders Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
| | - Jordi Barquinero
- Gene and Cell Therapy Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Thomas O Krag
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Tomàs Pinós
- Mitochondrial and Neuromuscular Disorders Unit, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona 08035, Spain .,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid 28029, Spain
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11
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Fiévet A, Bellanger D, Rieunier G, Dubois d'Enghien C, Sophie J, Calvas P, Carriere JP, Anheim M, Castrioto A, Flabeau O, Degos B, Ewenczyk C, Mahlaoui N, Touzot F, Suarez F, Hully M, Roubertie A, Aladjidi N, Tison F, Antoine-Poirel H, Dahan K, Doummar D, Nougues MC, Ioos C, Rougeot C, Masurel A, Bourjault C, Ginglinger E, Prieur F, Siri A, Bordigoni P, Nguyen K, Philippe N, Bellesme C, Demeocq F, Altuzarra C, Mathieu-Dramard M, Couderc F, Dörk T, Auger N, Parfait B, Abidallah K, Moncoutier V, Collet A, Stoppa-Lyonnet D, Stern MH. Functional classification of ATM variants in ataxia-telangiectasia patients. Hum Mutat 2019; 40:1713-1730. [PMID: 31050087 DOI: 10.1002/humu.23778] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 04/24/2019] [Accepted: 04/29/2019] [Indexed: 12/11/2022]
Abstract
Ataxia-telangiectasia (A-T) is a recessive disorder caused by biallelic pathogenic variants of ataxia-telangiectasia mutated (ATM). This disease is characterized by progressive ataxia, telangiectasia, immune deficiency, predisposition to malignancies, and radiosensitivity. However, hypomorphic variants may be discovered associated with very atypical phenotypes, raising the importance of evaluating their pathogenic effects. In this study, multiple functional analyses were performed on lymphoblastoid cell lines from 36 patients, comprising 49 ATM variants, 24 being of uncertain significance. Thirteen patients with atypical phenotype and presumably hypomorphic variants were of particular interest to test strength of functional analyses and to highlight discrepancies with typical patients. Western-blot combined with transcript analyses allowed the identification of one missing variant, confirmed suspected splice defects and revealed unsuspected minor transcripts. Subcellular localization analyses confirmed the low level and abnormal cytoplasmic localization of ATM for most A-T cell lines. Interestingly, atypical patients had lower kinase defect and less altered cell-cycle distribution after genotoxic stress than typical patients. In conclusion, this study demonstrated the pathogenic effects of the 49 variants, highlighted the strength of KAP1 phosphorylation test for pathogenicity assessment and allowed the establishment of the Ataxia-TeLangiectasia Atypical Score to predict atypical phenotype. Altogether, we propose strategies for ATM variant detection and classification.
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Affiliation(s)
- Alice Fiévet
- Institut Curie, PSL Research University, INSERM U830, Paris, France.,Institut Curie, Hôpital, Service de Génétique, Paris, France
| | - Dorine Bellanger
- Institut Curie, PSL Research University, INSERM U830, Paris, France
| | | | | | - Julia Sophie
- CHU de Toulouse, Service de Génétique Médicale, Toulouse, France
| | - Patrick Calvas
- CHU de Toulouse, Service de Génétique Médicale, Toulouse, France
| | - Jean-Paul Carriere
- Hopital des enfants de Toulouse, Unité de Neuropédiatrie, Toulouse, France
| | - Mathieu Anheim
- CHU de Strasbourg, Service de Neurologie, Strasbourg, France
| | - Anna Castrioto
- CHU de Grenoble, Pole de Psychiatrie et de Neurologie, Grenoble, France
| | - Olivier Flabeau
- CH de la côte Basque, Service de Neurologie, Bayonne, France
| | - Bertrand Degos
- Département des Maladies du Système Nerveux, Hôpitaux Universitaires Pitié Salpêtrière - Charles Foix, Paris, France
| | - Claire Ewenczyk
- Hôpitaux universitaires Pitié Salpêtrière - Charles Foix, Service de Génétique, Paris, France
| | - Nizar Mahlaoui
- Hôpital Necker Enfants Malades, Service d'Immunologie, d'Hématologie et de Rhumatologie Pédiatriques, Paris, France
| | - Fabien Touzot
- Hôpital Necker Enfants Malades, Service d'Immunologie, d'Hématologie et de Rhumatologie Pédiatriques, Paris, France
| | - Felipe Suarez
- Hôpital Necker Enfants Malades, Service d'Hématologie Adulte, Paris, France
| | - Marie Hully
- Hôpital Necker Enfants Malades, Service de Neurologie Pédiatrique, Paris, France
| | - Agathe Roubertie
- CHU de Montpellier, Service de Neuropédiatrie, Montpellier, France
| | | | - François Tison
- CHU de Bordeaux, Département de Neurologie, Bordeaux, France
| | - Hélène Antoine-Poirel
- Centre de Génétique Humaine, Cliniques Universitaires Saint-Luc & Université Catholique de Louvain, Brussels, Belgium
| | - Karine Dahan
- Centre de Génétique Humaine, Cliniques Universitaires Saint-Luc & Université Catholique de Louvain, Brussels, Belgium
| | - Diane Doummar
- Hopital Armand Trousseau, Service de Neurologie Pédiatrique, Paris, France
| | | | - Christine Ioos
- Hôpital Raymond Poincaré, Pôle de Pédiatrie, Garches, France
| | | | - Alice Masurel
- Hopital d'Enfants de Dijon, Service de Génétique, Dijon, France
| | - Caroline Bourjault
- CH de Bretagne sud, Site du Scorff, Service de Pédiatrie, Lorient, France
| | | | - Fabienne Prieur
- CHU de St Etienne, Hôpital Nord, Service de Génétique Médicale, Saint Etienne, France
| | - Aurélie Siri
- CHU de Nancy, Service de Neurologie, Nancy, France
| | - Pierre Bordigoni
- CHU Nancy, Hôpitaux de Brabois, Service de Pédiatrie II, Vandoeuvre, France
| | - Karine Nguyen
- Département de Génétique Médicale, Hopital de la Timone, Marseille, France
| | - Noel Philippe
- Hopital Debrousse, Service d'Hématologie Pédiatrique, Lyon, France
| | - Céline Bellesme
- GH Cochin-saint-Vincent de Paul, Service d'Endocrinologie et de Neurologie Pédiatrique, Paris, France
| | - François Demeocq
- CHU de Clermont-Ferrand, Hôtel Dieu, Service de Pédiatrie B, Clermont-Ferrand, France
| | | | | | - Fanny Couderc
- CH d'Aix en Provence - du Pays d'Aix, Service de Pédiatrie, Aix en Provence, France
| | - Thilo Dörk
- Gynecology Research Unit, Hannover Medical School, Hannover, Germany
| | - Nathalie Auger
- Gustave Roussy, Service Génétique des Tumeurs, Villejuif, France
| | - Béatrice Parfait
- Centre de ressources Biologiques, Hôpital Cochin, Assistance Publique-Hôpitaux de Paris, Paris, France
| | | | | | - Agnès Collet
- Institut Curie, Hôpital, Service de Génétique, Paris, France
| | - Dominique Stoppa-Lyonnet
- Institut Curie, PSL Research University, INSERM U830, Paris, France.,Institut Curie, Hôpital, Service de Génétique, Paris, France.,University Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marc-Henri Stern
- Institut Curie, PSL Research University, INSERM U830, Paris, France.,Institut Curie, Hôpital, Service de Génétique, Paris, France
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12
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Cao J, Shen R, Zhang W, Mao B, Shi Q, Zhou R, Liu Z, Zeng B, Chen X, Zhang C, Lu M, Han P, Wu J, Zhou A, Tan X. Clinical diagnosis and genetic counseling of atypical ataxia‑telangiectasia in a Chinese family. Mol Med Rep 2019; 19:3441-3448. [PMID: 30816533 PMCID: PMC6471340 DOI: 10.3892/mmr.2019.9992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 12/14/2018] [Indexed: 12/23/2022] Open
Abstract
Ataxia-telangiectasia (A-T) is an autosomal recessive chromosome breakage disorder caused by mutations in the ATM serine/threonine kinase (ATM) gene. Typically, it presents in early childhood with progressive cerebellar dysfunction, accompanied by immunodeficiency and oculocutaneous telangiectasia. In the present study, the clinical and genetic findings of a Chinese family affected with A-T in two live siblings, the proband (II-2) and his elder brother (II-1), as well as a fetus (II-3) were reported. General health, clinical neurological, electrophysiological (motor and sensory nerve conduction) and magnetic resonance imaging evaluations revealed that patients II-1 and II-2 had similar symptoms of ataxia, dysarthria, conjunctival hyperemia and elevated serum α-fetoprotein, whereas patient II-1 had earlier A-T onset at 2 years old and more serious problems with movement and intelligence. Targeted sequencing followed by Sanger sequencing revealed that these two patients carried the compound heterozygotes of a novel nonsense mutation c.5170G>T (p.Glu1724Ter) and a known nonsense mutation c.748C>T (p.Arg250Ter) in the ATM gene. Each mutation was inherited from an asymptomatic parent, which therefore confirmed the diagnosis of A-T. Given this, proband's mother performed prenatal diagnosis in her third pregnancy. Unfortunately, the fetus had the same causal mutations as its siblings and the pregnancy was terminated. The findings of the present study expanded the mutation spectrum of the ATM gene and may help in understanding the genetic basis of A-T, in order to guide genetic counseling and prenatal diagnosis.
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Affiliation(s)
- Jiangxia Cao
- Center for Prenatal Diagnosis, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430016, P.R. China
| | - Ruiqin Shen
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Wenqian Zhang
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Bing Mao
- Department of Neurology, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430016, P.R. China
| | - Qirong Shi
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Rui Zhou
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Zijing Liu
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Bing Zeng
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Xiaoling Chen
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Cai Zhang
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Min Lu
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Peng Han
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Jing Wu
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
| | - Aifen Zhou
- Center for Prenatal Diagnosis, Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430016, P.R. China
| | - Xuemei Tan
- BGI Genomics, BGI‑Shenzhen, Shenzhen, Guangdong 518083, P.R. China
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13
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Prevalence and characterization of ATM germline mutations in Chinese BRCA1/2-negative breast cancer patients. Breast Cancer Res Treat 2019; 174:639-647. [PMID: 30607632 DOI: 10.1007/s10549-018-05124-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 12/26/2018] [Indexed: 12/31/2022]
Abstract
PURPOSE The ataxia telangiectasia-mutated (ATM) gene is a moderate susceptibility gene for breast cancer. However, little is known about the breast cancer phenotypes associated with ATM mutation. We therefore investigated the spectrum and clinical characteristics of ATM germline mutations in Chinese breast cancer patients. METHODS A multi-gene panel was performed to screen for ATM germline mutations in 7657 BRCA1/2-negative breast cancer patients. All deleterious mutations were validated by independent polymerase chain reaction (PCR)-Sanger sequencing. RESULTS A total of 31 pathogenic mutations in the ATM gene across 30 carriers were identified, and the ATM mutation rate was 0.4% (30/7,657) in this cohort. The majority of the mutations (90.3%, 28/31) were nonsense or frameshift mutations. Of the total ATM mutations, 61.3% (19/31) were novel mutations and 13 recurrent mutations were found. ATM mutations carriers were significantly more likely to have a family history of breast and/or ovarian cancer (26.7% in carriers vs. 8.6% in non-carriers, p < 0.001), as well as a family history of any cancer (60.0% in carriers vs. 31.5% in non-carriers, p = 0.001). In addition, ATM mutations carriers were significantly more likely to have oestrogen receptor (ER)-positive (p = 0.011), progesterone receptor (PR)-positive (p = 0.040), and lymph node-positive breast cancer (p = 0.034). CONCLUSIONS The prevalence of the ATM mutation is approximately 0.4% in Chinese BRCA1/2-negative breast cancer. ATM mutation carriers are significantly more likely to have a family history of cancer and to develop ER- and/or PR-positive breast cancer or lymph node-positive breast cancer.
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14
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Ye F, Chai W, Yang M, Xie M, Yang L. Ataxia-telangiectasia with a novel ATM gene mutation and Burkitt leukemia: A case report. Mol Clin Oncol 2018; 9:493-498. [PMID: 30402232 PMCID: PMC6200993 DOI: 10.3892/mco.2018.1721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/17/2018] [Indexed: 01/22/2023] Open
Abstract
Ataxia-telangiectasia (A-T) is an infrequent autosomal recessive disorder that involves multiple systems and is characterized by progressive cerebellar ataxia, oculocutaneous telangiectasias, radiosensitivity, immune deficiency with recurrent respiratory infections, and a tendency to develop lymphoid malignancies. A-T is caused by mutations in the ATM gene, with >1,000 mutations reported to date and gradually increasing in number. Patients with A-T have an increased incidence of cancers. The aim of the present study was to retrospectively review the case of a patient who presented at the age of 5 years with cerebellar ataxia without telangiectasia, and was diagnosed with Burkitt leukemia by bone marrow biopsy and molecular testing at the age of 7 years at the Xiangya Hospital of Central South University (Changsha, China). The patient received chemotherapy with the pediatric CCCG-BNHL-2015 regimen (R4 group) and achieved a complete remission after 2 courses. However, recurrent respiratory infections and thrombosis occurred during chemotherapy. The diagnosis of A-T was confirmed by uncovering two variants of the ATM gene, including c.742C>T (p.R248X; rs730881336) in exon 7 and c.6067-c.6068 ins GAGGGAAGAT in exon 41 by whole-exome sequencing. Unfortunately, the patient's parents refused follow-up treatment and he succumbed to recurrent severe infections 4 months after the diagnosis of Burkitt leukemia. The diagnosis of A-T may be challenging, as its phenotype can be incomplete early in the course of the disease. Detailed medical history, characteristic clinical manifestations and increasingly developed exome sequencing techniques may be helpful in diagnosing this rare disease. Management should be based on multidisciplinary guidance and other treatment options must be investigated in the future.
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Affiliation(s)
- Fanghua Ye
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Wenwen Chai
- Department of Nuclear Medicine, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410008, P.R. China
| | - Minghua Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Min Xie
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Liangchun Yang
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
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15
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Dabrowski M, Bukowy-Bieryllo Z, Zietkiewicz E. Advances in therapeutic use of a drug-stimulated translational readthrough of premature termination codons. Mol Med 2018; 24:25. [PMID: 30134808 PMCID: PMC6016875 DOI: 10.1186/s10020-018-0024-7] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 05/01/2018] [Indexed: 12/31/2022] Open
Abstract
Premature termination codons (PTCs) in the coding regions of mRNA lead to the incorrect termination of translation and generation of non-functional, truncated proteins. Translational readthrough of PTCs induced by pharmaceutical compounds is a promising way of restoring functional protein expression and reducing disease symptoms, without affecting the genome or transcriptome of the patient. While in some cases proven effective, the clinical use of readthrough-inducing compounds is still associated with many risks and difficulties. This review focuses on problems directly associated with compounds used to stimulate PTC readthrough, such as their interactions with the cell and organism, their toxicity and bioavailability (cell permeability; tissue deposition etc.). Various strategies designed to overcome these problems are presented.
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Affiliation(s)
- Maciej Dabrowski
- Institute of Human Genetics; Polish Academy of Sciences, Poznan, Poland
| | | | - Ewa Zietkiewicz
- Institute of Human Genetics; Polish Academy of Sciences, Poznan, Poland.
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16
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Kosmidis G, Veerman CC, Casini S, Verkerk AO, van de Pas S, Bellin M, Wilde AAM, Mummery CL, Bezzina CR. Readthrough-Promoting Drugs Gentamicin and PTC124 Fail to Rescue Nav1.5 Function of Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes Carrying Nonsense Mutations in the Sodium Channel Gene SCN5A. Circ Arrhythm Electrophysiol 2017; 9:CIRCEP.116.004227. [PMID: 27784737 DOI: 10.1161/circep.116.004227] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 09/09/2016] [Indexed: 11/16/2022]
Abstract
BACKGROUND Several compounds have been reported to induce translational readthrough of premature stop codons resulting in the production of full-length protein by interfering with ribosomal proofreading. Here we examined the effect of 2 of these compounds, gentamicin and PTC124, in human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes bearing nonsense mutations in the sodium channel gene SCN5A, which are associated with conduction disease and potential lethal arrhythmias. METHODS AND RESULTS We generated hiPSC from 2 patients carrying the mutations R1638X and W156X. hiPSC-derived cardiomyocytes from both patients recapitulated the expected electrophysiological phenotype, as evidenced by reduced Na+ currents and action potential upstroke velocities compared with hiPSC-derived cardiomyocytes from 2 unrelated control individuals. While we were able to confirm the readthrough efficacy of the 2 drugs in Human Embryonic Kidney 293 cells, we did not observe rescue of the electrophysiological phenotype in hiPSC-derived cardiomyocytes from the patients. CONCLUSIONS We conclude that these drugs are unlikely to present an effective treatment for patients carrying the loss-of-function SCN5A gene mutations examined in this study.
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Affiliation(s)
- Georgios Kosmidis
- From the Department of Anatomy and Embryology, Leiden University Medical Center, Leiden (G.K., S.C., S.v.d.P., M.B., C.L.M.); and Heart Center, Department of Experimental and Clinical Cardiology (C.C.V., A.A.M.W., C.R.B.) and Department of Anatomy and Embryology, Academic Medical Center (A.O.V.), Amsterdam, The Netherlands
| | - Christiaan C Veerman
- From the Department of Anatomy and Embryology, Leiden University Medical Center, Leiden (G.K., S.C., S.v.d.P., M.B., C.L.M.); and Heart Center, Department of Experimental and Clinical Cardiology (C.C.V., A.A.M.W., C.R.B.) and Department of Anatomy and Embryology, Academic Medical Center (A.O.V.), Amsterdam, The Netherlands
| | - Simona Casini
- From the Department of Anatomy and Embryology, Leiden University Medical Center, Leiden (G.K., S.C., S.v.d.P., M.B., C.L.M.); and Heart Center, Department of Experimental and Clinical Cardiology (C.C.V., A.A.M.W., C.R.B.) and Department of Anatomy and Embryology, Academic Medical Center (A.O.V.), Amsterdam, The Netherlands
| | - Arie O Verkerk
- From the Department of Anatomy and Embryology, Leiden University Medical Center, Leiden (G.K., S.C., S.v.d.P., M.B., C.L.M.); and Heart Center, Department of Experimental and Clinical Cardiology (C.C.V., A.A.M.W., C.R.B.) and Department of Anatomy and Embryology, Academic Medical Center (A.O.V.), Amsterdam, The Netherlands
| | - Simone van de Pas
- From the Department of Anatomy and Embryology, Leiden University Medical Center, Leiden (G.K., S.C., S.v.d.P., M.B., C.L.M.); and Heart Center, Department of Experimental and Clinical Cardiology (C.C.V., A.A.M.W., C.R.B.) and Department of Anatomy and Embryology, Academic Medical Center (A.O.V.), Amsterdam, The Netherlands
| | - Milena Bellin
- From the Department of Anatomy and Embryology, Leiden University Medical Center, Leiden (G.K., S.C., S.v.d.P., M.B., C.L.M.); and Heart Center, Department of Experimental and Clinical Cardiology (C.C.V., A.A.M.W., C.R.B.) and Department of Anatomy and Embryology, Academic Medical Center (A.O.V.), Amsterdam, The Netherlands
| | - Arthur A M Wilde
- From the Department of Anatomy and Embryology, Leiden University Medical Center, Leiden (G.K., S.C., S.v.d.P., M.B., C.L.M.); and Heart Center, Department of Experimental and Clinical Cardiology (C.C.V., A.A.M.W., C.R.B.) and Department of Anatomy and Embryology, Academic Medical Center (A.O.V.), Amsterdam, The Netherlands
| | - Christine L Mummery
- From the Department of Anatomy and Embryology, Leiden University Medical Center, Leiden (G.K., S.C., S.v.d.P., M.B., C.L.M.); and Heart Center, Department of Experimental and Clinical Cardiology (C.C.V., A.A.M.W., C.R.B.) and Department of Anatomy and Embryology, Academic Medical Center (A.O.V.), Amsterdam, The Netherlands
| | - Connie R Bezzina
- From the Department of Anatomy and Embryology, Leiden University Medical Center, Leiden (G.K., S.C., S.v.d.P., M.B., C.L.M.); and Heart Center, Department of Experimental and Clinical Cardiology (C.C.V., A.A.M.W., C.R.B.) and Department of Anatomy and Embryology, Academic Medical Center (A.O.V.), Amsterdam, The Netherlands.
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17
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Lokki AI, Kaartokallio T, Holmberg V, Onkamo P, Koskinen LLE, Saavalainen P, Heinonen S, Kajantie E, Kere J, Kivinen K, Pouta A, Villa PM, Hiltunen L, Laivuori H, Meri S. Analysis of Complement C3 Gene Reveals Susceptibility to Severe Preeclampsia. Front Immunol 2017; 8:589. [PMID: 28611769 PMCID: PMC5446983 DOI: 10.3389/fimmu.2017.00589] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/03/2017] [Indexed: 11/29/2022] Open
Abstract
Preeclampsia (PE) is a common vascular disease of pregnancy with genetic predisposition. Dysregulation of the complement system has been implicated, but molecular mechanisms are incompletely understood. In this study, we determined the potential linkage of severe PE to the most central complement gene, C3. Three cohorts of Finnish patients and controls were recruited for a genetic case-control study. Participants were genotyped using Sequenom genotyping and Sanger sequencing. Initially, we studied 259 Finnish patients with severe PE and 426 controls from the Southern Finland PE and the Finnish population-based PE cohorts. We used a custom-made single nucleotide polymorphism (SNP) genotyping assay consisting of 98 SNPs in 18 genes that encode components of the complement system. Following the primary screening, C3 was selected as the candidate gene and consequently Sanger sequenced. Fourteen SNPs from C3 were also genotyped by a Sequenom panel in 960 patients with severe PE and 705 controls, including already sequenced individuals. Three of the 43 SNPs observed within C3 were associated with severe PE: rs2287845 (p = 0.038, OR = 1.158), rs366510 (p = 0.039, OR = 1.158), and rs2287848 (p = 0.041, OR = 1.155). We also discovered 16 SNP haplotypes with extreme linkage disequilibrium in the middle of the gene with a protective (p = 0.044, OR = 0.628) or a predisposing (p = 0.011, OR = 2.110) effect to severe PE depending on the allele combination. Genetic variants associated with PE are located in key domains of C3 and could thereby influence the function of C3. This is, as far as we are aware, the first candidate gene in the complement system with an association to a clinically relevant PE subphenotype, severe PE. The result highlights a potential role for the complement system in the pathogenesis of PE and may help in defining prognostic and therapeutic subgroups of preeclamptic women.
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Affiliation(s)
- A Inkeri Lokki
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - Tea Kaartokallio
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ville Holmberg
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Clinic of Infectious Diseases, HYKS Inflammation Center, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Päivi Onkamo
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Lotta L E Koskinen
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Päivi Saavalainen
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Seppo Heinonen
- Department of Obstetrics and Gynecology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Eero Kajantie
- Chronic Disease Prevention Unit, Department of Health, National Institute for Health and Welfare, Helsinki, Finland.,Children's Hospital, Helsinki University Hospital, University of Helsinki, Helsinki, Finland.,PEDEGO Research Unit, MRC Oulu, Oulu University Hospital, University of Oulu, Oulu, Finland
| | - Juha Kere
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.,Folkhälsan Institute of Genetics, Helsinki, Finland.,Molecular Neurology, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Katja Kivinen
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, UK
| | - Anneli Pouta
- PEDEGO Research Unit, MRC Oulu, Oulu University Hospital, University of Oulu, Oulu, Finland.,Department of Government Services, National Institute for Health and Welfare, Helsinki, Finland
| | - Pia M Villa
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Department of Obstetrics and Gynecology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | | | - Hannele Laivuori
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Department of Obstetrics and Gynecology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland.,Institute for Molecular Medicine Finland, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
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18
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Lavin MF, Yeo AJ, Kijas AW, Wolvetang E, Sly PD, Wainwright C, Sinclair K. Therapeutic targets and investigated treatments for Ataxia-Telangiectasia. Expert Opin Orphan Drugs 2016. [DOI: 10.1080/21678707.2016.1254618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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19
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Abolhassani H, Aghamohammadi A, Hammarström L. Monogenic mutations associated with IgA deficiency. Expert Rev Clin Immunol 2016; 12:1321-1335. [DOI: 10.1080/1744666x.2016.1198696] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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20
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Abstract
Nonsense-mediated mRNA decay (NMD) is an mRNA quality-control mechanism that typifies all eukaryotes examined to date. NMD surveys newly synthesized mRNAs and degrades those that harbor a premature termination codon (PTC), thereby preventing the production of truncated proteins that could result in disease in humans. This is evident from dominantly inherited diseases that are due to PTC-containing mRNAs that escape NMD. Although many cellular NMD targets derive from mistakes made during, for example, pre-mRNA splicing and, possibly, transcription initiation, NMD also targets ∼10% of normal physiological mRNAs so as to promote an appropriate cellular response to changing environmental milieus, including those that induce apoptosis, maturation or differentiation. Over the past ∼35 years, a central goal in the NMD field has been to understand how cells discriminate mRNAs that are targeted by NMD from those that are not. In this Cell Science at a Glance and the accompanying poster, we review progress made towards this goal, focusing on human studies and the role of the key NMD factor up-frameshift protein 1 (UPF1).
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
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21
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22
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Siva K, Covello G, Denti MA. Exon-skipping antisense oligonucleotides to correct missplicing in neurogenetic diseases. Nucleic Acid Ther 2014; 24:69-86. [PMID: 24506781 DOI: 10.1089/nat.2013.0461] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Alternative splicing is an important regulator of the transcriptome. However, mutations may cause alteration of splicing patterns, which in turn leads to disease. During the past 10 years, exon skipping has been looked upon as a powerful tool for correction of missplicing in disease and progress has been made towards clinical trials. In this review, we discuss the use of antisense oligonucleotides to correct splicing defects through exon skipping, with a special focus on diseases affecting the nervous system, and the latest stage achieved in its progress.
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Affiliation(s)
- Kavitha Siva
- 1 Center for Integrative Biology (CIBIO), University of Trento , Trento, Italy
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24
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Podralska MJ, Stembalska A, Ślęzak R, Lewandowicz-Uszyńska A, Pietrucha B, Kołtan S, Wigowska-Sowińska J, Pilch J, Mosor M, Ziółkowska-Suchanek I, Dzikiewicz-Krawczyk A, Słomski R. Ten new ATM alterations in Polish patients with ataxia-telangiectasia. Mol Genet Genomic Med 2014; 2:504-11. [PMID: 25614872 PMCID: PMC4303220 DOI: 10.1002/mgg3.98] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 06/20/2014] [Accepted: 06/25/2014] [Indexed: 11/23/2022] Open
Abstract
Inherited biallelic mutations of the ATM gene are responsible for the
development of ataxia telangiectasia (AT). The objective of the present study was to conduct
molecular analysis of the ATM gene in a cohort of 24 Polish patients with
ataxia-telangiectasia with aim being to provide an updated mutational spectrum in Polish AT
patients. As a result of molecular analysis, the status of recurrent mutation was confirmed and ten
new ATM variants were detected. Application of MLPA analysis allowed the detection of large genomic
deletion. Previously, this type of mutation had never been seen in our population. Finally, in
silico analysis was carried out for newly detected ATM alterations. In addition, functional analysis
was performed to evaluate the effects of intronic variants:
c.3402+30_3402+32delATC.
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Affiliation(s)
| | | | - Ryszard Ślęzak
- Department of Genetics, Wroclaw Medical University Wroclaw, Poland
| | - Aleksandra Lewandowicz-Uszyńska
- 3rd Department and Clinic of Paediatrics, Immunology and Rheumatology of Developmental Age, Wroclaw Medical University Wroclaw, Poland
| | - Barbara Pietrucha
- Department of Immunology, The Children's Memorial Health Institute Warsaw, Poland
| | - Sylwia Kołtan
- Department of Pediatrics, Hematology and Oncology, Institute of Pediatrics, Medical Academy Bydgoszcz, Poland
| | | | - Jacek Pilch
- Department of Child Neurology, Medical University of Silesia Katowice, Poland
| | - Maria Mosor
- Institute of Human Genetics of the Polish Academy of Sciences Poznań, Poland
| | | | | | - Ryszard Słomski
- Institute of Human Genetics of the Polish Academy of Sciences Poznań, Poland
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25
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Nonsense-mediated decay in genetic disease: friend or foe? MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 762:52-64. [PMID: 25485595 DOI: 10.1016/j.mrrev.2014.05.001] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 05/02/2014] [Accepted: 05/03/2014] [Indexed: 12/11/2022]
Abstract
Eukaryotic cells utilize various RNA quality control mechanisms to ensure high fidelity of gene expression, thus protecting against the accumulation of nonfunctional RNA and the subsequent production of abnormal peptides. Messenger RNAs (mRNAs) are largely responsible for protein production, and mRNA quality control is particularly important for protecting the cell against the downstream effects of genetic mutations. Nonsense-mediated decay (NMD) is an evolutionarily conserved mRNA quality control system in all eukaryotes that degrades transcripts containing premature termination codons (PTCs). By degrading these aberrant transcripts, NMD acts to prevent the production of truncated proteins that could otherwise harm the cell through various insults, such as dominant negative effects or the ER stress response. Although NMD functions to protect the cell against the deleterious effects of aberrant mRNA, there is a growing body of evidence that mutation-, codon-, gene-, cell-, and tissue-specific differences in NMD efficiency can alter the underlying pathology of genetic disease. In addition, the protective role that NMD plays in genetic disease can undermine current therapeutic strategies aimed at increasing the production of full-length functional protein from genes harboring nonsense mutations. Here, we review the normal function of this RNA surveillance pathway and how it is regulated, provide current evidence for the role that it plays in modulating genetic disease phenotypes, and how NMD can be used as a therapeutic target.
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Micale L, Augello B, Maffeo C, Selicorni A, Zucchetti F, Fusco C, De Nittis P, Pellico MT, Mandriani B, Fischetto R, Boccone L, Silengo M, Biamino E, Perria C, Sotgiu S, Serra G, Lapi E, Neri M, Ferlini A, Cavaliere ML, Chiurazzi P, Monica MD, Scarano G, Faravelli F, Ferrari P, Mazzanti L, Pilotta A, Patricelli MG, Bedeschi MF, Benedicenti F, Prontera P, Toschi B, Salviati L, Melis D, Di Battista E, Vancini A, Garavelli L, Zelante L, Merla G. Molecular analysis, pathogenic mechanisms, and readthrough therapy on a large cohort of Kabuki syndrome patients. Hum Mutat 2014; 35:841-50. [PMID: 24633898 PMCID: PMC4234006 DOI: 10.1002/humu.22547] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 03/05/2014] [Indexed: 12/04/2022]
Abstract
Kabuki syndrome (KS) is a multiple congenital anomalies syndrome characterized by characteristic facial features and varying degrees of mental retardation, caused by mutations in KMT2D/MLL2 and KDM6A/UTX genes. In this study, we performed a mutational screening on 303 Kabuki patients by direct sequencing, MLPA, and quantitative PCR identifying 133 KMT2D, 62 never described before, and four KDM6A mutations, three of them are novel. We found that a number of KMT2D truncating mutations result in mRNA degradation through the nonsense-mediated mRNA decay, contributing to protein haploinsufficiency. Furthermore, we demonstrated that the reduction of KMT2D protein level in patients’ lymphoblastoid and skin fibroblast cell lines carrying KMT2D-truncating mutations affects the expression levels of known KMT2D target genes. Finally, we hypothesized that the KS patients may benefit from a readthrough therapy to restore physiological levels of KMT2D and KDM6A proteins. To assess this, we performed a proof-of-principle study on 14 KMT2D and two KDM6A nonsense mutations using specific compounds that mediate translational readthrough and thereby stimulate the re-expression of full-length functional proteins. Our experimental data showed that both KMT2D and KDM6A nonsense mutations displayed high levels of readthrough in response to gentamicin treatment, paving the way to further studies aimed at eventually treating some Kabuki patients with readthrough inducers.
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Affiliation(s)
- Lucia Micale
- Medical Genetics Unit, IRCCS Casa Sollievo Della Sofferenza Hospital, San Giovanni Rotondo, Italy
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27
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Nakamura K, Fike F, Haghayegh S, Saunders-Pullman R, Dawson AJ, Dörk T, Gatti RA. A-TWinnipeg: Pathogenesis of rare ATM missense mutation c.6200C>A with decreased protein expression and downstream signaling, early-onset dystonia, cancer, and life-threatening radiotoxicity. Mol Genet Genomic Med 2014; 2:332-40. [PMID: 25077176 PMCID: PMC4113274 DOI: 10.1002/mgg3.72] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 01/29/2014] [Accepted: 02/02/2014] [Indexed: 12/16/2022] Open
Abstract
We studied 10 Mennonite patients who carry the c.6200C>A missense mutation (p.A2067D) in the ATM gene, all of whom exhibited a phenotypic variant of ataxia-telangiectasia (A-T) that is characterized by early-onset dystonia and late-onset mild ataxia, as previously described. This report provides the pathogenetic evidence for this mutation on cellular functions. Several patients have developed cancer and subsequently experienced life-threatening adverse reactions to radiation (radiotoxicity) and/or chemotherapy. As the c.6200C>A mutation is, thus far, unique to the Mennonite population and is always associated with the same haplotype or haplovariant, it was important to rule out any possible confounding DNA variant on the same haplotype. Lymphoblastoid cells derived from Mennonite patients expressed small amounts of ATM protein, which had no autophosphorylation activity at ATM Ser1981, and trace-to-absent transphosphorylation of downstream ATM targets. A-T lymphoblastoid cells stably transfected with ATM cDNA which had been mutated for c.6200C>A did not show a detectable amount of ATM protein. The same stable cell line with mutated ATM cDNA also showed a trace-to-absent transphosphorylation of downstream ATM targets SMC1pSer966 and KAP1pSer824. From these results, we conclude that c.6200A is the disease-causing ATM mutation on this haplotype. The presence of at least trace amounts of ATM kinase activity on some immunoblots may account for the late-onset, mild ataxia of these patients. The cause of the dystonia remains unclear. Because this dystonia-ataxia phenotype is often encountered in the Mennonite population in association with cancer and adverse reactions to chemotherapy, an early diagnosis is important.
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Affiliation(s)
- Kotoka Nakamura
- Department of Pathology and Laboratory Medicine, UCLA School of Medicine Los Angeles, California
| | - Francesca Fike
- Department of Pathology and Laboratory Medicine, UCLA School of Medicine Los Angeles, California
| | - Sara Haghayegh
- Department of Pathology and Laboratory Medicine, UCLA School of Medicine Los Angeles, California
| | | | - Angelika J Dawson
- Cytogenetics Laboratory, Division of Laboratory Medicine & Pathology, Departments of Biochemistry & Medical Genetics and Pediatrics & Child Health, Diagnostic Services of Manitoba, University of Manitoba Winnipeg, Manitoba, Canada
| | - Thilo Dörk
- Gynaecology Research Unit, Hannover Medical School Hannover, Germany
| | - Richard A Gatti
- Department of Pathology and Laboratory Medicine, UCLA School of Medicine Los Angeles, California ; Department of Human Genetics, UCLA School of Medicine Los Angeles, California ; Molecular Biology Institute, UCLA Los Angeles, California
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SMRT compounds abrogate cellular phenotypes of ataxia telangiectasia in neural derivatives of patient-specific hiPSCs. Nat Commun 2013; 4:1824. [PMID: 23652012 DOI: 10.1038/ncomms2824] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 03/28/2013] [Indexed: 12/26/2022] Open
Abstract
Ataxia telangiectasia is a devastating neurodegenerative disease caused primarily by loss of function mutations in ATM, a hierarchical DNA repair gene and tumour suppressor. So far, murine models of ataxia telangiectasia have failed to accurately recapitulate many aspects of the disease, most notably, the progressive cerebellar ataxia. Here we present a model of human ataxia telangiectasia using induced pluripotent stem cells, and show that small molecule read-through compounds, designed to induce read-through of mRNA around premature termination codons, restore ATM activity and improve the response to DNA damage. This platform allows for efficient screening of novel compounds, identification of target and off-target effects, and preclinical testing on relevant cell types for the pathogenic dissection and treatment of ataxia telangiectasia.
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29
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Role of pseudoexons and pseudointrons in human cancer. Int J Cell Biol 2013; 2013:810572. [PMID: 24204383 PMCID: PMC3800588 DOI: 10.1155/2013/810572] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/09/2013] [Indexed: 11/18/2022] Open
Abstract
In all eukaryotic organisms, pre-mRNA splicing and alternative splicing processes play an essential role in regulating the flow of information required to drive complex developmental and metabolic pathways. As a result, eukaryotic cells have developed a very efficient macromolecular machinery, called the spliceosome, to correctly recognize the pre-mRNA sequences that need to be inserted in a mature mRNA (exons) from those that should be removed (introns). In healthy individuals, alternative and constitutive splicing processes function with a high degree of precision and fidelity in order to ensure the correct working of this machinery. In recent years, however, medical research has shown that alterations at the splicing level play an increasingly important role in many human hereditary diseases, neurodegenerative processes, and especially in cancer origin and progression. In this minireview, we will focus on several genes whose association with cancer has been well established in previous studies, such as ATM, BRCA1/A2, and NF1. In particular, our objective will be to provide an overview of the known mechanisms underlying activation/repression of pseudoexons and pseudointrons; the possible utilization of these events as biomarkers of tumor staging/grading; and finally, the treatment options for reversing pathologic splicing events.
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Huang Y, Yang L, Wang J, Yang F, Xiao Y, Xia R, Yuan X, Yan M. Twelve novel Atm mutations identified in Chinese ataxia telangiectasia patients. Neuromolecular Med 2013; 15:536-40. [PMID: 23807571 PMCID: PMC3732755 DOI: 10.1007/s12017-013-8240-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/14/2013] [Indexed: 12/14/2022]
Abstract
Ataxia telangiectasia (A-T) is an autosomal recessive disease characterized mainly by progressive cerebellar ataxia, oculocutaneous telangiectasia, and immunodeficiency. This disease is caused by mutations of the ataxia telangiectasia mutated (Atm) gene. More than 500 Atm mutations that are responsible for A-T have been identified so far. However, there have been very few A-T cases reported in China, and only two Chinese A-T patients have undergone Atm gene analysis. In order to systemically investigate A-T in China and map their Atm mutation spectrum, we recruited eight Chinese A-T patients from six unrelated families nationwide. Using direct sequencing of genomic DNA and the multiplex ligation-dependent probe amplification, we identified twelve pathogenic Atm mutations, including one missense, four nonsense, five frameshift, one splicing, and one large genomic deletion. All the Atm mutations we identified were novel, and no homozygous mutation and founder-effect mutation were found. These results suggest that Atm mutations in Chinese populations are diverse and distinct largely from those in other ethnic areas.
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Affiliation(s)
- Yu Huang
- Department of Medical Genetics, Peking University Health Science Center, Beijing, China
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Havens MA, Duelli DM, Hastings ML. Targeting RNA splicing for disease therapy. WILEY INTERDISCIPLINARY REVIEWS. RNA 2013; 4:247-66. [PMID: 23512601 PMCID: PMC3631270 DOI: 10.1002/wrna.1158] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Splicing of pre-messenger RNA into mature messenger RNA is an essential step for the expression of most genes in higher eukaryotes. Defects in this process typically affect cellular function and can have pathological consequences. Many human genetic diseases are caused by mutations that cause splicing defects. Furthermore, a number of diseases are associated with splicing defects that are not attributed to overt mutations. Targeting splicing directly to correct disease-associated aberrant splicing is a logical approach to therapy. Splicing is a favorable intervention point for disease therapeutics, because it is an early step in gene expression and does not alter the genome. Significant advances have been made in the development of approaches to manipulate splicing for therapy. Splicing can be manipulated with a number of tools including antisense oligonucleotides, modified small nuclear RNAs (snRNAs), trans-splicing, and small molecule compounds, all of which have been used to increase specific alternatively spliced isoforms or to correct aberrant gene expression resulting from gene mutations that alter splicing. Here we describe clinically relevant splicing defects in disease states, the current tools used to target and alter splicing, specific mutations and diseases that are being targeted using splice-modulating approaches, and emerging therapeutics.
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Affiliation(s)
- Mallory A. Havens
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science. North Chicago, IL, 60064, USA. No conflicts of interest
| | - Dominik M. Duelli
- Department of Cellular and Molecular Pharmacology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA. No conflicts of interest
| | - Michelle L. Hastings
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science. North Chicago, IL, 60064, USA, Phone: 847-578-8517 Fax: 847-578-3253. No conflicts of interest
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Next-generation sequencing reveals deep intronic cryptic ABCC8 and HADH splicing founder mutations causing hyperinsulinism by pseudoexon activation. Am J Hum Genet 2013; 92:131-6. [PMID: 23273570 DOI: 10.1016/j.ajhg.2012.11.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 10/30/2012] [Accepted: 11/20/2012] [Indexed: 02/01/2023] Open
Abstract
Next-generation sequencing (NGS) enables analysis of the human genome on a scale previously unachievable by Sanger sequencing. Exome sequencing of the coding regions and conserved splice sites has been very successful in the identification of disease-causing mutations, and targeting of these regions has extended clinical diagnostic testing from analysis of fewer than ten genes per phenotype to more than 100. Noncoding mutations have been less extensively studied despite evidence from mRNA analysis for the existence of deep intronic mutations in >20 genes. We investigated individuals with hyperinsulinaemic hypoglycaemia and biochemical or genetic evidence to suggest noncoding mutations by using NGS to analyze the entire genomic regions of ABCC8 (117 kb) and HADH (94 kb) from overlapping ~10 kb PCR amplicons. Two deep intronic mutations, c.1333-1013A>G in ABCC8 and c.636+471G>T HADH, were identified. Both are predicted to create a cryptic splice donor site and an out-of-frame pseudoexon. Sequence analysis of mRNA from affected individuals' fibroblasts or lymphoblastoid cells confirmed mutant transcripts with pseudoexon inclusion and premature termination codons. Testing of additional individuals showed that these are founder mutations in the Irish and Turkish populations, accounting for 14% of focal hyperinsulinism cases and 32% of subjects with HADH mutations in our cohort. The identification of deep intronic mutations has previously focused on the detection of aberrant mRNA transcripts in a subset of disorders for which RNA is readily obtained from the target tissue or ectopically expressed at sufficient levels. Our approach of using NGS to analyze the entire genomic DNA sequence is applicable to any disease.
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Mallott J, Kwan A, Church J, Gonzalez-Espinosa D, Lorey F, Tang LF, Sunderam U, Rana S, Srinivasan R, Brenner SE, Puck J. Newborn screening for SCID identifies patients with ataxia telangiectasia. J Clin Immunol 2012; 33:540-9. [PMID: 23264026 PMCID: PMC3591536 DOI: 10.1007/s10875-012-9846-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 11/27/2012] [Indexed: 12/25/2022]
Abstract
Purpose Severe combined immunodeficiency (SCID) is characterized by failure of T lymphocyte development and absent or very low T cell receptor excision circles (TRECs), DNA byproducts of T cell maturation. Newborn screening for TRECs to identify SCID is now performed in several states using PCR of DNA from universally collected dried blood spots (DBS). In addition to infants with typical SCID, TREC screening identifies infants with T lymphocytopenia who appear healthy and in whom a SCID diagnosis cannot be confirmed. Deep sequencing was employed to find causes of T lymphocytopenia in such infants. Methods Whole exome sequencing and analysis were performed in infants and their parents. Upon finding deleterious mutations in the ataxia telangiectasia mutated (ATM) gene, we confirmed the diagnosis of ataxia telangiectasia (AT) in two infants and then tested archival newborn DBS of additional AT patients for TREC copy number. Results Exome sequencing and analysis led to 2 unsuspected gene diagnoses of AT. Of 13 older AT patients for whom newborn DBS had been stored, 7 samples tested positive for SCID under the criteria of California’s newborn screening program. AT children with low neonatal TRECs had low CD4 T cell counts subsequently detected (R = 0.64). Conclusions T lymphocytopenia in newborns can be a feature of AT, as revealed by TREC screening and exome sequencing. Although there is no current cure for the progressive neurological impairment of AT, early detection permits avoidance of infectious complications, while providing information for families regarding reproductive recurrence risks and increased cancer risks in patients and carriers.
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Affiliation(s)
- Jacob Mallott
- />Department of Pediatrics, University of California San Francisco, 513 Parnassus Avenue, HSE 301A, Box 0519, San Francisco, CA 94143-0519 USA
| | - Antonia Kwan
- />Department of Pediatrics, University of California San Francisco, 513 Parnassus Avenue, HSE 301A, Box 0519, San Francisco, CA 94143-0519 USA
| | - Joseph Church
- />Department of Pediatrics, Keck School of Medicine, University of Southern California and Children’s Hospital Los Angeles, Los Angeles, CA USA
| | - Diana Gonzalez-Espinosa
- />Department of Pediatrics, University of California San Francisco, 513 Parnassus Avenue, HSE 301A, Box 0519, San Francisco, CA 94143-0519 USA
| | - Fred Lorey
- />Genetic Disease Laboratory, California Department of Public Health, Richmond, CA USA
| | - Ling Fung Tang
- />Institute for Human Genetics, University of California San Francisco, San Francisco, CA USA
| | - Uma Sunderam
- />Innovations Labs, Tata Consulting Services, Hyderabad, AP India
| | - Sadhna Rana
- />Innovations Labs, Tata Consulting Services, Hyderabad, AP India
| | | | - Steven E. Brenner
- />Department of Plant and Microbial Biology, University of California, Berkeley, CA USA
| | - Jennifer Puck
- />Department of Pediatrics, University of California San Francisco, 513 Parnassus Avenue, HSE 301A, Box 0519, San Francisco, CA 94143-0519 USA
- />Institute for Human Genetics, University of California San Francisco, San Francisco, CA USA
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Cavalieri S, Pozzi E, Gatti RA, Brusco A. Deep-intronic ATM mutation detected by genomic resequencing and corrected in vitro by antisense morpholino oligonucleotide (AMO). Eur J Hum Genet 2012; 21:774-8. [PMID: 23211698 DOI: 10.1038/ejhg.2012.266] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Recent development of next-generation DNA sequencing (NGS) techniques is changing the approach to search for mutations in human genetic diseases. We applied NGS to study an A-T patient in which one of the two expected mutations was not found after DHPLC, cDNA sequencing and MLPA screening. The 160-kb ATM genomic region was divided into 31 partially overlapping fragments of 4-6 kb and amplified by long-range PCR in the patient and mother, who carried the same mutation by segregation. We identified six intronic variants that were shared by the two genomes and not reported in the dbSNP(132) database. Among these, c.1236-405C>T located in IVS11 was predicted to be pathogenic because it affected splicing. This mutation creates a cryptic novel donor (5') splice site (score 1.00) 405 bp upstream of the exon 12 acceptor (3') splice site. cDNA analysis showed the inclusion of a 212-bp non-coding 'pseudoexon' with a premature stop codon. We validated the functional effect of the splicing mutation using a minigene assay. Using antisense morpholino oligonucleotides, designed to mask the cryptic donor splice-site created by the c.1236-405C>T mutation, we abrogated the aberrant splicing product to a wild-type ATM transcript, and in vitro reverted the functional ATM kinase impairment of the patients' lymphoblasts. Resequencing is an effective strategy for identifying rare splicing mutations in patients for whom other mutation analyses have failed (DHPLC, MLPA, or cDNA sequencing). This is especially important because many of these patients will carry rare splicing variants that are amenable to antisense-based correction.
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Affiliation(s)
- Simona Cavalieri
- Università di Torino, Department of Medical Sciences & Azienda Ospedaliera Città della Salute e della Scienza, Turin, Italy
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35
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Lee HLR, Dougherty JP. Pharmaceutical therapies to recode nonsense mutations in inherited diseases. Pharmacol Ther 2012; 136:227-66. [PMID: 22820013 DOI: 10.1016/j.pharmthera.2012.07.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2012] [Indexed: 12/21/2022]
Abstract
Nonsense codons, generated from nonsense mutations or frameshifts, contribute significantly to the spectrum of inherited human diseases such as cystic fibrosis, Duchenne muscular dystrophy, hemophilia, spinal muscular atrophy, and many forms of cancer. The presence of a mutant nonsense codon results in premature termination to preclude the synthesis of a full-length protein and leads to aberrations in gene expression. Suppression therapy to recode a premature termination codon with an amino acid allowing readthrough to rescue the production of a full-length protein presents a promising strategy for treatment of patients suffering from debilitating nonsense-mediated disorders. Suppression therapy using aminoglycosides to promote readthrough in vitro have been known since the sixties. Recent progress in the field of recoding via pharmaceuticals has led to the continuous discovery and development of several pharmacological agents with nonsense suppression activities. Here, we review the mechanisms that are involved in discriminating normal versus premature termination codons, the factors involved in readthrough efficiency, the epidemiology of several well-known nonsense-mediated diseases, and the various pharmacological agents (aminoglycoside and non-aminoglycoside compounds) that are currently being employed in nonsense suppression therapy studies. We also discuss how these therapeutic agents can be used to regulate gene expression for gene therapy applications.
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Affiliation(s)
- Hui-Ling Rose Lee
- Department of Molecular Genetics, Microbiology, and Immunology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ, USA
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Process for immune defect and chromosomal translocation during early thymocyte development lacking ATM. Blood 2012; 120:789-99. [PMID: 22709691 DOI: 10.1182/blood-2012-02-413195] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Immune defect in ataxia telangiectasia patients has been attributed to either the failure of V(D)J recombination or class-switch recombination, and the chromosomal translocation in their lymphoma often involves the TCR gene. The ATM-deficient mouse exhibits fewer CD4 and CD8 single-positive T cells because of a failure to develop from the CD4(+)CD8(+) double-positive phase to the single-positive phase. Although the occurrence of chromosome 14 translocations involving TCR-δ gene in ATM-deficient lymphomas suggests that these are early events in T-cell development, a thorough analysis focusing on early T-cell development has never been performed. Here we demonstrate that ATM-deficient mouse thymocytes are perturbed in passing through the β- or γδ-selection checkpoint, leading in part to the developmental failure of T cells. Detailed karyotype analysis using the in vitro thymocyte development system revealed that RAG-mediated TCR-α/δ locus breaks occur and are left unrepaired during the troublesome β- or γδ-selection checkpoints. By getting through these selection checkpoints, some of the clones with random or nonrandom chromosomal translocations involving TCR-α/δ locus are selected and accumulate. Thus, our study visualized the first step of multistep evolutions toward lymphomagenesis in ATM-deficient thymocytes associated with T-lymphopenia and immunodeficiency.
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Gatti RA. SMRT compounds correct nonsense mutations in primary immunodeficiency and other genetic models. Ann N Y Acad Sci 2012; 1250:33-40. [PMID: 22364446 DOI: 10.1111/j.1749-6632.2012.06467.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Within less than 10 years after the realization of the double helix of DNA, the ability of aminoglycosides to influence the misreading or readthrough of premature termination codons was discovered. It took another three decades to clone and sequence disease genes and appreciate the similarity of mutation spectra for most inborn errors. Nonsense mutations once again have become the target of readthrough compounds. In this brief review, we trace the development in our laboratory of the next generation of readthrough agents, small molecule readthrough (SMRT) drug-like chemicals, and assays for comparing their in vitro activity. Possible mechanisms of action and potential clinical applications are considered.
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Affiliation(s)
- Richard A Gatti
- David Geffen/UCLA School of Medicine, Department of Pathology and Laboratory Medicine, and Human Genetics, Los Angeles, California 90095-1732, USA.
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