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Yang Y, Xia C, Song X, Tang X, Nie X, Xu W, Du C, Zhang H, Luo P. Application of a Multiplex Ligation-Dependent Probe Amplification-Based Next-Generation Sequencing Approach for the Detection of Pathogenesis of Duchenne Muscular Dystrophy and Spinal Muscular Atrophy Caused by Copy Number Aberrations. Mol Neurobiol 2024; 61:200-211. [PMID: 37596438 PMCID: PMC10791777 DOI: 10.1007/s12035-023-03572-9] [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: 12/29/2022] [Accepted: 08/04/2023] [Indexed: 08/20/2023]
Abstract
Both Duchenne muscular dystrophy (DMD; OMIM no. 310200) and spinal muscular atrophy (SMA; OMIM no. 253300/253550/253400/271150) are genetic disorders characterized by progressive muscle degeneration and weakness. Genetic copy number aberrations in the pathogenetic genes DMD and SMN1 lead to alterations in functional proteins, resulting in DMD and SMA, respectively. Multiplex ligation-dependent probe amplification (MLPA) has become a standard method for the detection of common copy number aberrations (CNAs), including DMD and SMN1 deletions, both of which are associated with poor clinical outcomes. However, traditional MLPA assays only accommodate a maximum of 60 MLPA probes per test. To increase the number of targeted sequences in one assay, an MLPA-based next-generation sequencing (NGS) assay has been developed that is based on the standard MLPA procedure, allows high-throughput screening for a large number of fragments and samples by integrating additional indices for detection, and can be analyzed on all Illumina NGS platforms.
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Affiliation(s)
- Yongchen Yang
- Department of Laboratory Medicine, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Building 7, 24, Lane 1400, West Beijing Road, Jing'an, Shanghai, 200040, People's Republic of China.
| | - Chaoran Xia
- Zhejiang Shaoxing Topgen Biomedical Technology Co. Ltd. Block B, Building 19, No. 3399 Kangxin Road, Pudong District, Shanghai, 201321, People's Republic of China.
| | - Xiaozhen Song
- Department of Laboratory Medicine, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Building 7, 24, Lane 1400, West Beijing Road, Jing'an, Shanghai, 200040, People's Republic of China
| | - Xiaojun Tang
- Department of Laboratory Medicine, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Building 7, 24, Lane 1400, West Beijing Road, Jing'an, Shanghai, 200040, People's Republic of China
| | - Xueling Nie
- Shanghai Shiji Medical Laboratory Institute, Floor 5, No. 3805, Zhoujiazui Road, Yangpu District, Shanghai, 200093, People's Republic of China
| | - Wuhen Xu
- Department of Laboratory Medicine, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Building 7, 24, Lane 1400, West Beijing Road, Jing'an, Shanghai, 200040, People's Republic of China
| | - Chengkan Du
- Department of Laboratory Medicine, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Building 7, 24, Lane 1400, West Beijing Road, Jing'an, Shanghai, 200040, People's Republic of China
| | - Hong Zhang
- Department of Laboratory Medicine, Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University, Building 7, 24, Lane 1400, West Beijing Road, Jing'an, Shanghai, 200040, People's Republic of China
| | - Peng Luo
- Zhejiang Shaoxing Topgen Biomedical Technology Co. Ltd. Block B, Building 19, No. 3399 Kangxin Road, Pudong District, Shanghai, 201321, People's Republic of China
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Gushchina LV, Bradley AJ, Vetter TA, Lay JW, Rohan NL, Frair EC, Wein N, Flanigan KM. Persistence of exon 2 skipping and dystrophin expression at 18 months after U7snRNA-mediated therapy in the Dup2 mouse model. Mol Ther Methods Clin Dev 2023; 31:101144. [PMID: 38027058 PMCID: PMC10679948 DOI: 10.1016/j.omtm.2023.101144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a progressive X-linked disease caused by mutations in the DMD gene that prevent the expression of a functional dystrophin protein. Exon duplications represent 6%-11% of mutations, and duplications of exon 2 (Dup2) are the most common (∼11%) of duplication mutations. An exon-skipping strategy for Dup2 mutations presents a large therapeutic window. Skipping one exon copy results in full-length dystrophin expression, whereas skipping of both copies (Del2) activates an internal ribosomal entry site (IRES) in exon 5, inducing the expression of a highly functional truncated dystrophin isoform. We have previously confirmed the therapeutic efficacy of AAV9.U7snRNA-mediated skipping in the Dup2 mouse model and showed the absence of off-target splicing effects and lack of toxicity in mice and nonhuman primates. Here, we report long-term dystrophin expression data following the treatment of 3-month-old Dup2 mice with the scAAV9.U7.ACCA vector. Significant exon 2 skipping and robust dystrophin expression in the muscles and hearts of treated mice persist at 18 months after treatment, along with the partial rescue of muscle function. These data extend our previous findings and show that scAAV9.U7.ACCA provides long-term protection by restoring the disrupted dystrophin reading frame in the context of exon 2 duplications.
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Affiliation(s)
- Liubov V. Gushchina
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Adrienne J. Bradley
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
| | - Tatyana A. Vetter
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Jacob W. Lay
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
| | - Natalie L. Rohan
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
| | - Emma C. Frair
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
| | - Nicolas Wein
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Kevin M. Flanigan
- The Center for Gene Therapy, Nationwide Children’s Hospital and The Ohio State University, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
- Department of Neurology, The Ohio State University, Columbus, OH, USA
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Erbe LS, Hoffjan S, Janßen S, Kneifel M, Krause K, Gerding WM, Döring K, Güttsches AK, Roos A, Buena Atienza E, Gross C, Lücke T, Nguyen HHP, Vorgerd M, Köhler C. Exome Sequencing and Optical Genome Mapping in Molecularly Unsolved Cases of Duchenne Muscular Dystrophy: Identification of a Causative X-Chromosomal Inversion Disrupting the DMD Gene. Int J Mol Sci 2023; 24:14716. [PMID: 37834164 PMCID: PMC10572545 DOI: 10.3390/ijms241914716] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 09/25/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe progressive muscle disease that mainly affects boys due to X-linked recessive inheritance. In most affected individuals, MLPA or sequencing-based techniques detect deletions, duplications, or point mutations in the dystrophin-encoding DMD gene. However, in a small subset of patients clinically diagnosed with DMD, the molecular cause is not identified with these routine methods. Evaluation of the 60 DMD patients in our center revealed three cases without a known genetic cause. DNA samples of these patients were analyzed using whole-exome sequencing (WES) and, if unconclusive, optical genome mapping (OGM). WES led to a diagnosis in two cases: one patient was found to carry a splice mutation in the DMD gene that had not been identified during previous Sanger sequencing. In the second patient, we detected two variants in the fukutin gene (FKTN) that were presumed to be disease-causing. In the third patient, WES was unremarkable, but OGM identified an inversion disrupting the DMD gene (~1.28 Mb) that was subsequently confirmed with long-read sequencing. These results highlight the importance of reanalyzing unsolved cases using WES and demonstrate that OGM is a useful method for identifying large structural variants in cases with unremarkable exome sequencing.
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Affiliation(s)
- Leoni S. Erbe
- Department of Human Genetics, Ruhr-University Bochum, 44801 Bochum, Germany; (L.S.E.); (W.M.G.); (K.D.); (H.H.P.N.)
| | - Sabine Hoffjan
- Department of Human Genetics, Ruhr-University Bochum, 44801 Bochum, Germany; (L.S.E.); (W.M.G.); (K.D.); (H.H.P.N.)
- Center for Rare Diseases Ruhr (CeSER), 44791 Bochum, Germany; (C.K.); (T.L.)
| | - Sören Janßen
- Department of Neuropediatrics, University Children’s Hospital, Ruhr-University Bochum, 44801 Bochum, Germany;
| | - Moritz Kneifel
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, 44801 Bochum, Germany; (M.K.); (K.K.); (A.-K.G.); (A.R.); (M.V.)
| | - Karsten Krause
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, 44801 Bochum, Germany; (M.K.); (K.K.); (A.-K.G.); (A.R.); (M.V.)
| | - Wanda M. Gerding
- Department of Human Genetics, Ruhr-University Bochum, 44801 Bochum, Germany; (L.S.E.); (W.M.G.); (K.D.); (H.H.P.N.)
| | - Kristina Döring
- Department of Human Genetics, Ruhr-University Bochum, 44801 Bochum, Germany; (L.S.E.); (W.M.G.); (K.D.); (H.H.P.N.)
| | - Anne-Katrin Güttsches
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, 44801 Bochum, Germany; (M.K.); (K.K.); (A.-K.G.); (A.R.); (M.V.)
| | - Andreas Roos
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, 44801 Bochum, Germany; (M.K.); (K.K.); (A.-K.G.); (A.R.); (M.V.)
| | - Elena Buena Atienza
- Institute of Medical Genetics and Applied Genomics, University Tübingen, 72074 Tübingen, Germany; (E.B.A.); (C.G.)
- NGS Competence Center Tübingen, 72076 Tübingen, Germany
| | - Caspar Gross
- Institute of Medical Genetics and Applied Genomics, University Tübingen, 72074 Tübingen, Germany; (E.B.A.); (C.G.)
- NGS Competence Center Tübingen, 72076 Tübingen, Germany
| | - Thomas Lücke
- Center for Rare Diseases Ruhr (CeSER), 44791 Bochum, Germany; (C.K.); (T.L.)
- Department of Neuropediatrics, University Children’s Hospital, Ruhr-University Bochum, 44801 Bochum, Germany;
| | - Hoa Huu Phuc Nguyen
- Department of Human Genetics, Ruhr-University Bochum, 44801 Bochum, Germany; (L.S.E.); (W.M.G.); (K.D.); (H.H.P.N.)
- Center for Rare Diseases Ruhr (CeSER), 44791 Bochum, Germany; (C.K.); (T.L.)
| | - Matthias Vorgerd
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, 44801 Bochum, Germany; (M.K.); (K.K.); (A.-K.G.); (A.R.); (M.V.)
| | - Cornelia Köhler
- Center for Rare Diseases Ruhr (CeSER), 44791 Bochum, Germany; (C.K.); (T.L.)
- Department of Neuropediatrics, University Children’s Hospital, Ruhr-University Bochum, 44801 Bochum, Germany;
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Pluta N, von Moers A, Pechmann A, Stenzel W, Goebel HH, Atlan D, Wolf B, Nanda I, Zaum AK, Rost S. Whole-Genome Sequencing Identified New Structural Variations in the DMD Gene That Cause Duchenne Muscular Dystrophy in Two Girls. Int J Mol Sci 2023; 24:13567. [PMID: 37686372 PMCID: PMC10488134 DOI: 10.3390/ijms241713567] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
Dystrophinopathies are the most common muscle diseases, especially in men. In women, on the other hand, a manifestation of Duchenne muscular dystrophy is rare due to X-chromosomal inheritance. We present two young girls with severe muscle weakness, muscular dystrophies, and creatine kinase (CK) levels exceeding 10,000 U/L. In the skeletal muscle tissues, dystrophin staining reaction showed mosaicism. The almost entirely skewed X-inactivation in both cases supported the possibility of a dystrophinopathy. Despite standard molecular diagnostics (including multiplex ligation-dependent probe amplification (MLPA) and next generation sequencing (NGS) gene panel sequencing), the genetic cause of the girls' conditions remained unknown. However, whole-genome sequencing revealed two reciprocal translocations between their X chromosomes and chromosome 5 and chromosome 19, respectively. In both cases, the breakpoints on the X chromosomes were located directly within the DMD gene (in introns 54 and 7, respectively) and were responsible for the patients' phenotypes. Additional techniques such as Sanger sequencing, conventional karyotyping and fluorescence in situ hybridization (FISH) confirmed the disruption of DMD gene in both patients through translocations. These findings underscore the importance of accurate clinical data combined with histopathological analysis in pinpointing the suspected underlying genetic disorder. Moreover, our study illustrates the viability of whole-genome sequencing as a time-saving and highly effective method for identifying genetic factors responsible for complex genetic constellations in Duchenne muscular dystrophy (DMD).
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Affiliation(s)
- Natalie Pluta
- Department of Human Genetics, University of Würzburg, 97074 Würzburg, Germany
| | - Arpad von Moers
- Department of Pediatrics and Neuropediatrics, DRK Kliniken Berlin, 14050 Berlin, Germany
| | - Astrid Pechmann
- Department of Neuropediatrics and Muscle Disorders, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Werner Stenzel
- Department of Neuropathology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | - Hans-Hilmar Goebel
- Department of Neuropathology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität zu Berlin, 10117 Berlin, Germany
| | | | - Beat Wolf
- iCoSys, University of Applied Sciences Western Switzerland, 1700 Fribourg, Switzerland
| | - Indrajit Nanda
- Department of Human Genetics, University of Würzburg, 97074 Würzburg, Germany
| | - Ann-Kathrin Zaum
- Department of Human Genetics, University of Würzburg, 97074 Würzburg, Germany
| | - Simone Rost
- Department of Human Genetics, University of Würzburg, 97074 Würzburg, Germany
- Medical Genetics Center (MGZ), 80335 Munich, Germany
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5
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Saad FA, Siciliano G, Angelini C. Advances in Dystrophinopathy Diagnosis and Therapy. Biomolecules 2023; 13:1319. [PMID: 37759719 PMCID: PMC10526396 DOI: 10.3390/biom13091319] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023] Open
Abstract
Dystrophinopathies are x-linked muscular disorders which emerge from mutations in the Dystrophin gene, including Duchenne and Becker muscular dystrophy, and dilated cardiomyopathy. However, Duchenne muscular dystrophy interconnects with bone loss and osteoporosis, which are exacerbated by glucocorticoids therapy. Procedures for diagnosing dystrophinopathies include creatine kinase assay, haplotype analysis, Southern blot analysis, immunological analysis, multiplex PCR, multiplex ligation-dependent probe amplification, Sanger DNA sequencing, and next generation DNA sequencing. Pharmacological therapy for dystrophinopathies comprises glucocorticoids (prednisone, prednisolone, and deflazacort), vamorolone, and ataluren. However, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and β-blockers are the first-line to prevent dilated cardiomyopathy in dystrophinopathy patients. Duchenne muscular dystrophy gene therapy strategies involve gene transfer, exon skipping, exon reframing, and CRISPR gene editing. Eteplirsen, an antisense-oligonucleotide drug for skipping exon 51 from the Dystrophin gene, is available on the market, which may help up to 14% of Duchenne muscular dystrophy patients. There are various FDA-approved exon skipping drugs including ExonDys-51 for exon 51, VyonDys-53 and Viltolarsen for exon 53 and AmonDys-45 for exon 45 skipping. Other antisense oligonucleotide drugs in the pipeline include casimersen for exon 45, suvodirsen for exon 51, and golodirsen for exon 53 skipping. Advances in the diagnosis and therapy of dystrophinopathies offer new perspectives for their early discovery and care.
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Affiliation(s)
- Fawzy A. Saad
- Department of Gene Therapy, Saad Pharmaceuticals, Juhkentali 8, 10132 Tallinn, Estonia
| | - Gabriele Siciliano
- Department of Clinical and Experimental Medicine, Pisa University School of Medicine, Via Paradisa 2, 56100 Pisa, Italy;
| | - Corrado Angelini
- Department of Neurosciences, Padova University School of Medicine, Via Giustiniani 5, 35128 Padova, Italy;
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Padmaswari MH, Agrawal S, Jia MS, Ivy A, Maxenberger DA, Burcham LA, Nelson CE. Delivery challenges for CRISPR-Cas9 genome editing for Duchenne muscular dystrophy. BIOPHYSICS REVIEWS 2023; 4:011307. [PMID: 36864908 PMCID: PMC9969352 DOI: 10.1063/5.0131452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Duchene muscular dystrophy (DMD) is an X-linked neuromuscular disorder that affects about one in every 5000 live male births. DMD is caused by mutations in the gene that codes for dystrophin, which is required for muscle membrane stabilization. The loss of functional dystrophin causes muscle degradation that leads to weakness, loss of ambulation, cardiac and respiratory complications, and eventually, premature death. Therapies to treat DMD have advanced in the past decade, with treatments in clinical trials and four exon-skipping drugs receiving conditional Food and Drug Administration approval. However, to date, no treatment has provided long-term correction. Gene editing has emerged as a promising approach to treating DMD. There is a wide range of tools, including meganucleases, zinc finger nucleases, transcription activator-like effector nucleases, and, most notably, RNA-guided enzymes from the bacterial adaptive immune system clustered regularly interspaced short palindromic repeats (CRISPR). Although challenges in using CRISPR for gene therapy in humans still abound, including safety and efficiency of delivery, the future for CRISPR gene editing for DMD is promising. This review will summarize the progress in CRISPR gene editing for DMD including key summaries of current approaches, delivery methodologies, and the challenges that gene editing still faces as well as prospective solutions.
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Affiliation(s)
| | - Shilpi Agrawal
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Mary S. Jia
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Allie Ivy
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Daniel A. Maxenberger
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Landon A. Burcham
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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Viggiano E, Picillo E, Passamano L, Onore ME, Piluso G, Scutifero M, Torella A, Nigro V, Politano L. Spectrum of Genetic Variants in the Dystrophin Gene: A Single Centre Retrospective Analysis of 750 Duchenne and Becker Patients from Southern Italy. Genes (Basel) 2023; 14:214. [PMID: 36672955 PMCID: PMC9859256 DOI: 10.3390/genes14010214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/29/2022] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Dystrophinopathies are X-linked recessive muscle disorders caused by mutations in the dystrophin (DMD) gene that include deletions, duplications, and point mutations. Correct diagnosis is important for providing adequate patient care and family planning, especially at this time when mutation-specific therapies are available. We report a large single-centre study on the spectrum of DMD gene variants observed in 750 patients analyzed for suspected Duchenne (DMD) or Becker (BMD) muscular dystrophy, over the past 30 years, at the Cardiomyology and Medical Genetics of the University of Campania. We found 534 (71.21%) large deletions, 73 (9.73%) large duplications, and 112 (14.93%) point mutations, of which 44 (5.9%) were small ins/del causing frame-shifts, 57 (7.6%) nonsense mutations, 8 (1.1%) splice site and 3 (0.4%) intronic mutations, and 31 (4.13%) non mutations. Moreover, we report the prevalence of the different types of mutations in patients with DMD and BMD according to their decade of birth, from 1930 to 2020, and correlate the data to the different techniques used over the years. In the most recent decades, we observed an apparent increase in the prevalence of point mutations, probably due to the use of Next-Generation Sequencing (NGS). In conclusion, in southern Italy, deletions are the most frequent variation observed in DMD and BMD patients followed by point mutations and duplications, as elsewhere in the world. NGS was useful to identify point mutations in cases of strong suspicion of DMD/BMD negative on deletions/duplications analyses. In the era of personalized medicine and availability of new causative therapies, a collective effort is necessary to enable DMD and BMD patients to have timely genetic diagnoses and avoid late implementation of standard of care and late initiation of appropriate treatment.
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Affiliation(s)
- Emanuela Viggiano
- Department of Prevention, Hygiene and Public Health Service, ASL Roma 2, 00157 Rome, Italy
| | - Esther Picillo
- Medical Genetics and Cardiomyology, Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, 80138 Napoli, Italy
| | - Luigia Passamano
- Medical Genetics and Cardiomyology, Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, 80138 Napoli, Italy
| | - Maria Elena Onore
- Medical Genetics and Cardiomyology, Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, 80138 Napoli, Italy
| | - Giulio Piluso
- Medical Genetics and Cardiomyology, Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, 80138 Napoli, Italy
| | - Marianna Scutifero
- Medical Genetics and Cardiomyology, Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, 80138 Napoli, Italy
| | - Annalaura Torella
- Medical Genetics and Cardiomyology, Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, 80138 Napoli, Italy
| | - Vincenzo Nigro
- Medical Genetics and Cardiomyology, Department of Precision Medicine, University of Campania “Luigi Vanvitelli”, 80138 Napoli, Italy
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Luisa Politano
- Cardiomyology and Medical Genetics, Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Napoli, Italy
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8
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Segarra-Casas A, Domínguez-González C, Hernández-Laín A, Sanchez-Calvin MT, Camacho A, Rivas E, Campo-Barasoain A, Madruga M, Ortez C, Natera-de Benito D, Nascimento A, Codina A, Rodriguez MJ, Gallano P, Gonzalez-Quereda L. Genetic diagnosis of Duchenne and Becker muscular dystrophy through mRNA analysis: new splicing events. J Med Genet 2022; 60:615-619. [DOI: 10.1136/jmg-2022-108828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/27/2022] [Indexed: 12/24/2022]
Abstract
BackgroundUp to 7% of patients with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD) remain genetically undiagnosed after routine genetic testing. These patients are thought to carry deep intronic variants, structural variants or splicing alterations not detected through multiplex ligation-dependent probe amplification or exome sequencing.MethodsRNA was extracted from seven muscle biopsy samples of patients with genetically undiagnosed DMD/BMD after routine genetic diagnosis. RT-PCR of theDMDgene was performed to detect the presence of alternative transcripts. Droplet digital PCR and whole-genome sequencing were also performed in some patients.ResultsWe identified an alteration in the mRNA level in all the patients. We detected three pseudoexons inDMDcaused by deep intronic variants, two of them not previously reported. We also identified a chromosomal rearrangement between Xp21.2 and 8p22. Furthermore, we detected three exon skipping events with unclear pathogenicity.ConclusionThese findings indicate that mRNA analysis of theDMDgene is a valuable tool to reach a precise genetic diagnosis in patients with a clinical and anatomopathological suspicion of dystrophinopathy that remain genetically undiagnosed after routine genetic testing.
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9
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Gushchina LV, Vetter TA, Frair EC, Bradley AJ, Grounds KM, Lay JW, Huang N, Suhaiba A, Schnell FJ, Hanson G, Simmons TR, Wein N, Flanigan KM. Systemic PPMO-mediated dystrophin expression in the Dup2 mouse model of Duchenne muscular dystrophy. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 30:479-492. [PMID: 36420217 PMCID: PMC9678653 DOI: 10.1016/j.omtn.2022.10.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 10/31/2022] [Indexed: 11/11/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating muscle-wasting disease that arises due to the loss of dystrophin expression, leading to progressive loss of motor and cardiorespiratory function. Four exon-skipping approaches using antisense phosphorodiamidate morpholino oligomers (PMOs) have been approved by the FDA to restore a DMD open reading frame, resulting in expression of a functional but internally deleted dystrophin protein, but in patients with single-exon duplications, exon skipping has the potential to restore full-length dystrophin expression. Cell-penetrating peptide-conjugated PMOs (PPMOs) have demonstrated enhanced cellular uptake and more efficient dystrophin restoration than unconjugated PMOs. In the present study, we demonstrate widespread PPMO-mediated dystrophin restoration in the Dup2 mouse model of exon 2 duplication, representing the most common single-exon duplication among patients with DMD. In this proof-of-concept study, a single intravenous injection of PPMO targeting the exon 2 splice acceptor site induced 45% to 68% exon 2-skipped Dmd transcripts in Dup2 skeletal muscles 15 days post-injection. Muscle dystrophin restoration peaked at 77% to 87% average dystrophin-positive fibers and 41% to 51% of normal signal intensity by immunofluorescence, and 15.7% to 56.8% of normal by western blotting 15 to 30 days after treatment. These findings indicate that PPMO-mediated exon skipping is a promising therapeutic strategy for muscle dystrophin restoration in the context of exon 2 duplications.
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Affiliation(s)
- Liubov V. Gushchina
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Tatyana A. Vetter
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Emma C. Frair
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Adrienne J. Bradley
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Kelly M. Grounds
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Jacob W. Lay
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Nianyuan Huang
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Aisha Suhaiba
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | | | | | - Tabatha R. Simmons
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Nicolas Wein
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Kevin M. Flanigan
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
- Department of Neurology, The Ohio State University, Columbus, OH, USA
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10
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Kaplan KM, Morgan KG. The importance of dystrophin and the dystrophin associated proteins in vascular smooth muscle. Front Physiol 2022; 13:1059021. [PMID: 36505053 PMCID: PMC9732661 DOI: 10.3389/fphys.2022.1059021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/14/2022] [Indexed: 11/26/2022] Open
Abstract
This review details the role of dystrophin and the dystrophin associated proteins (DAPs) in the vascular smooth muscle. Dystrophin is most comprehensively studied in the skeletal muscle due to serious symptoms found related to the skeletal muscle of patients with muscular dystrophy. Mutations in the dystrophin gene, or DAPs genes, result in a wide range of muscular dystrophies. In skeletal muscle, dystrophin is known to act to as a cytoskeletal stabilization protein and protects cells against contraction-induced damage. In skeletal muscle, dystrophin stabilizes the plasma membrane by transmitting forces generated by sarcomeric contraction to the extracellular matrix (ECM). Dystrophin is a scaffold that binds the dystroglycan complex (DGC) and has many associated proteins (DAPs). These DAPs include sarcoglycans, syntrophins, dystroglycans, dystrobrevin, neuronal nitric oxide synthase, and caveolins. The DAPs provide biomechanical support to the skeletal or cardiac plasma membrane during contraction, and loss of one or several of these DAPs leads to plasma membrane fragility. Dystrophin is expressed near the plasma membrane of all muscles, including cardiac and vascular smooth muscle, and some neurons. Dystrophic mice have noted biomechanical irregularities in the carotid arteries and spontaneous motor activity in portal vein altered when compared to wild type mice. Additionally, some studies suggest the vasculature of patients and animal models with muscular dystrophy is abnormal. Although the function of dystrophin and the DAPs in vascular smooth muscle is not thoroughly established in the field, this review makes the point that these proteins are expressed, and important and further study is warranted.
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11
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Zaum AK, Nanda I, Kress W, Rost S. Detection of pericentric inversion with breakpoint in DMD by whole genome sequencing. Mol Genet Genomic Med 2022; 10:e2028. [PMID: 35912688 PMCID: PMC9544221 DOI: 10.1002/mgg3.2028] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 03/25/2022] [Accepted: 07/08/2022] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Dystrophinopathies caused by variants in the DMD gene are a well-studied muscle disease. The most common type of variant in DMD are large deletions. Very rarely reported forms of variants are chromosomal translocations, inversions and deep intronic variants (DIVs) because they are not detectable by standard diagnostic techniques (sequencing of coding sequence, copy number variant detection). This might be the reason that some clinically and histologically proven dystrophinopathy cases remain unsolved. METHODS We used whole genome sequencing (WGS) to screen the entire DMD gene for variants in one of two brothers suffering from typical muscular dystrophy with strongly elevated creatine kinase levels. RESULTS Although a pathogenic DIV could not be detected, we were able to identify a pericentric inversion with breakpoints in DMD intron 44 and Xq13.3, which could be confirmed by Sanger sequencing in the index as well as in his brother and mother. As this variation affects a major part of DMD it is most likely disease causing. CONCLUSION Our findings elucidate that WGS is capable of detecting large structural rearrangements and might be suitable for the genetic diagnostics of dystrophinopathies in the future. In particular, inversions might be a more frequent cause for dystrophinopathies as anticipated and should be considered in genetically unsolved dystrophinopathy cases.
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Affiliation(s)
- Ann-Kathrin Zaum
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Indrajit Nanda
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Wolfram Kress
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Simone Rost
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
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12
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Waldrop MA, Moore SA, Mathews KD, Darbro BW, Medne L, Finkel R, Connolly AM, Crawford TO, Drachman D, Wein N, Habib AA, Krzesniak-Swinarska MA, Zaidman CM, Collins JJ, Jokela M, Udd B, Day JW, Ortiz-Guerrero G, Statland J, Butterfield RJ, Dunn DM, Weiss RB, Flanigan KM. Intron mutations and early transcription termination in Duchenne and Becker muscular dystrophy. Hum Mutat 2022; 43:511-528. [PMID: 35165973 PMCID: PMC9901284 DOI: 10.1002/humu.24343] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 02/05/2022] [Accepted: 02/07/2022] [Indexed: 11/11/2022]
Abstract
DMD pathogenic variants for Duchenne and Becker muscular dystrophy are detectable with high sensitivity by standard clinical exome analyses of genomic DNA. However, up to 7% of DMD mutations are deep intronic and analysis of muscle-derived RNA is an important diagnostic step for patients who have negative genomic testing but abnormal dystrophin expression in muscle. In this study, muscle biopsies were evaluated from 19 patients with clinical features of a dystrophinopathy, but negative clinical DMD mutation analysis. Reverse transcription-polymerase chain reaction or high-throughput RNA sequencing methods identified 19 mutations with one of three pathogenic pseudoexon types: deep intronic point mutations, deletions or insertions, and translocations. In association with point mutations creating intronic splice acceptor sites, we observed the first examples of DMD pseudo 3'-terminal exon mutations causing high efficiency transcription termination within introns. This connection between splicing and premature transcription termination is reminiscent of U1 snRNP-mediating telescripting in sustaining RNA polymerase II elongation across large genes, such as DMD. We propose a novel classification of three distinct types of mutations identifiable by muscle RNA analysis, each of which differ in potential treatment approaches. Recognition and appropriate characterization may lead to therapies directed toward full-length dystrophin expression for some patients.
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Affiliation(s)
- Megan A. Waldrop
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH 43205,Department of Neurology, The Ohio State University, Columbus, OH 43205,Department of Pediatrics, The Ohio State University, Columbus, OH 43205
| | - Steven A. Moore
- Department of Pathology, The University of Iowa, Iowa City, IA, 52242
| | | | | | - Livja Medne
- Children’s Hospital of Philadelphia, Philadelphia, PA 19104
| | | | - Anne M. Connolly
- Department of Neurology, Washington University, Saint Louis, MO 63110
| | | | | | - Nicolas Wein
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH 43205
| | | | | | - Craig M. Zaidman
- Department of Neurology, Washington University, Saint Louis, MO 63110
| | - James J. Collins
- Department of Pediatric Neurology, Mercy Hospitals, Springfield, MO 65804
| | - Manu Jokela
- Neuromuscular Research Center, Tampere University Hospital and University of Tampere, Tampere, Finland,Division of Clinical Neurosciences, Turku University Hospital and University of Turku, Turku, Finland
| | - Bjarne Udd
- Neuromuscular Research Center, Tampere University Hospital and University of Tampere, Tampere, Finland
| | - John W. Day
- Department of Neurology, University of Minnesota Medical Center, Minneapolis, MN 55454
| | | | - Jeff Statland
- Department of Neurology, University of Kansas, Kansas City, KS
| | - Russell J. Butterfield
- Department of Pediatrics, The University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Diane M. Dunn
- Department of Human Genetics, The University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Robert B. Weiss
- Department of Pediatrics, The University of Utah School of Medicine, Salt Lake City, UT 84112,Department of Human Genetics, The University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Kevin M. Flanigan
- The Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH 43205,Department of Neurology, The Ohio State University, Columbus, OH 43205,Department of Pediatrics, The Ohio State University, Columbus, OH 43205
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13
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Zambon AA, Waldrop MA, Alles R, Weiss RB, Conroy S, Moore-Clingenpeel M, Previtali S, Flanigan KM. Phenotypic Spectrum of Dystrophinopathy Due to Duchenne Muscular Dystrophy Exon 2 Duplications. Neurology 2022; 98:e730-e738. [PMID: 34937785 PMCID: PMC8865888 DOI: 10.1212/wnl.0000000000013246] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 12/13/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND OBJECTIVES To describe the phenotypic spectrum of dystrophinopathy in a large cohort of individuals with DMD exon 2 duplications (Dup2), who may be particularly amenable to therapies directed at restoring expression of either full-length dystrophin or nearly full-length dystrophin through utilization of the DMD exon 5 internal ribosome entry site (IRES). METHODS In this retrospective observational study, we analyzed data from large genotype-phenotype databases (the United Dystrophinopathy Project [UDP] and the Italian DMD network) and classified participants into Duchenne muscular dystrophy (DMD), intermediate muscular dystrophy (IMD), or Becker muscular dystrophy (BMD) phenotypes. Log-rank tests for time-to-event variables were used to compare age at loss of ambulation (LOA) in participants with Dup2 vs controls without Dup2 in the UDP database and for comparisons between steroid-treated vs steroid-naive participants with Dup2. RESULTS Among 66 participants with Dup2 (UDP = 40, Italy = 26), 61% were classified as DMD, 9% as IMD, and 30% as BMD. Median age at last observation was 15.4 years (interquartile range 8.79-26.0) and 75% had been on corticosteroids for at least 6 months. Age at LOA differed significantly between participants with Dup2 DMD and historical controls without Dup2 DMD (p < 0.001). Valid spirometry was limited but suggested a delay in the typical age-related decline in forced vital capacity and 24 of 55 participants with adequate cardiac data had cardiomyopathy. DISCUSSION Some patients with Dup2 display a milder disease course than controls without Dup2 DMD, and prolonged ambulation with corticosteroids suggests the potential of IRES activation as a molecular mechanism. As Dup2-targeted therapies reach clinical applications, this information is critical to aid in the interpretation of the efficacy of new treatments.
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Affiliation(s)
- Alberto A Zambon
- From Inspe and Division of Neuroscience (A.A.Z., S.P.), IRCCS Ospedale San Raffaele, Milan, Italy; The Center for Gene Therapy, Abigail Wexner Research Institute (M.A.W., R.A., K.M.F.), and Biostatistics Research Core (S.C., M.M.-C.), Nationwide Children's Hospital, Columbus, OH; Departments of Pediatrics and Neurology (M.A.W., K.M.F.), Ohio State University Medical Center, Columbus; and Department of Human Genetics (R.B.W.), University of Utah, Salt Lake City
| | - Megan A Waldrop
- From Inspe and Division of Neuroscience (A.A.Z., S.P.), IRCCS Ospedale San Raffaele, Milan, Italy; The Center for Gene Therapy, Abigail Wexner Research Institute (M.A.W., R.A., K.M.F.), and Biostatistics Research Core (S.C., M.M.-C.), Nationwide Children's Hospital, Columbus, OH; Departments of Pediatrics and Neurology (M.A.W., K.M.F.), Ohio State University Medical Center, Columbus; and Department of Human Genetics (R.B.W.), University of Utah, Salt Lake City
| | - Roxane Alles
- From Inspe and Division of Neuroscience (A.A.Z., S.P.), IRCCS Ospedale San Raffaele, Milan, Italy; The Center for Gene Therapy, Abigail Wexner Research Institute (M.A.W., R.A., K.M.F.), and Biostatistics Research Core (S.C., M.M.-C.), Nationwide Children's Hospital, Columbus, OH; Departments of Pediatrics and Neurology (M.A.W., K.M.F.), Ohio State University Medical Center, Columbus; and Department of Human Genetics (R.B.W.), University of Utah, Salt Lake City
| | - Robert B Weiss
- From Inspe and Division of Neuroscience (A.A.Z., S.P.), IRCCS Ospedale San Raffaele, Milan, Italy; The Center for Gene Therapy, Abigail Wexner Research Institute (M.A.W., R.A., K.M.F.), and Biostatistics Research Core (S.C., M.M.-C.), Nationwide Children's Hospital, Columbus, OH; Departments of Pediatrics and Neurology (M.A.W., K.M.F.), Ohio State University Medical Center, Columbus; and Department of Human Genetics (R.B.W.), University of Utah, Salt Lake City
| | - Sara Conroy
- From Inspe and Division of Neuroscience (A.A.Z., S.P.), IRCCS Ospedale San Raffaele, Milan, Italy; The Center for Gene Therapy, Abigail Wexner Research Institute (M.A.W., R.A., K.M.F.), and Biostatistics Research Core (S.C., M.M.-C.), Nationwide Children's Hospital, Columbus, OH; Departments of Pediatrics and Neurology (M.A.W., K.M.F.), Ohio State University Medical Center, Columbus; and Department of Human Genetics (R.B.W.), University of Utah, Salt Lake City
| | - Melissa Moore-Clingenpeel
- From Inspe and Division of Neuroscience (A.A.Z., S.P.), IRCCS Ospedale San Raffaele, Milan, Italy; The Center for Gene Therapy, Abigail Wexner Research Institute (M.A.W., R.A., K.M.F.), and Biostatistics Research Core (S.C., M.M.-C.), Nationwide Children's Hospital, Columbus, OH; Departments of Pediatrics and Neurology (M.A.W., K.M.F.), Ohio State University Medical Center, Columbus; and Department of Human Genetics (R.B.W.), University of Utah, Salt Lake City
| | - Stefano Previtali
- From Inspe and Division of Neuroscience (A.A.Z., S.P.), IRCCS Ospedale San Raffaele, Milan, Italy; The Center for Gene Therapy, Abigail Wexner Research Institute (M.A.W., R.A., K.M.F.), and Biostatistics Research Core (S.C., M.M.-C.), Nationwide Children's Hospital, Columbus, OH; Departments of Pediatrics and Neurology (M.A.W., K.M.F.), Ohio State University Medical Center, Columbus; and Department of Human Genetics (R.B.W.), University of Utah, Salt Lake City
| | - Kevin M Flanigan
- From Inspe and Division of Neuroscience (A.A.Z., S.P.), IRCCS Ospedale San Raffaele, Milan, Italy; The Center for Gene Therapy, Abigail Wexner Research Institute (M.A.W., R.A., K.M.F.), and Biostatistics Research Core (S.C., M.M.-C.), Nationwide Children's Hospital, Columbus, OH; Departments of Pediatrics and Neurology (M.A.W., K.M.F.), Ohio State University Medical Center, Columbus; and Department of Human Genetics (R.B.W.), University of Utah, Salt Lake City.
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14
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Ataluren-Promising Therapeutic Premature Termination Codon Readthrough Frontrunner. Pharmaceuticals (Basel) 2021; 14:ph14080785. [PMID: 34451881 PMCID: PMC8398184 DOI: 10.3390/ph14080785] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 07/30/2021] [Accepted: 08/06/2021] [Indexed: 02/08/2023] Open
Abstract
Around 12% of hereditary disease-causing mutations are in-frame nonsense mutations. The expression of genes containing nonsense mutations potentially leads to the production of truncated proteins with residual or virtually no function. However, the translation of transcripts containing premature stop codons resulting in full-length protein expression can be achieved using readthrough agents. Among them, only ataluren was approved in several countries to treat nonsense mutation Duchenne muscular dystrophy (DMD) patients. This review summarizes ataluren’s journey from its identification, via first in vitro activity experiments, to clinical trials in DMD, cystic fibrosis, and aniridia. Additionally, data on its pharmacokinetics and mechanism of action are presented. The range of diseases with underlying nonsense mutations is described for which ataluren therapy seems to be promising. What is more, experiments in which ataluren did not show its readthrough activity are also included, and reasons for their failures are discussed.
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15
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Guevara-Fujita ML, Huaman-Dianderas F, Obispo D, Sánchez R, Barrenechea V, Rojas-Málaga D, Estrada-Cuzcano A, Trubnykova M, Cornejo-Olivas M, Marca V, Gallardo B, Dueñas-Roque M, Protzel A, Castañeda C, Abarca H, Celis L, La Serna-Infantes J, Fujita R. MLPA followed by target-NGS to detect mutations in the dystrophin gene of Peruvian patients suspected of DMD/DMB. Mol Genet Genomic Med 2021; 9:e1759. [PMID: 34327855 PMCID: PMC8457708 DOI: 10.1002/mgg3.1759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/09/2021] [Accepted: 07/08/2021] [Indexed: 11/11/2022] Open
Abstract
Background We report the molecular analysis of the DMD gene in a group of Peruvian patients with Duchenne/Becker dystrophinopathy. This is the first study to thoroughly characterize mutations in this population. Methods We used the combination of multiplex ligation‐dependent probe amplification (MLPA) and sequencing analysis of the DMD gene. We recruited Peruvian patients in 2 years from reference national hospitals. We performed DNA tests in 152 patients, checking first exon deletion/duplication by MLPA, and subsequently, if negative, samples were sequenced to detect point mutations. Results The average age for diagnosis was 9.8 years, suggesting a delay for timely diagnosis and care. We found causal DMD mutations in 125 patients: 72 (57.6%) exon deletions/duplications (41.6% deletions, 16.0% duplications), and 53 (42.4%) point mutations (27.2% nonsense, 9.6% small indels, and 5.6% splice site). Conclusion Due to our genetic background, we expected a higher number of novel and recurrent causal mutations in our sample. Results showed 16% of novel mutations, similar to other well‐studied populations.
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Affiliation(s)
- María Luisa Guevara-Fujita
- Centro de Genética y Biología Molecular, Instituto de Investigación, Facultad de Medicina Humana, Universidad de San Martín de Porres, Lima, Peru
| | - Francia Huaman-Dianderas
- Centro de Genética y Biología Molecular, Instituto de Investigación, Facultad de Medicina Humana, Universidad de San Martín de Porres, Lima, Peru
| | - Daisy Obispo
- Centro de Genética y Biología Molecular, Instituto de Investigación, Facultad de Medicina Humana, Universidad de San Martín de Porres, Lima, Peru
| | - Rodrigo Sánchez
- Centro de Genética y Biología Molecular, Instituto de Investigación, Facultad de Medicina Humana, Universidad de San Martín de Porres, Lima, Peru
| | - Victor Barrenechea
- Centro de Genética y Biología Molecular, Instituto de Investigación, Facultad de Medicina Humana, Universidad de San Martín de Porres, Lima, Peru
| | - Diana Rojas-Málaga
- Centro de Genética y Biología Molecular, Instituto de Investigación, Facultad de Medicina Humana, Universidad de San Martín de Porres, Lima, Peru.,Laboratório de Genética Molecular, Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Rio Grande do Sul, Brazil
| | - Alejandro Estrada-Cuzcano
- Centro de Genética y Biología Molecular, Instituto de Investigación, Facultad de Medicina Humana, Universidad de San Martín de Porres, Lima, Peru.,Paris-Saclay Institute of Neuroscience, CERTO-Retina France, CNRS, Université Paris-Saclay, Orsay, 91405, France
| | - Milana Trubnykova
- Servicio de Genética y Errores Innatos del Metabolismo del Instituto Nacional de Salud del Niño, Lima, Peru
| | - Mario Cornejo-Olivas
- Neurogenetics Research Center, Instituto Nacional de Ciencias Neurológicas, Lima, Peru.,Center for Global Health, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Victoria Marca
- Neurogenetics Research Center, Instituto Nacional de Ciencias Neurológicas, Lima, Peru
| | - Bertha Gallardo
- Servicio de Genética y Errores Innatos del Metabolismo del Instituto Nacional de Salud del Niño, Lima, Peru
| | | | - Ana Protzel
- Hospital Nacional Edgardo Rebagliati Martins, EsSalud, Lima, Peru
| | | | - Hugo Abarca
- Servicio de Genética y Errores Innatos del Metabolismo del Instituto Nacional de Salud del Niño, Lima, Peru
| | - Luis Celis
- Servicio de Genética, Instituto de Salud del Niño San Borja, Lima, Peru
| | | | - Ricardo Fujita
- Centro de Genética y Biología Molecular, Instituto de Investigación, Facultad de Medicina Humana, Universidad de San Martín de Porres, Lima, Peru
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16
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Xiao T, Wu B, Cao Y, Liu R, Cheng G, Wang L, Zhuang D, Zhao Z, Wang H, Zhou W. Genetic identification of pathogenic variations of the DMD gene: a retrospective study from 10,481 neonatal patients based on next-generation sequencing data. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:766. [PMID: 34268379 PMCID: PMC8246177 DOI: 10.21037/atm-20-7102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 02/07/2021] [Indexed: 12/20/2022]
Abstract
Background An elevated level of creatine kinase (CK) is usually the primary screening marker for Duchenne muscular dystrophy (DMD)/Becker muscular dystrophy (BMD). This study investigated the clinical application of next-generation sequencing (NGS) in newborns with a possible diagnosis of DMD/BMD in the neonatal intensive care unit (NICU). Methods NGS data from the NICU between June 1, 2016, and June 30, 2020, were reanalyzed by an in-house pipeline. Other methods confirmed the genetic findings, and clinical follow-up was performed until August 1, 2020. Results Of the 10,481 newborns, 19 (0.18%, 19/10,481) cases with pathogenic variations of the DMD gene were identified, including 13 (68.4%, 13/19) deletions, 4 (21.1%, 4/19) duplications, and 2 (10.5%, 2/19) nonsense mutations. Eight of the cases were diagnosed with DMD. Therapeutic strategies were modified for these patients. Six cases were diagnosed with BMD. Five patients except for 1 deceased patient were further followed-up, and clinical management was adjusted based on the clinical symptoms. The remaining 5 cases were indeterminate for DMD and BMD. Genetic counseling and further follow-up were performed or suggested. Conclusions Our study showed that DMD/BMD could be diagnosed earlier in the neonatal stage before the typical clinical symptoms appear. Early diagnosis may provide an opportunity for guiding the care and treatment of patients. However, ethical issues need to be kept in mind in the process of genetic counseling.
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Affiliation(s)
- Tiantian Xiao
- Department of Neonates, Key Laboratory of Neonatal Diseases, Ministry of Health, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China.,Department of Neonatology, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Bingbing Wu
- Center for Molecular Medicine, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Yun Cao
- Department of Neonates, Key Laboratory of Neonatal Diseases, Ministry of Health, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Renchao Liu
- Center for Molecular Medicine, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Guoqiang Cheng
- Department of Neonates, Key Laboratory of Neonatal Diseases, Ministry of Health, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Laishuan Wang
- Department of Pediatrics, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Deyi Zhuang
- Department of Pediatrics, Xiamen Children's Hospital, Xiamen, China
| | - Zhengyan Zhao
- Department of Child Health Care, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Huijun Wang
- Center for Molecular Medicine, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Wenhao Zhou
- Department of Neonates, Key Laboratory of Neonatal Diseases, Ministry of Health, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China.,Center for Molecular Medicine, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
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17
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Politano L. Read-through approach for stop mutations in Duchenne muscular dystrophy. An update. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2021; 40:43-50. [PMID: 33870095 PMCID: PMC8033424 DOI: 10.36185/2532-1900-041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 03/15/2021] [Indexed: 01/12/2023]
Abstract
Dystrophinopathies are allelic conditions caused by deletions, duplications and point-mutations in the DMD gene, located on the X chromosome (Xp21.2). Mutations that prematurely interrupt the dystrophin protein synthesis lead to the most severe clinical form, Duchenne muscular Dystrophy, characterized by early involvement of muscle strength. There is no known cure for dystrophinopathies. In DMD, treatment with corticosteroids have changed the natural history and the progression of the disease, prolonging ambulation, and slowing the onset of respiratory and cardiac involvement and scoliosis by several years. In the last few years, new perspectives and options are deriving from the discovery of pharmacological approaches able to restore normal, full-length dystrophin and potentially reverse the course of the disease. Read-through (RT) of nonsense mutations, thanks to its ability to bypass the premature stop codon and to act on virtually any region of the dystrophin gene, independently of the location in which the mutation resides, is one of these promising approaches. This non-systematic review shows the different steps that, passing from yeast to humans, have made it possible to use this innovative successful approach to treat serious diseases such as Duchenne muscular dystrophy.
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Affiliation(s)
- Luisa Politano
- Cardiomiology and Medical Genetics, "Luigi Vanvitelli" University, Naples, Italy
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18
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Ma J, Risher N, Northcutt V, Moon YC, Weetall M, Welch E, Colacino J, Almstead N, Kong R. Ataluren metabolism: Ataluren-O-1β-acyl glucuronide is a stable circulating metabolite in mouse, rat, dog and human. Drug Metab Pharmacokinet 2021; 38:100393. [PMID: 33872944 DOI: 10.1016/j.dmpk.2021.100393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 03/07/2021] [Accepted: 03/23/2021] [Indexed: 11/28/2022]
Abstract
Ataluren is an aromatic acid derivative with a 1,2,4-oxodiazole moiety. Ataluren-O-1β-acyl glucuronide is a prominent circulatory metabolite in mice, rats, dogs, and humans following oral administration of ataluren. The objective of this paper was to evaluate the stability in vitro and in vivo of ataluren-O-1β-acyl glucuronide metabolite. Ultrahigh performance liquid chromatography-mass spectrometry methods were developed to separate and monitor ataluren-O-1β-acyl glucuronide and its possible migration isomers. In vitro stability was assessed in phosphate buffered saline as well as in control rat and human plasma. The disappearance of ataluren-O-1β-acyl glucuronide and the formation of migration isomers were monitored by the ultrahigh performance liquid chromatography-mass spectrometry methods. In vitro, ataluren-O-1β-acyl glucuronide underwent isomerization with an estimated half-life of approximately 1 h. However, ataluren-O-1β-acyl glucuronide was stable and was the only detectable acyl glucuronide following oral administration of ataluren in mice, rats, dogs, and humans using the same analytical methods. Ataluren acyl glucuronide in mouse, rat, dog, and human plasma could be hydrolyzed by β-glucuronidase, further confirming the structure of O-1β-acyl glucuronide. These results demonstrated that ataluren-O-1β-acyl glucuronide did not undergo migration in vivo. No clinical safety concern related to ataluren-O-1β-acyl glucuronide migration has been detected.
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Affiliation(s)
- Jiyuan Ma
- PTC Therapeutics, Inc., South Plainfield, NJ, USA.
| | | | | | | | | | - Ellen Welch
- PTC Therapeutics, Inc., South Plainfield, NJ, USA.
| | | | | | - Ronald Kong
- PTC Therapeutics, Inc., South Plainfield, NJ, USA.
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19
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Pre-clinical dose-escalation studies establish a therapeutic range for U7snRNA-mediated DMD exon 2 skipping. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 21:325-340. [PMID: 33898631 PMCID: PMC8047432 DOI: 10.1016/j.omtm.2021.03.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 03/18/2021] [Indexed: 01/09/2023]
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked progressive disease characterized by loss of dystrophin protein that typically results from truncating mutations in the DMD gene. Current exon-skipping therapies have sought to treat deletion mutations that abolish an open reading frame (ORF) by skipping an adjacent exon, in order to restore an ORF that allows translation of an internally deleted yet partially functional protein, as is seen with many patients with the milder Becker muscular dystrophy (BMD) phenotype. In contrast to that approach, skipping of one copy of a duplicated exon would be expected to result in a full-length transcript and production of a wild-type protein. We have developed an adeno-associated virus (AAV)-based U7snRNA exon-skipping approach directed toward exon 2, duplications of which represent 10% of all DMD duplication mutations. Deletion of exon 2 results in utilization of an exon 5 internal ribosome entry site (IRES) that allows translation beginning in exon 6 of a highly protective dystrophin protein, providing a wide therapeutic window for treatment. Both intramuscular and systemic administration of this vector in the Dup2 mouse model results in robust dystrophin expression and correction of muscle physiologic defects, allowing dose escalation to establish a putative minimal efficacious dose for a human clinical trial.
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20
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Stephenson AA, Flanigan KM. Gene editing and modulation for Duchenne muscular dystrophy. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 182:225-255. [PMID: 34175043 DOI: 10.1016/bs.pmbts.2021.01.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a progressive muscle disease caused by loss of dystrophin protein, encoded by the DMD gene. DMD manifests early in childhood as difficulty walking, progresses to loss of ambulation by the teens, and leads to death in early adulthood. Adeno-associated virus-vectorized gene therapies to restore dystrophin protein expression using gene replacement or antisense oligonucleotide-mediated pre-mRNA splicing modulation have emerged, making great strides in uncovering barriers to gene therapies for DMD and other genetic diseases. While this first-generation of DMD therapies are being evaluated in ongoing clinical trials, uncertainties regarding durability and therapeutic efficacy prompted the development of new experimental therapies for DMD that take advantage of somatic cell gene editing. These experimental therapies continue to advance toward clinic trials, but questions remain unanswered regarding safety and translatable efficacy. Here we review the advancements toward treatment of DMD using gene editing and modulation therapies, with an emphasis on those nearest to clinical applications.
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Affiliation(s)
- Anthony A Stephenson
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, United States
| | - Kevin M Flanigan
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, United States; Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States; Department of Neurology, College of Medicine, The Ohio State University, Columbus, OH, United States.
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21
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Lu X, Han C, Mai J, Jiang X, Liao J, Hou Y, Cui D. Novel Intronic Mutations Introduce Pseudoexons in DMD That Cause Muscular Dystrophy in Patients. Front Genet 2021; 12:657040. [PMID: 33936175 PMCID: PMC8085517 DOI: 10.3389/fgene.2021.657040] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/18/2021] [Indexed: 02/05/2023] Open
Abstract
Background: Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are two subtypes of muscular dystrophy diseases caused by pathogenic mutations in the DMD gene. Until now, more than 4,600 disease-causing mutations in DMD have been reported. However, only 33 mutations were deep intronic, cases with this type of mutations were limited. Methods: In this study, we used a combination of complementary DNA (cDNA) and target DNA sequencing analysis in addition to conventional whole-exome sequencing (WES). Results: Three novel hemizygous mutations IVS11 + 17811C > G (c.1331 + 17811C > G), IVS21 + 3252A > G (c.2803 + 3252A > G) and IVS40 + 362A > G (c.5739 + 362A > G) were identified in DMD patients, while a reported hemizygous mutation IVS62-285A > G (c.9225-285A > G) was found in the BMD patient. These DMD mutations lead to pseudoexon insertions, causing the generation of truncated and dysfunctional dystrophin. Conclusion: This study defines three novel and one reported intronic mutations, which can result in DMD/BMD. We also emphasize the need to combine WES and cDNA-based methods to detect the variant in the very large DMD gene in which the mutational spectrum is complex.
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Affiliation(s)
- Xinguo Lu
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Chunxi Han
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
- *Correspondence: Chunxi Han,
| | - Jiahui Mai
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Xianping Jiang
- Department of Pathology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Jianxiang Liao
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | | | - Di Cui
- Running Gene Inc., Beijing, China
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22
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de Souza F, Bittar Braune C, Dos Santos Nucera APC. Duchenne muscular dystrophy: an overview to the cardiologist. Expert Rev Cardiovasc Ther 2020; 18:867-872. [PMID: 32985912 DOI: 10.1080/14779072.2020.1828065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy in children, affecting approximately one in 3,500-5,000 liveborn boys. The main signs and symptoms include gait disturbances beginning in early childhood, with later onset of respiratory and cardiac function disorders, both directly affecting the prognosis. AREAS COVERED The recent improvement of mechanical ventilation increased the mean DMD survival age; however, there has been little progress in the treatment and prevention of cardiac complications, which currently predominantly impact survival. Cardiological evaluation with imaging methods, such as echocardiography and magnetic resonance imaging, can improve the understanding and detect changes in cardiac function early. EXPERT OPINION Close monitoring by the cardiologists and early treatment, with adequate heart disease stratification, may be the key to prolong the lives of these patients until more promising therapies are available and can predict DMD prognosis and progression more accurately. The objective of this brief review is to update the cardiologists by highlighting the most relevant aspects of treatment and follow-up, in a practical and concise way.
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Affiliation(s)
- Fabio de Souza
- Cardiology Section, Department of Specialized Medicine, School of Medicine and Surgery, Federal University of the State of Rio De Janeiro , Rio de Janeiro, Brazil
| | | | - Ana Paula Cassetta Dos Santos Nucera
- Cardiology Section, Department of Specialized Medicine, School of Medicine and Surgery, Federal University of the State of Rio De Janeiro , Rio de Janeiro, Brazil
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23
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Tong YR, Geng C, Guan YZ, Zhao YH, Ren HT, Yao FX, Ling C, Wang DC, Chen L, Cui LY, Zhang SY, Dai Y. A Comprehensive Analysis of 2013 Dystrophinopathies in China: A Report From National Rare Disease Center. Front Neurol 2020; 11:572006. [PMID: 33101180 PMCID: PMC7554367 DOI: 10.3389/fneur.2020.572006] [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: 06/12/2020] [Accepted: 08/24/2020] [Indexed: 12/17/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive neuromuscular disorders caused by mutations in DMD. A high-quality database of DMD/BMD is essential not only for clinical practice but also for fundamental research. Here, we aimed to build the largest Chinese national dystrophinopathy database using the National Rare Diseases Registry System of China. Peking Union Medical College Hospital (PUMCH) was the National Rare Diseases Center of China. This research involved 2013 patients with dystrophinopathies, whose diagnoses were confirmed; they were registered and followed up at PUMCH from March 2011 to December 2018. Family history, clinical signs, and treatment data were reported for patients with DMD and BMD at different rates. All six serum biochemical indexes could accurately distinguish between DMD and BMD patients. Copy number variations were the most frequent mutation type (79.2% in DMD and 84.3% in BMD), of which large deletions accounted for 88.4 and 88.6%, large duplications accounted for 11.6 and 11.4% in DMD and BMD, respectively. An exon deletion hotspot, located in exons 45-54, was observed in DMD, and intron 44 was the most frequent deletion starting point (26.5%). Duplication and single nucleotide variations appeared to be uniformly distributed among all exons. Eleven patients were identified to have ultrarare mutation types. Eleven other patients suffered from two separate mutations simultaneously, some of which may have taken place via dependent mechanisms. Thus, we have established the largest hospital-based Chinese dystrophinopathy database via the National Rare Diseases Registry System. This study provides valuable information for further diagnostic and therapeutic studies of dystrophinopathy.
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Affiliation(s)
- Yuan-Ren Tong
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Chang Geng
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yu-Zhou Guan
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yan-Huan Zhao
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Hai-Tao Ren
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Feng-Xia Yao
- Laboratory of Clinical Genetics, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Chao Ling
- Laboratory of Clinical Genetics, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Dan-Chen Wang
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Lin Chen
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Li-Ying Cui
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Shu-Yang Zhang
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yi Dai
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
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24
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Abstract
Gene-specific treatment for hereditary muscle diseases has made great progress in recent years. The pathomechanisms of many of these diseases could be decrypted using molecular genetic techniques, paving the way for disease-modifying treatment options. A milestone was undoubtedly the successful translation of the antisense oligonucleotide (ASO) technology into clinical practice, with gene-specific ASOs being approved for the first time in 2016 for the treatment of spinal muscular atrophy and Duchenne muscular dystrophy. This article reviews recent developments in the field of antisense and gene therapies for hereditary muscle diseases.
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25
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Long L, Yang X, Southwood M, Moore S, Crosby A, Upton PD, Dunmore BJ, Morrell NW. Targeting translational read-through of premature termination mutations in BMPR2 with PTC124 for pulmonary arterial hypertension. Pulm Circ 2020; 10:2045894020935783. [PMID: 32733669 PMCID: PMC7372630 DOI: 10.1177/2045894020935783] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 05/28/2020] [Indexed: 02/02/2023] Open
Abstract
Pulmonary arterial hypertension is a fatal disorder of the lung circulation in which accumulation of vascular cells progressively obliterates the pulmonary arterioles. This results in sustained elevation in pulmonary artery pressure leading eventually to right heart failure. Approximately, 80% of familial and 20% of sporadic idiopathic pulmonary arterial hypertension cases are caused by mutations in the bone morphogenetic protein receptor type 2 (BMPR2). Nonsense mutations in BMPR2 are amongst the most common mutations found, where the insertion of a premature termination codon causes mRNA degradation via activation of the nonsense-mediated decay pathway leading to a state of haploinsufficiency. Ataluren (PTC124), a compound that permits ribosomal read-through of premature stop codons, has been previously reported to increase BMPR2 protein expression in cells derived from pulmonary arterial hypertension patients harbouring nonsense mutations. In this study, we characterised the effects of PTC124 on a range of nonsense BMPR2 mutations, focusing on the R584X mutation both in vitro and in vivo. Treatment with PTC124 partially restored BMPR2 protein expression in blood outgrowth endothelial cells isolated from a patient harbouring the R584X mutation. Furthermore, a downstream bone morphogenetic protein signalling target, Id1, was rescued by PTC124 treatment. Mutant cells also exhibited increased lipopolysaccharide-induced permeability, which was reversed by PTC124 treatment. Increased proliferation and apoptosis in R584X blood outgrowth endothelial cells were also significantly reduced by PTC124. Moreover, oral PTC124 increased lung BMPR2 protein expression in mice harbouring the R584X mutation (Bmpr2 +/R584X ). Our findings provide support for future experimental medicine studies of PTC124 in pulmonary arterial hypertension patients with specific nonsense BMPR2 mutations.
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Affiliation(s)
- Lu Long
- Department of Medicine, University of
Cambridge School of Clinical Medicine, Cambridge, UK
| | - Xudong Yang
- Department of Medicine, University of
Cambridge School of Clinical Medicine, Cambridge, UK
| | - Mark Southwood
- Pathology Research, Royal Papworth
Hospital NHS Foundation Trust, Cambridge, UK
| | - Stephen Moore
- Department of Medicine, University of
Cambridge School of Clinical Medicine, Cambridge, UK
| | - Alexi Crosby
- Department of Medicine, University of
Cambridge School of Clinical Medicine, Cambridge, UK
| | - Paul D. Upton
- Department of Medicine, University of
Cambridge School of Clinical Medicine, Cambridge, UK
| | - Benjamin J. Dunmore
- Department of Medicine, University of
Cambridge School of Clinical Medicine, Cambridge, UK
| | - Nicholas W. Morrell
- Department of Medicine, University of
Cambridge School of Clinical Medicine, Cambridge, UK,Nicholas W. Morrell, Division of Respiratory
Medicine, Department of Medicine, Box 157, Addenbrooke's Hospital, Hills Road,
Cambridge CB2 0QQ, United Kingdom.
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26
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Hu C, Li X. Gene therapeutic strategies and relevant clinical trials in neuromuscular disorder in China. Gene Ther 2020; 27:321-328. [PMID: 32591735 DOI: 10.1038/s41434-020-0158-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 05/14/2020] [Accepted: 05/19/2020] [Indexed: 12/19/2022]
Abstract
Neuromuscular disorder is a diverse group of genetic disease, among which Duchenne muscular dystrophy and Spinal muscular atrophy are most common. Recently, the great breakthroughs of gene targeted therapeutic strategies are leading a profound revolution in the standard care of neuromuscular disorders over the world including China. This review will offer an outline of the molecular pathogenesis, clinical progress, critical trials, as well as the challenges of new gene therapy in the treatment of Spinal muscular atrophy and Duchenne muscular dystrophy in China, mainly includes mRNA splicing modulators and adeno-associated virus mediated gene replacement. We hope to highlight some important findings about the critical development of gene therapy in this field, which might be helpful for suggesting potential therapeutic treatment for neuromuscular disease in China.
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Affiliation(s)
- Chaoping Hu
- Neurology Department, Children's Hospital of Fudan University, NO.399 Wanyuan Road, Shanghai, China
| | - Xihua Li
- Neurology Department, Children's Hospital of Fudan University, NO.399 Wanyuan Road, Shanghai, China.
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27
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Duchenne and Becker muscular dystrophy carriers: Evidence of cardiomyopathy by exercise and cardiac MRI testing. Int J Cardiol 2020; 316:257-265. [PMID: 32473283 DOI: 10.1016/j.ijcard.2020.05.052] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 01/16/2023]
Abstract
BACKGROUND Varied detection methods have resulted in conflicting reports on the prevalence of cardiac disease in Duchenne and Becker muscular dystrophy carriers (MDC). METHODS We performed a prospective cohort study of 77 genetically-confirmed MDC mothers, 22 non-carrier mothers, and 25 controls. All participants underwent Cardiopulmonary Exercise Testing (CPET) and Cardiac Magnetic Resonance imaging (CMR). RESULTS 25% of carriers had ventricular ectopy in recovery of exercise (RecVE) as compared to 1 non-carrier and no controls (p = .003). No difference in age or maximal oxygen consumption was noted. 11 carriers had abnormal (<55%) left ventricular ejection fraction by CMR. Evidence of late gadolinium enhancement (LGE) was noted in 48% of MDC, 1 non-carrier patient and no control subjects (p < .0001). Subset analysis of LGE+ and LGE- subjects revealed differences in age (44.1 v 38.6 yrs.; p = .005), presence of RecVE, (38.9% v 10.5%, p = .004), and high serum creatine kinase (CK) (> 289 U/l; 52.8% v 31.6%, p = .065). CONCLUSION We describe the prevalence of disease using CPET and CMR in genetically-proven MDC. 49% of carriers had fibrosis, opposed to 5% of non-carriers, highlighting the importance of genetic testing in this population. Despite cardiomyopathy, functional assessment by treadmill was normal, illustrating the discrepancy in cardiac and skeletal muscle impacts. Age, RecVE and serum CK appear to have an important role in predicting cardiomyopathy. Serum CK levels suggest that a systemic higher global disease severity and not tissue heterogeneity may be the etiology for greater cardiac disease and relatively spared skeletal muscle disease in this population. Clinical Trial Registration https://clinicaltrials.gov/ct2/show/NCT02972580?term=mendell&cond=Duchenne+Muscular+Dystrophy&rank=5; ClinicalTrials.gov Identifier: NCT02972580.
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28
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Deng J, Zhang H, Li C, Huang H, Liu S, Yang H, Xie K, Wang Q, Lei D, Wu J. 46,XX Testicular Disorders of Sex Development With DMD Gene Mutation: First Case Report Identified Prenatally by Integrated Analyses in China. Front Genet 2020; 10:1350. [PMID: 32153624 PMCID: PMC7045042 DOI: 10.3389/fgene.2019.01350] [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: 08/27/2019] [Accepted: 12/10/2019] [Indexed: 11/25/2022] Open
Abstract
The present study describes the first prenatally diagnosed 46,XX testicular disorders of sex development (46,XX testicular DSD) case with DMD gene mutation by integrated analyses in a Chinese pedigree. Chromosome karyotype G-banding analysis of the proband showed a 46,XX karyotype, but B-ultrasound analysis demonstrated the existence of scrotum, testis and penis which inferred a male sexual differentiation. Aneuploidy and copy number variation (CNV) detection by low-coverage single-end whole genome sequencing (WGS) revealed a de novo SRY (sex-determining region Y) gene positive fragment of 224.34 kb length (chrY:2,649,472-2,873,810) which explained the gonadal/genital-chromosomal inconsistency in the proband. Additionally, targeted-region-capture-based DMD gene sequencing and Sanger verification confirmed a widely reported pathogenic heterozygous nonsense mutation (NM_004006, c.9100C>T, p.Arg3034Ter) in the dystrophin-coding gene named DMD. This study emphasizes that integrated analyses of the imaging results, cytogenetics, and molecular features can play an important role in prenatal diagnosis. It requires the combination of more detection techniques with higher resolution than karyotyping to determine the genetic and biological sex of fetuses in prenatal diagnosis. To conclusively determine both the biological and genetic sex of the fetus at the time of prenatal diagnosis particularly in cases that involve X-linked conditions is of vital importance, which would crucially influence the decision-making regarding abortions. This study will help in prenatal diagnosis of DMD in future, also providing a new perspective that enables the genetic diagnosis of sex reversal in pregnancy. Moreover, genetic counseling/analysis for early diagnosis and pre-symptom interventions are warranted.
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Affiliation(s)
- Jianlian Deng
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, China.,BGI-Shenzhen, Shenzhen, China
| | - Haoqing Zhang
- Center of Prenatal Diagnosis, Chenzhou No.1 People's Hospital, Hunan, China
| | - Caiyun Li
- Center of Prenatal Diagnosis, Chenzhou No.1 People's Hospital, Hunan, China
| | - Hui Huang
- BGI Genomics, BGI-Shenzhen, Shenzhen, China
| | - Saijun Liu
- BGI Genomics, BGI-Shenzhen, Shenzhen, China
| | - Huanming Yang
- BGI-Shenzhen, Shenzhen, China.,James D. Watson Institute of Genome Sciences, Hangzhou, China
| | - Kaili Xie
- Division of Obstetrics,Zhuzhou Central Hospital, Hunan, China
| | - Qiong Wang
- Genetic Eugenics Division, The Maternal and Child Health Hospital of Changde City, Hunan, China
| | - Dongzhu Lei
- Center of Prenatal Diagnosis, Chenzhou No.1 People's Hospital, Hunan, China
| | - Jing Wu
- BGI Genomics, BGI-Shenzhen, Shenzhen, China
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29
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30
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Consensus on the diagnosis, treatment and follow-up of patients with Duchenne muscular dystrophy. NEUROLOGÍA (ENGLISH EDITION) 2019. [DOI: 10.1016/j.nrleng.2018.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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31
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Antoury L, Hu N, Darras B, Wheeler TM. Urine mRNA to identify a novel pseudoexon causing dystrophinopathy. Ann Clin Transl Neurol 2019; 6:1106-1112. [PMID: 31211175 PMCID: PMC6562067 DOI: 10.1002/acn3.777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 03/20/2019] [Indexed: 11/16/2022] Open
Abstract
In muscular dystrophies, identification of pathogenic pseudoexons involves sequencing of the target gene cDNA derived from muscle mRNA. Here we use a urine “liquid biopsy,” droplet digital PCR, and sequencing of PCR products to identify a novel cryptic splice site in DMD intron 67 that causes dystrophinopathy. Pseudoexon inclusion is 35% in urine cells, 34% in urine extracellular RNA (exRNA), and 54% in muscle biopsy tissue, but absent in serum exRNA. Our results suggest that cryptic splice site use varies depending on the RNA source, and that urine RNA has the potential to substitute for muscle biopsies to identify DMD pseudoexons.
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Affiliation(s)
- Layal Antoury
- Department of Neurology Massachusetts General Hospital Boston Massachusetts.,Harvard Medical School Boston Massachusetts
| | - Ningyan Hu
- Department of Neurology Massachusetts General Hospital Boston Massachusetts.,Harvard Medical School Boston Massachusetts
| | - Basil Darras
- Harvard Medical School Boston Massachusetts.,Department of Neurology Boston Children's Hospital Boston Massachusetts
| | - Thurman M Wheeler
- Department of Neurology Massachusetts General Hospital Boston Massachusetts.,Harvard Medical School Boston Massachusetts
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32
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Ke Q, Zhao ZY, Mendell JR, Baker M, Wiley V, Kwon JM, Alfano LN, Connolly AM, Jay C, Polari H, Ciafaloni E, Qi M, Griggs RC, Gatheridge MA. Progress in treatment and newborn screening for Duchenne muscular dystrophy and spinal muscular atrophy. World J Pediatr 2019; 15:219-225. [PMID: 30904991 DOI: 10.1007/s12519-019-00242-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/25/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Advances in treatment for Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA) hold promise for children with these disorders. Accurate genetic diagnosis, early in the disease process, will allow these treatments to be most effective. Newborn screening (NBS) for SMA has been recommended in the United States, and a pilot DMD NBS program is underway in Hangzhou, China. DATA SOURCES A PubMed search, limited to the past 5 years, was conducted to identify: (1) therapeutic advancements for DMD/SMA approved by the United States Food and Drug Administration or the European Medicine Agency and (2) The status of NBS for DMD/SMA. RESULTS We review the current state of approved treatments for DMD/SMA. We present recommendations regarding the future of NBS for these diseases, with a focus on the outcomes and challenges of SMA NBS in New York, USA, and the DMD NBS pilot program in Hangzhou, China. CONCLUSIONS Approved treatments for DMD and SMA may change the natural history of these diseases. Long-term studies of these treatments are underway. To avoid the known diagnostic delay associated with these disorders and provide optimal effectiveness of these treatments, early identification of patients through NBS will be necessary. Establishing comprehensive follow-up plans for positively identified patients will need to be in place for NBS programs to be successful.
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Affiliation(s)
- Qing Ke
- Department of Neurology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zheng-Yan Zhao
- Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jerry R Mendell
- Department of Pediatrics and Neurology, Nationwide Children's Hospital, Columbus, OH, USA
| | - Mei Baker
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Veronica Wiley
- Disciplines of Genetic Medicine and Pediatric and Child Health, University of Sydney, Sydney, Australia
| | - Jennifer M Kwon
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Lindsay N Alfano
- Department of Pediatrics, Nationwide Children's Hospital, Columbus, OH, USA
| | - Anne M Connolly
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Catherine Jay
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | | | - Emma Ciafaloni
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Ming Qi
- Department of Clinical Laboratory, Zhejiang University School of Medicine, Hangzhou, China
| | - Robert C Griggs
- Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Michele A Gatheridge
- Department of Neurology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Box 673, Rochester, NY, 14642, USA.
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Nakamura A. Mutation-Based Therapeutic Strategies for Duchenne Muscular Dystrophy: From Genetic Diagnosis to Therapy. J Pers Med 2019; 9:jpm9010016. [PMID: 30836656 PMCID: PMC6462977 DOI: 10.3390/jpm9010016] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 02/22/2019] [Accepted: 02/22/2019] [Indexed: 02/06/2023] Open
Abstract
Duchenne and Becker muscular dystrophy (DMD/BMD) are X-linked muscle disorders caused by mutations of the DMD gene, which encodes the subsarcolemmal protein dystrophin. In DMD, dystrophin is not expressed due to a disruption in the reading frame of the DMD gene, resulting in a severe phenotype. Becker muscular dystrophy exhibits a milder phenotype, having mutations that maintain the reading frame and allow for the production of truncated dystrophin. To date, various therapeutic approaches for DMD have been extensively developed. However, the pathomechanism is quite complex despite it being a single gene disorder, and dystrophin is expressed not only in a large amount of skeletal muscle but also in cardiac, vascular, intestinal smooth muscle, and nervous system tissue. Thus, the most appropriate therapy would be complementation or restoration of dystrophin expression, such as gene therapy using viral vectors, readthrough therapy, or exon skipping therapy. Among them, exon skipping therapy with antisense oligonucleotides can restore the reading frame and yield the conversion of a severe phenotype to one that is mild. In this paper, I present the significance of molecular diagnosis and the development of mutation-based therapeutic strategies to complement or restore dystrophin expression.
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Affiliation(s)
- Akinori Nakamura
- Department of Neurology, National Hospital Organization, Matsumoto Medical Center, 2-20-30 Murai-machi Minami, Matsumoto 399-8701, Japan.
- Third Department of Medicine, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan.
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Andrews JG, Lamb MM, Conway K, Street N, Westfield C, Ciafaloni E, Matthews D, Cunniff C, Pandya S, Fox DJ. Diagnostic Accuracy of Phenotype Classification in Duchenne and Becker Muscular Dystrophy Using Medical Record Data1. J Neuromuscul Dis 2019; 5:481-495. [PMID: 30320597 DOI: 10.3233/jnd-180306] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Dystrophinopathies are caused by mutations in DMD resulting in progressive muscle weakness. They are historically divided into the more severe Duchenne (DMD) and milder Becker (BMD) muscular dystrophy phenotypes. Classification is important for research and clinical care. The purpose of this study was to describe a multi-variable approach to classifying cases from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) and to assess the accuracy of the diagnostic classification scheme. We used age at loss of mobility, molecular testing results, and age at symptom onset to classify cases as having DMD or BMD and to assess sensitivity and specificity. Mobility status showed low sensitivity and high specificity for predicting DMD (65.5% and 99.3%, respectively) and BMD (62.8% and 97.7%, respectively) phenotypes. Molecular testing showed 90.9% sensitivity and 66.4% specificity for DMD; 76.3% sensitivity and 90.0% specificity for BMD. Age of onset predicted DMD with sensitivity of 73.9% and specificity of 69.0%; BMD had 99.7% specificity and 36.7% sensitivity. Mobility status, molecular test results, and age at symptom onset are important but inconsistent measures for accurately classifying individuals into DMD or BMD phenotypes. These results have implications for prognosis in newly diagnosed individuals and for classifying phenotype in clinical trials.
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Affiliation(s)
| | - Molly M Lamb
- Department of Epidemiology, Colorado School of Public Health, University of Colorado, Aurora, Colorado, USA
| | - Kristin Conway
- Department of Epidemiology, The University of Iowa, Iowa City, Iowa, USA
| | - Natalie Street
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | - Emma Ciafaloni
- Department of Neurology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Dennis Matthews
- Physical Medicine and Rehabilitation, School of Medicine, University of Colorado, Aurora, Colorado, USA
| | - Christopher Cunniff
- Department of Pediatrics, Weill Cornell Medical College, New York, New York, USA
| | - Shree Pandya
- Department of Neurology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Deborah J Fox
- New York State Department of Health, Albany, New York, USA
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Ruggiero L, Iodice R, Esposito M, Dubbioso R, Tozza S, Vitale F, Santoro L, Manganelli F. One-year follow up of three Italian patients with Duchenne muscular dystrophy treated with ataluren: is earlier better? Ther Adv Neurol Disord 2018; 11:1756286418809588. [PMID: 30542376 PMCID: PMC6236582 DOI: 10.1177/1756286418809588] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 08/21/2018] [Indexed: 12/27/2022] Open
Abstract
Background Ataluren was approved for the treatment of nmDMD, both the efficacy and safety have been previously reported only from clinical trials but no report exists about real-life experience. Patient/methods we describe three Italian children with nmDMD treated with ataluren for 1 year. Measurements were made every 3 months and was evaluated the 6-Minute Walking Distance (6MWD). Results Case1 involves a patient with a 6MWD at T0 of 360 m, who started ataluren therapy at age 10 years. Case2 is a child who began treatment with ataluren at age 8 years when he had severe ambulatory compromise (6MWD < 75 m at T0). A third patient (case3) had a 6MWD of 320 m when he started ataluren therapy at age 5 years. The best improvement in 6MWD was observed in case3, a patient in whom treatment with ataluren was started much earlier. In case1, ataluren was started relatively late and 6MWD was maintained at a stable level. Surprisingly, we observed a 50% improvement in 6MWD in case2, a patient who began therapy early, but with a severe loss of lower limb muscle function at the time. Conclusions treatment responses depend on the patient's age and disease severity when therapy was initiated. On the basis of our experience, the main factor that influences the effectiveness seems to be earlier instigation of therapy and positive results may still be achieved in patients with more severe muscle involvement. Interestingly, these three boys with phenotypically different nmDMD provide useful information regarding future therapeutic recommendations for the ataluren administration in real clinical practice.
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Affiliation(s)
| | - Rosa Iodice
- Department of Neurosciences, Reproductive and
Odontostomatological Sciences, University Federico II of Naples, Naples,
Italy
| | - Marcello Esposito
- Department of Neurosciences, Reproductive and
Odontostomatological Sciences, University Federico II of Naples, Naples,
Italy
| | - Raffaele Dubbioso
- Department of Neurosciences, Reproductive and
Odontostomatological Sciences, University Federico II of Naples, Naples,
Italy
| | - Stefano Tozza
- Department of Neurosciences, Reproductive and
Odontostomatological Sciences, University Federico II of Naples, Naples,
Italy
| | - Floriana Vitale
- Department of Neurosciences, Reproductive and
Odontostomatological Sciences, University Federico II of Naples, Naples,
Italy
| | - Lucio Santoro
- Department of Neurosciences, Reproductive and
Odontostomatological Sciences, University Federico II of Naples, Naples,
Italy
| | - Fiore Manganelli
- Department of Neurosciences, Reproductive and
Odontostomatological Sciences, University Federico II of Naples, Naples,
Italy
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At the Crossroads of Clinical and Preclinical Research for Muscular Dystrophy-Are We Closer to Effective Treatment for Patients? Int J Mol Sci 2018; 19:ijms19051490. [PMID: 29772730 PMCID: PMC5983724 DOI: 10.3390/ijms19051490] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/03/2018] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
Among diseases affecting skeletal muscle, muscular dystrophy is one of the most devastating and complex disorders. The term ‘muscular dystrophy’ refers to a heterogeneous group of genetic diseases associated with a primary muscle defect that leads to progressive muscle wasting and consequent loss of muscle function. Muscular dystrophies are accompanied by numerous clinical complications and abnormalities in other tissues that cause extreme discomfort in everyday life. The fact that muscular dystrophy often takes its toll on babies and small children, and that many patients die at a young age, adds to the cruel character of the disease. Clinicians all over the world are facing the same problem: they have no therapy to offer except for symptom-relieving interventions. Patients, their families, but also clinicians, are in urgent need of an effective cure. Despite advances in genetics, increased understanding of molecular mechanisms underlying muscle disease, despite a sweeping range of successful preclinical strategies and relative progress of their implementation in the clinic, therapy for patients is currently out of reach. Only a greater comprehension of disease mechanisms, new preclinical studies, development of novel technologies, and tight collaboration between scientists and physicians can help improve clinical treatment. Fortunately, inventiveness in research is rapidly extending the limits and setting new standards for treatment design. This review provides a synopsis of muscular dystrophy and considers the steps of preclinical and clinical research that are taking the muscular dystrophy community towards the fundamental goal of combating the traumatic disease.
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Al-Ghamdi F, Darras BT, Ghosh PS. Spectrum of Neuromuscular Disorders With HyperCKemia From a Tertiary Care Pediatric Neuromuscular Center. J Child Neurol 2018; 33:389-396. [PMID: 29577809 DOI: 10.1177/0883073818758455] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Elevated creatine kinase is a useful screening test in the diagnostic workup of patients with neuromuscular disorders. We did a retrospective study of children with hyperCKemia (>175 IU/L) who were followed in the neuromuscular program of a tertiary care pediatric center from 2005 to 2016. Patients with hyperCKemia were divided into 2 groups: myopathic and nonmyopathic. Within the myopathic group, there were 3 arbitrary subgroups based on creatine kinase values: A (creatine kinase >10 times normal), B (creatine kinase 5-10 times normal), and C (creatine kinase 1-5 times normal). The 3 major categories of myopathies across all the subgroups were muscular dystrophies (commonest) followed by metabolic myopathies and inflammatory myopathies. Among the nonmyopathic causes of hyperCKemia, spinal muscular atrophy was the commonest. Muscular dystrophies should be considered in children with hyperCKemia, muscle weakness, or calf hypertrophy, and metabolic myopathies to be considered in children with recurrent rhabdomyolysis.
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Affiliation(s)
- Fouad Al-Ghamdi
- 1 Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,2 King Fahad Specialist Hospital, Al Muraikabat, Dammam, Saudi Arabia
| | - Basil T Darras
- 1 Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Partha S Ghosh
- 1 Department of Neurology, Boston Children's Hospital, Boston, MA, USA
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Wein N, Vulin A, Findlay AR, Gumienny F, Huang N, Wilton SD, Flanigan KM. Efficient Skipping of Single Exon Duplications in DMD Patient-Derived Cell Lines Using an Antisense Oligonucleotide Approach. J Neuromuscul Dis 2018; 4:199-207. [PMID: 28869484 DOI: 10.3233/jnd-170233] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Exon skipping strategies in Duchenne muscular dystrophy (DMD) have largely been directed toward altering splicing of exons flanking out-of-frame deletions, with the goal of restoring an open mRNA reading frame that leads to production of an internally deleted but partially functional dystrophin protein. OBJECTIVE We sought to apply exon skipping to duplication mutations, assuming that the inherently limited efficiency of antisense oligonucleotide-induced exon skipping would more frequently skip a single copy of a duplicated exon, rather than both and result in significant amounts of wild-type DMD mRNA. METHODS We tested this hypothesis in fibroblast cell lines derived from patients with a variety of single or multiple exon duplications that have been modified to allow transdifferentiation into a myogenic lineage. RESULTS Using a variety of 2'O-methyl antisense oligonucleotides, significant skipping was induced for each duplication leading to a wild-type transcript as a major mRNA product. CONCLUSIONS This study provides another proof of concept for the feasibility of therapeutic skipping in patients carrying exon duplications in order to express wild-type, full-length mRNA, although careful evaluation of the skipping efficiency should be performed as some exons are easier to skip than others. Such a personalized strategy is expected to be highly beneficial for this subset of DMD patients, compared to inducing expression of an internally-deleted dystrophin.
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Affiliation(s)
- Nicolas Wein
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Adeline Vulin
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Andrew R Findlay
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Felecia Gumienny
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Nianyuan Huang
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Steve D Wilton
- Perron Institute for Neurological and Translational Science, Center for Comparative Genomics, Murdoch University, Perth, Australia
| | - Kevin M Flanigan
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University, Columbus, OH, USA.,Department of Neurology, The Ohio State University, Columbus, OH, USA
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Nascimento Osorio A, Medina Cantillo J, Camacho Salas A, Madruga Garrido M, Vilchez Padilla JJ. Consensus on the diagnosis, treatment and follow-up of patients with Duchenne muscular dystrophy. Neurologia 2018. [PMID: 29526319 DOI: 10.1016/j.nrl.2018.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
INTRODUCTION Duchenne muscular dystrophy (DMD) is the most common myopathy in children, with a worldwide prevalence of approximately 0.5 cases per 10,000 male births. It is characterised by a progressive muscular weakness manifesting in early childhood, with the subsequent appearance of musculoskeletal, respiratory, and cardiac complications, causing disability, dependence, and premature death. Currently, DMD is mainly managed with multidisciplinary symptomatic treatment, with favourable results in terms of the progression of the disease. It is therefore crucial to establish clear, up-to-date guidelines enabling early detection, appropriate treatment, and monitoring of possible complications. DEVELOPMENT We performed a literature search of the main biomedical databases for articles published in the last 10years in order to obtain an overview of the issues addressed by current guidelines and to identify relevant issues for which no consensus has yet been established. The degree of evidence and level of recommendation of the information obtained were classified and ordered according to the criteria of the American Academy of Neurology. CONCLUSIONS DMD management should be multidisciplinary and adapted to the patient's profile and the stage of clinical progression. In addition to corticotherapy, treatment targeting gastrointestinal, respiratory, cardiac, and orthopaedic problems, as well as physiotherapy, should be provided with a view to improving patients' quality of life. Genetic studies play a key role in the management of the disease, both in detecting cases and potential carriers and in characterising the mutation involved and developing new therapies.
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Affiliation(s)
- A Nascimento Osorio
- Unidad de Patología Neuromuscular, Servicio de Neurología, Hospital Sant Joan de Déu, Esplugues de Llobregat, Barcelona, España
| | - J Medina Cantillo
- Servicio de Medicina Física y Rehabilitación, Hospital Sant Joan de Déu Esplugues de Llobregat, Barcelona, España
| | - A Camacho Salas
- Sección de Neurología Infantil, Servicio de Neurología, Hospital Universitario 12 de Octubre, Madrid, España
| | - M Madruga Garrido
- Sección de Neurología Pediátrica, Hospital Universitario Virgen del Rocío, Sevilla, España
| | - J J Vilchez Padilla
- Servicio de Neurología, Hospital Universitario y Politécnico de La Fe, Valencia, España; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) y Departamento de Medicina, Universidad de Valencia, Valencia, España.
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Huang L, Low A, Damle SS, Keenan MM, Kuntz S, Murray SF, Monia BP, Guo S. Antisense suppression of the nonsense mediated decay factor Upf3b as a potential treatment for diseases caused by nonsense mutations. Genome Biol 2018; 19:4. [PMID: 29334995 PMCID: PMC5769327 DOI: 10.1186/s13059-017-1386-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/29/2017] [Indexed: 01/08/2023] Open
Abstract
Background About 11% of all human genetic diseases are caused by nonsense mutations that generate premature translation termination codons (PTCs) in messenger RNAs (mRNA). PTCs not only lead to the production of truncated proteins, but also often result in decreased mRNA abundance due to nonsense-mediated mRNA decay (NMD). Although pharmacological inhibition of NMD could be an attractive therapeutic approach for the treatment of diseases caused by nonsense mutations, NMD also regulates the expression of 10–20% of the normal transcriptome. Results Here, we investigate whether NMD can be inhibited to stabilize mutant mRNAs, which may subsequently produce functional proteins, without having a major impact on the normal transcriptome. We develop antisense oligonucleotides (ASOs) to systematically deplete each component in the NMD pathway. We find that ASO-mediated depletion of each NMD factor elicits different magnitudes of NMD inhibition in vitro and are differentially tolerated in normal mice. Among all of the NMD factors, Upf3b depletion is well tolerated, consistent with previous reports that UPF3B is not essential for development and regulates only a subset of the endogenous NMD substrates. While minimally impacting the normal transcriptome, Upf3b-ASO treatment significantly stabilizes the PTC-containing dystrophin mRNA in mdx mice and coagulation factor IX mRNA in a hemophilia mouse model. Furthermore, when combined with reagents promoting translational read-through, Upf3b-ASO treatment leads to the production of functional factor IX protein in hemophilia mice. Conclusions These data demonstrate that ASO-mediated reduction of the NMD factor Upf3b could be an effective and safe approach for the treatment of diseases caused by nonsense mutations. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1386-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lulu Huang
- Ionis Pharmaceuticals, Inc., Carlsbad, California, USA
| | - Audrey Low
- Ionis Pharmaceuticals, Inc., Carlsbad, California, USA
| | - Sagar S Damle
- Ionis Pharmaceuticals, Inc., Carlsbad, California, USA
| | | | - Steven Kuntz
- Ionis Pharmaceuticals, Inc., Carlsbad, California, USA
| | | | - Brett P Monia
- Ionis Pharmaceuticals, Inc., Carlsbad, California, USA
| | - Shuling Guo
- Ionis Pharmaceuticals, Inc., Carlsbad, California, USA.
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CUGC for Duchenne muscular dystrophy (DMD). Eur J Hum Genet 2018; 26:749-757. [PMID: 29330543 DOI: 10.1038/s41431-017-0013-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 08/08/2017] [Accepted: 09/09/2017] [Indexed: 11/08/2022] Open
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Waldrop MA, Gumienny F, El Husayni S, Frank DE, Weiss RB, Flanigan KM. Low-level dystrophin expression attenuating the dystrophinopathy phenotype. Neuromuscul Disord 2017; 28:116-121. [PMID: 29305136 DOI: 10.1016/j.nmd.2017.11.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 11/15/2017] [Accepted: 11/16/2017] [Indexed: 12/29/2022]
Abstract
The reading frame rule suggests that Duchenne muscular dystrophy (DMD) results from DMD mutations causing an out-of-frame transcript, whereas the milder Becker muscular dystrophy results from mutations causing an in-frame transcript. However, predicted nonsense mutations may instead result in altered splicing and an in-frame transcript. Here we report a 10-year-old boy with a predicted nonsense mutation in exon 42 who had a 6-minute walk time of 157% of that of age matched DMD controls, characterized as intermediate muscular dystrophy. RNA sequencing analysis from a muscle biopsy revealed only 6.0-9.8% of DMD transcripts were in-frame, excluding exon 42, and immunoblot demonstrated only 3.2% dystrophin protein expression. Another potential genetic modifier noted was homozygosity for the protective IAAM LTBP4 haplotype. This case suggests that very low levels of DMD exon skipping and dystrophin protein expression may result in amelioration of skeletal muscle weakness, a finding relevant to current dystrophin-restoring therapies.
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Affiliation(s)
- Megan A Waldrop
- The Center for Gene Therapy, Nationwide Children's Hospital, Columbus, OH 43205, USA; Department of Neurology, The Ohio State University, Columbus, OH 43205, USA; Department of Pediatrics, The Ohio State University, Columbus, OH 43205, USA
| | - Felecia Gumienny
- The Center for Gene Therapy, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Saleh El Husayni
- Department of Translational Development, Sarepta Therapeutics, Inc., Cambridge, MA 02142, USA
| | - Diane E Frank
- Department of Translational Development, Sarepta Therapeutics, Inc., Cambridge, MA 02142, USA
| | - Robert B Weiss
- Department of Human Genetics, The University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Kevin M Flanigan
- The Center for Gene Therapy, Nationwide Children's Hospital, Columbus, OH 43205, USA; Department of Neurology, The Ohio State University, Columbus, OH 43205, USA; Department of Pediatrics, The Ohio State University, Columbus, OH 43205, USA.
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Tsuda T, Fitzgerald KK. Dystrophic Cardiomyopathy: Complex Pathobiological Processes to Generate Clinical Phenotype. J Cardiovasc Dev Dis 2017; 4:jcdd4030014. [PMID: 29367543 PMCID: PMC5715712 DOI: 10.3390/jcdd4030014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/27/2017] [Accepted: 08/30/2017] [Indexed: 02/06/2023] Open
Abstract
Duchenne muscular dystrophy (DMD), Becker muscular dystrophy (BMD), and X-linked dilated cardiomyopathy (XL-DCM) consist of a unique clinical entity, the dystrophinopathies, which are due to variable mutations in the dystrophin gene. Dilated cardiomyopathy (DCM) is a common complication of dystrophinopathies, but the onset, progression, and severity of heart disease differ among these subgroups. Extensive molecular genetic studies have been conducted to assess genotype-phenotype correlation in DMD, BMD, and XL-DCM to understand the underlying mechanisms of these diseases, but the results are not always conclusive, suggesting the involvement of complex multi-layers of pathological processes that generate the final clinical phenotype. Dystrophin protein is a part of dystrophin-glycoprotein complex (DGC) that is localized in skeletal muscles, myocardium, smooth muscles, and neuronal tissues. Diversity of cardiac phenotype in dystrophinopathies suggests multiple layers of pathogenetic mechanisms in forming dystrophic cardiomyopathy. In this review article, we review the complex molecular interactions involving the pathogenesis of dystrophic cardiomyopathy, including primary gene mutations and loss of structural integrity, secondary cellular responses, and certain epigenetic and other factors that modulate gene expressions. Involvement of epigenetic gene regulation appears to lead to specific cardiac phenotypes in dystrophic hearts.
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Affiliation(s)
- Takeshi Tsuda
- Nemours Cardiac Center, Nemours/Alfred I. duPont Hospital for Children, Wilmington, 1600 Rockland Rd, DE 19803, USA.
| | - Kristi K Fitzgerald
- Nemours Cardiac Center, Nemours/Alfred I. duPont Hospital for Children, Wilmington, 1600 Rockland Rd, DE 19803, USA.
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Vieitez I, Gallano P, González-Quereda L, Borrego S, Marcos I, Millán J, Jairo T, Prior C, Molano J, Trujillo-Tiebas M, Gallego-Merlo J, García-Barcina M, Fenollar M, Navarro C. Mutational spectrum of Duchenne muscular dystrophy in Spain: study of 284 cases. NEUROLOGÍA (ENGLISH EDITION) 2017. [DOI: 10.1016/j.nrleng.2015.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Deep intronic variants introduce DMD pseudoexon in patient with muscular dystrophy. Neuromuscul Disord 2017; 27:631-634. [DOI: 10.1016/j.nmd.2017.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/27/2017] [Accepted: 04/05/2017] [Indexed: 12/27/2022]
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46
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Kamdar F, Garry DJ. Dystrophin-Deficient Cardiomyopathy. J Am Coll Cardiol 2017; 67:2533-46. [PMID: 27230049 DOI: 10.1016/j.jacc.2016.02.081] [Citation(s) in RCA: 231] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/16/2016] [Accepted: 02/23/2016] [Indexed: 12/25/2022]
Abstract
Dystrophinopathies are a group of distinct neuromuscular diseases that result from mutations in the structural cytoskeletal Dystrophin gene. Dystrophinopathies include Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), X-linked dilated cardiomyopathy, as well as DMD and BMD female carriers. The primary presenting symptom in most dystrophinopathies is skeletal muscle weakness. However, cardiac muscle is also a subtype of striated muscle and is similarly affected in many of the muscular dystrophies. Cardiomyopathies associated with dystrophinopathies are an increasingly recognized manifestation of these neuromuscular disorders and contribute significantly to their morbidity and mortality. Recent studies suggest that these patient populations would benefit from cardiovascular therapies, annual cardiovascular imaging studies, and close follow-up with cardiovascular specialists. Moreover, patients with DMD and BMD who develop end-stage heart failure may benefit from the use of advanced therapies. This review focuses on the pathophysiology, cardiac involvement, and treatment of cardiomyopathy in the dystrophic patient.
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Affiliation(s)
- Forum Kamdar
- Cardiovascular Division, Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota
| | - Daniel J Garry
- Cardiovascular Division, Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota.
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Targeting Nonsense Mutations in Diseases with Translational Read-Through-Inducing Drugs (TRIDs). BioDrugs 2016; 30:49-74. [PMID: 26886021 DOI: 10.1007/s40259-016-0157-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In recent years, remarkable advances in the ability to diagnose genetic disorders have been made. The identification of disease-causing genes allows the development of gene-specific therapies with the ultimate goal to develop personalized medicines for each patient according to their own specific genetic defect. In-depth genotyping of many different genes has revealed that ~12% of inherited genetic disorders are caused by in-frame nonsense mutations. Nonsense (non-coding) mutations are caused by point mutations, which generate premature termination codons (PTCs) that cause premature translational termination of the mRNA, and subsequently inhibit normal full-length protein expression. Recently, a gene-based therapeutic approach for genetic diseases caused by nonsense mutations has emerged, namely the so-called translational read-through (TR) therapy. Read-through therapy is based on the discovery that small molecules, known as TR-inducing drugs (TRIDs), allow the translation machinery to suppress a nonsense codon, elongate the nascent peptide chain, and consequently result in the synthesis of full-length protein. Several TRIDs are currently under investigation and research has been performed on several genetic disorders caused by nonsense mutations over the years. These findings have raised hope for the usage of TR therapy as a gene-based pharmacogenetic therapy for nonsense mutations in various genes responsible for a variety of genetic diseases.
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Newcomb TM, Flanigan KM. Reassessing carrier status for dystrophinopathies. NEUROLOGY-GENETICS 2016; 2:e108. [PMID: 27761523 PMCID: PMC5053119 DOI: 10.1212/nxg.0000000000000108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The cloning of the DMD gene, and the identifications of mutations in it as the cause of Duchenne muscular dystrophy (DMD), makes a compelling story that is aptly told elsewhere.1 The locus-the largest in the human genome-consists of 79 exons, distributed over 2.5 million nucleotides on the X chromosome, which are assembled into a complementary DNA (cDNA) of around 14 kb encoding the predominant muscle isoform of the dystrophin protein.2 The size of the gene, and the number of exons, had historically made mutation analysis challenging. For more than a decade, the standard clinical assay was a multiplex PCR test that amplified sequences from a limited number of exons; nevertheless, because it included exons within the deletion hotspots of the gene, this method could confirm the presence of mutations in up to 98% of boys with exonic deletions.3,4.
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Affiliation(s)
- Tara M Newcomb
- Department of Neurology (T.M.N.), the University of Utah School of Medicine, Salt Lake City; The Center for Gene Therapy (K.M.F.), Nationwide Children's Hospital, Columbus, OH; and Departments of Pediatrics and Neurology (K.M.F.), Ohio State University, Columbus
| | - Kevin M Flanigan
- Department of Neurology (T.M.N.), the University of Utah School of Medicine, Salt Lake City; The Center for Gene Therapy (K.M.F.), Nationwide Children's Hospital, Columbus, OH; and Departments of Pediatrics and Neurology (K.M.F.), Ohio State University, Columbus
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Vieitez I, Gallano P, González-Quereda L, Borrego S, Marcos I, Millán JM, Jairo T, Prior C, Molano J, Trujillo-Tiebas MJ, Gallego-Merlo J, García-Barcina M, Fenollar M, Navarro C. Mutational spectrum of Duchenne muscular dystrophy in Spain: Study of 284 cases. Neurologia 2016; 32:377-385. [PMID: 26968818 DOI: 10.1016/j.nrl.2015.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 12/09/2015] [Accepted: 12/12/2015] [Indexed: 10/22/2022] Open
Abstract
INTRODUCTION Duchenne muscular dystrophy (DMD) is a severe X-linked recessive neuromuscular disease that affects one in 3500 live-born males. The total absence of dystrophin observed in DMD patients is generally caused by mutations that disrupt the reading frame of the DMD gene, and about 80% of cases harbour deletions or duplications of one or more exons. METHODS We reviewed 284 cases of males with a genetic diagnosis of DMD between 2007 and 2014. These patients were selected from 8 Spanish reference hospitals representing most areas of Spain. Multiplex PCR, MLPA, and sequencing were performed to identify mutations. RESULTS Most of these DMD patients present large deletions (46.1%) or large duplications (19.7%) in the dystrophin gene. The remaining 34.2% correspond to point mutations, and half of these correspond to nonsense mutations. In this study we identified 23 new mutations in DMD: 7 large deletions and 16 point mutations. CONCLUSIONS The algorithm for genetic diagnosis applied by the participating centres is the most appropriate for genotyping patients with DMD. The genetic specificity of different therapies currently being developed emphasises the importance of identifying the mutation appearing in each patient; 38.7% of the cases in this series are eligible to participate in current clinical trials.
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Affiliation(s)
- I Vieitez
- Grupo de Patología Neonatal y Pediátrica, Enfermedades raras, Instituto de Investigación Biomédica de Ourense-Pontevedra-Vigo (IBI), Vigo, España; Complexo Hospitalario Universitario de Vigo (CHUVI), SERGAS, Vigo, España
| | - P Gallano
- Departamento de Genética, Hospital de la Santa Creu i Sant Pau, Barcelona, España; CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Instituto de Salud Carlos III, Madrid, España
| | - L González-Quereda
- Departamento de Genética, Hospital de la Santa Creu i Sant Pau, Barcelona, España; CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Instituto de Salud Carlos III, Madrid, España
| | - S Borrego
- Departamento de Genética, Reproducción y Medicina fetal, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, España; CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Instituto de Salud Carlos III, Madrid, España
| | - I Marcos
- Departamento de Genética, Reproducción y Medicina fetal, Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, España; CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Instituto de Salud Carlos III, Madrid, España
| | - J M Millán
- Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario La Fe, Valencia, España; CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Instituto de Salud Carlos III, Madrid, España
| | - T Jairo
- Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario La Fe, Valencia, España; CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Instituto de Salud Carlos III, Madrid, España
| | - C Prior
- Instituto de Genética Médica y Molecular (INGEMM), Hospital Universitario La Paz, Madrid, España
| | - J Molano
- Instituto de Genética Médica y Molecular (INGEMM), Hospital Universitario La Paz, Madrid, España
| | - M J Trujillo-Tiebas
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, España; CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Instituto de Salud Carlos III, Madrid, España
| | - J Gallego-Merlo
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, España; CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Instituto de Salud Carlos III, Madrid, España
| | - M García-Barcina
- Unidad de Genética, Hospital Universitario de Basurto, Vizcaya, España
| | - M Fenollar
- Sección de Genética Clínica, Servicio de Análisis Clínicos, Hospital Clínico San Carlos, Madrid, España
| | - C Navarro
- Complexo Hospitalario Universitario de Vigo (CHUVI), SERGAS, Vigo, España.
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Vulin A, Wein N, Simmons TR, Rutherford AM, Findlay AR, Yurkoski JA, Kaminoh Y, Flanigan KM. The first exon duplication mouse model of Duchenne muscular dystrophy: A tool for therapeutic development. Neuromuscul Disord 2015; 25:827-34. [PMID: 26365037 DOI: 10.1016/j.nmd.2015.08.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 12/27/2022]
Abstract
Exon duplication mutations account for up to 11% of all cases of Duchenne muscular dystrophy (DMD), and a duplication of exon 2 is the most common duplication in patients. For use as a platform for testing of duplication-specific therapies, we developed a mouse model that carries a Dmd exon 2 duplication. By using homologous recombination we duplicated exon 2 within intron 2 at a location consistent with a human duplication hotspot. mRNA analysis confirms the inclusion of a duplicated exon 2 in mouse muscle. Dystrophin expression is essentially absent by immunofluorescent and immunoblot analysis, although some muscle specimens show very low-level trace dystrophin expression. Phenotypically, the mouse shows similarities to mdx, the standard laboratory model of DMD. In skeletal muscle, areas of necrosis and phagocytosis are seen at 3 weeks, with central nucleation prominent by four weeks, recapitulating the "crisis" period in mdx. Marked diaphragm fibrosis is noted by 6 months, and remains unchanged at 12 months. Our results show that the Dup2 mouse is both pathologically (in degree and distribution) and physiologically similar to mdx. As it recapitulates the most common single exon duplication found in DMD patients, this new model will be a useful tool to assess the potential of duplicated exon skipping.
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Affiliation(s)
- Adeline Vulin
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Nicolas Wein
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Tabatha R Simmons
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Andrea M Rutherford
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Andrew R Findlay
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Jacqueline A Yurkoski
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Yuuki Kaminoh
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA
| | - Kevin M Flanigan
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA; Department of Neurology, The Ohio State University, Columbus, OH, USA.
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