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Braga VLL, Lima DP, Mariano TC, Lima PLGDSB, Maia ABDA, da Silva Meireles WW, de Oliveira Pessoa KT, de Oliveira CM, Ribeiro EM, Nóbrega PR, Pessoa ALS. Higher Prevalence of Nonsense Pathogenic DMD Variants in a Single-Center Cohort from Brazil: A Genetic Profile Study That May Guide the Choice of Disease-Modifying Treatments. Brain Sci 2023; 13:1521. [PMID: 38002481 PMCID: PMC10669865 DOI: 10.3390/brainsci13111521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 11/26/2023] Open
Abstract
Dystrophinopathies are muscle diseases caused by pathogenic variants in DMD, the largest gene described in humans, representing a spectrum of diseases ranging from asymptomatic creatine phosphokinase elevation to severe Duchenne muscular dystrophy (DMD). Several therapeutic strategies are currently in use or under development, each targeting different pathogenic variants. However, little is known about the genetic profiles of northeast Brazilian patients with dystrophinopathies. We describe the spectrum of pathogenic DMD variants in a single center in northeast Brazil. This is an observational, cross-sectional study carried out through molecular-genetic analysis of male patients diagnosed with dystrophinopathies using Multiplex Ligation-dependent Probe Amplification (MLPA) followed by Next-Generation Sequencing (NGS)-based strategies. A total of 94 male patients were evaluated. Deletions (43.6%) and duplications (10.6%) were the most recurring patterns of pathogenic variants. However, small variants were present in 47.1% of patients, most of them nonsense variants (27.6%). This is the largest South American single-center case series of dystrophinopathies to date. We found a higher frequency of treatment-amenable nonsense single-nucleotide variants than most previous studies. These findings may have implications for diagnostic strategies in less-known populations, as a higher frequency of nonsense variants may mean a higher possibility of treating patients with disease-modifying drugs.
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Affiliation(s)
- Vitor Lucas Lopes Braga
- Division of Pediatry, Hospital Infantil Albert Sabin, Fortaleza 60410-794, CE, Brazil; (V.L.L.B.); (A.B.d.A.M.)
| | - Danielle Pessoa Lima
- Division of Geriatry, Walter Cantidio University Hospital, Federal University of Ceara, Fortaleza 60430-372, CE, Brazil;
| | - Tamiris Carneiro Mariano
- Division of Neurogenetics and Neuromuscular Disorders, Hospital Infantil Albert Sabin, Fortaleza 60410-794, CE, Brazil;
| | | | - Ana Beatriz de Almeida Maia
- Division of Pediatry, Hospital Infantil Albert Sabin, Fortaleza 60410-794, CE, Brazil; (V.L.L.B.); (A.B.d.A.M.)
| | | | | | | | | | - Paulo Ribeiro Nóbrega
- Division of Neurology, Walter Cantidio University Hospital, Federal University of Ceara, Fortaleza 60430-372, CE, Brazil
- Campus Parque Ecológico, Centro Universitário Christus, Fortaleza 60160-230, CE, Brazil
| | - André Luiz Santos Pessoa
- Albert Sabin Children’s Hospital, Fortaleza 60410-794, CE, Brazil;
- Faculty of Medicine, State University of Ceará (UECE), Fortaleza 60714-903, CE, Brazil
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Schneider NB, Roos EC, Staub ALP, Bevilacqua IP, de Almeida AC, de Camargo Martins T, Ramos NB, Loze P, Saute JAM, Etges APBDS, Polanczyk CA. Estimated costs for Duchenne muscular dystrophy care in Brazil. Orphanet J Rare Dis 2023; 18:159. [PMID: 37349725 DOI: 10.1186/s13023-023-02767-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 06/04/2023] [Indexed: 06/24/2023] Open
Abstract
BACKGROUND The economic burden of rare diseases on health systems is still not widely measured, with the generation of accurate information about the costs with medical care for subjects with rare diseases being crucial when defining health policies. Duchenne Muscular Dystrophy (DMD) is the most common form of muscular dystrophy, with new technologies recently being studied for its management. Information about the costs related to the disease in Latin America is scarce, and the objective of this study is to evaluate the annual hospital, home care and transportation costs per patient with DMD treatment in Brazil. RESULTS Data from 27 patients were included, the median annual cost per patient was R$ 17,121 (IQR R$ 6,786; 25,621). Home care expenditures accounted for 92% of the total costs, followed by hospital costs (6%) and transportation costs (2%). Medications and loss of family, and patient's productivity are among the most representative consumption items. When disease worsening due to loss of the ability to walk was incorporated to the analysis, it was shown that wheelchair users account for an incremental cost of 23% compared with non-wheelchair users. CONCLUSIONS This is an original study in Latin America to measure DMD costs using the micro-costing technique. Generating accurate information about costs is crucial to provide health managers with information that could help establish more sustainable policies when deciding upon rare diseases in emerging countries.
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Affiliation(s)
- Nayê Balzan Schneider
- National Institute of Science and Technology for Health Technology Assessment (IATS)- CNPq/Brazil (project: 465518/2014-1), Porto Alegre, Brazil
- Programa de Pós-Graduação em Epidemiologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Erica Caetano Roos
- Programa de Pós-Graduação em Engenharia de Produção, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Ana Lúcia Portella Staub
- Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre, Neurogenética, Porto Alegre, Brazil
| | | | | | | | | | - Priscilla Loze
- Produtos Roche Químicos e Farmacêuticos S/A, São Paulo, SP, Brazil
| | - Jonas Alex Morales Saute
- Centro de Pesquisa Clínica, Hospital de Clínicas de Porto Alegre, Neurogenética, Porto Alegre, Brazil
- Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Programa de Pós-Graduação em Medicina: Ciências Médicas, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Departamento de Medicina Interna, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Serviço de Neurologia, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Ana Paula Beck da Silva Etges
- National Institute of Science and Technology for Health Technology Assessment (IATS)- CNPq/Brazil (project: 465518/2014-1), Porto Alegre, Brazil.
- Programa de Pós-Graduação em Epidemiologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
- School of Technology, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Carisi Anne Polanczyk
- National Institute of Science and Technology for Health Technology Assessment (IATS)- CNPq/Brazil (project: 465518/2014-1), Porto Alegre, Brazil
- Programa de Pós-Graduação em Epidemiologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Departamento de Medicina Interna, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Hospital Moinhos de Vento, Porto Alegre, Rio Grande do Sul, Brazil
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3
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Triana-Fonseca P, Parada-Márquez JF, Silva-Aldana CT, Zambrano-Arenas D, Arias-Gomez LL, Morales-Fonseca N, Medina-Méndez E, Restrepo CM, Silgado-Guzmán DF, Fonseca-Mendoza DJ. Genetic Profile of the Dystrophin Gene Reveals New Mutations in Colombian Patients Affected with Muscular Dystrophinopathy. APPLICATION OF CLINICAL GENETICS 2021; 14:399-408. [PMID: 34629887 PMCID: PMC8493106 DOI: 10.2147/tacg.s317721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/31/2021] [Indexed: 11/23/2022]
Abstract
Background Duchenne and Becker muscular dystrophies (DMD/BMD) are the most common human dystrophinopathies with recessive X-linked inheritance. Dystrophin gene deletions and duplications are the most common mutations, followed by point mutations. The aim of this study is to characterize the mutational profile of the dystrophin gene in Colombian patients with DMD/BMD. Material and Methods Mutational profiling was determined in 69 affected patients using Sanger sequencing, next-generation sequencing (NGS) and/or multiplex ligation dependent-probes amplification (MLPA). Genetic variants were classified according to molecular consequence and new variants were determined through database and literature analysis. Results Mutational profile in affected patients revealed that large deletions/duplications analyzed by MLPA accounted for 72.5% of all genetic variations. By using Sanger sequencing or NGS, we identified point mutations in 15.9% and small deletions in 11.6% of the patients. New mutations were found, most of them were point mutations or small deletions (10.1%). Conclusion Our results described the genetic profile of the dystrophin gene in Colombian patients with DMD and contribute to efforts to identify molecular variants in Latin American populations. For our population, 18.8% of cases could be treated with FDA or MDA approved molecular therapies based on specific mutations. These data contribute to the establishment of appropriate genetic counseling and potential treatment.
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Affiliation(s)
| | | | - Claudia T Silva-Aldana
- Department of Molecular Diagnosis, Genética Molecular de Colombia SAS, Bogotá, DC, Colombia
| | | | | | | | - Esteban Medina-Méndez
- Department of Molecular Diagnosis, Genética Molecular de Colombia SAS, Bogotá, DC, Colombia
| | - Carlos M Restrepo
- Center for Research in Genetics and Genomics - CIGGUR, GENIUROS Research Group, School of Medicine and Health Sciences, Universidad Del Rosario, Bogotá, DC, Colombia
| | | | - Dora Janeth Fonseca-Mendoza
- Center for Research in Genetics and Genomics - CIGGUR, GENIUROS Research Group, School of Medicine and Health Sciences, Universidad Del Rosario, Bogotá, DC, Colombia
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Nagabushana D, Polavarapu K, Bardhan M, Arunachal G, Gunasekaran S, Preethish-Kumar V, Anjanappa RM, Thomas P, Sadasivan A, Vengalil S, Nashi S, Chawla T, Warrier M, Keerthipriya M, Raju S, Mohan D, Nalini A. Comparison of The Carrier Frequency of Pathogenic Variants of DMD Gene in an Indian Cohort. J Neuromuscul Dis 2021; 8:525-535. [PMID: 33843695 DOI: 10.3233/jnd-210658] [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] [Indexed: 01/18/2023]
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is an X-linked disorder caused due to large deletions, duplications,and small pathogenic variants. This article compares the carrier frequency of different pathogenic variants in the DMD gene for the first time in an Indian cohort. METHODS Ninety-one mothers of genetically confirmed DMD probands are included in this study. Pathogenic variants in the DMD gene in probands were detected by multiplex ligation-dependent probe amplification (MLPA) or next-generation sequencing (NGS). Maternal blood samples were evaluated either by MLPA or Sanger sequencing. The demographic and clinical details for screening of muscle weakness and cardiomyopathy were collected from the confirmed carriers. RESULTS Out of 91 probands, large deletions and duplications were identified in 46 and 6 respectively, while 39 had small variants. Among the small variants, substitutions predicted to cause nonsense mutations were the most common (61.5%), followed by frameshift causing small insertion/deletions (25.6%) and splice affecting intronic variants (12.8%). Notably, 19 novel small variants predicted to be disease-causing were identified. Of the 91 mothers, 53 (58.7%) were confirmed to be carriers. Exonic deletions had a significantly lower carrier frequency of 47.8% as compared to small variants (64.1%). The mean age of the carriers at evaluation was 30 years. Among the carriers, two were symptomatic with onset in the 4th decade, manifesting with progressive proximal muscle weakness and dilated cardiomyopathy. CONCLUSION Carrier frequency of small pathogenic variants differs significantly from large deletions. Small pathogenic variants are more commonly inherited, whereas large deletions arise de novo.
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Affiliation(s)
- Divya Nagabushana
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Kiran Polavarapu
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India.,Children's Hospital of Eastern Ontario Research Institute, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada.,Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON, Canada.,Brain and Mind Research Institute, University of Ottawa, ON, Canada
| | - Mainak Bardhan
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Gautham Arunachal
- Department of Human Genetics, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Swetha Gunasekaran
- Department of Human Genetics, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | | | - Ram Murthy Anjanappa
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - PriyaTreesa Thomas
- Department of Psychiatric Social Work, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Arun Sadasivan
- Department of Psychiatric Social Work, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Seena Vengalil
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Saraswati Nashi
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Tanushree Chawla
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Manjusha Warrier
- Department of Psychiatric Social Work, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Muddasu Keerthipriya
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Sanita Raju
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Dhaarini Mohan
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Atchayaram Nalini
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
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5
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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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Luce L, Carcione M, Mazzanti C, Buonfiglio PI, Dalamón V, Mesa L, Dubrovsky A, Corderí J, Giliberto F. Theragnosis for Duchenne Muscular Dystrophy. Front Pharmacol 2021; 12:648390. [PMID: 34149409 PMCID: PMC8209366 DOI: 10.3389/fphar.2021.648390] [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: 12/31/2020] [Accepted: 05/17/2021] [Indexed: 12/12/2022] Open
Abstract
Dystrophinopathies cover a spectrum of rare progressive X-linked muscle diseases, arising from DMD mutations. They are among the most common pediatric muscular dystrophies, being Duchenne muscular dystrophy (DMD) the most severe form. Despite the fact that there is still no cure for these serious diseases, unprecedented advances are being made for the development of therapies for DMD. Some of which are already conditionally approved: exon skipping and premature stop codon read-through. The present work aimed to characterize the mutational spectrum of DMD in an Argentinian cohort, to identify candidates for available pharmacogenetic treatments and finally, to conduct a comparative analysis of the Latin American (LA) frequencies of mutations amenable for available DMD therapies. We studied 400 patients with clinical diagnosis of dystrophinopathy, implementing a diagnostic molecular algorithm including: MLPA/PCR/Sanger/Exome and bioinformatics. We also performed a meta-analysis of LA's metrics for DMD available therapies. The employed algorithm resulted effective for the achievement of differential diagnosis, reaching a detection rate of 97%. Because of this, corticosteroid treatment was correctly indicated and validated in 371 patients with genetic confirmation of dystrophinopathy. Also, 20 were eligible for exon skipping of exon 51, 21 for exon 53, 12 for exon 45 and another 70 for premature stop codon read-through therapy. We determined that 87.5% of DMD patients will restore the reading frame with the skipping of only one exon. Regarding nonsense variants, UGA turned out to be the most frequent premature stop codon observed (47%). According to the meta-analysis, only four LA countries (Argentina, Brazil, Colombia and Mexico) provide the complete molecular algorithm for dystrophinopathies. We observed different relations among the available targets for exon skipping in the analyzed populations, but a more even proportion of nonsense variants (∼40%). In conclusion, this manuscript describes the theragnosis carried out in Argentinian dystrophinopathy patients. The implemented molecular algorithm proved to be efficient for the achievement of differential diagnosis, which plays a crucial role in patient management, determination of the standard of care and genetic counseling. Finally, this work contributes with the international efforts to characterize the frequencies and variants in LA, pillars of drug development and theragnosis.
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Affiliation(s)
- Leonela Luce
- Laboratorio de Distrofinopatías, Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Inmunología, Genética y Metabolismo (INIGEM), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Micaela Carcione
- Laboratorio de Distrofinopatías, Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Inmunología, Genética y Metabolismo (INIGEM), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Chiara Mazzanti
- Laboratorio de Distrofinopatías, Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Inmunología, Genética y Metabolismo (INIGEM), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Paula I Buonfiglio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) "Dr. Héctor N. Torres", CONICET, Buenos Aires, Argentina
| | - Viviana Dalamón
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) "Dr. Héctor N. Torres", CONICET, Buenos Aires, Argentina
| | - Lilia Mesa
- Instituto de Neurociencias, Fundación Favaloro, Buenos Aires, Argentina
| | - Alberto Dubrovsky
- Instituto de Neurociencias, Fundación Favaloro, Buenos Aires, Argentina
| | - José Corderí
- Instituto de Neurociencias, Fundación Favaloro, Buenos Aires, Argentina
| | - Florencia Giliberto
- Laboratorio de Distrofinopatías, Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Inmunología, Genética y Metabolismo (INIGEM), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
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7
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Intrafamilial phenotypic heterogeneity related to a new DMD splice site variant. Neuromuscul Disord 2021; 31:788-797. [PMID: 34312044 DOI: 10.1016/j.nmd.2021.05.013] [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: 08/16/2020] [Revised: 05/21/2021] [Accepted: 05/26/2021] [Indexed: 11/20/2022]
Abstract
Dystrophinopathies are a group of X-linked neuromuscular disorders that result from pathogenic variants in the DMD gene. Their pathophysiological substrate is the defective expression of dystrophin in many tissues. While patients from the same pedigree usually present similar dystrophin expression and clinical course, the extent of cardiac and skeletal muscle involvement may not correlate in the same individual. We identified a new splice site variant c.2803+5G>C (NM_004006) ClinVar VCV000803902, located in intron 22 of DMD in a Brazilian family that present a broad phenotypic and histological heterogeneity. One of the subjects had a typical Duchenne muscular dystrophy (DMD) phenotype, whereas the others had Becker muscular dystrophy (BMD). Cardiac involvement was remarkable in some of the BMD patients, but not in the DMD patient. Western blot analysis of skeletal muscle revealed much lower levels of calsequestrin in the most severely affected patient compared to his brother, whose phenotype is BMD, highlighting the potential role of proteins involved in skeletal muscle calcium homeostasis in differential degrees of dystrophinopathies.
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8
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Torella A, Zanobio M, Zeuli R, del Vecchio Blanco F, Savarese M, Giugliano T, Garofalo A, Piluso G, Politano L, Nigro V. The position of nonsense mutations can predict the phenotype severity: A survey on the DMD gene. PLoS One 2020; 15:e0237803. [PMID: 32813700 PMCID: PMC7437896 DOI: 10.1371/journal.pone.0237803] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/03/2020] [Indexed: 12/23/2022] Open
Abstract
A nonsense mutation adds a premature stop signal that hinders any further translation of a protein-coding gene, usually resulting in a null allele. To investigate the possible exceptions, we used the DMD gene as an ideal model. First, because dystrophin absence causes Duchenne muscular dystrophy (DMD), while its reduction causes Becker muscular dystrophy (BMD). Second, the DMD gene is X-linked and there is no second allele that can interfere in males. Third, databases are accumulating reports on many mutations and phenotypic data. Finally, because DMD mutations may have important therapeutic implications. For our study, we analyzed large databases (LOVD, HGMD and ClinVar) and literature and revised critically all data, together with data from our internal patients. We totally collected 2593 patients. Positioning these mutations along the dystrophin transcript, we observed a nonrandom distribution of BMD-associated mutations within selected exons and concluded that the position can be predictive of the phenotype. Nonsense mutations always cause DMD when occurring at any point in fifty-one exons. In the remaining exons, we found milder BMD cases due to early 5’ nonsense mutations, if reinitiation can occur, or due to late 3’ nonsense when the shortened product retains functionality. In the central part of the gene, all mutations in some in-frame exons, such as in exons 25, 31, 37 and 38 cause BMD, while mutations in exons 30, 32, 34 and 36 cause DMD. This may have important implication in predicting the natural history and the efficacy of therapeutic use of drug-stimulated translational readthrough of premature termination codons, also considering the action of internal natural rescuers. More in general, our survey confirm that a nonsense mutation should be not necessarily classified as a null allele and this should be considered in genetic counselling.
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Affiliation(s)
- Annalaura Torella
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania “Luigi Vanvitelli”, Napoli, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Mariateresa Zanobio
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania “Luigi Vanvitelli”, Napoli, Italy
| | - Roberta Zeuli
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania “Luigi Vanvitelli”, Napoli, Italy
| | | | - Marco Savarese
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania “Luigi Vanvitelli”, Napoli, Italy
- Folkhälsan Research Center, Medicum, University of Helsinki, Helsinki, Finland
| | - Teresa Giugliano
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania “Luigi Vanvitelli”, Napoli, Italy
| | - Arcomaria Garofalo
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania “Luigi Vanvitelli”, Napoli, Italy
| | - Giulio Piluso
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania “Luigi Vanvitelli”, Napoli, Italy
| | - Luisa Politano
- Dipartimento di Medicina Sperimentale, Università degli Studi della Campania “Luigi Vanvitelli”, Napoli, Italy
| | - Vincenzo Nigro
- Dipartimento di Medicina di Precisione, Università degli Studi della Campania “Luigi Vanvitelli”, Napoli, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- * E-mail:
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9
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Predominance of Dystrophinopathy Genotypes in Mexican Male Patients Presenting as Muscular Dystrophy with A Normal Multiplex Polymerase Chain Reaction DMD Gene Result: A Study Including Targeted Next-Generation Sequencing. Genes (Basel) 2019; 10:genes10110856. [PMID: 31671740 PMCID: PMC6895915 DOI: 10.3390/genes10110856] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 01/02/2023] Open
Abstract
The complete mutational spectrum of dystrophinopathies and limb-girdle muscular dystrophy (LGMD) remains unknown in Mexican population. Seventy-two unrelated Mexican male patients (73% of pediatric age) with clinical suspicion of muscular dystrophy and no evidence of DMD gene deletion on multiplex polymerase chain reaction (mPCR) analysis were analyzed by multiplex ligation-dependent probe amplification (MLPA). Those with a normal result were subjected to Sanger sequencing or to next-generation sequencing for DMD plus 10 selected LGMD-related genes. We achieved a diagnostic genotype in 80.5% (n = 58/72) of patients with predominance of dystrophinopathy-linked genotypes (68%, n = 49/72), followed by autosomal recessive LGMD-related genotypes (types 2A-R1, 2C-R5, 2E-R4, 2D-R3 and 2I-R9; 12.5%, n = 9/72). MLPA showed 4.2% of false-negatives for DMD deletions assessed by mPCR. Among the small DMD variants, 96.5% (n = 28/29) corresponded to null-alleles, most of which (72%) were inherited through a carrier mother. The FKRP p.[Leu276Ile]; [Asn463Asp] genotype is reported for the first time in Mexican patients as being associated with dilated cardiomyopathy. Absence of dysferlinopathies could be related to the small sample size and/or the predominantly pediatric age of patients. The employed strategy seems to be an affordable diagnosis approach for Mexican muscular dystrophy male patients and their families.
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10
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Tomar S, Moorthy V, Sethi R, Chai J, Low PS, Hong STK, Lai PS. Mutational spectrum of dystrophinopathies in Singapore: Insights for genetic diagnosis and precision therapy. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2019; 181:230-244. [DOI: 10.1002/ajmg.c.31704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/21/2019] [Accepted: 04/22/2019] [Indexed: 12/26/2022]
Affiliation(s)
- Swati Tomar
- Department of Paediatrics, Yong Loo Lin School of MedicineNational University of Singapore Singapore
| | - Vikaesh Moorthy
- Yong Loo Lin School of MedicineNational University of Singapore Singapore
| | - Raman Sethi
- Department of Paediatrics, Yong Loo Lin School of MedicineNational University of Singapore Singapore
| | - Josiah Chai
- Department of Neurology, National Neuroscience Institute Singapore
| | - Poh Sim Low
- Department of Paediatrics, Yong Loo Lin School of MedicineNational University of Singapore Singapore
| | - Stacey Tay Kiat Hong
- Department of Paediatrics, Yong Loo Lin School of MedicineNational University of Singapore Singapore
| | - Poh San Lai
- Department of Paediatrics, Yong Loo Lin School of MedicineNational University of Singapore Singapore
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11
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Aartsma-Rus A, Hegde M, Ben-Omran T, Buccella F, Ferlini A, Gallano P, Howell RR, Leturcq F, Martin AS, Potulska-Chromik A, Saute JA, Schmidt WM, Sejersen T, Tuffery-Giraud S, Uyguner ZO, Witcomb LA, Yau S, Nelson SF. Evidence-Based Consensus and Systematic Review on Reducing the Time to Diagnosis of Duchenne Muscular Dystrophy. J Pediatr 2019; 204:305-313.e14. [PMID: 30579468 DOI: 10.1016/j.jpeds.2018.10.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/27/2018] [Accepted: 10/24/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Madhuri Hegde
- Department of Human Genetics, Emory University School of Medicine/School of Biological Sciences, Georgia Institute of Technology/Perkin Elmer Genetics, Atlanta, GA
| | - Tawfeg Ben-Omran
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | | | | | - Pia Gallano
- U705 CIBERER, Servei de Genetica, Hospital de Sant Pau, Barcelona, Spain
| | | | - France Leturcq
- Department of Genetics and Molecular Biology, Hospitalier Universitaire Paris Centre, Cochin Hospital, Paris, France
| | - Ann S Martin
- Parent Project Muscular Dystrophy, Hackensack, NJ
| | | | - Jonas A Saute
- Medical Genetics and Neurology Services, Hospital de Clinicas de Porto Alegre/Internal Medicine Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Wolfgang M Schmidt
- Neuromuscular Research Department, Medical University of Vienna, Vienna, Austria
| | - Thomas Sejersen
- Department of Women's and Children's Health, Karolinska Institute/Astrid Lindgrens Barnsjukhus, Karolinska University Hospital, Stockholm, Sweden
| | - Sylvie Tuffery-Giraud
- Laboratory of Rare Genetic Diseases (LGMR), University of Montpellier, Montpellier, France
| | - Zehra Oya Uyguner
- Department of Medical Genetics, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | | | - Shu Yau
- Viapath Analytics, Guy's Hospital, London, United Kingdom
| | - Stanley F Nelson
- Department of Human Genetics, University of California, Los Angeles, CA.
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