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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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Zinina E, Bulakh M, Chukhrova A, Ryzhkova O, Sparber P, Shchagina O, Polyakov A, Kutsev S. Specificities of the DMD Gene Mutation Spectrum in Russian Patients. Int J Mol Sci 2022; 23:ijms232112710. [PMID: 36361501 PMCID: PMC9658738 DOI: 10.3390/ijms232112710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/07/2022] Open
Abstract
Duchenne/Becker muscular dystrophy (DMD/BMD) is the most common form of muscular dystrophy, accounting for over 50% of all cases. In this regard, in Russia we carry out a program of selective screening for DMD/BMD, which mainly involves male patients. The main inclusion criteria are an increase in the level of creatine phosphokinase (>2000 U/L) or an established clinical diagnosis. At the first stage of screening, patients are scanned for extended deletions and duplications in the DMD gene using multiplex ligase-dependent probe amplification (MLPA SALSA P034 and P035 DMD probemix, MRC-Holland). The second stage is the search for small mutations using a custom NGS panel, which includes 31 genes responsible for various forms of limb-girdle muscular dystrophy. In a screening of 1025 families with a referral Duchenne/Becker diagnosis, pathogenic and likely pathogenic variants in the DMD gene were found in 788 families (in 76.9% of cases). In the current study, we analyzed the mutation spectrum of the DMD gene in Russian patients and noted certain differences between the examined cohort and the multi-ethnic cohort. The analysis of the DMD gene mutation spectrum is essential for patients with DMD/BMD because the exact mutation type determines the application of a specific therapeutic method.
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Dama T, Chheda P, Limaye S, Pande S, Vinarkar S. Evaluation of Single Exon Deletions in DMD/BMD: Technical and Analytical Concerns. Neurol India 2022; 70:1615-1617. [PMID: 36076667 DOI: 10.4103/0028-3886.355142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background Oftentimes, a variation at the multiplex ligation-dependent probe amplification (MLPA) probe binding site leads to improper hybridrization/ligation of the probe showing up as a deletion of an exon leading to false positive results for the detection of Duchenne muscular dystrophy (DMD)/Becker muscular dystrophy (BMD). Objective Investigating cases with single exon deletion using an alternate method [polymerase chain reaction (PCR) or sequencing] for confirmation of the deletion. Methods We evaluated males with single exon deletion (n = 49) in our study population (2015-2019). Forty-six were confirmed by an alternate method (conventional PCR/Sanger's sequencing) to confirm the deletion. Results We observed 25.12% single exon deletions in our study cohort. Further evaluation determined a false positive rate of 6.12%. Three out of 49 single exon deletions had a point mutation near the probe-binding site, indicating a false positive result. Single exon deletions, thus, need to be evaluated with extreme caution, and point mutations, if any, need to be characterized to determine the nature of their pathogenicity.
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Affiliation(s)
- Tavisha Dama
- Department of Molecular Pathology, Metropolis Healthcare Ltd., Mumbai, Maharashtra, India
| | - Pratiksha Chheda
- Department of Molecular Pathology, Metropolis Healthcare Ltd., Mumbai, Maharashtra, India
| | - Shweta Limaye
- Department of Molecular Pathology, Metropolis Healthcare Ltd., Mumbai, Maharashtra, India
| | - Shailesh Pande
- Department of Medical Genetics, Metropolis Healthcare Ltd., Mumbai, Maharashtra, India
| | - Sushant Vinarkar
- Department of Molecular Pathology, Metropolis Healthcare Ltd., Mumbai, Maharashtra, India
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Zamani G, Hosseinpour S, Ashrafi MR, Mohammadi M, Badv RS, Tavasoli AR, Akbari MG, Bereshneh AH, Malamiri RA, Heidari M. Characteristics of disease progression and genetic correlation in ambulatory Iranian boys with Duchenne muscular dystrophy. BMC Neurol 2022; 22:162. [PMID: 35501714 PMCID: PMC9059913 DOI: 10.1186/s12883-022-02687-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 04/26/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy in the pediatric population. The manifestations of this disease include progressive muscle weakness, gait dysfunction, and motor impairment, leading to a loss of ambulation by the age of 13 years. Molecular diagnosis is the standard diagnostic tool for DMD. This study aimed to investigate disease progression and genetic patterns in Iranian ambulant boys and to find the correlation between genotypes and motor function phenotypes. METHODS This study was performed on 152 DMD patients. Clinical history, including the disease phenotype, steroid therapy, and the North Star Ambulatory Assessment (NSAA) score, was taken for all the patients. Molecular diagnoses were confirmed by multiplex ligation-dependent probe amplification and next-generation sequencing tests. RESULTS A total of 152 Iranian DMD patients were examined in this study. The mean age at the time of disease onset was 4.04 ± 2.00 years, and the mean age at diagnosis was 5.05 ± 2.08 years. The mean age of ambulation loss was 10.9 years. Contracture was reported in 38.9% of cases. In terms of age, the mean total NSAA score showed a peak at 4 years of age, with a mean NSAA score of 24. Annual changes in the NSAA score were determined for all cases, based on the mutation type and exon site. Deletion mutation was found in 79.1% of cases, duplication in 6.8%, nonsense in 12.8%, and splice site in 1.4%. The most common single exon deletion was exon 44 (5.3%), and the most common multiexon deletions were attributed to exons 45-50 and exons 45-52 (4.6%). The results did not indicate any correlation between the mutation type and age at the time of disease onset, loss of ambulation age, and wheelchair dependence; however, a significant association was found between contracture and mutation type. The results showed a significant difference in the NSAA score between the deletion and nonsense groups at the age of 3 years (P = 0.04). No significant correlation was found between the phenotype and exon site. Overall, 91.1% of the study population had a history of corticosteroid use, and 54.1% showed compliance with rehabilitation therapy. CONCLUSION This study demonstrated the phenotypes and mutational features of Iranian DMD boys and provided information regarding the natural motor history of the disease, disease progression, diagnosis, and status of DMD management in Iran. The present findings can promote the development of clinical trials and future advanced molecular therapies in Iran.
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Affiliation(s)
- Gholamreza Zamani
- Pediatrics Center of Excellence, Department of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Sareh Hosseinpour
- Department of Pediatric Neurology, Vali-e-Asr Hospital, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Reza Ashrafi
- Pediatrics Center of Excellence, Department of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Mohammadi
- Pediatrics Center of Excellence, Department of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Pediatrics Center of Excellence, Department of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Reza Tavasoli
- Pediatrics Center of Excellence, Department of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Masood Ghahvechi Akbari
- Physical Medicine and Rehabilitation Department, Children's Medical Center , Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Hosseini Bereshneh
- Prenatal Diagnosis and Genetic Research Center, Dastgheib Hospital, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Reza Azizi Malamiri
- Department of Pediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Morteza Heidari
- Pediatrics Center of Excellence, Department of Pediatric Neurology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
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A population-based study of mortality due to muscular dystrophies across a 36-year period in Spain. Sci Rep 2022; 12:3750. [PMID: 35260676 PMCID: PMC8904487 DOI: 10.1038/s41598-022-07814-z] [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: 07/16/2021] [Accepted: 02/22/2022] [Indexed: 12/02/2022] Open
Abstract
Muscular dystrophies (MD) are a group of rare hereditary degenerative diseases. Our aim was to analyze the mortality pattern in Spain from 1981 to 2016 to assess the temporal trend and discern possible geographic differences using population-based data. Annual deaths related to MD were obtained from the National Statistics Institute with codes 359.1 of the ICD-9 (1981–1998) and G71.0 of the ICD-10 (1999–2016). Age-adjusted mortality rates were calculated and changes in mortality trends were identified. The standardized mortality ratios (SMR) and their respective 95% confidence intervals were calculated by district for 1999–2016. Smoothed SMRs and posterior probability were also assessed and then mapped to look for patterns or geographic distribution. All rates were expressed per 1,000,000 inhabitants. A total of 2,512 deaths (73.8% men) were identified. The age-adjusted mortality rates varied from 0.63 (95% CI 0.40–0.95) in 1981 to 1.51 (95% CI 1.17–1.93) in 2016. MD mortality showed a significant increase of 8.81% per year (95% CI 5.0–12.7) from 1981 to 1990, remaining stable afterwards. Areas with risk of death higher than expected for Spain as a whole were identified, not showing a specific regional pattern. In conclusion, the rising trend in MD mortality might be attributable to advanced improvements in diagnostic techniques leading to a rise in prevalence. Further research on the districts with the highest mortality would be necessary.
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Lingineni K, Aggarwal V, Morales JF, Conrado DJ, Corey D, Vong C, Burton J, Larkindale J, Romero K, Schmidt S, Kim S. Development of a model-based clinical trial simulation platform to optimize the design of clinical trials for Duchenne muscular dystrophy. CPT Pharmacometrics Syst Pharmacol 2022; 11:318-332. [PMID: 34877803 PMCID: PMC8923721 DOI: 10.1002/psp4.12753] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/25/2021] [Accepted: 11/23/2021] [Indexed: 12/23/2022] Open
Abstract
Early clinical trials of therapies to treat Duchenne muscular dystrophy (DMD), a fatal genetic X‐linked pediatric disease, have been designed based on the limited understanding of natural disease progression and variability in clinical measures over different stages of the continuum of the disease. The objective was to inform the design of DMD clinical trials by developing a disease progression model‐based clinical trial simulation (CTS) platform based on measures commonly used in DMD trials. Data were integrated from past studies through the Duchenne Regulatory Science Consortium founded by the Critical Path Institute (15 clinical trials and studies, 1505 subjects, 27,252 observations). Using a nonlinear mixed‐effects modeling approach, longitudinal dynamics of five measures were modeled (NorthStar Ambulatory Assessment, forced vital capacity, and the velocities of the following three timed functional tests: time to stand from supine, time to climb 4 stairs, and 10 meter walk‐run time). The models were validated on external data sets and captured longitudinal changes in the five measures well, including both early disease when function improves as a result of growth and development and the decline in function in later stages. The models can be used in the CTS platform to perform trial simulations to optimize the selection of inclusion/exclusion criteria, selection of measures, and other trial parameters. The data sets and models have been reviewed by the US Food and Drug Administration and the European Medicines Agency; have been accepted into the Fit‐for‐Purpose and Qualification for Novel Methodologies pathways, respectively; and will be submitted for potential endorsement by both agencies.
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Affiliation(s)
- Karthik Lingineni
- Department of Pharmaceutics, Center for Pharmacometrics and Systems Pharmacology, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | | | - Juan Francisco Morales
- Department of Pharmaceutics, Center for Pharmacometrics and Systems Pharmacology, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | | | - Diane Corey
- Critical Path Institute, Tucson, Arizona, USA
| | - Camille Vong
- Global Product Development, Pfizer Inc, Cambridge, Massachusetts, USA
| | | | | | | | - Stephan Schmidt
- Department of Pharmaceutics, Center for Pharmacometrics and Systems Pharmacology, College of Pharmacy, University of Florida, Orlando, Florida, USA
| | - Sarah Kim
- Department of Pharmaceutics, Center for Pharmacometrics and Systems Pharmacology, College of Pharmacy, University of Florida, Orlando, Florida, USA
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Schiava M, Amos R, VanRuiten H, McDermott MP, Martens WB, Gregory S, Mayhew A, McColl E, Tawil R, Willis T, Bushby K, Griggs RC, Guglieri M. Clinical and Genetic Characteristics in Young, Glucocorticoid-Naive Boys With Duchenne Muscular Dystrophy. Neurology 2022; 98:e390-e401. [PMID: 34857536 PMCID: PMC8793104 DOI: 10.1212/wnl.0000000000013122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 11/16/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Duchenne muscular dystrophy (DMD) is a pediatric neuromuscular disorder caused by mutations in the dystrophin gene. Genotype-phenotype associations have been examined in glucocorticoid-treated boys, but there are few data on the young glucocorticoid-naive DMD population. A sample of young glucocorticoid-naive DMD boys is described, and genotype-phenotype associations are investigated. METHODS Screening and baseline data were collected for all the participants in the Finding the Optimum Corticosteroid Regime for Duchenne Muscular Dystrophy (FOR-DMD) study, an international, multicenter, randomized, double-blind, clinical trial comparing 3 glucocorticoid regimens in glucocorticoid-naive, genetically confirmed boys with DMD between 4 and <8 years of age. RESULTS One hundred ninety-six boys were recruited. The mean ± SD age at randomization was 5.8 ± 1.0 years. The predominant mutation type was out-of-frame deletions (67.4%, 130 of 193), of which 68.5% (89 of 130) were amenable to exon skipping. The most frequent mutations were deletions amenable to exon 51 skipping (13.0%, 25 of 193). Stop codon mutations accounted for 10.4% (20 of 193). The mean age at first parental concerns was 29.8 ± 18.7 months; the mean age at genetic diagnosis was 53.9 ± 21.9 months; and the mean diagnostic delay was 25.9 ± 18.2 months. The mean diagnostic delay for boys diagnosed after an incidental finding of isolated hyperCKemia (n = 19) was 6.4 ± 7.4 months. The mean ages at independent walking and talking in sentences were 17.1 ± 4.2 and 29.0 ± 10.7 months, respectively. Median height percentiles were below the 25th percentile regardless of age group. No genotype-phenotype associations were identified expect for boys with exon 8 skippable deletions, who had better performance on time to walk/run 10 m (p = 0.02) compared to boys with deletions not amenable to skipping. DISCUSSION This study describes clinical and genetic characteristics of a sample of young glucocorticoid-naive boys with DMD. A low threshold for creatine kinase testing can lead to an earlier diagnosis. Motor and speech delays were common presenting symptoms. The effects of low pretreatment height on growth and adult height require further study. These findings may promote earlier recognition of DMD and inform study design for future clinical trials. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifier: NCT01603407.
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Affiliation(s)
- Marianela Schiava
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Rachel Amos
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Henriette VanRuiten
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Michael P McDermott
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Williams B Martens
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Stephanie Gregory
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Anna Mayhew
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Elaine McColl
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Rabi Tawil
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Tracey Willis
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Kate Bushby
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Robert C Griggs
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK
| | - Michela Guglieri
- From the John Walton Muscular Dystrophy Research Centre (M.S., A.M., K.B., M.G.), Clinical and Translational Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trusts; Great North Children Hospital (R.A., H.V.R.), Newcastle Hospitals NHS Foundation Trusts, UK; Department of Biostatistics and Computational Biology (M.P.M.) and Department of Neurology (M.P.M., W.B.M., S.G., R.T., R.C.G.), University of Rochester Medical Centre, NY; Newcastle University (E.M.); and The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust (T.W.), Oswestry, UK.
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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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9
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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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10
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Santin R, Vieira IA, Nunes JC, Benevides ML, Quadros F, Brusius-Facchin AC, Macedo G, Bertoni APS. A novel DMD intronic alteration: a potentially disease-causing variant of an intermediate muscular dystrophy phenotype. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2021; 40:93-100. [PMID: 34355126 PMCID: PMC8290513 DOI: 10.36185/2532-1900-048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
Pathogenic germline variants in DMD gene, which encodes the well-known cytoskeletal protein named dystrophin, are associated with a wide range of dystrophinopathies disorders, such as Duchenne muscular dystrophy (DMD, severe form), Becker muscular dystrophy (BMD, mild form) and intermediate muscular dystrophy (IMD). Muscle biopsy, immunohistochemistry, molecular (multiplex ligation-dependent probe amplification (MLPA)/next-generation sequencing (NGS) and Sanger methods) and in silico analyses were performed in order to identify alterations in DMD gene and protein in a patient with a clinical manifestation and with high creatine kinase levels. Herein, we described a previously unreported intronic variant in DMD and reduced dystrophin staining in the muscle biopsy. This novel DMD variant allele, c.9649+4A>T that was located in a splice donor site within intron 66. Sanger sequencing analysis from maternal DNA showed the presence of both variant c.9649+4A>T and wild-type (WT) DMD alleles. Different computational tools suggested that this nucleotide change might affect splicing through a WT donor site disruption, occurring in an evolutionarily conserved region. Indeed, we observed that this novel variant, could explain the reduced dystrophin protein levels and discontinuous sarcolemmal staining in muscle biopsy, which suggests that c.9649+4A>T allele may be re-classified as pathogenic in the future. Our data show that the c.9649+4A>T intronic sequence variant in the DMD gene may be associated with an IMD phenotype and our findings reinforce the importance of a more precise diagnosis combining muscle biopsy, molecular techniques and comprehensive in silico approaches in the clinical cases with negative results for conventional genetic analysis.
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Affiliation(s)
- Ricardo Santin
- Santa Casa de Misericórdia de Porto Alegre, (ISCMPA), Porto Alegre, Rio Grande do Sul, Brazil
| | - Igor Araujo Vieira
- Programa de Pós Graduação em Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
- Laboratório de Medicina Genômica, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil
| | - Jean Costa Nunes
- Neurodiagnostic Brazil - Floranópolis, Santa Catarina (SC), Brazil
- Departmento de Patologia, Universidade Federal de Santa Catarina (UFSC), Hospital Polydoro Ernani de São Thiago, SC, Brazil
| | - Maria Luiza Benevides
- Departmento de Neurologia, Hospital Governador Celso Ramos, Santa Catarina (SC), Brazil
| | - Fernanda Quadros
- Santa Casa de Misericórdia de Porto Alegre, (ISCMPA), Porto Alegre, Rio Grande do Sul, Brazil
| | - Ana Carolina Brusius-Facchin
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil
| | - Gabriel Macedo
- Laboratório de Medicina Genômica, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil
- Programa de Medicina Personalizada, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil
| | - Ana Paula Santin Bertoni
- Departamento de Ciências Básicas da Saúde and Laboratório de Biologia Celular, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil
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11
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Gadgil A, Raczyńska KD. U7 snRNA: A tool for gene therapy. J Gene Med 2021; 23:e3321. [PMID: 33590603 PMCID: PMC8243935 DOI: 10.1002/jgm.3321] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 01/22/2021] [Accepted: 02/09/2021] [Indexed: 12/25/2022] Open
Abstract
Most U-rich small nuclear ribonucleoproteins (snRNPs) are complexes that mediate the splicing of pre-mRNAs. U7 snRNP is an exception in that it is not involved in splicing but is a key factor in the unique 3' end processing of replication-dependent histone mRNAs. However, by introducing controlled changes in the U7 snRNA histone binding sequence and in the Sm motif, it can be used as an effective tool for gene therapy. The modified U7 snRNP (U7 Sm OPT) is thus not involved in the processing of replication-dependent histone pre-mRNA but targets splicing by inducing efficient skipping or inclusion of selected exons. U7 Sm OPT is of therapeutic importance in diseases that are an outcome of splicing defects, such as myotonic dystrophy, Duchenne muscular dystrophy, amyotrophic lateral sclerosis, β-thalassemia, HIV-1 infection and spinal muscular atrophy. The benefits of using U7 Sm OPT for gene therapy are its compact size, ability to accumulate in the nucleus without causing any toxic effects in the cells, and no immunoreactivity. The risk of transgene misregulation by using U7 Sm OPT is also low because it is involved in correcting the expression of an endogenous gene controlled by its own regulatory elements. Altogether, using U7 Sm OPT as a tool in gene therapy can ensure lifelong treatment, whereas an oligonucleotide or other drug/compound would require repeated administration. It would thus be strategic to harness these unique properties of U7 snRNP and deploy it as a tool in gene therapy.
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Affiliation(s)
- Ankur Gadgil
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of BiologyAdam Mickiewicz UniversityPoznanPoland
- Center for Advanced TechnologyAdam Mickiewicz UniversityPoznanPoland
| | - Katarzyna Dorota Raczyńska
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of BiologyAdam Mickiewicz UniversityPoznanPoland
- Center for Advanced TechnologyAdam Mickiewicz UniversityPoznanPoland
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12
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Dara M, Razban V, Talebzadeh M, Moradi S, Dianatpour M. Using CRISPR/Cas9 System to Knock out Exon 48 in DMD Gene. Avicenna J Med Biotechnol 2021; 13:54-57. [PMID: 34012519 PMCID: PMC8112140 DOI: 10.18502/ajmb.v13i2.5517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Background: Out of frame mutations in DMD gene cause Duchenne Muscular Dystrophy (DMD) which is a neuromuscular progressive genetic disorder. In DMD patients, lack of dystrophin causes progressive muscle degeneration, which results in heart and respiratory failure leading to premature death. At present, there is no certain treatment for DMD. DMD gene is the largest gene in human genome by 2.2 mega base pairs and contains 79 exons. In the past few years, gene therapy has been considered a promising DMD treatment, and among various gene-editing technologies, CRISPR/Cas9 system is shown to be more precise and reliable. The aim of this study was to assess the possibility of knocking out exon 48 by using a pair of sgRNAs. Methods: A pair of guide RNAs (gRNAs) was designed to cleave DMD gene and induce deletion of exon 48. gRNAs were transfected to the HEK-293 cell line and then the deletion in genomic DNA was analyzed by PCR and subsequent Sanger sequencing. Results: Exon 48 was successfully deleted and therefore exon 47 was joined to exon 49. Conclusion: This result indicated that CRISPR/Cas9 system could be used to edit DMD gene precisely.
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Affiliation(s)
- Mahintaj Dara
- Department of Molecular Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Vahid Razban
- Department of Molecular Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mahdieh Talebzadeh
- Department of Molecular Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sepideh Moradi
- Department of Molecular Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mehdi Dianatpour
- Department of Medical Genetics, Shiraz University of Medical Sciences, Shiraz, Iran.,Stem Cell Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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13
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Zimowski JG, Purzycka J, Pawelec M, Ozdarska K, Zaremba J. Small mutations in Duchenne/Becker muscular dystrophy in 164 unrelated Polish patients. J Appl Genet 2021; 62:289-295. [PMID: 33420945 DOI: 10.1007/s13353-020-00605-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 12/09/2020] [Accepted: 12/22/2020] [Indexed: 10/22/2022]
Abstract
In the 164 patients with Duchenne/Becker muscular dystrophy, we found 142 different small mutations including 51 novel mutations not listed in the LOVD, the UMD-DMD, the ClinVar, and the HGMD databases. Among all mutations, nonsense mutations occurred in 45.7%, frameshift mutations in 32.9%, and splicing mutations in 19.5%. Small mutations were distributed throughout the whole dystrophin gene. Splicing mutations were twice more common in BMD patients than in DMD patients. Eighty-two percent of mothers of the males affected with DMD/BMD were found to be carriers of small mutations.
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Affiliation(s)
- Janusz G Zimowski
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957, Sobieskiego 9, Warsaw, Poland. .,, Warsaw, Poland.
| | - Joanna Purzycka
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957, Sobieskiego 9, Warsaw, Poland
| | - Magdalena Pawelec
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957, Sobieskiego 9, Warsaw, Poland
| | - Katarzyna Ozdarska
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957, Sobieskiego 9, Warsaw, Poland
| | - Jacek Zaremba
- Department of Genetics, Institute of Psychiatry and Neurology, 02-957, Sobieskiego 9, Warsaw, Poland
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14
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Advances in Genetic Characterization and Genotype-Phenotype Correlation of Duchenne and Becker Muscular Dystrophy in the Personalized Medicine Era. J Pers Med 2020; 10:jpm10030111. [PMID: 32899151 PMCID: PMC7565713 DOI: 10.3390/jpm10030111] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 12/18/2022] Open
Abstract
Currently, Duchenne muscular dystrophy (DMD) and the related condition Becker muscular dystrophy (BMD) can be usually diagnosed using physical examination and genetic testing. While BMD features partially functional dystrophin protein due to in-frame mutations, DMD largely features no dystrophin production because of out-of-frame mutations. However, BMD can feature a range of phenotypes from mild to borderline DMD, indicating a complex genotype–phenotype relationship. Despite two mutational hot spots in dystrophin, mutations can arise across the gene. The use of multiplex ligation amplification (MLPA) can easily assess the copy number of all exons, while next-generation sequencing (NGS) can uncover novel or confirm hard-to-detect mutations. Exon-skipping therapy, which targets specific regions of the dystrophin gene based on a patient’s mutation, is an especially prominent example of personalized medicine for DMD. To maximize the benefit of exon-skipping therapies, accurate genetic diagnosis and characterization including genotype–phenotype correlation studies are becoming increasingly important. In this article, we present the recent progress in the collection of mutational data and optimization of exon-skipping therapy for DMD/BMD.
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15
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Wonkam‐Tingang E, Nguefack S, Esterhuizen AI, Chelo D, Wonkam A. DMD-related muscular dystrophy in Cameroon: Clinical and genetic profiles. Mol Genet Genomic Med 2020; 8:e1362. [PMID: 32543101 PMCID: PMC7434738 DOI: 10.1002/mgg3.1362] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/20/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Most of the previous studies on Duchenne Muscular Dystrophy (DMD) were conducted in Caucasian, Asian, and Arab populations. Therefore, little is known about the features of this disease in Africans. In this study, we aimed to determine the clinical characteristics of DMD, and the common mutations associated with this condition in a group of Cameroonian patients. METHODS We recruited DMD patients and performed a general physical examination on each of them. Multiplex ligand-dependant probe amplification was carried out to investigate exon deletions and duplications in the DMD gene (OMIM: 300377) of patients and their mothers. RESULTS A total of 17 male patients from 14 families were recruited, aged 14 ± 5.1 (8-23) years. The mean age at onset of symptoms was 4.6 ± 1.5 years, and the mean age at diagnosis was 12.1 ± 5.2 years. Proximal muscle weakness was noted in all patients and calf hypertrophy in the large majority of them (88.2%; 15/17). Flexion contractures were particularly frequent on the ankle (85.7%; 12/14). Wasting of shoulder girdle and thigh muscles was present in 50% (6/12) and 46.2% (6/13) of patients, respectively. No patient presented with hearing impairment. Deletions in DMD gene (OMIM: 300377) occurred in 45.5% of patients (5/11), while duplications were observed in 27.3% (3/11). Both mutation types were clustered between exons 45 and 50, and the proportion of de novo mutation was estimated at 18.2% (2/11). CONCLUSION Despite the first symptoms of DMD occurring in infancy, the diagnosis is frequently made later in adolescence, indicating an underestimation of the number of cases of DMD in Cameroon. Future screening of deletions and duplications in patients from Cameroon should focus on the distal part of the gene.
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Affiliation(s)
- Edmond Wonkam‐Tingang
- Division of Human GeneticsDepartment of PathologyUniversity of Cape TownCape TownSouth Africa
| | - Séraphin Nguefack
- Department of PaediatricsFaculty of Medicine and Biomedical SciencesUniversity of Yaoundé IYaoundéCameroon
- Paediatrics UnitDivision of Paediatric NeurologyGynaeco‐Obstetric and Paediatric HospitalYaoundéCameroon
| | - Alina I. Esterhuizen
- Division of Human GeneticsDepartment of PathologyUniversity of Cape TownCape TownSouth Africa
- National Health Laboratory ServiceGroote Schuur HospitalCape TownSouth Africa
| | - David Chelo
- Department of PaediatricsFaculty of Medicine and Biomedical SciencesUniversity of Yaoundé IYaoundéCameroon
- Division of Paediatric Cardiology, Mother and Child HospitalYaoundéCameroon
| | - Ambroise Wonkam
- Division of Human GeneticsDepartment of PathologyUniversity of Cape TownCape TownSouth Africa
- Department of MedicineUniversity of Cape TownCape TownSouth Africa
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16
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Sun C, Shen L, Zhang Z, Xie X. Therapeutic Strategies for Duchenne Muscular Dystrophy: An Update. Genes (Basel) 2020; 11:genes11080837. [PMID: 32717791 PMCID: PMC7463903 DOI: 10.3390/genes11080837] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/14/2020] [Accepted: 07/21/2020] [Indexed: 12/25/2022] Open
Abstract
Neuromuscular disorders encompass a heterogeneous group of conditions that impair the function of muscles, motor neurons, peripheral nerves, and neuromuscular junctions. Being the most common and most severe type of muscular dystrophy, Duchenne muscular dystrophy (DMD), is caused by mutations in the X-linked dystrophin gene. Loss of dystrophin protein leads to recurrent myofiber damage, chronic inflammation, progressive fibrosis, and dysfunction of muscle stem cells. Over the last few years, there has been considerable development of diagnosis and therapeutics for DMD, but current treatments do not cure the disease. Here, we review the current status of DMD pathogenesis and therapy, focusing on mutational spectrum, diagnosis tools, clinical trials, and therapeutic approaches including dystrophin restoration, gene therapy, and myogenic cell transplantation. Furthermore, we present the clinical potential of advanced strategies combining gene editing, cell-based therapy with tissue engineering for the treatment of muscular dystrophy.
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Affiliation(s)
- Chengmei Sun
- Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining 314400, China; (C.S.); (L.S.); (Z.Z.)
- Department of Medical Oncology, the Second Affiliated Hospital of Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Luoan Shen
- Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining 314400, China; (C.S.); (L.S.); (Z.Z.)
| | - Zheng Zhang
- Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining 314400, China; (C.S.); (L.S.); (Z.Z.)
| | - Xin Xie
- Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining 314400, China; (C.S.); (L.S.); (Z.Z.)
- Department of Medical Oncology, the Second Affiliated Hospital of Zhejiang University School of Medicine, Zhejiang University, Hangzhou 310009, China
- Correspondence: ; Tel.: +86-0571-87572326
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Polavarapu K, Preethish-Kumar V, Sekar D, Vengalil S, Nashi S, Mahajan NP, Thomas PT, Sadasivan A, Warrier M, Gupta A, Arunachal G, Debnath M, Keerthipriya MS, Pradeep-Chandra-Reddy C, Puttegowda A, John AP, Tavvala A, Gunasekaran S, Sathyaprabha TN, Chandra SR, Kramer B, Delhaas T, Nalini A. Mutation pattern in 606 Duchenne muscular dystrophy children with a comparison between familial and non-familial forms: a study in an Indian large single-center cohort. J Neurol 2019; 266:2177-2185. [PMID: 31139960 DOI: 10.1007/s00415-019-09380-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 05/14/2019] [Accepted: 05/16/2019] [Indexed: 10/26/2022]
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18
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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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19
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Min YL, Li H, Rodriguez-Caycedo C, Mireault AA, Huang J, Shelton JM, McAnally JR, Amoasii L, Mammen PPA, Bassel-Duby R, Olson EN. CRISPR-Cas9 corrects Duchenne muscular dystrophy exon 44 deletion mutations in mice and human cells. SCIENCE ADVANCES 2019; 5:eaav4324. [PMID: 30854433 PMCID: PMC6402849 DOI: 10.1126/sciadv.aav4324] [Citation(s) in RCA: 169] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 01/28/2019] [Indexed: 05/16/2023]
Abstract
Mutations in the dystrophin gene cause Duchenne muscular dystrophy (DMD), which is characterized by lethal degeneration of cardiac and skeletal muscles. Mutations that delete exon 44 of the dystrophin gene represent one of the most common causes of DMD and can be corrected in ~12% of patients by editing surrounding exons, which restores the dystrophin open reading frame. Here, we present a simple and efficient strategy for correction of exon 44 deletion mutations by CRISPR-Cas9 gene editing in cardiomyocytes obtained from patient-derived induced pluripotent stem cells and in a new mouse model harboring the same deletion mutation. Using AAV9 encoding Cas9 and single guide RNAs, we also demonstrate the importance of the dosages of these gene editing components for optimal gene correction in vivo. Our findings represent a significant step toward possible clinical application of gene editing for correction of DMD.
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Affiliation(s)
- Yi-Li Min
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Hui Li
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Cristina Rodriguez-Caycedo
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Alex A. Mireault
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Jian Huang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - John M. Shelton
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - John R. McAnally
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Leonela Amoasii
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Exonics Therapeutics, 490 Arsenal Way, Watertown, MA 02472, USA
| | - Pradeep P. A. Mammen
- Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Rhonda Bassel-Duby
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Eric N. Olson
- Department of Molecular Biology, Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Sen. Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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Elhawary NA, Jiffri EH, Jambi S, Mufti AH, Dannoun A, Kordi H, Khogeer A, Jiffri OH, Elhawary AN, Tayeb MT. Molecular characterization of exonic rearrangements and frame shifts in the dystrophin gene in Duchenne muscular dystrophy patients in a Saudi community. Hum Genomics 2018; 12:18. [PMID: 29631625 PMCID: PMC5891934 DOI: 10.1186/s40246-018-0152-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 04/02/2018] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND In individuals with Duchenne muscular dystrophy (DMD), exon skipping treatment to restore a wild-type phenotype or correct the frame shift of the mRNA transcript of the dystrophin (DMD) gene are mutation-specific. To explore the molecular characterization of DMD rearrangements and predict the reading frame, we simultaneously screened all 79 DMD gene exons of 45 unrelated male DMD patients using a multiplex ligation-dependent probe amplification (MLPA) assay for deletion/duplication patterns. Multiplex PCR was used to confirm single deletions detected by the MLPA. RESULTS There was an obvious diagnostic delay, with an extremely statistically significant difference between the age at initial symptoms and the age of clinical evaluation of DMD cases (t value, 10.3; 95% confidence interval 5.95-8.80, P < 0.0001); the mean difference between the two groups was 7.4 years. Overall, we identified 147 intragenic rearrangements: 46.3% deletions and 53.7% duplications. Most of the deletions (92.5%) were between exons 44 and 56, with exon 50 being the most frequently involved (19.1%). Eight new rearrangements, including a mixed deletion/duplication and double duplications, were linked to seven cases with DMD. Of all the cases, 17.8% had duplications with no hot spots. In addition, confirmation of the reading frame hypothesis helped account for new DMD rearrangements in this study. We found that 81% of our Saudi patients would potentially benefit from exon skipping, of which 42.9% had a mutation amenable to skipping of exon 51. CONCLUSIONS Our study could generate considerable data on mutational rearrangements that may promote future experimental therapies in Saudi Arabia.
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Affiliation(s)
- Nasser A Elhawary
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia.
- Department of Molecular Genetics, Faculty of Medicine, Ain Shams University, Cairo, 11566, Egypt.
| | - Essam H Jiffri
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdul-Aziz University, Jeddah, Saudi Arabia
| | - Samira Jambi
- Department of Pediatrics, Al Hada Military Hospital, Al Hada, Saudi Arabia
| | - Ahmad H Mufti
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia
| | - Anas Dannoun
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia
| | - Hassan Kordi
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia
| | - Asim Khogeer
- Department of Plan and Research, General Directorate of Health Affairs, Mecca Region, Ministry of Health, Mecca, Saudi Arabia
| | - Osama H Jiffri
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdul-Aziz University, Jeddah, Saudi Arabia
| | | | - Mohammed T Tayeb
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia
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Molecular characterization of exonic rearrangements and frame shifts in the dystrophin gene in Duchenne muscular dystrophy patients in a Saudi community. Hum Genomics 2018. [PMID: 29631625 DOI: 10.1186/s40246-018-0152-8]] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In individuals with Duchenne muscular dystrophy (DMD), exon skipping treatment to restore a wild-type phenotype or correct the frame shift of the mRNA transcript of the dystrophin (DMD) gene are mutation-specific. To explore the molecular characterization of DMD rearrangements and predict the reading frame, we simultaneously screened all 79 DMD gene exons of 45 unrelated male DMD patients using a multiplex ligation-dependent probe amplification (MLPA) assay for deletion/duplication patterns. Multiplex PCR was used to confirm single deletions detected by the MLPA. RESULTS There was an obvious diagnostic delay, with an extremely statistically significant difference between the age at initial symptoms and the age of clinical evaluation of DMD cases (t value, 10.3; 95% confidence interval 5.95-8.80, P < 0.0001); the mean difference between the two groups was 7.4 years. Overall, we identified 147 intragenic rearrangements: 46.3% deletions and 53.7% duplications. Most of the deletions (92.5%) were between exons 44 and 56, with exon 50 being the most frequently involved (19.1%). Eight new rearrangements, including a mixed deletion/duplication and double duplications, were linked to seven cases with DMD. Of all the cases, 17.8% had duplications with no hot spots. In addition, confirmation of the reading frame hypothesis helped account for new DMD rearrangements in this study. We found that 81% of our Saudi patients would potentially benefit from exon skipping, of which 42.9% had a mutation amenable to skipping of exon 51. CONCLUSIONS Our study could generate considerable data on mutational rearrangements that may promote future experimental therapies in Saudi Arabia.
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