scholarly journals Restoring Dystrophin Expression in Duchenne Muscular Dystrophy: Current Status of Therapeutic Approaches

2019 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
Yuko Shimizu-Motohashi ◽  
Hirofumi Komaki ◽  
Norio Motohashi ◽  
Shin’ichi Takeda ◽  
Toshifumi Yokota ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Stop Codon ◽  
Genetic Disorder ◽  
Premature Stop Codon ◽  
Exon Skipping ◽  
Current Status ◽  
Therapeutic Approaches ◽  
Dystrophin Expression

Duchenne muscular dystrophy (DMD), a rare genetic disorder characterized by progressive muscle weakness, is caused by the absence or a decreased amount of the muscle cytoskeletal protein dystrophin. Currently, several therapeutic approaches to cure DMD are being investigated, which can be categorized into two groups: therapies that aim to restore dystrophin expression, and those that aim to compensate for the lack of dystrophin. Therapies that restore dystrophin expression include read-through therapy, exon skipping, vector-mediated gene therapy, and cell therapy. Of these approaches, the most advanced are the read-through and exon skipping therapies. In 2014, ataluren, a drug that can promote ribosomal read-through of mRNA containing a premature stop codon, was conditionally approved in Europe. In 2016, eteplirsen, a morpholino-based chemical capable of skipping exon 51 in premature mRNA, received conditional approval in the USA. Clinical trials on vector-mediated gene therapy carrying micro- and mini- dystrophin are underway. More innovative therapeutic approaches include CRISPR/Cas9-based genome editing and stem cell-based cell therapies. Here we review the current status of therapeutic approaches for DMD, focusing on therapeutic approaches that can restore dystrophin.

scholarly journals Theragnosis for Duchenne Muscular Dystrophy

2021 ◽  
Vol 12 ◽  
Author(s):  
Leonela Luce ◽  
Micaela Carcione ◽  
Chiara Mazzanti ◽  
Paula I. Buonfiglio ◽  
Viviana Dalamón ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Latin American ◽  
Stop Codon ◽  
Meta Analysis ◽  
Premature Stop Codon ◽  
Exon Skipping ◽  
Corticosteroid Treatment ◽  
Severe Form

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.

scholarly journals From diagnosis to therapy in Duchenne muscular dystrophy

2020 ◽  
Vol 48 (3) ◽  
pp. 813-821 ◽  
Author(s):  
Arran Babbs ◽  
Maria Chatzopoulou ◽  
Ben Edwards ◽  
Sarah E. Squire ◽  
Isabel V.L. Wilkinson ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Wasting ◽  
Exon Skipping ◽  
Short Review ◽  
Current Status ◽  
Muscle Membrane ◽  
Therapeutic Approaches ◽  
Wasting Disease ◽  
Muscle Wasting Disease

Genetic approaches for the diagnosis and treatment of inherited muscle diseases have advanced rapidly in recent years. Many of the advances have occurred in the treatment of Duchenne muscular dystrophy (DMD), a muscle wasting disease where affected boys are typically wheelchair bound by age 12 years and generally die in their twenties from respiratory failure or cardiomyopathy. Dystrophin is a 421 kD protein which links F-actin to the extracellular matrix via the dystrophin-associated protein complex (DAPC) at the muscle membrane. In the absence of dystrophin, the DAPC is lost, making the muscle membrane more susceptible to contraction-induced injury. The identification of the gene causing DMD in 1986 resulted in improved diagnosis of the disease and the identification of hotspots for mutation. There is currently no effective treatment. However, there are several promising genetic therapeutic approaches at the preclinical stage or in clinical trials including read-through of stop codons, exon skipping, delivery of dystrophin minigenes and the modulation of expression of the dystrophin related protein, utrophin. In spite of significant progress, the problem of targeting all muscles, including diaphragm and heart at sufficiently high levels, remains a challenge. Any therapy also needs to consider the immune response and some treatments are mutation specific and therefore limited to a subgroup of patients. This short review provides a summary of the current status of DMD therapy with a particular focus on those genetic strategies that have been taken to the clinic.

Eteplirsen treatment for Duchenne muscular dystrophy

Neurology ◽  
2018 ◽  
Vol 90 (24) ◽  
pp. e2146-e2154 ◽  
Author(s):  
Jay S. Charleston ◽  
Frederick J. Schnell ◽  
Johannes Dworzak ◽  
Cas Donoghue ◽  
Sarah Lewis ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Western Blot ◽  
Reverse Transcription ◽  
Exon Skipping ◽  
Fold Increase ◽  
Cell Penetration ◽  
Reverse Transcription Pcr ◽  
Dystrophin Expression ◽  
Immunofluorescence Intensity

ObjectiveTo describe the quantification of novel dystrophin production in patients with Duchenne muscular dystrophy (DMD) after long-term treatment with eteplirsen.MethodsClinical study 202 was an observational, open-label extension of the randomized, controlled study 201 assessing the safety and efficacy of eteplirsen in patients with DMD with a confirmed mutation in the DMD gene amenable to correction by skipping of exon 51. Patients received once-weekly IV doses of eteplirsen 30 or 50 mg/kg. Upper extremity muscle biopsy samples were collected at combined study week 180, blinded, and assessed for dystrophin-related content by Western blot, Bioquant software measurement of dystrophin-associated immunofluorescence intensity, and percent dystrophin-positive fibers (PDPF). Results were contrasted with matched untreated biopsies from patients with DMD. Reverse transcription PCR followed by Sanger sequencing of newly formed slice junctions was used to confirm the mechanism of action of eteplirsen.ResultsReverse transcription PCR analysis and sequencing of the newly formed splice junction confirmed that 100% of treated patients displayed the expected skipped exon 51 sequence. In treated patients vs untreated controls, Western blot analysis of dystrophin content demonstrated an 11.6-fold increase (p = 0.007), and PDPF analysis demonstrated a 7.4-fold increase (p < 0.001). The PDPF findings were confirmed in a re-examination of the sample (15.5-fold increase, p < 0.001). Dystrophin immunofluorescence intensity was 2.4-fold greater in treated patients than in untreated controls (p < 0.001).ConclusionTaken together, the 4 assays, each based on unique evaluation mechanisms, provided evidence of eteplirsen muscle cell penetration, exon skipping, and induction of novel dystrophin expression.Classification of evidenceThis study provides Class II evidence of the muscle cell penetration, exon skipping, and induction of novel dystrophin expression by eteplirsen, as confirmed by 4 assays.

P.20.12 Gene therapy of Duchenne Muscular Dystrophy using rAAV vectors: Patterns of dystrophin expression and histological improvements

2013 ◽  
Vol 23 (9-10) ◽  
pp. 842
Author(s):  
Y. Cherel ◽  
C. Le Guiner ◽  
L. Guigand ◽  
M. Dutilleul ◽  
T. Larcher ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Dystrophin Expression

The history of muscular dystrophy: a unique story

2013 ◽  
Author(s):  
Alan E. H. Emery ◽  
Marcia L. H. Emery
Keyword(s):  
Gene Therapy ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Effective Treatment ◽  
Genetic Disorder ◽  
Protein Product ◽  
Responsible Gene ◽  
History Of ◽  
Common Genetic Disorder

Chapter 1 discusses the history of Duchenne muscular dystrophy, a serious condition and the second most common genetic disorder in many countries. Its cause was unknown until relatively recently and there has been no effective treatment. However, the responsible gene and its protein product have now been identified and gene therapy is under serious consideration.

WED 237 Phosphorodiamidate morpholino oligomers for treatment of duchenne muscular dystrophy

2018 ◽  
Vol 89 (10) ◽  
pp. A34.2-A34
Author(s):  
Maresh Kate ◽  
Tiet May ◽  
Guglieri Michela ◽  
Domingos Joana ◽  
Straub Volker ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Western Blot ◽  
Clinical Studies ◽  
Novel Mutation ◽  
Cumulative Risk ◽  
Exon Skipping ◽  
Dystrophin Expression ◽  
Polymerase Chain ◽  
Phosphorodiamidate Morpholino Oligomers

Exon skipping is a novel, mutation-specific approach to treating patients with Duchenne muscular dystrophy (DMD). Phosphorodiamidate morpholino oligomers are nucleic acid analogues that selectively redirect pre-mRNA splicing to enable production of internally truncated dystrophin.In exon 51 skipping (eteplirsen; n=36) and exon 53 skipping (golodirsen; n=25) clinical studies, internally shortened dystrophin mRNA was observed in all treated patients (per reverse transcription polymerase chain reaction). Eteplirsen increased dystrophin expression 15.5-fold, 11.6-fold, and 2.4-fold vs untreated controls (percent dystrophin-positive fibres, Western blot, and immunohistochemistry intensity, respectively; all, p≤0.007) in a 180 week study, and 2.8-fold (Western blot; p=0.008) in a 48 week study. Golodirsen increased dystrophin expression 10.7-fold (Western blot) over baseline following 48 weeks of treatment. Over 4 years, versus comparable external controls, eteplirsen slowed ambulatory decline (6 min walk test difference, 165 m; p=0.001) and cumulative risk of losing ambulation (83% vs 17%). In 2 clinical studies that included non-ambulatory patients, eteplirsen slowed pulmonary decline versus natural history data (assessed by spirometry).Eteplirsen and golodirsen demonstrated clinical and biochemical effects in patients with DMD; ongoing studies of these compounds are further characterising their effects in various patient populations.

Hybrid minigene splicing assay verified the pathogenicity of a novel splice site variant in the dystrophin gene of a Chinese patient with typical Duchenne muscular dystrophy phenotype

2016 ◽  
Vol 54 (9) ◽  
pp. 1435-1440 ◽  
Author(s):  
Zhihong Wang ◽  
Yanhong Lin ◽  
Liping Qiu ◽  
Dezhu Zheng ◽  
Aizhen Yan ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Splice Site ◽  
Sanger Sequencing ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Splice Site Mutation ◽  
Dystrophin Gene ◽  
Site Mutation ◽  
Aberrant Splicing

AbstractBackground:Duchenne muscular dystrophy (DMD) is typically caused by disrupting the reading frame of the dystrophin gene: approximately 70%–80% of mutational events are represented by deletions or duplications of one or more exons in the dystrophin gene, and the remaining cases by subtle mutations, including point mutations, small indels, small inversions, and complex small rearrangements. The dystrophin gene is the largest known gene with one of the highest known rates of new mutations.Methods:Deletions and duplications were detected in theDMDgene of the proband by using multiple ligation-dependent probe amplification (MLPA). Targeted next-generation sequencing (NGS) was used in the subtle mutation detection, followed by Sanger sequencing confirmation. The effect of the mutation on the splicing of theDMDgene was assessed by bioinformatics prediction and hybrid minigene splicing assay (HMSA).Results:Neither duplication nor deletion was found in theDMDgene of the proband. While a novel splice site mutation c.6762+1G>C was identified in the proband by NGS and Sanger sequencing, and his mother was heterozygous at the same site. Bioinformatics predicted that the 5′ donor splice site of intron 46 disappeared because of the mutation, which would lead to aberrant splicing and introduce premature stop codon. The HMSA results were in agreement with the prediction.Conclusions:The novel splice site mutation caused DMD in the proband by aberrant splicing. We suggested that combined applications of MLPA, NGS, HMSA and bioinformatics are comprehensive and effective methods for diagnosis and aberrant splicing study of DMD.

Sign in / Sign up

Export Citation Format

Share Document