scholarly journals Genetic Variation Analysis and Treatment Strategy of 20 Patients with Dystrophin Gene Mutations

2020 ◽  
Author(s):  
Yedan Liu ◽  
Jun Chen ◽  
Mei Hou ◽  
Yanhui Zhang ◽  
Ya Guo ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Clinical Manifestation ◽  
De Novo ◽  
Point Mutations ◽  
Clinical Manifestations ◽  
Gene Mutations ◽  
Dystrophin Gene ◽  
Elevated Concentration ◽  
Genetic Sequencing ◽  
First Time

Abstract Background. Dystrophin (DMD) gene mutations canaffect muscular dystrophin isoform expression and result in progressive muscular dystrophy including Duchenne and Becker muscular dystrophies (DMD and BMD). To establish the correlation between phenotype and genotype and exemplify the current and future treatment for muscular dystrophy disorders, we investigated 20 patients suffering from a dystrophinopathy andsummarized clinical manifestation and gene mutations of them. Case presentation.The clinical manifestations, physical examination, laboratory work, and gene mutation results were collected in 20 patients with DMD or BMD diagnosed by clinical phenotype and genetic sequencing from July 2015 to December 2019. Multiplex ligation probe amplification (MLPA) and next-generation sequencing (NGS) were used to detect mutations in the DMD gene, and detected mutations were confirmed by Sanger sequencing. The clinical manifestation of patients was characterized by progressive symmetrical muscle degeneration, limb weakness, and pseudohypertrophy along with the elevated concentration of creatine kinase, alanine aminotransferase,and aspartate aminotransferase.We found 11 dystrophin gene deletions (55%) and 4 duplication mutations (20%) among the affected patients. However, we also found point mutations including 1 nonsense (20%), 3 frameshifts (60%), and 1 splice sites (20%) mutations in the rest 5 patients. Among the 15 cases of exon deletion or duplication mutations, 7 were inherited from the mother, 3 were de-novo, while the other 5 were not tested. Besides, all 5 point-mutation cases were inherited from the mother, among which 4 point mutations were identified for the first time and linked to the disease phenotype. Conclusions.We provided clinical portraits, genetic results, and the molecular effects of mutations in patients. Four novel point mutations were identified for the first time and associated with the development of DMD and BMD. Further, we expanded knowledge of the DMD variant spectrum and exemplified the emerging therapies in muscular dystrophy.

scholarly journals Genetic Variation Analysis and Treatment Strategy of 20 Patients with Dystrophin Gene Mutations

2020 ◽  
Author(s):  
Yedan Liu ◽  
Jun Chen ◽  
Mei Hou ◽  
Yanhui Zhang ◽  
Ya Guo ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Clinical Manifestation ◽  
De Novo ◽  
Point Mutations ◽  
Clinical Manifestations ◽  
Gene Mutations ◽  
Dystrophin Gene ◽  
Elevated Concentration ◽  
Genetic Sequencing ◽  
First Time

Abstract BackgroundDystrophin (DMD) gene mutations can affect muscular dystrophin isoform expression and result in progressive muscular dystrophy including Duchenne and Becker muscular dystrophies (DMD and BMD). To establish the correlation between phenotype and genotype and exemplify the current and future treatment for muscular dystrophy disorders, we investigated 20 patients suffering from a dystrophinopathy and summarized clinical manifestation and gene mutations of them. MethodsThe clinical manifestations, physical examination, laboratory work, and gene mutation results were collected in 20 patients with DMD or BMD diagnosed by clinical phenotype and genetic sequencing from July 2015 to December 2019. Multiplex ligation probe amplification (MLPA) and next-generation sequencing (NGS) were used to detect mutations in the DMD gene, and detected mutations were confirmed by Sanger sequencing. ResultsThe clinical manifestation of patients was characterized by progressive symmetrical muscle degeneration, limb weakness, and pseudohypertrophy along with the elevated concentration of creatine kinase, alanine aminotransferase, and aspartate aminotransferase. We found 11 dystrophin gene deletions (55%) and 4 duplication mutations (20%) among the affected patients. However, we also found point mutations including 1 nonsense (20%), 3 frameshifts (60%), and 1 splice sites (20%) mutations in the rest 5 patients. Among the 15 cases of exon deletion or duplication mutations, 7 were inherited from the mother, 3 were de-novo, while the other 5 were not tested. Besides, all 5 point-mutation cases were inherited from the mother, among which 4 point mutations were identified for the first time and linked to the disease phenotype. ConclusionsWe provided clinical portraits, genetic results, and the molecular effects of mutations in patients. Four novel point mutations were identified for the first time and associated with the development of DMD and BMD. Further, we expanded knowledge of the DMD variant spectrum and exemplified the emerging therapies in muscular dystrophy.

scholarly journals Genetic Variation Analysis and Treatment Strategy of 20 Patients with Dystrophin Gene Mutations

2020 ◽  
Author(s):  
Yedan Liu ◽  
Jun Chen ◽  
Mei Hou ◽  
Yanhui Zhang ◽  
Ya Guo ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Clinical Manifestation ◽  
De Novo ◽  
Point Mutations ◽  
Clinical Manifestations ◽  
Gene Mutations ◽  
Dystrophin Gene ◽  
Elevated Concentration ◽  
Genetic Sequencing ◽  
First Time

Abstract Introduction.Dystrophin (DMD) gene mutations can affect muscular dystrophin isoform expression and result in progressive muscular dystrophy including Duchenne and Becker muscular dystrophies (DMD and BMD). To establish the correlation between phenotype and genotype and exemplify the current and future treatment for muscular dystrophy disorders, we investigated 20 patients suffering from a dystrophinopathy and summarized clinical manifestation and gene mutations of them.Methods.The clinical manifestations, physical examination, laboratory work, and gene mutation results were collected in 20 patients with DMD or BMD diagnosed by clinical phenotype and genetic sequencing from July 2015 to December 2019. Multiplex ligation probe amplification (MLPA) and next-generation sequencing (NGS) were used to detect mutations in the DMD gene, and detected mutations were confirmed by Sanger sequencing.Results.The clinical manifestation of patients was characterized by progressive symmetrical muscle degeneration, limb weakness, and pseudohypertrophy along with the elevated concentration of creatine kinase, alanine aminotransferase, and aspartate aminotransferase. We found 11 dystrophin gene deletions (55%) and 4 duplication mutations (20%) among the affected patients. However, we also found point mutations including 1 nonsense (20%), 3 frameshifts (60%), and 1 splice sites (20%) mutations in the rest 5 patients. Among the 15 cases of exon deletion or duplication mutations, 7 were inherited from the mother, 3 were de-novo, while the other 5 were not tested. Besides, all 5 point-mutation cases were inherited from the mother, among which 4 point mutations were identified for the first time and linked to the disease phenotype.Conclusions.We provided clinical portraits, genetic results, and the molecular effects of mutations in patients. Four novel point mutations were identified for the first time and associated with the development of DMD and BMD. Further, we expanded knowledge of the DMD variant spectrum and exemplified the emerging therapies in muscular dystrophy.

scholarly journals Early Diagnosis and Treatment – The Use of Ataluren in the Effective Management of Duchenne Muscular Dystrophy

2018 ◽  
Vol 13 (1) ◽  
pp. 31
Author(s):  
Eugenio Mercuri ◽  
Ros Quinlivan ◽  
Sylvie Tuffery-Giraud
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
De Novo ◽  
Point Mutations ◽  
Dystrophin Gene ◽  
Phase Iii ◽  
Female Carrier ◽  
De Novo Mutations ◽  
Nonsense Mutations ◽  
Disease Modifying

The understanding of the natural history of Duchenne muscular dystrophy (DMD) is increasing rapidly and new treatments are emerging that have the potential to substantially improve the prognosis for patients with this disabling and life-shortening disease. For many, however, there is a long delay between the appearance of symptoms and DMD diagnosis, which reduces the possibility of successful treatment. DMD results from mutations in the large dystrophin gene of which one-third are de novo mutations and two-thirds are inherited from a female carrier. Roughly 75% of mutations are large rearrangements and 25% are point mutations. Certain deletions and nonsense mutations can be treated whereas many other mutations cannot currently be treated. This emphasises the need for early genetic testing to identify the mutation, guide treatment and inform genetic counselling. Treatments for DMD include corticosteroids and more recently, ataluren has been approved in Europe, the first disease-modifying therapy for treating DMD caused by nonsense mutations. The use of ataluren in DMD is supported by positive results from phase IIb and phase III studies in which the treatment produced marked improvements in the 6-minute walk test, timed function tests such as the 10 m walk/run test and the 4-stair ascent/descent test compared with placebo. In these trials, ataluren was well tolerated and adverse event profiles were similar to placebo. As such disease-modifying treatments become more widely available, the outlook for children with DMD will improve but physicians must be aware of the disease, rapidly initiate testing where it is suspected and promptly begin appropriate treatment.

scholarly journals Evaluating the potential of novel genetic approaches for the treatment of Duchenne muscular dystrophy

2021 ◽  
Author(s):  
Vratko Himič ◽  
Kay E. Davies
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Structural Integrity ◽  
Viral Vector ◽  
Exon Skipping ◽  
Dystrophin Gene ◽  
Pharmacological Treatments ◽  
Genetic Sequencing ◽  
Reading Frame ◽  
Target Effects

AbstractDuchenne muscular dystrophy (DMD) is an X-linked progressive muscle-wasting disorder that is caused by a lack of functional dystrophin, a cytoplasmic protein necessary for the structural integrity of muscle. As variants in the dystrophin gene lead to a disruption of the reading frame, pharmacological treatments have only limited efficacy; there is currently no effective therapy and consequently, a significant unmet clinical need for DMD. Recently, novel genetic approaches have shown real promise in treating DMD, with advancements in the efficacy and tropism of exon skipping and surrogate gene therapy. CRISPR-Cas9 has the potential to be a ‘one-hit’ curative treatment in the coming decade. The current limitations of gene editing, such as off-target effects and immunogenicity, are in fact partly constraints of the delivery method itself, and thus research focus has shifted to improving the viral vector. In order to halt the loss of ambulation, early diagnosis and treatment will be pivotal. In an era where genetic sequencing is increasingly utilised in the clinic, genetic therapies will play a progressively central role in DMD therapy. This review delineates the relative merits of cutting-edge genetic approaches, as well as the challenges that still need to be overcome before they become clinically viable.

scholarly journals Autophagy in the heart is enhanced and independent of disease progression in mus musculus dystrophinopathy models

2019 ◽  
Vol 8 ◽  
pp. 204800401987958
Author(s):  
HR Spaulding ◽  
C Ballmann ◽  
JC Quindry ◽  
MB Hudson ◽  
JT Selsby
Keyword(s):  
Skeletal Muscle ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Disease Progression ◽  
Gene Mutations ◽  
Dystrophin Gene ◽  
Mdx Mice ◽  
Dystrophin Deficiency ◽  
Muscle Wasting Disease ◽  
Dystrophin Protein

Background Duchenne muscular dystrophy is a muscle wasting disease caused by dystrophin gene mutations resulting in dysfunctional dystrophin protein. Autophagy, a proteolytic process, is impaired in dystrophic skeletal muscle though little is known about the effect of dystrophin deficiency on autophagy in cardiac muscle. We hypothesized that with disease progression autophagy would become increasingly dysfunctional based upon indirect autophagic markers. Methods Markers of autophagy were measured by western blot in 7-week-old and 17-month-old control (C57) and dystrophic (mdx) hearts. Results Counter to our hypothesis, markers of autophagy were similar between groups. Given these surprising results, two independent experiments were conducted using 14-month-old mdx mice or 10-month-old mdx/Utrn± mice, a more severe model of Duchenne muscular dystrophy. Data from these animals suggest increased autophagosome degradation. Conclusion Together these data suggest that autophagy is not impaired in the dystrophic myocardium as it is in dystrophic skeletal muscle and that disease progression and related injury is independent of autophagic dysfunction.

scholarly journals Cardiac Involvement in Dystrophin-Deficient Females: Current Understanding and Implications for the Treatment of Dystrophinopathies

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 765 ◽  
Author(s):  
Kenji Rowel Q. Lim ◽  
Narin Sheri ◽  
Quynh Nguyen ◽  
Toshifumi Yokota
Keyword(s):  
Muscular Dystrophy ◽  
Molecular Mechanisms ◽  
Cardiac Involvement ◽  
Gene Mutations ◽  
Dystrophin Gene ◽  
Becker Muscular Dystrophy ◽  
Female Carrier ◽  
Daily Life Activities ◽  
Cardiac Manifestations ◽  
Available Information

Duchenne muscular dystrophy (DMD) is a fatal X-linked recessive condition caused primarily by out-of-frame mutations in the dystrophin gene. In males, DMD presents with progressive body-wide muscle deterioration, culminating in death as a result of cardiac or respiratory failure. A milder form of DMD exists, called Becker muscular dystrophy (BMD), which is typically caused by in-frame dystrophin gene mutations. It should be emphasized that DMD and BMD are not exclusive to males, as some female dystrophin mutation carriers do present with similar symptoms, generally at reduced levels of severity. Cardiac involvement in particular is a pressing concern among manifesting females, as it may develop into serious heart failure or could predispose them to certain risks during pregnancy or daily life activities. It is known that about 8% of carriers present with dilated cardiomyopathy, though it may vary from 0% to 16.7%, depending on if the carrier is classified as having DMD or BMD. Understanding the genetic and molecular mechanisms underlying cardiac manifestations in dystrophin-deficient females is therefore of critical importance. In this article, we review available information from the literature on this subject, as well as discuss the implications of female carrier studies on the development of therapies aiming to increase dystrophin levels in the heart.

Mutations in the AML1 Gene Define an Unfavorable Subgroup in Acute Myeloid Leukemia with FAB M0.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4340-4340
Author(s):  
Frank Dicker ◽  
Mirjam Klaus ◽  
Torsten Haferlach ◽  
Wolfgang Kern ◽  
Wolfgang Hiddemann ◽  
...  
Keyword(s):  
High Performance ◽  
De Novo ◽  
Mutation Screening ◽  
Point Mutations ◽  
Gene Mutations ◽  
Normal Karyotype ◽  
Runt Domain ◽  
Screening Efficiency ◽  
Genetic Aberration ◽  
Aml1 Gene

Abstract The AML1/RUNX1 gene is the most frequent target for chromosomal translocations in leukemia. Recently point mutations in the AML1 gene have been demonstrated as another mode of genetic aberration. AML1 mutations have been reported in de novo MDS and AML, as well as in therapy related MDS and AML. The AML M0 subtype has been found to be most frequently affected by sporadic AML1 gene mutations. We analysed AML1 gene mutations in a cohort of 49 M0 patients. Mutation screening was performed either with SSCP (n=21) and/or denaturating High Performance Liquid Chromatography (dHPLC) (n=33), 5 cases were analyzed by both methods. SSCP screening of exons 3–5 of the AML1 gene was carried out at the genomic level. These exons cover the socalled Runt domain, which is most frequently mutated. Fragments with aberrant mobility were sequenced. With this method 5 cases were found to be mutated. Subsequently, to improve the screening efficiency an assay using dHPLC was established. Hereby, we screened the cDNA of patient samples for mutations in amino acid codons 1–277 of the AML1b transcript, where the Runt domain is located between codons 49 and 178. All 5 cases detected by SSCP were confirmed by dHPLC. Nine mutations were detected in the cohort of 28 cases (32%) which had not been analyzed by SSCP. In total, 14 of the 49 samples (29%) tested were identified to be mutated, which is a slightly higher frequency than previously reported. In the cohort of 35 AML1 non-mutated cases 20 (57%) had a normal karyotype and 15 (43%) an aberrant karyotypes, whereas only 6 of the 14 AML1 mutated cases (43%) had a normal karyotype (p=0.001). Three of the AML1 mutated cases (21%) also had FLT3 mutations. One had an FLT3-LM, one an FLT3-TKD mutation, and one case both LM and TKD mutations. Clinical follow up data were available for 33 patients (22 AML1 non- mutated, 11 AML1 mutated). The median OS and EFS of the AML1 non-mutated versus the mutated group was 276 days versus 63 days (p = 0.0679) and 276 vs. 63 days (p=0.0630) respectively. Thus the AML1 mutated cases tend to have a worse clinical outcome. When other AML subtypes were screened for AML1 mutations, i.e. M1 (n=26), M2 (n=21) and M4 (n=3), only 1 additional AML1 mutation was detected, confirming the highest prevalence of AML1 mutations in M0. In conclusion, 1) we established a new assay to screen for AML1 mutations. 2) We confirmed the high incidence of AML1 gene mutations in AML M0, both in cases with normal and aberrant karyotype. 3) For the first time we demonstrated that AML1 mutations define an unfavorable subentity in AML M0.

scholarly journals Genotypes and Phenotypes of MEF2C Haploinsufficiency Syndrome: New Cases and Novel Point Mutations

2021 ◽  
Vol 9 ◽  
Author(s):  
Lin Wan ◽  
Xinting Liu ◽  
Linyan Hu ◽  
Huimin Chen ◽  
Yulin Sun ◽  
...  
Keyword(s):  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Point Mutations ◽  
Clinical Manifestations ◽  
Poor Performance ◽  
Genetic Alterations ◽  
Mendelian Inheritance ◽  
Whole Exome ◽  
Patients With Epilepsy ◽  
Free Status

Aim: MEF2C haploinsufficiency syndrome (MCHS) is a severe neurodevelopmental disorder. We describe the clinical phenotypes and genotypes of seven patients with MCHS to enhance the understanding of clinical manifestations and genetic alterations associated with MCHS.Method: Seven patients (6 females and 1 male, aged between 2 years 5 months and 6 years) who had MEF2C mutations, and their parents underwent trio-based whole-exome sequencing; subsequently, their clinical features were assessed. A literature review of patients with MCHS was performed by searching the PubMed and Online Mendelian Inheritance in Man databases.Results: Seven mutations were identified, of which six were unreported in the past; of the reported cases, five patients had de novo mutations but two had an undefined inheritance pattern. All patients presented delays in developmental milestones, severe intellectual disabilities and lack of speech. Six patients exhibited infantile hypotonia, five patients experienced stereotypic movements and were unable to walk, four patients exhibited poor eye contact indicative of autism and two showed poor performance. While six patients experienced seizure, five among them became seizure free after receiving anti-seizure medicine. Three patients showed a regression in their development, whereas the mothers of two patients exhibited mosaicism but were healthy without any abovementioned symptoms.Interpretation: Regression was not a common phenomenon but occurred in MCHS. The prognosis of MCHS patients with epilepsy was good, but most patients can achieve a seizure-free status. Healthy people may have low-level mosaicism and carry a pathogenic MEF2C mutation.

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