scholarly journals Molecular and Clinical Implications of Variant Repeats in Myotonic Dystrophy Type 1

2021 ◽  
Vol 23 (1) ◽  
pp. 354
Author(s):  
Stojan Peric ◽  
Jovan Pesovic ◽  
Dusanka Savic-Pavicevic ◽  
Vidosava Rakocevic Stojanovic ◽  
Giovanni Meola
Keyword(s):  
Dna Methylation ◽  
Myotonic Dystrophy ◽  
Age At Onset ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Structural Variations ◽  
Ctg Repeats ◽  
Monogenic Diseases ◽  
Additional Level

Myotonic dystrophy type 1 (DM1) is one of the most variable monogenic diseases at phenotypic, genetic, and epigenetic level. The disease is multi-systemic with the age at onset ranging from birth to late age. The underlying mutation is an unstable expansion of CTG repeats in the DMPK gene, varying in size from 50 to >1000 repeats. Generally, large expansions are associated with an earlier age at onset. Additionally, the most severe, congenital DM1 form is typically associated with local DNA methylation. Genetic variability of DM1 mutation is further increased by its structural variations due to presence of other repeats (e.g., CCG, CTC, CAG). These variant repeats or repeat interruptions seem to confer an additional level of epigenetic variability since local DNA methylation is frequently associated with variant CCG repeats independently of the expansion size. The effect of repeat interruptions on DM1 molecular pathogenesis is not investigated enough. Studies on patients indicate their stabilizing effect on DMPK expansions because no congenital cases were described in patients with repeat interruptions, and the age at onset is frequently later than expected. Here, we review the clinical relevance of repeat interruptions in DM1 and genetic and epigenetic characteristics of interrupted DMPK expansions based on patient studies.

scholarly journals Molecular Genetics and Genetic Testing in Myotonic Dystrophy Type 1

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Dušanka Savić Pavićević ◽  
Jelena Miladinović ◽  
Miloš Brkušanin ◽  
Saša Šviković ◽  
Svetlana Djurica ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Molecular Genetics ◽  
Myotonic Dystrophy ◽  
Age At Onset ◽  
Gender Effect ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Ctg Repeats ◽  
Parental Gender

Myotonic dystrophy type 1 (DM1) is the most common adult onset muscular dystrophy, presenting as a multisystemic disorder with extremely variable clinical manifestation, from asymptomatic adults to severely affected neonates. A striking anticipation and parental-gender effect upon transmission are distinguishing genetic features in DM1 pedigrees. It is an autosomal dominant hereditary disease associated with an unstable expansion of CTG repeats in the 3′-UTR of theDMPKgene, with the number of repeats ranging from 50 to several thousand. The number of CTG repeats broadly correlates with both the age-at-onset and overall severity of the disease. Expanded DM1 alleles are characterized by a remarkable expansion-biased and gender-specific germline instability, and tissue-specific, expansion-biased, age-dependent, and individual-specific somatic instability. Mutational dynamics in male and female germline account for observed anticipation and parental-gender effect in DM1 pedigrees, while mutational dynamics in somatic tissues contribute toward the tissue-specificity and progressive nature of the disease. Genetic test is routinely used in diagnostic procedure for DM1 for symptomatic, asymptomatic, and prenatal testing, accompanied with appropriate genetic counseling and, as recommended, without predictive information about the disease course. We review molecular genetics of DM1 with focus on those issues important for genetic testing and counseling.

scholarly journals Neuropathology does not Correlate with Regional Differences in the Extent of Expansion of CTG Repeats in the Brain with Myotonic Dystrophy Type 1

2010 ◽  
Vol 43 (6) ◽  
pp. 149-156 ◽  
Author(s):  
Kyoko Itoh ◽  
Maki Mitani ◽  
Kunihiko Kawamoto ◽  
Naonobu Futamura ◽  
Itaru Funakawa ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Regional Differences ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Ctg Repeats ◽  
The Brain

scholarly journals Inhibition of Postn Rescues Myogenesis Defects in Myotonic Dystrophy Type 1 Myoblast Model

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaopeng Shen ◽  
Zhongxian Liu ◽  
Chunguang Wang ◽  
Feng Xu ◽  
Jingyi Zhang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Myotonic Dystrophy ◽  
Cell Model ◽  
Neutralizing Antibody ◽  
Underlying Mechanism ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Ctg Repeats ◽  
Myoblast Cells

Myotonic dystrophy type 1 (DM1) is an inherited neuromuscular disease caused by expanded CTG repeats in the 3′ untranslated region (3′UTR) of the DMPK gene. The myogenesis process is defective in DM1, which is closely associated with progressive muscle weakness and wasting. Despite many proposed explanations for the myogenesis defects in DM1, the underlying mechanism and the involvement of the extracellular microenvironment remained unknown. Here, we constructed a DM1 myoblast cell model and reproduced the myogenesis defects. By RNA sequencing (RNA-seq), we discovered that periostin (Postn) was the most significantly upregulated gene in DM1 myogenesis compared with normal controls. This difference in Postn was confirmed by real-time quantitative PCR (RT-qPCR) and western blotting. Moreover, Postn was found to be significantly upregulated in skeletal muscle and myoblasts of DM1 patients. Next, we knocked down Postn using a short hairpin RNA (shRNA) in DM1 myoblast cells and found that the myogenesis defects in the DM1 group were successfully rescued, as evidenced by increases in the myotube area, the fusion index, and the expression of myogenesis regulatory genes. Similarly, Postn knockdown in normal myoblast cells enhanced myogenesis. As POSTN is a secreted protein, we treated the DM1 myoblast cells with a POSTN-neutralizing antibody and found that DM1 myogenesis defects were successfully rescued by POSTN neutralization. We also tested the myogenic ability of myoblasts in the skeletal muscle injury mouse model and found that Postn knockdown improved the myogenic ability of DM1 myoblasts. The activity of the TGF-β/Smad3 pathway was upregulated during DM1 myogenesis but repressed when inhibiting Postn with a Postn shRNA or a POSTN-neutralizing antibody, which suggested that the TGF-β/Smad3 pathway might mediate the function of Postn in DM1 myogenesis. These results suggest that Postn is a potential therapeutical target for the treatment of myogenesis defects in DM1.

Somatic instability of CTG repeats in the cerebellum of myotonic dystrophy type 1

2013 ◽  
Vol 48 (1) ◽  
pp. 105-108 ◽  
Author(s):  
Kenji Jinnai ◽  
Maki Mitani ◽  
Naonobu Futamura ◽  
Kunihiko Kawamoto ◽  
Itaru Funakawa ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Ctg Repeats ◽  
Somatic Instability

scholarly journals Towards development of a statistical framework to evaluate myotonic dystrophy type 1 mRNA biomarkers in the context of a clinical trial

2019 ◽  
Author(s):  
Adam Kurkiewicz ◽  
Anneli Cooper ◽  
Emily McIlwaine ◽  
Sarah A. Cumming ◽  
Berit Adam ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Myotonic Dystrophy ◽  
Genetic Disorder ◽  
Age At Onset ◽  
Alternative Polyadenylation ◽  
Microarray Dataset ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Statistical Framework

AbstractMyotonic dystrophy type 1 (DM1) is a rare genetic disorder, characterised by muscular dystrophy, myotonia, and other symptoms. DM1 is caused by the expansion of a CTG repeat in the 3’-untranslated region of DMPK. Longer CTG expansions are associated with greater symptom severity and earlier age at onset. The primary mechanism of pathogenesis is thought to be mediated by a gain of function of the CUG-containing RNA, that leads to trans-dysregulation of RNA metabolism of many other genes. Specifically, the alternative splicing (AS) and alternative polyadenylation (APA) of many genes is known to be disrupted. In the context of clinical trials of emerging DM1 treatments, it is important to be able to objectively quantify treatment efficacy at the level of molecular biomarkers. We show how previously described candidate mRNA biomarkers can be used to model an effective reduction in CTG length, using modern high-dimensional statistics (machine learning), and a blood and muscle mRNA microarray dataset. We show how this model could be used to detect treatment effects in the context of a clinical trial.

Expanded CTG repeats trigger miRNA alterations in Drosophila that are conserved in myotonic dystrophy type 1 patients

2012 ◽  
Vol 22 (4) ◽  
pp. 704-716 ◽  
Author(s):  
Juan M. Fernandez-Costa ◽  
Amparo Garcia-Lopez ◽  
Sheila Zuñiga ◽  
Victoria Fernandez-Pedrosa ◽  
Amelia Felipo-Benavent ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Ctg Repeats

scholarly journals The Need for Establishing a Universal CTG Sizing Method in Myotonic Dystrophy Type 1

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 757 ◽  
Author(s):  
Alfonsina Ballester-Lopez ◽  
Ian Linares-Pardo ◽  
Emma Koehorst ◽  
Judit Núñez-Manchón ◽  
Guillem Pintos-Morell ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Accurate Determination ◽  
Disease Onset ◽  
Clinical Severity ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Ctg Repeats ◽  
Long Pcr ◽  
Ctg Expansion

The number of cytosine-thymine-guanine (CTG) repeats (‘CTG expansion size’) in the 3′untranslated region (UTR) region of the dystrophia myotonica-protein kinase (DMPK) gene is a hallmark of myotonic dystrophy type 1 (DM1), which has been related to age of disease onset and clinical severity. However, accurate determination of CTG expansion size is challenging due to its characteristic instability. We compared five different approaches (heat pulse extension polymerase chain reaction [PCR], long PCR-Southern blot [with three different primers sets—1, 2 and 3] and small pool [SP]-PCR) to estimate CTG expansion size in the progenitor allele as well as the most abundant CTG expansion size, in 15 patients with DM1. Our results indicated variability between the methods (although we found no overall differences between long PCR 1 and 2 and SP-PCR, respectively). While keeping in mind the limited sample size of our patient cohort, SP-PCR appeared as the most suitable technique, with an inverse significant correlation found between CTG expansion size of the progenitor allele, as determined by this method, and age of disease onset (r = −0.734, p = 0.016). Yet, in light of the variability of the results obtained with the different methods, we propose that an international agreement is needed to determine which is the most suitable method for assessing CTG expansion size in DM1.

scholarly journals Correction of RNA-Binding Protein CUGBP1 and GSK3β Signaling as Therapeutic Approach for Congenital and Adult Myotonic Dystrophy Type 1

2019 ◽  
Vol 21 (1) ◽  
pp. 94 ◽  
Author(s):  
Lubov Timchenko
Keyword(s):  
Myotonic Dystrophy ◽  
Complex Disease ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Ctg Repeats ◽  
Toxic Rna

Myotonic dystrophy type 1 (DM1) is a complex genetic disease affecting many tissues. DM1 is caused by an expansion of CTG repeats in the 3′-UTR of the DMPK gene. The mechanistic studies of DM1 suggested that DMPK mRNA, containing expanded CUG repeats, is a major therapeutic target in DM1. Therefore, the removal of the toxic RNA became a primary focus of the therapeutic development in DM1 during the last decade. However, a cure for this devastating disease has not been found. Whereas the degradation of toxic RNA remains a preferential approach for the reduction of DM1 pathology, other approaches targeting early toxic events downstream of the mutant RNA could be also considered. In this review, we discuss the beneficial role of the restoring of the RNA-binding protein, CUGBP1/CELF1, in the correction of DM1 pathology. It has been recently found that the normalization of CUGBP1 activity with the inhibitors of GSK3 has a positive effect on the reduction of skeletal muscle and CNS pathologies in DM1 mouse models. Surprisingly, the inhibitor of GSK3, tideglusib also reduced the toxic CUG-containing RNA. Thus, the development of the therapeutics, based on the correction of the GSK3β-CUGBP1 pathway, is a promising option for this complex disease.

scholarly journals Repeat Interruptions Modify Age at Onset in Myotonic Dystrophy Type 1 by Stabilizing DMPK Expansions in Somatic Cells

2018 ◽  
Vol 9 ◽  
Author(s):  
Jovan Pešović ◽  
Stojan Perić ◽  
Miloš Brkušanin ◽  
Goran Brajušković ◽  
Vidosava Rakočević-Stojanović ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Age At Onset ◽  
Somatic Cells ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type

DNA methylation at the DMPK gene locus is associated with cognitive functions in myotonic dystrophy type 1

Epigenomics ◽  
2020 ◽  
Vol 12 (23) ◽  
pp. 2051-2064
Author(s):  
Édith Breton ◽  
Cécilia Légaré ◽  
Gayle Overend ◽  
Simon-Pierre Guay ◽  
Darren Monckton ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Myotonic Dystrophy ◽  
Cognitive Functions ◽  
Gene Locus ◽  
Blot Hybridization ◽  
Southern Blot Hybridization ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Dmpk Gene

Aim: Myotonic dystrophy type 1 (DM1) is caused by an unstable trinucleotide (CTG) expansion at the DMPK gene locus. Cognitive dysfunctions are often observed in the condition. We investigated the association between DMPK blood DNA methylation (DNAm) and cognitive functions in DM1, considering expansion length and variant repeats (VRs). Method: Data were obtained from 115 adult-onset DM1 patients. Molecular analyses consisted of pyrosequencing, small pool PCR and Southern blot hybridization. Cognitive functions were assessed by validated neuropsychological tests. Results: For patients without VRs (n = 103), blood DNAm at baseline independently contributed to predict cognitive functions 9 years later. Patients with VRs (n = 12) had different DNAm and cognitive profiles. Conclusion: DNAm allows to better understand DM1-related cognitive dysfunction etiology.

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