scholarly journals Robust Detection of Somatic Mosaicism and Repeat Interruptions by Long-Read Targeted Sequencing in Myotonic Dystrophy Type 1

2021 ◽  
Vol 22 (5) ◽  
pp. 2616
Author(s):  
Antoine Mangin ◽  
Laure de Pontual ◽  
Yu-Chih Tsai ◽  
Laetitia Monteil ◽  
Mathilde Nizon ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Trinucleotide Repeat ◽  
De Novo ◽  
Somatic Mosaicism ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Robust Detection ◽  
Long Read ◽  
Ctg Repeat

Myotonic dystrophy type 1 (DM1) is the most complex and variable trinucleotide repeat disorder caused by an unstable CTG repeat expansion, reaching up to 4000 CTG in the most severe cases. The genetic and clinical variability of DM1 depend on the sex and age of the transmitting parent, but also on the CTG repeat number, presence of repeat interruptions and/or on the degree of somatic instability. Currently, it is difficult to simultaneously and accurately determine these contributing factors in DM1 patients due to the limitations of gold standard methods used in molecular diagnostics and research laboratories. Our study showed the efficiency of the latest PacBio long-read sequencing technology to sequence large CTG trinucleotides, detect multiple and single repeat interruptions and estimate the levels of somatic mosaicism in DM1 patients carrying complex CTG repeat expansions inaccessible to most methods. Using this innovative approach, we revealed the existence of de novo CCG interruptions associated with CTG stabilization/contraction across generations in a new DM1 family. We also demonstrated that our method is suitable to sequence the DM1 locus and measure somatic mosaicism in DM1 families carrying more than 1000 pure CTG repeats. Better characterization of expanded alleles in DM1 patients can significantly improve prognosis and genetic counseling, not only in DM1 but also for other tandem DNA repeat disorders.

scholarly journals Simple Repeat-Primed PCR Analysis of the Myotonic Dystrophy Type 1 Gene in a Clinical Diagnostics Environment

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Philippa A. Dryland ◽  
Elaine Doherty ◽  
Jennifer M. Love ◽  
Donald R. Love
Keyword(s):  
Myotonic Dystrophy ◽  
Trinucleotide Repeat ◽  
Neuromuscular Disorder ◽  
Clinical Diagnostics ◽  
Pcr Analysis ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Diagnostic Laboratory ◽  
Ctg Repeat

Myotonic dystrophy type 1 is an autosomal dominant neuromuscular disorder that is caused by the expansion of a CTG trinucleotide repeat in the DMPK gene. The confirmation of a clinical diagnosis of DM-1 usually involves PCR amplification of the CTG repeat-containing region and subsequent sizing of the amplification products in order to deduce the number of CTG repeats. In the case of repeat hyperexpansions, Southern blotting is also used; however, the latter has largely been superseded by triplet repeat-primed PCR (TP-PCR), which does not yield a CTG repeat number but nevertheless provides a means of stratifying patients regarding their disease severity. We report here a combination of forward and reverse TP-PCR primers that allows for the simple and effective scoring of both the size of smaller alleles and the presence or absence of expanded repeat sequences. In addition, the CTG repeat-containing TP-PCR forward primer can target both the DM-1 and Huntington disease genes, thereby streamlining the work flow for confirmation of clinical diagnoses in a diagnostic laboratory.

Origin of the myotonic dystrophy type 1 mutation in Mexican population and influence of Amerindian ancestry on CTG repeat allelic distribution

2017 ◽  
Vol 27 (12) ◽  
pp. 1106-1114 ◽  
Author(s):  
N.M. Murillo-Melo ◽  
L.C. Márquez-Quiróz ◽  
R. Gómez ◽  
L. Orozco ◽  
E. Mendoza-Caamal ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Mexican Population ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Allelic Distribution ◽  
Ctg Repeat

scholarly journals Increased Muscleblind levels by chloroquine treatment improve myotonic dystrophy type 1 phenotypes in in vitro and in vivo models

2019 ◽  
Vol 116 (50) ◽  
pp. 25203-25213 ◽  
Author(s):  
Ariadna Bargiela ◽  
Maria Sabater-Arcis ◽  
Jorge Espinosa-Espinosa ◽  
Miren Zulaica ◽  
Adolfo Lopez de Munain ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Rna Binding ◽  
Trinucleotide Repeat ◽  
Rna Binding Proteins ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Muscle Area ◽  
In Vivo Models

Myotonic dystrophy type 1 (DM1) is a life-threatening and chronically debilitating neuromuscular disease caused by the expansion of a CTG trinucleotide repeat in the 3′ UTR of the DMPK gene. The mutant RNA forms insoluble structures capable of sequestering RNA binding proteins of the Muscleblind-like (MBNL) family, which ultimately leads to phenotypes. In this work, we demonstrate that treatment with the antiautophagic drug chloroquine was sufficient to up-regulate MBNL1 and 2 proteins in Drosophila and mouse (HSALR) models and patient-derived myoblasts. Extra Muscleblind was functional at the molecular level and improved splicing events regulated by MBNLs in all disease models. In vivo, chloroquine restored locomotion, rescued average cross-sectional muscle area, and extended median survival in DM1 flies. In HSALR mice, the drug restored muscular strength and histopathology signs and reduced the grade of myotonia. Taken together, these results offer a means to replenish critically low MBNL levels in DM1.

Leukocyte CTG repeat length correlates with severity of myotonia in myotonic dystrophy type 1

Neurology ◽  
2004 ◽  
Vol 62 (7) ◽  
pp. 1081-1089 ◽  
Author(s):  
E. L. Logigian ◽  
R. T. Moxley ◽  
C. L. Blood ◽  
C. A. Barbieri ◽  
W. B. Martens ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Repeat Length ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Ctg Repeat

scholarly journals MSH2 knock-down shows CTG repeat stability and concomitant upstream demethylation at the DMPK locus in myotonic dystrophy type 1 human embryonic stem cells

2020 ◽  
Author(s):  
Silvie Franck ◽  
Lise Barbé ◽  
Simon Ardui ◽  
Yannick De Vlaeminck ◽  
Joke Allemeersch ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Myotonic Dystrophy ◽  
Human Embryonic Stem Cells ◽  
Embryonic Stem ◽  
Cpg Methylation ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Ctg Repeat

Abstract Myotonic dystrophy type 1 (DM1) is caused by expansion of a CTG repeat in the DMPK gene, where expansion size and somatic mosaicism correlates with disease severity and age of onset. While it is known that the mismatch repair protein MSH2 contributes to the unstable nature of the repeat, its role on other disease-related features, such as CpG methylation upstream of the repeat, is unknown. In this study, we investigated the effect of an MSH2 knock-down (MSH2KD) on both CTG repeat dynamics and CpG methylation pattern in human embryonic stem cells (hESC) carrying the DM1 mutation. Repeat size in MSH2 wild type (MSH2WT) and MSH2KD DM1 hESC was determined by PacBio sequencing and CpG methylation by bisulfite massive parallel sequencing. We found stabilization of the CTG repeat concurrent with a gradual loss of methylation upstream of the repeat in MSH2KD cells, while the repeat continued to expand and upstream methylation remained unchanged in MSH2WT control lines. Repeat instability was re-established and biased towards expansions upon MSH2 transgenic re-expression in MSH2KD lines while upstream methylation was not consistently re-established. We hypothesize that the hypermethylation at the mutant DM1 locus is promoted by the MMR machinery and sustained by a constant DNA repair response, establishing a potential mechanistic link between CTG repeat instability and upstream CpG methylation. Our work represents a first step towards understanding how epigenetic alterations and repair pathways connect and contribute to the DM1 pathology.

scholarly journals Intrinsically cell-penetrating multivalent and multitargeting ligands for myotonic dystrophy type 1

2019 ◽  
Vol 116 (18) ◽  
pp. 8709-8714 ◽  
Author(s):  
JuYeon Lee ◽  
Yugang Bai ◽  
Ullas V. Chembazhi ◽  
Shaohong Peng ◽  
Kevin Yum ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Trinucleotide Repeat ◽  
Cell Penetrating Peptides ◽  
Cell Permeability ◽  
Myotonic Dystrophy Type 1 ◽  
Myotonic Dystrophy Type ◽  
Multivalent Ligands ◽  
Biological Studies ◽  
Cell Penetrating

Developing highly active, multivalent ligands as therapeutic agents is challenging because of delivery issues, limited cell permeability, and toxicity. Here, we report intrinsically cell-penetrating multivalent ligands that target the trinucleotide repeat DNA and RNA in myotonic dystrophy type 1 (DM1), interrupting the disease progression in two ways. The oligomeric ligands are designed based on the repetitive structure of the target with recognition moieties alternating with bisamidinium groove binders to provide an amphiphilic and polycationic structure, mimicking cell-penetrating peptides. Multiple biological studies suggested the success of our multivalency strategy. The designed oligomers maintained cell permeability and exhibited no apparent toxicity both in cells and in mice at working concentrations. Furthermore, the oligomers showed important activities in DM1 cells and in a DM1 liver mouse model, reducing or eliminating prominent DM1 features. Phenotypic recovery of the climbing defect in adult DM1Drosophilawas also observed. This design strategy should be applicable to other repeat expansion diseases and more generally to DNA/RNA-targeted therapeutics.

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