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JACC. Clinical Electrophysiology Dec 2021
Topics: Cardiac Conduction System Disease; Humans; Myotonic Dystrophy
PubMed: 34949430
DOI: 10.1016/j.jacep.2021.10.005 -
Chang Gung Medical Journal Aug 2005Myotonic dystrophies or dystrophia myotonica (DM) is a clinical syndrome that includes myotonic dystrophy type 1 (DM1), myotonic dystrophy type 2 (DM2), myotonic... (Review)
Review
Myotonic dystrophies or dystrophia myotonica (DM) is a clinical syndrome that includes myotonic dystrophy type 1 (DM1), myotonic dystrophy type 2 (DM2), myotonic dystrophy type 3 (DM3), and so forth. The terminology was recommended by the new nomenclature for myotonic dystrophies of an International Panel for Consensus. Previous studies have shown that DM1 is caused by the expansion of a cytosine-thymine-guanine (CTG) repeat in the DM protein kinase gene on chromosome 19, and DM2 is caused by an expansion of a cytosine-cytosine-thymine-guanine (CCTG) repeat in the zinc finger protein 9 (ZNF9) gene on chromosome 3. Because DM1 and DM2 have very similar clinical presentations, the diagnosis of these two disorders needs to be confirmed by molecular genetic analysis. Recently, DM3 was reported to include a multisystem myotonic disorder with frontotemporal dementia, and a linkage to chromosome 15q21-24. Although the age at onset, disease severity, and cerebral abnormality on a brain magnetic resonance spectrometry may correlate with the number of triplet repeats in the blood cells of DM1, it is too early to reach a conclusion. In Taiwan, the prevalence of DM1 is much lower than in Western countries. Previous studies have shown that the central nervous system symptomatology is correlated mainly with the white matter lesions in the brain MRI, but the CNS manifestations seem unrelated to the numbers of CTG triplet repeats in the blood cells. The inverse correlation between age at onset and CTG repeat length is significant only in patients with small expansions of about 100-250 triplet repeats. Transmission contraction of the repeat size is likely to occur in alleles with large repeats and is associated with paternal transmission. In congenital DM1, individual variability of muscle differentiation does occur, in spite of the same number of CTG repeats in the leukocytes.
Topics: Brain; Humans; Magnetic Resonance Imaging; Myotonic Dystrophy; Myotonin-Protein Kinase; Protein Serine-Threonine Kinases; Trinucleotide Repeats
PubMed: 16265841
DOI: No ID Found -
International Journal of Molecular... May 2020Myopathies represent a wide spectrum of heterogeneous diseases mainly characterized by the abnormal structure or functioning of skeletal muscle. The current paper... (Review)
Review
Myopathies represent a wide spectrum of heterogeneous diseases mainly characterized by the abnormal structure or functioning of skeletal muscle. The current paper provides a comprehensive overview of cognitive deficits observed in various myopathies by consulting the main libraries (Pubmed, Scopus and Google Scholar). This review focuses on the causal classification of myopathies and concomitant cognitive deficits. In most studies, cognitive deficits have been found after clinical observations while lesions were also present in brain imaging. Most studies refer to hereditary myopathies, mainly Duchenne muscular dystrophy (DMD), and myotonic dystrophies (MDs); therefore, most of the overview will focus on these subtypes of myopathies. Most recent bibliographical sources have been preferred.
Topics: Brain; Cognitive Dysfunction; Humans; Muscular Dystrophy, Duchenne; Myotonic Dystrophy
PubMed: 32471196
DOI: 10.3390/ijms21113795 -
Neurobiology of Disease Dec 2019Myotonic Dystrophy type 1 (DM1) is a neuromuscular disease showing strong genetic anticipation, and is caused by the expansion of a CTG repeat tract in the 3'-UTR of the... (Review)
Review
Myotonic Dystrophy type 1 (DM1) is a neuromuscular disease showing strong genetic anticipation, and is caused by the expansion of a CTG repeat tract in the 3'-UTR of the DMPK gene. Congenital Myotonic Dystrophy (CDM1) represents the most severe form of the disease, with prenatal onset, symptoms distinct from adult onset DM1, and a high rate of perinatal mortality. CDM1 is usually associated with very large CTG expansions, but this correlation is not absolute and cannot explain the distinct clinical features and the strong bias for maternal transmission. This review focuses upon the molecular and epigenetic factors that modulate disease severity and might be responsible for CDM1. Changes in the epigenetic status of the DM1 locus and in gene expression have recently been observed. Increasing evidence supports a role of a CTCF binding motif as a cis-element, upstream of the DMPK CTG tract, whereby CpG methylation of this site regulates the interaction of the insulator protein CTCF as a modulating trans-factor responsible for the inheritance and expression of CDM1.
Topics: Animals; DNA Methylation; Epigenesis, Genetic; Humans; Myotonic Dystrophy; Myotonin-Protein Kinase; Trinucleotide Repeat Expansion
PubMed: 31326502
DOI: 10.1016/j.nbd.2019.104533 -
International Journal of Molecular... Mar 2022Myotonic dystrophy type 1 (DM1) is a multisystemic disorder of genetic origin. Progressive muscular weakness, atrophy and myotonia are its most prominent neuromuscular... (Review)
Review
Myotonic dystrophy type 1 (DM1) is a multisystemic disorder of genetic origin. Progressive muscular weakness, atrophy and myotonia are its most prominent neuromuscular features, while additional clinical manifestations in multiple organs are also common. Overall, DM1 features resemble accelerated aging. There is currently no cure or specific treatment for myotonic dystrophy patients. However, in recent years a great effort has been made to identify potential new therapeutic strategies for DM1 patients. Metformin is a biguanide antidiabetic drug, with potential to delay aging at cellular and organismal levels. In DM1, different studies revealed that metformin rescues multiple phenotypes of the disease. This review provides an overview of recent findings describing metformin as a novel therapy to combat DM1 and their link with aging.
Topics: Humans; Hypoglycemic Agents; Metformin; Muscle Weakness; Myotonic Dystrophy; Phenotype
PubMed: 35270043
DOI: 10.3390/ijms23052901 -
Drug Discovery Today Dec 2018Myotonic dystrophy 1 (DM1) is a multisystemic neuromuscular disease caused by a dominantly inherited 'CTG' repeat expansion in the gene encoding DM Protein Kinase... (Review)
Review
Myotonic dystrophy 1 (DM1) is a multisystemic neuromuscular disease caused by a dominantly inherited 'CTG' repeat expansion in the gene encoding DM Protein Kinase (DMPK). The repeats are transcribed into mRNA, which forms hairpins and binds with high affinity to the Muscleblind-like (MBNL) family of proteins, sequestering them from their normal function. The loss of function of MBNL proteins causes numerous downstream effects, primarily the appearance of nuclear foci, mis-splicing, and ultimately myotonia and other clinical symptoms. Antisense and other RNA-mediated technologies have been applied to target toxic-repeat mRNA transcripts to restore MBNL protein function in DM1 models, such as cells and mice, and in humans. This technique has had promising results in DM1 therapeutics by alleviating pathogenic phenotypes.
Topics: Animals; Humans; Myotonic Dystrophy; Myotonin-Protein Kinase; RNA; RNA, Messenger
PubMed: 30086404
DOI: 10.1016/j.drudis.2018.08.004 -
Current Opinion in Genetics &... Jun 2017Myotonic dystrophy (DM) is a dominantly-inherited genetic disorder affecting skeletal muscle, heart, brain, and other organs. DM type 1 is caused by expansion of a CTG... (Review)
Review
Myotonic dystrophy (DM) is a dominantly-inherited genetic disorder affecting skeletal muscle, heart, brain, and other organs. DM type 1 is caused by expansion of a CTG triplet repeat in DMPK, whereas DM type 2 is caused by expansion of a CCTG tetramer repeat in CNBP. In both cases the DM mutations lead to expression of dominant-acting RNAs. Studies of RNA toxicity have now revealed novel mechanisms and new therapeutic targets. Preclinical data have suggested that RNA dominance is responsive to therapeutic intervention and that DM therapy can be approached at several different levels. Here we review recent efforts to alleviate RNA toxicity in DM.
Topics: Gene Expression Regulation; Genetic Therapy; Humans; Mutation; Myotonic Dystrophy; Myotonin-Protein Kinase; RNA, Antisense; RNA-Binding Proteins; Trinucleotide Repeat Expansion
PubMed: 28376341
DOI: 10.1016/j.gde.2017.03.007 -
JACC. Clinical Electrophysiology Aug 2021
Topics: Death, Sudden, Cardiac; Electrocardiography; Humans; Myotonic Dystrophy; Precision Medicine
PubMed: 34412868
DOI: 10.1016/j.jacep.2021.07.002 -
Neuroepidemiology 2022Myotonic dystrophy (DM), the most common muscular dystrophy in adults, is a group of autosomal inherited neuromuscular disorders characterized by progressive muscle... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Myotonic dystrophy (DM), the most common muscular dystrophy in adults, is a group of autosomal inherited neuromuscular disorders characterized by progressive muscle weakness, myotonia, and cardiac conduction abnormalities. Due to the different gene mutations, DM has been subclassified into DM type 1 (DM1) and type 2 (DM2). However, the prevalence studies on DM and its subtypes are insufficient.
METHODS
The PubMed (1966-2022), MEDLINE (1950-2022), Web of Science (1864-2022), and Cochrane Library (2022) databases were searched for original research articles published in English. The quality of the included studies was assessed by a checklist adapted from Strengthening the Reporting of Observational studies in Epidemiology. To derive the pooled epidemiological prevalence estimates, a meta-analysis was performed using the random-effects model. Heterogeneity was assessed using the Cochrane Q statistic and the I2 statistic.
RESULTS
A total of 17 studies were included in the systematic review and meta-analysis. Of the 17 studies evaluated, 14 studies were considered medium quality, 2 studies were considered high quality, and 1 study was considered low quality. The global prevalence of DM varied widely from 0.37 to 36.29 cases per 100,000. The pooled estimate of the prevalence of DM was 9.99 cases (95% CI: 5.62-15.53) per 100,000. The pooled estimate of the prevalence of DM1 was 9.27 cases (95% CI: 4.73-15.21) per 100,000, ranging from 0.37 to 36.29 cases per 100,000. The pooled estimate of the prevalence of DM2 was 2.29 cases (95% CI: 0.17-6.53) per 100,000, ranging from 0.00 to 24.00 cases per 100,000.
CONCLUSION
Our study provided accurate estimates of the prevalence of DM. The high heterogeneity and the lack of high-quality studies highlight the need to conduct higher quality studies on orphan diseases.
Topics: Adult; Humans; Myotonic Dystrophy; Prevalence
PubMed: 35483324
DOI: 10.1159/000524734 -
Drug Discovery Today Nov 2017Myotonic dystrophy type 1 (DM1) is a rare multisystemic neuromuscular disorder caused by expansion of CTG trinucleotide repeats in the noncoding region of the DMPK gene.... (Review)
Review
Myotonic dystrophy type 1 (DM1) is a rare multisystemic neuromuscular disorder caused by expansion of CTG trinucleotide repeats in the noncoding region of the DMPK gene. Mutant DMPK transcripts are toxic and alter gene expression at several levels. Chiefly, the secondary structure formed by CUGs has a strong propensity to capture and retain proteins, like those of the muscleblind-like (MBNL) family. Sequestered MBNL proteins cannot then fulfill their normal functions. Many therapeutic approaches have been explored to reverse these pathological consequences. Here, we review the myriad of small molecules that have been proposed for DM1, including examples obtained from computational rational design, HTS, drug repurposing, and therapeutic gene modulation.
Topics: Animals; Drug Design; Drug Repositioning; Gene Expression Regulation; High-Throughput Screening Assays; Humans; Myotonic Dystrophy; Myotonin-Protein Kinase; Trinucleotide Repeats
PubMed: 28780071
DOI: 10.1016/j.drudis.2017.07.011