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Current Opinion in Neurology Oct 2014Myotonic dystrophies type 1 and type 2 are progressive multisystem genetic disorders with clinical and genetic features in common. Myotonic dystrophy type 1 is the most... (Review)
Review
PURPOSE OF REVIEW
Myotonic dystrophies type 1 and type 2 are progressive multisystem genetic disorders with clinical and genetic features in common. Myotonic dystrophy type 1 is the most prevalent muscular dystrophy in adults and has a wide phenotypic spectrum. The average age of death in myotonic dystrophy type 1 is in the fifth decade. In comparison, myotonic dystrophy type 2 tends to cause a milder phenotype with later onset of symptoms and is less common than myotonic dystrophy type 1. Historically, patients with myotonic dystrophy type 1 have not received the medical and social input they need to maximize their quality and quantity of life. This review describes the improved understanding in the molecular and clinical features of myotonic dystrophy type 1 as well as the screening of clinical complications and their management. We will also discuss new potential genetic treatments.
RECENT FINDINGS
An active approach to screening and management of myotonic dystrophies type 1 and type 2 requires a multidisciplinary medical, rehabilitative and social team. This process will probably improve morbidity and mortality for patients. Genetic treatments have been successfully used in in-vitro and animal models to reverse the physiological, histopathological and transcriptomic features.
SUMMARY
Molecular therapeutics for myotonic dystrophy will probably bridge the translational gap between bench and bedside in the near future. There will still be a requirement for clinical screening of patients with myotonic dystrophy with proactive and systematic management of complications.
Topics: Disease Management; Humans; Myotonic Dystrophy
PubMed: 25121518
DOI: 10.1097/WCO.0000000000000128 -
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 -
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 -
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 -
Current Neurology and Neuroscience... Oct 2018To update current knowledge regarding sleep disturbances and myotonic dystrophies so as to better understand if sleep symptoms may help in the early recognition of the... (Review)
Review
PURPOSE OF REVIEW
To update current knowledge regarding sleep disturbances and myotonic dystrophies so as to better understand if sleep symptoms may help in the early recognition of the two genetic subtypes: myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2).
RECENT FINDINGS
Sleep-disordered breathing (SDB), restless legs syndrome, periodic limb movements in sleep, hypersomnia, and REM sleep dysregulation are frequently described in DM1 patients. SDB does not always explain hypersomnia, but a central dysregulation of sleep-wake modulation is reported mainly in DM1. Sleep apnea, restless legs syndrome, and REM sleep without atonia have been reported in single case reports and small case series of DM2. DM2 is less prevalent and more recently described than DM1, with a milder phenotype than DM1. The most frequent sleep disorders in DM1 are hypersomnia, SDB, periodic limb movements, and a narcoleptic-like phenotype, whereas restless legs syndrome, SDB, and REM sleep without atonia seem to be the most frequent sleep disorders in DM2. Comparative sleep studies are strongly required to delineate the sleep phenotype of myotonic dystrophies.
Topics: Humans; Myotonic Dystrophy; Sleep Apnea Syndromes; Sleep Wake Disorders; Sleep, REM
PubMed: 30382420
DOI: 10.1007/s11910-018-0903-x -
The Journal of Clinical Endocrinology... Sep 2021Myotonic dystrophy is a dominantly inherited multisystem disorder that results from increased CTG repeats in the 3' region of the myotonic dystrophy protein kinase gene... (Review)
Review
Myotonic dystrophy is a dominantly inherited multisystem disorder that results from increased CTG repeats in the 3' region of the myotonic dystrophy protein kinase gene (DMPK). The mutant DMPK mRNA remains in the nucleus and sequesters RNA-binding proteins, including regulators of mRNA splicing. Myotonic dystrophy is characterized by a highly variable phenotype that includes muscle weakness and myotonia, and the disorder may affect the function of many endocrine glands. DMPK mRNA is expressed in muscle, testis, liver, pituitary, thyroid, and bone; the mutated form leads to disruption of meiosis and an increase in fetal insulin receptor-A relative to adult insulin receptor-B, resulting in adult primary testicular failure and insulin resistance predisposing to diabetes, respectively. Patients with myotonic dystrophy are also at increased risk for hyperlipidemia, nonalcoholic fatty liver disease, erectile dysfunction, benign and malignant thyroid nodules, bone fractures, miscarriage, preterm delivery, and failed labor during delivery. Circulating parathyroid hormone and adrenocorticotropic hormone levels may be elevated, but the mechanisms for these associations are unclear. This review summarizes what is known about endocrine dysfunction in individuals with myotonic dystrophy.
Topics: Endocrine System; Endocrine System Diseases; Female; Humans; Male; Myotonic Dystrophy; Myotonin-Protein Kinase; RNA, Messenger; RNA-Binding Proteins
PubMed: 34125228
DOI: 10.1210/clinem/dgab430 -
International Journal of Molecular... Nov 2019Myotonic dystrophy involves two types of chronically debilitating rare neuromuscular diseases: type 1 (DM1) and type 2 (DM2). Both share similarities in molecular cause,... (Review)
Review
Myotonic dystrophy involves two types of chronically debilitating rare neuromuscular diseases: type 1 (DM1) and type 2 (DM2). Both share similarities in molecular cause, clinical signs, and symptoms with DM2 patients usually displaying milder phenotypes. It is well documented that key clinical symptoms in DM are associated with a strong mis-regulation of RNA metabolism observed in patient's cells. This mis-regulation is triggered by two leading DM-linked events: the sequestration of Muscleblind-like proteins (MBNL) and the mis-regulation of the CUGBP RNA-Binding Protein Elav-Like Family Member 1 (CELF1) that cause significant alterations to their important functions in RNA processing. It has been suggested that DM1 may be treatable through endogenous modulation of the expression of MBNL and CELF1 proteins. In this study, we analyzed the recent identification of the involvement of microRNA (miRNA) molecules in DM and focus on the modulation of these miRNAs to therapeutically restore normal MBNL or CELF1 function. We also discuss additional prospective miRNA targets, the use of miRNAs as disease biomarkers, and additional promising miRNA-based and miRNA-targeting drug development strategies. This review provides a unifying overview of the dispersed data on miRNA available in the context of DM.
Topics: Alternative Splicing; Animals; CELF1 Protein; Drug Discovery; Gene Expression Regulation; Genetic Therapy; Humans; MicroRNAs; Myotonic Dystrophy; RNA-Binding Proteins
PubMed: 31717488
DOI: 10.3390/ijms20225600 -
Muscle & Nerve Aug 2023Myotonic dystrophies (DMs) are autosomal dominant diseases in which expression of a mutant expanded repeat mRNA leads to abnormal splicing of downstream effector genes...
INTRODUCTION/AIMS
Myotonic dystrophies (DMs) are autosomal dominant diseases in which expression of a mutant expanded repeat mRNA leads to abnormal splicing of downstream effector genes thought to be responsible for their multisystem involvement. Cancer risk and cancer-related deaths are increased in DM patients relative to the general population. We aimed at determining the frequency and type of cancers in both DM1 and DM2 vs a non-DM muscular dystrophy cohort.
METHODS
A retrospective, cross-sectional study was carried out on patients with genetically confirmed DM1, DM2, facioscapulohumeral muscular dystrophy (FSHD), and oculopharyngeal muscular dystrophy (OPMD) at our institutions from 2000 to 2020.
RESULTS
One hundred eighty-five DM1, 67 DM2, 187 FSHD, and 109 OPMD patients were included. Relative to non-DM, DM patients had an increased cancer risk that was independent of age and sex. Specifically, an increased risk of sex-related (ovarian) and non-sex-related (non-melanoma skin, urological, and hematological) cancers was observed in DM1 and DM2, respectively. The length of CTG repeat expansion was not associated with cancer occurrence in the DM1 group.
DISCUSSION
In addition to current consensus-based care recommendations, our findings prompt consideration of screening for skin, urological, and hematological cancers in DM2 patients, and screening of ovarian malignancies in DM1 female patients.
Topics: Humans; Female; Myotonic Dystrophy; Cross-Sectional Studies; Muscular Dystrophy, Facioscapulohumeral; Retrospective Studies; Melanoma
PubMed: 36790141
DOI: 10.1002/mus.27801 -
Applied Physiology, Nutrition, and... Nov 2018Neuromuscular disorders (NMDs) are chronic conditions that affect the neuromuscular system. Many NMDs currently have no cure; however, as more effective therapies become... (Review)
Review
Neuromuscular disorders (NMDs) are chronic conditions that affect the neuromuscular system. Many NMDs currently have no cure; however, as more effective therapies become available for NMD patients, these individuals will exhibit improved health and/or prolonged lifespans. As a result, persons with NMDs will likely desire to engage in a more diverse variety of activities of daily living, including increased physical activity or exercise. Therefore, there is a need to increase our knowledge of the effects of acute exercise and chronic training on the neuromuscular system in NMD contexts. Here, we discuss the disease mechanisms and exercise biology of Duchenne muscular dystrophy (DMD), spinal muscular atrophy (SMA), and myotonic dystrophy type 1 (DM1), which are among the most prevalent NMDs in children and adults. Evidence from clinical and preclinical studies are reviewed, with emphasis on the functional outcomes of exercise, as well as on the putative cellular mechanisms that drive exercise-induced remodelling of the neuromuscular system. Continued investigation of the molecular mechanisms of exercise adaptation in DMD, SMA, and DM1 will assist in enhancing our understanding of the biology of these most prevalent NMDs. This information may also be useful for guiding the development of novel therapeutic targets for future pursuit.
Topics: Exercise; Humans; Muscular Atrophy, Spinal; Muscular Dystrophy, Duchenne; Myotonic Dystrophy
PubMed: 29944848
DOI: 10.1139/apnm-2018-0229