Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Myotonic Dystrophy”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2005

[Molecular pathways to myotonic dystrophy].

Myotonic dystrophy(DM), the most common form of adult-onset muscular dystrophy, comprises at least 2 sub-types, DM1 and DM2. DM1 is caused by the expansion of a CTG repeat located in the 3' untranslated region (3UTR) of the DM protein kinase (DMPK) gene. Recently, the expansion of a CCTG tetranucleotide repeat located in the first intron of the ZNF9 gene was identified as the mutation responsible for DM2. Since both DM1 and DM2 are caused by the expansion of repetitive sequences, some common factors that interact with these sequences might be involved in the pathogenesis of DM. MBNL (muscleblind) 1 is a candidate for such factors and is thought to be sequestered by the expanded forms of DM transcripts.

Humans↗
PubMed1997

[Clinical and molecular genetic analyses of congenital myotonic dystrophy].

Myotonic dystrophy (DM) results from the amplification of an unstable CTG repeat in the 3' untranslated region of a transcript encoding an MtPK. Infants with congenital DM are shown to have on average a greater amplification of the CTG repeat than is seen in the noncongenital DM patients. The major clinical features of congenital DM are bilateral facial weakness, hypotonia, feeding difficulties, respiratory distress, delayed motor development and mental retardation. We present 6 patients, aged 11-35 years, from unrelated 5 families with clinical symptoms of congenital DM. The four of the patients were inherited paternally and only one showed a reduction in the CTG repeat size.

Gene Amplification↗
PubMed1976

Basal metabolic rate in patients with hydrocephalus. On the cause of lowered basal metabolic rate in myotonic dystrophy.

Myotonic dystrophy seems to have a hypometabolism of non-thyroid origin. The hypometabolism could hypothetically be caused by : 1) reduction in muscle mass, 2) hydrocephalus ex vacuo, an integral part of the disorder, or 3) the basic disease process itself. Possibility 2) was explored by determining basal metabolic rate (BMR) in 41 patients with dilatation. A BMR of less than -10 per cent was found in eight cases. The ventricles were categorized in three groups according to width. No decrease in mean BMR was found in cases with a marked ventricular enlargement. Thus, ventricular dilatation per se does not seem to lead to hypometabolism.

Adult↗
PubMed1993

[Advances in molecular genetics of myotonic dystrophy].

Myotonic dystrophy (DM) is the most common muscular dystrophy affecting adults among Caucasian and Japanese populations, with an average incidence of 12.5 in 100,000 in Caucasians and 5.5 in 100,000 in the Japanese. Recently the DM gene was cloned and characterized showing homology with the family of serine-threonine protein kinase. In DM patients expansion of an unstable trinucleotide CTG repeat, located within the 3' untranslated region of DM kinase gene, is involved. In this review we outline the molecular biological aspects of DM including DNA diagnosis, anticipation, differences between paternal and maternal transmission, founder chromosome and expression of the gene.

Blotting, Southern↗
PubMed1995

Somatic cell heterogeneity between DNA extracted from lymphocytes and skeletal muscle in congenital myotonic dystrophy.

Myotonic dystrophy (DM) results from the expansion of an unstable CTG trinucleotide repeat in the 3' untranslated region of mRNA encoding a putative serine/threonine protein kinase. The degree of the CTG repeat amplification in genomic DNAs extracted from lymphocytes correlates with disease severity. We have analyzed the amplification of the CTG repeat of DNAs extracted from skeletal muscles and lymphocytes in five congenital DM patients. The amplification from skeletal muscles showed an increase of about 1.5 kb to 3.5 kb larger than that from lymphocytes in all patients. Furthermore, we have investigated the somatic instability of the CTG repeat in various tissues from a severe congenital DM patient.

Adolescent↗
PubMed2003

RNA leaching of transcription factors disrupts transcription in myotonic dystrophy.

Myotonic dystrophy type 1 (DM1) is caused by a CUGn expansion (n approximately 50 to 5000) in the 3' untranslated region of the mRNA of the DM protein kinase gene. We show that mutant RNA binds and sequesters transcription factors (TFs), with up to 90% depletion of selected TFs from active chromatin. Diverse genes are consequently reduced in expression, including the ion transporter CIC-1, which has been implicated in myotonia. When TF specificity protein 1 (Sp1) was overexpressed in DM1-affected cells, low levels of messenger RNA for CIC-1 were restored to normal. Transcription factor leaching from chromatin by mutant RNA provides a potentially unifying pathomechanistic explanation for this disease.

Binding Sites↗
PubMed1997

[Oligosaccharide abnormalities and expansion of the CTG repeat of MT-PK gene in patients with myotonic dystrophy].

Myotonic dystrophy is a hereditary disorder with multisystem abnormalities associated with expansion of the CTG repeat within the 3' non-coding region of the myotonin protein kinase. CTG repeat length has been shown to correlate with the clinical symptoms and age at onset of the disease. Plasma membrane has been considered to be one of the affected organ in MyD. The oligosaccharide abnormalities of the erythrocyte membrane, skeletal muscle membrane as well as immunoglobulin G were detected in patients with MyD. The characteristic oligosaccharide moiety of these membranes and proteins was a decrease of galactose contents and an increase of exposed N-acetylglucosamine at the non-reducing end of oligosaccharides. The degree of oligosaccharide abnormalities of the skeletal muscle from MyD patients was correlated well with the CTG expansion of MT-PK.

Acetylglucosamine↗
PubMed1995

A molecular protocol for diagnosing myotonic dystrophy.

Myotonic dystrophy (DM) is an autosomal dominant genetic disease caused by an unstable CTG repeat sequence in the 3' untranslated region of the myotonin protein kinase gene. The CTG repeat is present 5-30 times in the normal population, whereas DM patients have CTG expansions of 50 to several thousand repeats. The age of onset of the disorder and the severity of the phenotype is roughly correlated with the size of the CTG expansion. We developed a molecular protocol for the diagnosis of DM based on an initial polymerase chain reaction screen to detect normal-sized alleles and small expansions, followed by an improved Southern protocol to detect larger expansions.

Adult↗
PubMed1995

[Respiratory failure: respiratory disorder during sleep in patients with myotonic dystrophy].

Myotonic dystrophy (MyD) patients have been reported to show severe nocturnal desaturation related to sleep respiratory disorders. However, the reason of respiratory failure in MyD has remained unclear. In this study, ten patients with MyD underwent overnight polysomnography to evaluate the mechanisms which would cause respiratory failure, compared with Duchenne muscular dystrophy (DMD) patients in these three views: 1) sleep-related nocturnal desaturation, 2) histopathological evaluation of respiratory muscles, and 3) abnormalities of respiratory center. Nocturnal desaturation was more prominent in MyD rather than DMD. Apnea-hypopnea index (AHI) was higher in MyD than DMD. Type of respiratory disorder during sleep was mainly central apnea-hypopnea pattern, including Cheyne-Stokes respiration. In histopathological findings, central core change in respiratory muscle related to respiratory muscle fatigue was found less frequently in MyD than DMD. In respiratory center function, MyD showed hyporesponse to both alveolar hypercapnic and hypoxic stimulation. However, DMD showed normal response to both stimulations. We concluded that respiratory failure in patients with MyD would be attributed to respiratory center disorder rather than respiratory muscle weakness, which is the main cause of respiratory failure in patients with DMD.

Humans↗
PubMed1998

Disruption of splicing regulated by a CUG-binding protein in myotonic dystrophy.

Myotonic dystrophy (DM) is caused by a CTG expansion in the 3' untranslated region of the DM gene. One model of DM pathogenesis suggests that RNAs from the expanded allele create a gain-of-function mutation by the inappropriate binding of proteins to the CUG repeats. Data presented here indicate that the conserved heterogeneous nuclear ribonucleoprotein, CUG-binding protein (CUG-BP), may mediate the trans-dominant effect of the RNA. CUG-BP was found to bind to the human cardiac troponin T (cTNT) pre-messenger RNA and regulate its alternative splicing. Splicing of cTNT was disrupted in DM striated muscle and in normal cells expressing transcripts that contain CUG repeats. Altered expression of genes regulated posttranscriptionally by CUG-BP therefore may contribute to DM pathogenesis.

Alternative Splicing↗
PubMed1991

[Myotonic dystrophy].

Myotonic dystrophy (MD) is illustrated by a characteristic case report. MD is a dominantly inherited multi-organic disease with complete penetrance, but with highly variable expression illustrated by the near relatives of this patient. The disease usually follows a slow, progressive course. The cardinal symptoms are myotonia, muscle atrophia, cataract and a characteristic facial appearance. Cardial arrhythmias, endocrine and mental changes also occur. The liability to arrhythmias and the weakened respiratory muscles of the patients which lead to ventilatory insufficiency makes anesthesia and surgical operation risky. The diagnosis, which is made by electromyography, is easy in typical cases, but suspicion that the disease is present is seldom raised in very mild cases if there is no recognition of familial cases. Meticulous examination of near relatives of severe cases is therefore essential to take advantage of the possibilities of prenatal diagnosis recently made possible through developments in DNA technology.

Adult↗
PubMed2004

Upper airway calibre and impedance in patients with Steinert's myotonic dystrophy.

Myotonic dystrophy (MD) can be responsible for increased inspiratory muscle loading, the origin of which is debated, with some authors incriminating distal lesions and others central abnormalities. Using a recent non-invasive method based on single transient pressure-wave reflection analysis, we measured central airway calibre from the mouth to the carina and respiratory impedance in a group of adults with MD, a group of patients with sleep apnoea syndrome (SAS) but no neuromuscular disease, and a group of normal controls. All participants were awake during the measurements. We found no reduction in central airway calibre in the patients with the adult form of MD, as compared to the normal controls. These data suggest that MD may be associated with peripheral airway obstruction related to alterations in the elastic properties of the lung.

Adult↗
PubMed1993

Origin of the expansion mutation in myotonic dystrophy.

Myotonic dystrophy (DM) is caused by the expansion of a CTG trinucleotide repeat. The mutation is in complete linkage disequilibrium with a nearly two-allele insertion/deletion polymorphism, suggesting a single origin for the mutation or predisposing mutation. To trace this-ancestral event, we have studied the association of CTG repeat alleles in a normal population to alleles of the insertion/deletion polymorphism and of a (CA)n repeat marker 90 kilobases from the DM mutation. The results strongly suggest that the initial predisposing event(s) consisted of a transition from a (CTG)5 allele to an allele with 19 to 30 repeats. The heterogeneous class of (CTG)19-30 alleles which has an overall frequency of about 10%, may constitute a reservoir for recurrent DM mutations.

Alleles↗
PubMed2003

Unusual clinical findings and Complex III deficiency in a family with myotonic dystrophy.

Myotonic dystrophy type 1 (DM1), an autosomal dominant disease characterized by a CTG expansion in the 3' region of the DMPK gene in chromosome 19, is a highly heterogeneous disease. In this study, we present a family with early onset-classical type DM, and a homogeneous phenotype highlighted by severe neuromuscular symptoms and mental dysfunction with subcortical-type dementia. Neuroradiological abnormalities included brain atrophy, white matter lesions, and basal ganglia calcifications. A very large CTG triplet expansion was present in the DMPK locus in leukocytes in the three patients. One patient showed ragged-red fibers (RRF) and a defect complex III of the respiratory chain, but no mutations were found in the cytochrome b gene of mtDNA.

Age of Onset↗
PubMed1992

[Aggravation of hypoxemia in supine position in myotonic dystrophy].

Myotonic dystrophy (MyD) involves a variety of systems. Respiratory disorders are common, namely elevation of diaphragm, alveolar hypoventilation, aspiration pneumonia and sleep apnea. We evaluated respiratory involvement. The subjects were 11 patients with MyD. Also 6 patients with limb girdle muscular dystrophy (LG) were examined to be compared with MyD. Both groups had the similar activities of daily living. All of them never complained of dyspnea. Arterial blood gas studies were performed in supine position and standing position. A new evidence was found that hypoxemia was aggravated and alveolar-arterial oxygen pressure difference was increased in supine position in MyD. Next, pulmonary function tests were done in supine position and sitting position. Functional residual capacity (FRC) were more reduced in supine position in MyD compared with LG. The value to subtract closing capacity from FRC was negative in supine position in MyD, showing closing phenomenon. We propose the mechanism of the aggravation of hypoxemia may be the following. The reduction of FRC caused by respiratory muscle involvement brings out the closing phenomenon. Abnormal uneven distribution of ventilation-perfusion ratio happens and then hypoxemia is worsened in supine position in MyD.

Adult↗
PubMed2006

Misregulation of alternative splicing causes pathogenesis in myotonic dystrophy.

Myotonic dystrophy (DM), the most common form of adult onset muscular dystrophy, affects skeletal muscle, heart, and the central nervous system (CNS). Mortality results primarily from muscle wasting and cardiac arrhythmias. There are two forms of the disease: DM1 and DM2. DM1, which constitutes 98% of cases, is caused by a CTG expansion in the 3' untranslated region (UTR) of the DMPK gene. DM2 is caused by a CCTG expansion in the first intron of the ZNF9 gene. RNA containing CUG- or CCUG-expanded repeats are transcribed but are retained in the nucleus in foci. Disease pathogenesis results primarily from a gain of function of the expanded RNAs, which alter developmentally regulated alternative splicing as well as pathways of muscle differentiation. The toxic RNA has been implicated in sequestration of splicing regulators and transcription factors thereby causing specific symptoms of the disease. Here we review the proposed mechanisms for the toxic effects of the expanded repeats and discuss the molecular mechanisms of splicing misregulation and disease pathogenesis.

Alternative Splicing↗
PubMed1999

[Premutation in myotonic dystrophy].

Myotonic dystrophy(MyD) is caused by the abnormal expansion of CTG repeats in the 3' untranslated region of a gene encoding a protein kinase. Although some sporadic cases of MyD have been reported, the molecular basis of the intergenerational CTG expansion from asymptomatic parents is not fully understood. To determine the frequency of sporadic cases, we surveyed our clinical records of 40 MyD patients. Four cases with no family history were found, and we analyzed DNA extracted from the peripheral-blood lymphocytes of 2 unrelated patients and their family members. We identified 3 asymptomatic cases, 2 male and 1 female, with premutations which were genetically defined as 40 to 50 abnormal repeats of CTG. The fact that, in our study, the transmitting parents were both male may indicate that paternal transmission could be significant in sporadic MyD cases. We also reviewed the literature of premutation in triplet diseases and discussed the molecular mechanism of marked elongation in triplet repeats during transmission.

Female↗
PubMed1995

[Abnormalities of N-linked oligosaccharide moieties of glycoproteins in patients with myotonic dystrophy].

Myotonic dystrophy (MyD) is an inheritant disease which results from an abnormal expansion of trinucleotide repeat of myotonin protein kinase. MyD has been considered as one of membrane diseases as several functional disturbances were detected on the plasma membranes in patients with MyD. We reported here that some proteins and tissues in patients with MyD took only incomplete processing of N-glycans. The characteristic feature of the oligosaccharide moieties was so unique that N-glycans of glycoproteins such as immunoglobulin G, proteins on the erythrocyte membrane and the insulin receptor revealed reduced content of N-acetylneuraminic acid and galactose. In other words, these glycoproteins in patients with MyD had N-linked oligosaccharides which terminated with N-acetyglucosamine at the non-reducing ends. These specific defect of glycosylation may indicate the disturbances of the sarcoplasmic reticulum or the Golgi apparatus and be one of the factors which construct the membrane disorder observed in patients with MyD.

Glycoproteins↗