13 results on '"Myotonia Congenita pathology"'
Search Results
2. Ryanodine receptor Ca 2+ release channel post-translational modification: Central player in cardiac and skeletal muscle disease.
- Author
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Denniss A, Dulhunty AF, and Beard NA
- Subjects
- Animals, Calcium Signaling, Excitation Contraction Coupling physiology, Heart Failure genetics, Heart Failure pathology, Humans, Muscle Contraction physiology, Muscle, Skeletal metabolism, Muscle, Skeletal pathology, Myocardium metabolism, Myocardium pathology, Myotonia Congenita genetics, Myotonia Congenita pathology, Phosphorylation, Reactive Oxygen Species metabolism, Ryanodine Receptor Calcium Release Channel genetics, Sarcoplasmic Reticulum metabolism, Calcium metabolism, Heart Failure metabolism, Myotonia Congenita metabolism, Protein Processing, Post-Translational, Ryanodine Receptor Calcium Release Channel metabolism
- Abstract
Calcium release from internal stores is a quintessential event in excitation-contraction coupling in cardiac and skeletal muscle. The ryanodine receptor Ca
2+ release channel is embedded in the internal sarcoplasmic reticulum Ca2+ store, which releases Ca2+ into the cytoplasm, enabling contraction. Ryanodine receptors form the hub of a macromolecular complex extending from the extracellular space to the sarcoplasmic reticulum lumen. Ryanodine receptor activity is influenced by the integrated effects of associated co-proteins, ions, and post-translational phosphor and redox modifications. In healthy muscle, ryanodine receptors are phosphorylated and redox modified to basal levels, to support cellular function. A pathological increase in the degree of both post-translational modifications disturbs intracellular Ca2+ signalling, and is implicated in various cardiac and skeletal disorders. This review summarises our current understanding of the mechanisms linking ryanodine receptor post-translational modification to heart failure and skeletal myopathy and highlights the challenges and controversies within the field., (Copyright © 2018 Elsevier Ltd. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
3. Myotonia congenita: novel mutations in CLCN1 gene and functional characterizations in Italian patients.
- Author
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Ulzi G, Lecchi M, Sansone V, Redaelli E, Corti E, Saccomanno D, Pagliarani S, Corti S, Magri F, Raimondi M, D'Angelo G, Modoni A, Bresolin N, Meola G, Wanke E, Comi GP, and Lucchiari S
- Subjects
- Adolescent, Adult, Aged, Cell Line, Cell Membrane genetics, Cell Membrane pathology, Child, Electric Conductivity, Female, Humans, Italy, Male, Middle Aged, Myotonia Congenita pathology, Myotonia Congenita physiopathology, Patch-Clamp Techniques, Young Adult, Chloride Channels genetics, Genetic Predisposition to Disease genetics, Mutation, Missense genetics, Myotonia Congenita genetics
- Abstract
Myotonia congenita is an autosomal dominantly or recessively inherited muscle disorder causing impaired muscle relaxation and variable degrees of permanent muscle weakness, abnormal currents linked to the chloride channel gene (CLCN1) encoding the chloride channel on skeletal muscle membrane. We describe 12 novel mutations: c.1606G>C (p.Val536Leu), c.2533G>A (p.Gly845Ser), c.2434C>T (p.Gln812X), c.1499T>G (p.E500X), c.1012C>T (p.Arg338X), c.2403+1G>A, c.2840T>A (p.Val947Glu), c.1598C>T (p.Thr533Ile), c.1110delC, c.590T>A (p.Ile197Arg), c.2276insA Fs800X, c.490T>C (p.Trp164Arg) in 22 unrelated Italian patients. To further understand the functional outcome of selected missense mutations (p.Trp164Arg, p.Ile197Arg and p.Gly845Ser, and the previously reported p.Gly190Ser) we characterized the biophysical properties of mutant ion channels in tsA cell model. In the physiological range of muscle membrane potential, all the tested mutations, except p.Gly845Ser, reduced the open probability, increased the fast and slow components of deactivation and affected pore properties. This suggests a decrease in macroscopic chloride currents impairing membrane potential repolarization and causing hyperexcitability in muscle membranes. Detailed clinical features are given of the 8 patients characterized by cell electrophysiology. These data expand the spectrum of CLCN1 mutations and may contribute to genotype-phenotype correlations. Furthermore, we provide insights into the fine protein structure of ClC-1 and its physiological role in the maintenance of membrane resting potential., (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
4. Activity-induced weakness in recessive myotonia congenita with a novel (696+1G>A) mutation.
- Author
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McKay OM, Krishnan AV, Davis M, and Kiernan MC
- Subjects
- Action Potentials physiology, Adult, Electric Stimulation, Electromyography methods, Humans, Male, Median Nerve physiopathology, Median Nerve radiation effects, Muscle, Skeletal physiopathology, Muscle, Skeletal radiation effects, Myotonia Congenita pathology, Myotonia Congenita physiopathology, Reaction Time, Chloride Channels genetics, Muscle Contraction physiology, Mutation genetics, Myotonia Congenita genetics
- Abstract
Objective: To investigate the cause of the transient weakness that occurs in recessive myotonia congenita (RMC) following sustained muscle contraction., Methods: Nerve excitability studies were performed on a 35-year-old male with RMC due to a novel 696+1G>A CLCN1 mutation. The median nerve was stimulated at the wrist and compound muscle action potentials (CMAPs) were recorded from abductor pollicis brevis (APB). Stimulus-response behaviour using two stimulus durations, threshold electrotonus to 100-ms polarizing currents, a current threshold relationship and the recovery of excitability following supramaximal stimulation were recorded at rest. Excitability parameters were also recorded before and after maximal voluntary contraction (MVC) of APB against resistance for 60s. Results were compared to data obtained from 12 normal controls., Results: Baseline axonal excitability parameters were all normal, indicating that axonal function was normal at the point of stimulation. Following one minute of MVC, excitability parameters demonstrated a significant increase in threshold when compared to controls (RMC 54.9%; controls 15.5+/-3.1%). In the RMC patient, this increase in threshold was associated with a 39% reduction in the amplitude of the maximal CMAP, which remained unaffected in controls., Conclusions: The reduction in maximal CMAP is likely to represent muscle activation failure due to depolarization block, with the increase in threshold possibly reflecting a compensatory attempt by motor axons to overcome prolonged contraction-induced changes in the muscle membrane., Significance: The prolonged recovery of excitability following sustained muscle contraction is likely to be a contributing factor to symptoms of weakness and fatigue experienced by RMC patients.
- Published
- 2006
- Full Text
- View/download PDF
5. Unstable DNA in a patient with a severe form of congenital myotonic dystrophy.
- Author
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Tachi N, Ohya K, Chiba S, and Sato T
- Subjects
- Adult, Blotting, Southern, DNA blood, Electrophoresis, Polyacrylamide Gel, Female, Humans, Infant, Newborn, Muscles pathology, Myotonia Congenita pathology, Polymorphism, Genetic, DNA metabolism, Myotonia Congenita metabolism
- Abstract
Recently, an unstable DNA (expanded CTG repeat) was identified as the mutation that causes myotonic dystrophy (DM). By Southern blot analysis of DNA derived from peripheral blood, patients with congenital form of DM are shown to have greater expansion of DM specific band than is seen in the analyses of adult form of DM. We present here tissue expression of unstable DNA in an autopsied case of severe congenital form of DM. Our study revealed the largest expanding band of 19 kb was uniformly seen in various tissues from an autopsied infant with congenital form of DM.
- Published
- 1993
- Full Text
- View/download PDF
6. Congenital myotonic dystrophy; a report on thirteen cases and a review of the literature.
- Author
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Hageman AT, Gabreëls FJ, Liem KD, Renkawek K, and Boon JM
- Subjects
- Brain abnormalities, Brain pathology, Child, Preschool, Female, Humans, Infant, Infant, Newborn, Lip abnormalities, Male, Muscles pathology, Myotonia Congenita genetics, Myotonia Congenita pathology, Pregnancy, Psychomotor Performance physiology, Myotonia Congenita physiopathology
- Abstract
The congenital variant of myotonic dystrophy (CMD) is a severe disease with a high mortality. CMD is only seen in the offspring of mothers who themselves have myotonic dystrophy (MD). We present 13 patients with clinical symptoms of CMD and neuropathological findings of five of them. The most characteristic symptoms during pregnancy are reduced fetal movements and polyhydramnios. In the neonatal period generalized hypotonia, facial weakness, hyporeflexia, feeding and respiratory difficulties are present. Most of the children have a characteristic tented upper lip. The symptoms greatly diminish after a few weeks. All the children who survive the neonatal period are psychomotor retarded. On pathological examination no specific features were found in muscle tissue or in the brain. The pathogenesis and the cause of the maternal inheritance of CMD is not clear. A review of the literature is provided.
- Published
- 1993
- Full Text
- View/download PDF
7. Myotonia congenita. A histochemical and ultrastructural study in the goat: comparison with abnormalities found in human myotonia dystrophica.
- Author
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Atkinson JB, Swift LL, and Lequire VS
- Subjects
- Adolescent, Adult, Animals, Calcium analysis, Cell Fractionation, Disease Models, Animal, Female, Goats, Histocytochemistry, Humans, Male, Mitochondria analysis, Mitochondria ultrastructure, Muscles analysis, Muscles ultrastructure, Myotonia Congenita pathology, Myotonia Congenita veterinary, Myotonic Dystrophy veterinary, Sarcolemma ultrastructure, Muscles pathology, Myotonic Dystrophy pathology
- Abstract
Muscle biopsy specimens from the myotonic goat, an animal model of heritable myotonia, were examined histochemically and by electron microscopy. After Periodic acid-Schiff (PAS) staining with diastase digestion, there was increased PAS-positive material within myotonic goat fibers, as compared with those of normal goats. Myotonic muscle stained with alizarin red S, a histochemical stain for calcium, also had an increased staining reaction when compared with muscle from normal goats. Several ultrastructural abnormalities were found in myotonic goat muscle using routine osmium and uranyl acetate staining. These included increased density of the t-tubules, electron-dense material within t-tubules, proliferation and dilatation of sarcotubular elements, and abnormal mitochondria in the myotonic biopsy specimens. To further study muscle ultrastructure, ruthenium red and lanthanum were used as electron microscopic stains with specificity for membranes. There was increased density of the sarcolemma and t-tubules in myotonic muscle stained with ruthenium red as compared to normal, and lanthanum produced a darker staining reaction of the myotonic goat sarcolemma. The histochemical and ultrastructural differences between normal and myotonic goat muscle were interpreted to be consistent with a morphologic basis for the abnormal contraction-relaxation properties characteristic of myotonia.
- Published
- 1981
8. Evidence of myotonic origin of type 2B muscle fibre deficiency in myotonia and paramyotonia congenita.
- Author
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Heene R
- Subjects
- Animals, Humans, Muscles pathology, Myotonia pathology, Myotonia Congenita pathology
- Abstract
Available experimental and clinical evidence strongly suggests that deficiency in type 2B muscle fibres in generalized myotonia and paramyotonia congenita will develop consequent to lasting myotonic activity as its adequate stimulus. Type 2B fibre deficiency need not be regarded as the product of a hypothetical genetic factor.
- Published
- 1986
- Full Text
- View/download PDF
9. Muscle pathology of myotonia congenita.
- Author
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Crews J, Kaiser KK, and Brooke MH
- Subjects
- Adenosine Triphosphatases analysis, Adolescent, Adult, Female, Humans, Male, Muscles enzymology, Myotonia Congenita genetics, Muscles pathology, Myotonia Congenita pathology
- Abstract
We have investigated the muscle biopsies of 8 patients with myotonia congenita. There were 2 families with autosomal recessive inheritance (5 cases), 1 with autosomal dominant inheritance, and 2 sporadic cases. Mild abnormalities were seen with routine pathological preparations which were nondiagnostic. Histochemical studies of fiber subtypes demonstrated a complete absence of Type 2B muscle fibers in all of our patients regardless of the type of inheritance. this is the first reporot of an entity in which there is a consistent absence of a muscle fiber type, and some speculation has been made as to the possible causes.
- Published
- 1976
- Full Text
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10. Familial granulovacuolar lobular myopathy with electrical myotonia.
- Author
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Juguilon A, Chad D, Bradley WG, Adelman L, Kelemen J, Bosch P, and Munsat TL
- Subjects
- Adult, Biopsy, Diagnosis, Differential, Electromyography, Female, Humans, Lactates blood, Male, Motor Neurons physiology, Muscles pathology, Muscular Atrophy genetics, Muscular Atrophy pathology, Myotonia Congenita diagnosis, Myotonia Congenita pathology, Neural Conduction, alpha-Glucosidases metabolism, Cytoplasmic Granules ultrastructure, Myotonia Congenita genetics, Organoids ultrastructure, Synaptic Transmission, Vacuoles ultrastructure
- Abstract
We report 3 patients with a myopathy characterized by profound selective muscle wasting and weakness, electrical myotonia without clinical myotonia and an unusual muscle biopsy. Cryostat sections showed muscle fibers with vacuoles containing hematoxylinophilic granules, and 30% of type I fibers showed demarcation of their sarcoplasm into "lobules" due apparently to reorganization of myofibrillar elements. The electrical myotonia suggests an underlying muscle membrane defect. Two of the patients are siblings suggesting that the disorder may be inherited.
- Published
- 1982
- Full Text
- View/download PDF
11. A quantitative study of the muscle satellite cells in various neuromuscular disorders.
- Author
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Ishimoto S, Goto I, Ohta M, and Kuroiwa Y
- Subjects
- Adult, Amyotrophic Lateral Sclerosis pathology, Child, Child, Preschool, Female, Humans, Male, Microscopy, Electron, Middle Aged, Muscles physiology, Muscles physiopathology, Muscles ultrastructure, Muscular Dystrophies pathology, Myotonia Congenita pathology, Neuromuscular Diseases physiopathology, Reference Values, Muscles pathology, Neuromuscular Diseases pathology
- Abstract
The regenerative ability of muscles was studied in various neuromuscular disorders by quantitative electron microscopy using two indices of both the satellite cell population and the euchromatin percentage of satellite cell nucleus. Both the number of satellite cells and the euchromatin percentage were increased in polymyositis. Duchenne muscular dystrophy and myotonic dystrophy showed only an increased number of satellite cells without increased euchromatin percentage, while amyotrophic lateral sclerosis had only an increased euchromatin percentage without increased satellite cell number. These results suggest that some defects of satellite cell function probably exist in progressive muscular dystrophy and amyotrophic lateral sclerosis, while in polymyositis the muscle fiber may have the ability to regenerate completely. The euchromatin percentages of myonuclei were increased in polymyositis and Duchenne muscular dystrophy, but not in amyotrophic lateral sclerosis or myotonic dystrophy compared to those of controls. This suggests the activated function of the remaining muscle fibers in polymyositis and Duchenne muscular dystrophy.
- Published
- 1983
- Full Text
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12. Type 2B muscle fibre deficiency in myotonia and paramyotonia congenita. A genetically determined histochemical fibre type pattern?
- Author
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Heene R, Gabriel RR, Manz F, and Schimrigk K
- Subjects
- Adenosine Triphosphatases metabolism, Adolescent, Adult, Biopsy, Child, Female, Histocytochemistry, Humans, Male, Middle Aged, Muscles enzymology, Myotonia Congenita enzymology, Myotonia Congenita genetics, Syndrome, Muscles pathology, Myotonia Congenita pathology
- Abstract
The histochemical ATPase fibre type pattern was examined in muscle biopsy samples obtained from patients with recessive myotonia, paramyotonia and from one patient with dominant myotonia. Absence (less than or equal to 5%) of 2B fibres was a genuine finding in the minority of the cases. In additional cases of recessive myotonia, a deficiency (less than or equal to 15%) of 2B fibres was observed. Absence or deficiency of 2B fibres was not related to the minor myopathic alterations or to (para-)myotonic activity. It is hypothesised that absence of 2B fibres is a dominant or a recessive autosomal trait, and deficiency of 2B fibres is a recessive trait. Reported findings and our own observations suggest the possibility of a genetic combination of myotonia and absence/deficiency of 2B fibres. Implications of these hypotheses are proposed.
- Published
- 1986
- Full Text
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13. [Eulenburg's paramyotonia].
- Author
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Julien J, Vital C, Vallat JM, and Martin F
- Subjects
- Adult, Biopsy, Calcium blood, Diagnosis, Differential, Extremities, Facial Muscles, Humans, Hyperkalemia complications, Hyperkalemia diagnosis, Male, Muscles pathology, Myotonia Congenita diagnosis, Myotonia Congenita pathology, Paralysis etiology, Potassium administration & dosage, Cold Temperature, Myotonia Congenita genetics, Pharynx
- Published
- 1971
- Full Text
- View/download PDF
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