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Seminars in Neurology Sep 1991
Review
Topics: Adult; Diagnosis, Differential; Electromyography; Female; Humans; Male; Myotonia Congenita; Neuromuscular Diseases
PubMed: 1947488
DOI: 10.1055/s-2008-1041229 -
Ugeskrift For Laeger Sep 2004
Review
Topics: Diagnosis, Differential; Humans; Myotonia Congenita
PubMed: 15384367
DOI: No ID Found -
Muscle & Nerve 1981Fourteen patients with paramyotonia congenita were examined clinically. Patients of 3 families had no myotonia in a warm environment while in a cold environment they...
Fourteen patients with paramyotonia congenita were examined clinically. Patients of 3 families had no myotonia in a warm environment while in a cold environment they developed paradoxical myotonia (myotonia aggravated by repeated muscle contraction). Patients of a 4th family had myotonia associated with after-activity in a warm environment which was not paradoxical. This myotonia was aggravated by cooling. In a warm environment the resting muscles of all patients showed no spontaneous electromyographic activity except for occasional myotonic runs. On cooling, spontaneous fibrillations developed. This was most intense at 32 degrees C-28 degrees C (muscle temperature). On deeper cooling it ceased. In contrast, 5 patients with myotonia congenita did not show such activity during cooling. In all paramyotonic patients cooling (30 degrees C-25 degrees C) produced muscle paralysis, which outlasted rewarming by several hours. At 32 degrees C-30 degrees C muscle relaxation was slowed. Recording of electromyographic activity and isometric contractions of the long finger flexors during cooling revealed that the slowing of muscle relaxation in paramyotonia is not as closely linked to after-activity as is the slowing of muscle relaxation in myotonia congenita.
Topics: Adolescent; Adult; Aged; Child; Cold Temperature; Electromyography; Female; Hot Temperature; Humans; Lidocaine; Male; Middle Aged; Muscle Contraction; Muscle Relaxation; Myotonia Congenita; Tocainide
PubMed: 6793868
DOI: 10.1002/mus.880040507 -
Muscle & Nerve Apr 2010The aims of this study were to (1) characterize the clinical phenotype, (2) define the causative mutation, and (3) correlate the clinical phenotype with genotype in a...
Myotonia congenita in a large consanguineous Arab family: insight into the clinical spectrum of carriers and double heterozygotes of a novel mutation in the chloride channel CLCN1 gene.
The aims of this study were to (1) characterize the clinical phenotype, (2) define the causative mutation, and (3) correlate the clinical phenotype with genotype in a large consanguineous Arab family with myotonia congenita. Twenty-four family members from three generations were interviewed and examined. Genomic DNA was extracted from peripheral blood samples for sequencing the exons of the CLCN1 gene. Twelve individuals with myotonia congenita transmitted the condition in an autosomal dominant manner with incomplete penetrance. A novel missense mutation [568GG>TC (G190S)] was found in a dose-dependent clinical phenotype. Although heterozygous individuals were asymptomatic or mildly affected, the homozygous individuals were severely affected. The mutation is a glycine-to-serine residue substitution in a well-conserved motif in helix D of the CLC-1 chloride channel in the skeletal muscle plasmalemma. A novel mutation, 568GG>TC (G190S) in the CLCN1 gene, is responsible for autosomal dominant myotonia congenita with a variable phenotypic spectrum.
Topics: Adolescent; Adult; Amino Acid Sequence; Arabs; Base Sequence; Child; Chloride Channels; Consanguinity; Female; Genetic Carrier Screening; Humans; Male; Molecular Sequence Data; Mutation; Myotonia Congenita; Pedigree; Young Adult
PubMed: 19697366
DOI: 10.1002/mus.21525 -
Internal Medicine (Tokyo, Japan) Jun 1996A sporadic Japanese case of myotonia congenita with painful muscle cramps is reported. Electromyographic examinations disclosed myotonic discharge with dive bomber...
A sporadic Japanese case of myotonia congenita with painful muscle cramps is reported. Electromyographic examinations disclosed myotonic discharge with dive bomber sounds at insertion, and high-amplitude, high-frequency motor unit potentials during the muscle cramps. Biopsied muscle specimens and EMG findings showed non-specific mild myopathic changes. There was no abnormal expansion of CTG repeat within the myotonic dystrophy gene. This patient's disorder closely resembles Becker's myotonia congenita Type II though the family history of was non contributory.
Topics: Biopsy; Diagnosis, Differential; Electromyography; Glycolysis; Humans; Male; Middle Aged; Muscle Cramp; Myotonia Congenita; Myotonic Dystrophy; Pain
PubMed: 8835606
DOI: 10.2169/internalmedicine.35.507 -
Journal of Medical Genetics Apr 1998An epidemiological and genetic investigation of myotonia congenita was carried out in northern Finland. Altogether 58 patients were identified (of whom 54 lived in the...
An epidemiological and genetic investigation of myotonia congenita was carried out in northern Finland. Altogether 58 patients were identified (of whom 54 lived in the study area) in 23 families, with a prevalence of 7.3 per 100000. The majority of the families originated from a sparsely populated area in western Lapland. The mean age at onset of the disease was 11 years with a range of 2 to 45 years. The mean time that had passed before verification of the clinical disease was 18 (SD 14) years. The sex ratio M/F was 2.2/1.0. Forty-seven cases were familial and 11 were sporadic. In six families/pedigrees the inheritance was compatible with autosomal recessive and in two families with autosomal dominant inheritance. In five additional families, in which autosomal recessive inheritance seemed most plausible, vertical transmission was also noticed. This could be explained either by consanguinity of the parents or by variant expression of the mutation(s) involved. Our results suggest that myotonia congenita is unusually frequent in northern Finland, most probably as a consequence of an enrichment of the gene mutation(s) in the population.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Finland; Humans; Male; Middle Aged; Myotonia Congenita; Pedigree
PubMed: 9598722
DOI: 10.1136/jmg.35.4.293 -
Rheumatology (Oxford, England) Dec 2021
Topics: Female; Humans; Immunosuppressive Agents; Lupus Erythematosus, Systemic; Middle Aged; Myotonia Congenita
PubMed: 34382064
DOI: 10.1093/rheumatology/keab648 -
Journal of the Neurological Sciences Jul 2012Myotonia congenita is an autosomal dominantly or recessively inherited muscle disorder causing impaired muscle relaxation and variable degrees of permanent muscle...
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.
Topics: Adolescent; Adult; Aged; Cell Line; Cell Membrane; Child; Chloride Channels; Electric Conductivity; Female; Genetic Predisposition to Disease; Humans; Italy; Male; Middle Aged; Mutation, Missense; Myotonia Congenita; Patch-Clamp Techniques; Young Adult
PubMed: 22521272
DOI: 10.1016/j.jns.2012.03.024 -
Medical History Apr 1968
Topics: Denmark; History, 19th Century; Myotonia Congenita; Neurology
PubMed: 4875197
DOI: 10.1017/s0025727300013077 -
The New England Journal of Medicine Apr 1972
Topics: Adolescent; Female; Humans; Myotonia Congenita; Phenytoin
PubMed: 5061081
DOI: 10.1056/nejm197204202861615