-
A.M.A. Archives of Neurology and... Jul 1958
Topics: Heredity; Humans; Myotonia Congenita; Myotonic Disorders
PubMed: 13544644
DOI: 10.1001/archneurpsyc.1958.02340070019001 -
Neurology Mar 1987We have studied 14 patients from a kindred with an autosomal dominant form of myotonia, with features differing from most cases of autosomal dominant or recessive...
We have studied 14 patients from a kindred with an autosomal dominant form of myotonia, with features differing from most cases of autosomal dominant or recessive myotonia congenita. All patients had painful muscle stiffness that was provoked by fasting and oral potassium administration and was relieved by carbohydrate-containing foods. Muscle biopsies showed the presence of type 1, 2A, and 2B fibers, as opposed to the absence of type 2B fibers seen in some patients with myotonia congenita. Acetazolamide was dramatically effective in alleviating myotonia in all patients and was more effective than other antimyotonic agents.
Topics: Acetazolamide; Adult; Female; Glucose; Humans; Male; Muscles; Myotonia Congenita; Pedigree; Potassium
PubMed: 3822145
DOI: 10.1212/wnl.37.3.488 -
Paediatric Anaesthesia Sep 2013Myotonia congenita and periodic paralyses are hereditary skeletal muscle channelopathies. In these disorders, various channel defects in the sarcolemma lead to a... (Review)
Review
Myotonia congenita and periodic paralyses are hereditary skeletal muscle channelopathies. In these disorders, various channel defects in the sarcolemma lead to a severely disturbed membrane excitability of the affected skeletal muscles. The clinical picture can range from severe myotonic reactions (e.g., masseter spasm, opisthotonus) to attacks of weakness and paralysis. Provided here is a short overview of the pathomechanisms behind such wide-ranging phenotypic presentations in these patients, followed by recommendations concerning the management of anesthesia in such populations.
Topics: Anesthesia; Channelopathies; Humans; Hypokalemia; Muscle, Skeletal; Myotonia Congenita; Paralyses, Familial Periodic; Patient Care Planning; Sarcolemma
PubMed: 23802937
DOI: 10.1111/pan.12217 -
Ryoikibetsu Shokogun Shirizu 2001
-
Journal of Electromyography and... Dec 2019Myotonia congenita (MC) is caused by pathogenic variants in the CLCN1 gene coding the chloride channel protein.
INTRODUCTION
Myotonia congenita (MC) is caused by pathogenic variants in the CLCN1 gene coding the chloride channel protein.
METHODS
To test the hypothesis that needle EMG could be helpful in distinguishing between the recessive and dominant MC, we performed EMG examination in 36 patients (23 men) aged 4-61 years with genetically proven MC: in 30 patients with autosomal recessive MC (Becker MC) and in 6 with autosomal dominant MC (Thomsen MC).
RESULTS
Myotonic discharges were recorded in 95.8% of examined muscles. For the whole MC group we observed a significant positive correlation between parameters of motor unit activity potentials (MUAPs) in vastus lateralis and tibialis anterior muscles and the duration of the disease. Similar correlation for biceps brachii also was found in Becker MC subgroup only.
DISCUSSION
EMG could still be helpful in diagnosis of MC and together with provocative tests might be useful in differentiation between recessive and autosomal MC.
Topics: Adolescent; Adult; Child; Child, Preschool; Diagnosis, Differential; Electromyography; Evoked Potentials, Motor; Female; Genes, Dominant; Genes, Recessive; Humans; Male; Middle Aged; Muscle, Skeletal; Mutation; Myotonia Congenita
PubMed: 31610484
DOI: 10.1016/j.jelekin.2019.102362 -
ELife Apr 2021In addition to the hallmark muscle stiffness, patients with recessive myotonia congenita (Becker disease) experience debilitating bouts of transient weakness that remain...
In addition to the hallmark muscle stiffness, patients with recessive myotonia congenita (Becker disease) experience debilitating bouts of transient weakness that remain poorly understood despite years of study. We performed intracellular recordings from muscle of both genetic and pharmacologic mouse models of Becker disease to identify the mechanism underlying transient weakness. Our recordings reveal transient depolarizations (plateau potentials) of the membrane potential to -25 to -35 mV in the genetic and pharmacologic models of Becker disease. Both Na and Ca currents contribute to plateau potentials. Na persistent inward current (NaPIC) through Na1.4 channels is the key trigger of plateau potentials and current through Ca1.1 Ca channels contributes to the duration of the plateau. Inhibiting NaPIC with ranolazine prevents the development of plateau potentials and eliminates transient weakness in vivo. These data suggest that targeting NaPIC may be an effective treatment to prevent transient weakness in myotonia congenita.
Topics: Animals; Disease Models, Animal; Female; Male; Membrane Potentials; Mice; Myotonia Congenita; Sodium
PubMed: 33904400
DOI: 10.7554/eLife.65691 -
Muscle & Nerve Oct 2017Exercise has not been investigated in myotonia congenita (MC). We investigated whether regular aerobic training can reduce myotonia and improve fitness.
INTRODUCTION
Exercise has not been investigated in myotonia congenita (MC). We investigated whether regular aerobic training can reduce myotonia and improve fitness.
METHODS
Untrained patients with MC (age: 24-62 years; n = 6) completed 28 ± 3 sessions of 30-minute cycle ergometer training at 75% of maximal capacity for 11 ± 1 weeks. Fitness was evaluated by maximal oxygen uptake. The level of myotonia was assessed by the Myotonia Behavior Scale, 14 step stair test, timed up and go test, and hand and eye closure-open tests.
RESULTS
Training increased fitness by 9% (95% confidence interval [CI], 1-17%; P = 0.02) and maximal workload by 10% (95% CI, 3-18%; P = 0.03). None of the myotonia tests changed in a clinically meaningful way.
CONCLUSIONS
Regular endurance training improves fitness and maximal workload performance in patients with MC. The lack of creatine kinase elevations indicates that muscle damage did not occur. Improved fitness, however, did not change myotonic symptoms in this small cohort. Muscle Nerve 56: 696-699, 2017.
Topics: Adult; Exercise; Exercise Therapy; Female; Follow-Up Studies; Humans; Male; Middle Aged; Myotonia; Myotonia Congenita; Physical Endurance; Physical Fitness; Treatment Outcome
PubMed: 28039888
DOI: 10.1002/mus.25549 -
Neuromuscular Disorders : NMD Mar 1993The classification of periodic paralyses and myotonic syndromes has been a subject of debates for the last 40 yr. Recent advances in molecular biology have led... (Comparative Study)
Comparative Study Review
The classification of periodic paralyses and myotonic syndromes has been a subject of debates for the last 40 yr. Recent advances in molecular biology have led geneticists to reconsider this old question, using a candidate gene approach. Two groups of disorders have now emerged: (1) muscle sodium channel-associated diseases which include hyperkalemic periodic paralysis and its clinical variants, as well as paramyotonia congenita; (2) muscle chloride channel-associated disorders which comprise both the dominant and recessive form of myotonia congenita. This review is focussed on these recent discoveries.
Topics: Genotype; Humans; Ion Channels; Mutation; Myotonia Congenita; Paralyses, Familial Periodic; Phenotype; Sarcolemma; Syndrome
PubMed: 7689379
DOI: 10.1016/0960-8966(93)90001-z -
Journal of the Indian Medical... Apr 1952
Topics: Humans; Myotonia Congenita
PubMed: 14938568
DOI: No ID Found -
The Journal of Pediatrics Dec 1949
Topics: Humans; Myotonia; Myotonia Congenita
PubMed: 15395008
DOI: 10.1016/s0022-3476(49)80120-x