Transient weakness and altered membrane characteristic in recessive generalized myotonia (Becker)

  title={Transient weakness and altered membrane characteristic in recessive generalized myotonia (Becker)},
  author={Reinhardt Rüdel and Kenneth Ricker and Frank Lehmann-Horn},
  journal={Muscle \& Nerve},
The isometric force of arm and leg muscles was studied in five unrelated patients with recessive generalized myotonia (Becker). The symptom of myotonia was present mainly in the legs, whereas transient weakness was the prominent symptom in the arms. Tocainide improved both symptoms, although it improved the stiffness more than the weakness. A specimen of intact muscle fibers was excised from the external intercostal muscle of one of the patients. The resting potential of the fibers was normal… 
Abnormalities of the fast sodium current in myotonic dystrophy, recessive generalized myotonia, and adynamia episodica
C cultured from the biopsied muscles of patients with myotonic dystrophy, three patients with recessive generalized myotonia, and a patient with adynamia episodica, the time constants of activation and inactivation showed a characteristic pattern of abnormalities.
The mechanism underlying transient weakness in myotonia congenita
Transient weakness in myotonia congenita is caused by depolarization secondary to activation of persistent Na+ current in skeletal muscle, and targeting NaPIC with ranolazine prevents the development of plateau potentials and eliminates transient weakness in vivo.
Altered sodium channel behaviour causes myotonia in dominantly inherited myotonia congenita
Altered Na+ channel activity and reduced Cl− conductance cause hyperexcitability in recessive generalized myotonia (becker)
It is concluded that a combination of reduced Cl− conductance and the reopenings of Na+ channels underlie the electrical afteractivity in recessive generalized myotonia.
Myotonic disorders.
Propagation disturbance of motor unit action potentials during transient paresis in generalized myotonia: a high-density surface EMG study.
It is concluded that the transient paresis is explained by a deteriorating muscle membrane function, ending in conduction block and pareis, and shows how spatiotemporal information, available through non-invasive high-density sEMG, may provide novel insights into electrophysiological aspects of membrane dysfunction.
Schwartz–Jampel syndrome: II. Na+ channel defect causes myotonia
It is hypothesized that altered membrane conductances are responsible for the hyperexcitability and the associated slowed relaxation in skeletal muscle fibers from a patient with Schwartz–Jampel syndrome.
Myotonia and the muscle chloride channel
Clinical and molecular data show that dominantly inherited Thomsen's myotonia is most often a very mild disorder that shows considerable clinical heterogeneity, and one Italian family is shown to have a novel dominant mutation--I290M.
Transient weakness and compound muscle action potential decrement in myotonia congenita
Twenty‐five Turkish patients with recessive myotonia congenita (RMC), 16 of whom had genetic confirmation, were studied. Nineteen had transient weakness. In the upper extremities, onset age of


Muscle weakness after rest in myotonic disorders; an electrophysiological study.
Intramuscular stimulation and recording techniques show that a separate defect in the myotonic muscle from that which causes the hyperexcitability of the fibre membrane is the site of this defect.
Hypokalemic periodic paralysis: In vitro investigation of muscle fiber membrane parameters
It was concluded that the basic defects are a reduced excitability and an increased sodium conductance, and that these defects are aggravated on reduction of the extracellular potassium concentration.
Muscle stiffness and electrical activity in paramyotonia congenita
It was concluded that the slowed muscle relaxation is more important as a factor contributing to paramyotonic stiffness than spontaneous force generation.
Membrane defects in paramyotonia congenita with and without myotonia in a warm environment
Analysis of the membrane current densities using voltage clamps with 3 microelectrodes revealed that in paramyotonic patients at 37°C all component conductances were normal, except for a decreased CI conductance in the patient who had myotonia in a warm environment, which explains the clinical symptoms of weakness and paralysis.
Clinical study of paramyotonia congenita with and without myotonia in a warm environment
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 slowed of Muscle relaxation in myotonia congenita.
  • S. Bryant
  • Chemistry, Medicine
    Annals of the New York Academy of Sciences
  • 1979
The myotonic goat is the oldest recognized animal model for an inherited human skeletal muscle disease syndrome and its use in all scientific studies since the first report by White and Plaskett in 1904 can be clearly traced to the Tennessee strain.
The resting membrane parameters of human intercostal muscle at low, normal, and high extracellular potassium
Membrane parameters at the respective resting potentials in low, normal, and high extracellular potassium solutions were determined in intercostal muscle fibers from 15 patients with no known neuromuscular disease, following the predictions by the constant field theory.
Muscular paralysis in myotonia congenita.
While examining a patient with myotonia congenita, it was found that stimulation of the ulnar nerve with frequencies of 5 or 8 cps caused the amplitude of the muscle action potential to decrease rapid
Successful treatment with tocainide of recessive generalized congenital myotonia
A patient with recessive generalized congenital myotonia and severe, disabling weakness underwent various forms of treatment while being monitored electrophysiologically, and tocainide yielded good results.
On the repetitive discharge in myotonic muscle fibres
1. Muscle fibres from myotonic goats respond to injected constant currents with a train of action potentials. If the number of action potentials in an evoked train exceeds 10–15, stopping the current