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Previous Volume 328:482-489 February 18, 1993 Number 7 Next

	Since this article has no abstract, we have provided an extract of the first 100 words of the full text and any section headings.

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The myotonic muscle disorders represent a heterogeneous group of clinically similar diseases sharing the feature of myotonia: delayed relaxation of muscle after voluntary contraction (action myotonia) or mechanical stimulation (percussion myotonia). In classic myotonia the myotonia improves as muscles warm up, whereas in paradoxical myotonia (paramyotonia) it worsens with repeated muscle contractions. Electrophysiologically, myotonia is characterized by the repetitive electrical activity of muscle fibers. Two decades of work on the electrophysiology of myotonia focused attention on the muscle cell membrane as the site of the molecular defects of these diseases. Genetic-linkage studies have now pinpointed the lesions to chromosomal loci . . . [Full Text of this Article]

The Myotonic Diseases

Physiology

Ion-Channel Structure and Modulation

Sodium Channels

Chloride Channels

Protein Kinases

Identification of Molecular Alterations and Correlation with Phenotype

Sodium-Channel Disorders

Chloride-Channel Disorders

Protein Kinase Disorders

Implications of Genetic Classification

Diagnosis and Treatment

Understanding Ion Channels and Their Regulation

Source Information

From the Departments of Neurology and Human Genetics, University of Utah School of Medicine, Salt Lake City (L.J.P.); the Department of Anatomy, Charing Cross and Westminster Medical School, London (K.J.J.); and the Department of Neurology, University of Rochester School of Medicine, Rochester, N.Y. (R.C.G.).

Address reprint requests to Dr. Ptacek at the Department of Neurology, University of Utah School of Medicine/Medical Center, 50 N. Medical Dr., Salt Lake City, UT 84132.

References

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