J Korean Med Sci.  2002 Dec;17(6):856-860. 10.3346/jkms.2002.17.6.856.

A Korean Family with Arg1448Cys Mutation of SCN4A Channel Causing Paramyotonia Congenita: Electrophysiologic, Histopathologic, and Molecular Genetic Studies

• Kim DS
• Kim EJ
• Jung DS
• Park KH
• Kim IJ
• Kwak KY
• Kim CM
• Ko HY

• KMID: 648803
• DOI: http://doi.org/10.3346/jkms.2002.17.6.856

Abstract

A family with paramyotonia congenita (PC) is presented. At least 10 family members were affected in an autosomal dominant inheritance pattern. The proband had cold-sensitive muscle stiffness, paradoxical myotonia, and intermittent muscle weakness since childhood. The serum level of creatine kinase was mildly elevated and short exercise test with cooling revealed a drastic reduction of compound muscle action potentials with repetitive discharges. Muscle biopsy revealed marked variation in the fiber size and increased internal nuclei. The molecular biological study revealed a common missense mutation (Arg1448Cys) at the voltage-gated sodium channel gene (SCN4A). The repetitive CMAP discharges during short exercise test with cooling observed in the proband has not been reported previously. This observation needs to be confirmed among PC patients with different mutations. This is the first report on a PC family confirmed by the molecular biological technique in Korea.

Keyword

Myotonic Disorders; Sodium Channels

MeSH Terms

Adult
Arginine/*chemistry
Cell Nucleus/metabolism
Creatine Kinase/blood
Cysteine/*chemistry
DNA Mutational Analysis
Exercise
Female
Humans
Korea
Male
*Mutation, Missense
Myotonic Disorders/*genetics
Pedigree
Phenotype
Sodium Channels/*genetics/metabolism