Document Detail

Phenotypic variability in myotonia congenita.
MedLine Citation:
PMID:  15786415     Owner:  NLM     Status:  MEDLINE    
Myotonia congenita is a hereditary chloride channel disorder characterized by delayed relaxation of skeletal muscle (myotonia). It is caused by mutations in the skeletal muscle chloride channel gene CLCN1 on chromosome 7. The phenotypic spectrum of myotonia congenita ranges from mild myotonia disclosed only by clinical examination to severe and disabling myotonia with transient weakness and myopathy. The most severe phenotypes are seen in patients with two mutated alleles. Heterozygotes are often asymptomatic but for some mutations heterozygosity is sufficient to cause pronounced myotonia, although without weakness and myopathy. Thus, the phenotype depends on the mutation type to some extent, but this does not explain the fact that severity varies greatly between heterozygous family members and may even vary with time in the individual patient. In this review, existing knowledge about phenotypic variability is summarized, and the possible contributing factors are discussed.
Eskild Colding-Jørgensen
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Muscle & nerve     Volume:  32     ISSN:  0148-639X     ISO Abbreviation:  Muscle Nerve     Publication Date:  2005 Jul 
Date Detail:
Created Date:  2005-06-22     Completed Date:  2005-08-02     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7803146     Medline TA:  Muscle Nerve     Country:  United States    
Other Details:
Languages:  eng     Pagination:  19-34     Citation Subset:  IM    
Department of Clinical Neurophysiology 19, Glostrup Hospital, University of Copenhagen DK-2600 Glostrup, Denmark.
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MeSH Terms
Chloride Channels / genetics*
Genetic Variation*
Myotonia Congenita / genetics*,  physiopathology*
Reg. No./Substance:
0/CLC-1 channel; 0/Chloride Channels

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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