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New mutation of the Na channel in the severe form of potassium-aggravated myotonia.
- Source :
-
Muscle & Nerve . May2009, Vol. 39 Issue 5, p666-673. 8p. - Publication Year :
- 2009
-
Abstract
- Myotonia manifests in several hereditary diseases, including hyperkalemic periodic paralysis (HyperPP), paramyotonia congenita (PMC), and potassium-aggravated myotonia (PAM). These are allelic disorders originating from missense mutations in the gene that codes the skeletal muscle sodium channel, Nav1.4. Moreover, a severe form of PAM has been designated as myotonia permanens. A new mutation of Nav1.4, Q1633E, was identified in a Japanese family presenting with the PAM phenotype. The proband suffered from cyanotic attacks during infancy. The mutated amino acid residue is located on the EF-hand calcium-binding motif in the intracellular C-terminus. A functional analysis of the mutant channel using the voltage-clamp method revealed disruption of fast inactivation, a slower rate of current decay, and a depolarized shift in the voltage dependence of availability. This study has identified a new mutation of PAM with a severe phenotype and emphasizes the importance of the C-terminus for fast inactivation of the sodium channel. Muscle Nerve 39: 666-673, 2009 [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 0148639X
- Volume :
- 39
- Issue :
- 5
- Database :
- Academic Search Index
- Journal :
- Muscle & Nerve
- Publication Type :
- Academic Journal
- Accession number :
- 71240477
- Full Text :
- https://doi.org/10.1002/mus.21155