Voltage sensor charge loss accounts for most cases of hypokalemic periodic paralysis.
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Matthews E, Labrum R, Sweeney MG, Sud R, Haworth A, Chinnery PF, Meola G, Schorge S, Kullmann DM, Davis MB, Hanna MG
Voltage sensor charge loss accounts for most cases of hypokalemic periodic paralysis.
Neurology. 2009 May 5;72(18):1544-7. doi: 10.1212/01.wnl.0000342387.65477.46. Epub 2008 Dec 31.
- PubMed ID
- 19118277 [ View in PubMed]
- Abstract
BACKGROUND: Several missense mutations of CACNA1S and SCN4A genes occur in hypokalemic periodic paralysis. These mutations affect arginine residues in the S4 voltage sensors of the channel. Approximately 20% of cases remain genetically undefined. METHODS: We undertook direct automated DNA sequencing of the S4 regions of CACNA1S and SCN4A in 83 cases of hypokalemic periodic paralysis. RESULTS: We identified reported CACNA1S mutations in 64 cases. In the remaining 19 cases, mutations in SCN4A or other CACNA1S S4 segments were found in 10, including three novel changes and the first mutations in channel domains I (SCN4A) and III (CACNA1S). CONCLUSIONS: All mutations affected arginine residues, consistent with the gating pore cation leak hypothesis of hypokalemic periodic paralysis. Arginine mutations in S4 segments underlie 90% of hypokalemic periodic paralysis cases.