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A novel mutation in KCNA1 causes episodic ataxia without myokymia
Author(s) -
Lee Hane,
Wang Hui,
Jen Joanna C.,
Sabatti Chiara,
Baloh Robert W.,
Nelson Stanley F.
Publication year - 2004
Publication title -
human mutation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 162
eISSN - 1098-1004
pISSN - 1059-7794
DOI - 10.1002/humu.9295
Subject(s) - myokymia , biology , ataxia , mutation , genetics , channelopathy , fasciculation , neuroscience , gene , electromyography
We describe a unique family in which several individual are affected with episodes of ataxia that best fit the phenotype of episodic ataxia type 2 (EA2). All of the affected family members had episodes typically lasting for several hours, and none of them had muscle abnormalities including myokymia. Episodic ataxia type 1 (EA1) was not considered initially as a clinical diagnosis for the affected individuals in this family. However, by linkage mapping, sequencing and polymorphism analysis, all affecteds were found to have a novel mutation in KCNA1 . Numerous missense mutations have been described previously in KCNA1 that cause EA1. The mutation c.1025G>T replaces a highly conserved serine with isoleucine at position 342 (p.Ser342Ile) in the highly conserved fifth transmembrane domain of the KCNA1 . This mutation leads to a distinct clinical phenotype without myokymia broadening the scope of clinical characteristics of EA1 and highlighting the heterogeneity of phenotypic effects from distinct missense mutations. © 2004 Wiley‐Liss, Inc.