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Cacna1g is a genetic modifier of epilepsy caused by mutation of voltage‐gated sodium channel Scn2a
Author(s) -
Calhoun Jeffrey D.,
Hawkins Nicole A.,
Zachwieja Nicole J.,
Kearney Jennifer A.
Publication year - 2016
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/epi.13390
Subject(s) - sodium channel , epilepsy , mutation , genetics , sodium , neuroscience , chemistry , biology , gene , organic chemistry
Summary More than 1,200 mutations in neuronal voltage‐gated sodium channel (VGSC) genes have been identified in patients with several epilepsy syndromes. A common feature of genetic epilepsies is variable expressivity among individuals with the same mutation. The Scn2a Q54 transgenic mouse model has a mutation in Scn2a that results in spontaneous epilepsy. Scn2a Q54 phenotype severity varies depending on the genetic strain background, making it a useful model for identifying and characterizing epilepsy modifier genes. Scn2a Q54 mice on the [C57 BL /6Jx SJL /J]F1 background exhibit earlier seizure onset, elevated spontaneous seizure frequency, and decreased survival compared to Scn2a Q54 mice congenic on the C57 BL /6J strain. Genetic mapping and RNA ‐Seq analysis identified Cacna1g as a candidate modifier gene at the Moe1 locus, which influences Scn2a Q54 phenotype severity. In this study, we evaluated the modifier potential of Cacna1g , encoding the Cav3.1 voltage‐gated calcium channel, by testing whether transgenic alteration of Cacna1g expression modifies severity of the Scn2a Q54 seizure phenotype. Scn2a Q54 mice exhibited increased spontaneous seizure frequency with elevated Cacna1g expression and decreased seizure frequency with decreased Cacna1g expression. These results provide support for Cacna1g as an epilepsy modifier gene and suggest that modulation of Cav3.1 may be an effective therapeutic strategy.