Cacna1g is a genetic modifier of epilepsy caused by mutation of voltage-gated sodium channel Scn2a.
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 [C57BL/6JxSJL/J]F1 background exhibit earlier seizure onset, elevated spontaneous seizure frequency, and decreased survival compared to Scn2a(Q54) mice congenic on the C57BL/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.
Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, U.S.A.|Department of Medicine, Vanderbilt University, Nashville, Tennessee, U.S.A.
Jeffrey D
JD
Calhoun
Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, U.S.A.|Neuroscience Program, Vanderbilt University, Nashville, Tennessee, U.S.A.
Nicole A
NA
Hawkins
Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, U.S.A.
Nicole J
NJ
Zachwieja
Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, U.S.A.|Department of Medicine, Vanderbilt University, Nashville, Tennessee, U.S.A.
Jennifer A
JA
Kearney
D000818:Animals; D020747:Calcium Channels, T-Type / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D004827:Epilepsy / Q000235:genetics* / Q000503:physiopathology*; D005786:Gene Expression Regulation / Q000235:genetics*; D005838:Genotype; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics*; D062551:NAV1.2 Voltage-Gated Sodium Channel / Q000235:genetics*; D010641:Phenotype
C498197:Cacna1g protein, mouse; D020747:Calcium Channels, T-Type; D062551:NAV1.2 Voltage-Gated Sodium Channel; C568251:SCN2A protein, human
Genetics; Mouse model; Seizures; Voltage-gated calcium channels; Voltage-gated ion channels