Functional Characterization of a Genetic Epilepsy with Febrile Seizures Plus Adult Mouse Model

Background: Genetic epilepsy with febrile seizures plus (GEFS+) is a type of epileptic syndrome closely related to heredity factors, which can be caused by gene mutations. However, it still remains unclear how these mutations result in seizures. Previously, we identified a new heterozygous missense mutation of the gene, H258R, in the GEFS+ family; the electric currents of the human embryonic kidney 293 (HEK293) cells co-expressing Kvβ3 (H258R) and Kv1.1 showed obvious inactivation. This study sought to examine the effects of this mutation on the potassium channels in the mammalian brain.

Methods: Mutant mice were generated by introducing the human H258R missense mutation within exon 10 at an equivalent position in the mouse gene via CRISPR/Cas9 and homologous recombination. A patch clamp was used to detect the potassium currents in the pyramidal cells of the hippocampal CA1 region of the mutant mice. The total potassium currents of the pyramidal cells in the hippocampal CA1 region of [wild-type (WT)] and (H258R) adult mice were recorded with increased voltage.

Results: We found a decreased total potassium current in the H258R group but no significant differences at a maximum voltage (+80 mV; P>0.05).

Conclusions: These results suggest that the mutation reduced hippocampal potassium currents in this mouse model.