Gabra2, which encodes the GABAA α2 subunit, is a crucial gene as GABAA receptors are involved in the inhibitory neurotransmission pathway with gamma-aminobutyric acid (GABA) being the major inhibitory neurotransmitter in the brain. This pathway is vital for maintaining the balance between neuronal excitation and inhibition, and thus is of great biological importance. Genetic models, especially mouse models, have been valuable in studying Gabra2 [3].

In mouse models, Gabra2 has been identified as a genetic modifier in multiple epilepsy-related conditions. In Scn1a+/- mice which model Dravet syndrome, a B6-specific single nucleotide deletion in Gabra2 reduces its mRNA and protein levels. Repairing this deletion restores Gabra2 expression, increases the abundance of α2-containing GABAA receptors in hippocampal synapses, and rescues epilepsy phenotypes, validating Gabra2 as a genetic modifier of Dravet syndrome [1]. In Scn8a encephalopathy mouse models, the C57BL/6J strain has a splice site mutation in Gabra2 that reduces its expression. The protective wild-type allele from the SJL/J strain delays seizure onset and extends lifespan in Scn8a mutant mice. Correcting the Gabra2 splice site variant in C57BL/6J mice restores transcript abundance, increases seizure onset age, and extends survival of Scn8a mutant mice, suggesting GABRA2 as a potential therapeutic target for SCN8A encephalopathy [2,4].

In conclusion, Gabra2 is essential for the proper function of the inhibitory neurotransmission pathway via its encoding of the GABAA α2 subunit. Mouse models, especially those with gene knockout or modification of Gabra2, have revealed its role as a genetic modifier in Dravet syndrome and Scn8a encephalopathy, highlighting its significance in understanding the pathogenesis of these epilepsy-related diseases and potentially guiding therapeutic development.