 Oocytes injected with α1, β2, and γ2 subunits produce large GABA inducible currents whereas those injected with K289M mutant instead of wild-type subunits produce currents much smaller (about 10% of wild-type).This abnormal current is not the result of non-incorporation of mutant subunits since mutant containing receptors are still sensitive to benzodiazepines, a property for which functional γ subunits are required.Because of these results, it is believed that the GEFS+ phenotype in these individuals is a result of hyperexcitability.