Genes encoding the GABAAR subunit have been identified as causative genes of idiopathic generalized epilepsy (IGE) and/or developmental and epileptic encephalopathy (DEE), including GABRA1, GABRA2, GABRB3, GABRA5, GABRB1, GABRB2, GABRB3, and GABRG2 (OMIM, database).1 Here, GABRB3 is linked to developmental and epileptic encephalopathy.