First, we analyzed data from neuronal networks derived from patients with Dravet Syndrome (DS) and Generalized Epilepsy with Febrile Seizures plus (GEFS+), both epileptic encephalopathies linked to a variant in SCN1A, which encodes part of the voltage-gated sodium channel NaV1.1 (PAT001 GEFS and PAT001 DS from van Hugte et al.7). Here, SCN1A is linked to encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.