As described above, in contrast to syndromes that are caused by mutations in genes that play a primary role in the formation of neuronal excitability (for example, Dravet syndrome and SCN1A gene), abnormalities in spontaneous EEG and behavioral seizures are observed much less often in Mecp2-, Cdkl5- and FoxG1-deficient mice (reviewed in [205]). This evidence concerns the gene MECP2 and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.