For example, zebrafish have two similar homologs of the human SCN1A gene, scn1laa and scn1lab; both genes are expressed in the brain and homozygous loss-of-function mutation in scn1lab results in epilepsy and serves as a model for Dravet syndrome [34, 54, 55]. The gene discussed is SCN1A; the disease is encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.