SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: In humans, seizure onset in Dravet syndrome can be as early as 4–6 months of age [1, 35, 36], and the time course of transcriptional events is analogous to that in the mouse, with SCN1A mRNA expression accumulating during and after infancy, and exon 20N inclusion declining from 60–80% during embryonic development to 5–10% by 6 months of age [37].