Furthermore, the observation of Scn1a haploinsufficiency resulting from Scn1b deletion suggests an additive mechanism for the severity of the Scn1b−/− model compared with Scn1a+/− DS mice, which have a later age of seizure onset and a lower rate of SUDEP50 compared to Scn1b−/− mice.26 Here, SCN1A is linked to Dravet syndrome.