SCN1A and Acute encephalopathy: Epilepsy-related deaths, most of which result from SUDEP and acute encephalopathy with SE, account for the vast majority of premature mortality in DS (up to 81%).[3,4] High SUDEP rates in DS may be explained by epilepsy severity.[4] Approximately 3-fourths of DS patients have a mutation in the voltage-gated sodium channel gene, SCN1A,[1,2,5] which has been suggested as a possible candidate gene related to SUDEP.[4,6]