For some genetic DEEs, the variation in outcomes may involve factors beyond features examined here, such as the variation across the rest of the genome, as has been shown for SCN1A-related Dravet syndrome and other rare genetic neurological conditions.44,52,53 These nuances highlight the potential complexity in developing specific gene-based disease-modifying treatments. This evidence concerns the gene SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.