While Sudden Unexpected Death in Epilepsy (SUDEP) is reported to occur in individuals with CDD, data from large cohort studies suggests the frequency of SUDEP within the CDD population is lower than for Dravet syndrome or SCN8A-DEE, given the frequencies of these disorders (35–37). This evidence concerns the gene SCN8A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.