Variants detected in epilepsy-related genes (DEPDC5, CHD2, SCN8A and IQSEC2) have been reported in patients with SCN1A variants and were considered to contribute to blended phenotypes comprising features of the disorder associated with the epilepsy gene and Dravet syndrome [31]. Here, IQSEC2 is linked to encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.