The presence of two disease-causing rare variants can lead to blended phenotypes, as shown by the presence of symptomatic FCD and a DEPDC5 variant in one individual with a clear Dravet syndrome phenotype due to a causal variant in SCN1A, with additional examples in other genes (CHD2, IQSEC2 and SCN8A). This evidence concerns the gene IQSEC2 and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.