A gene-based collapsing analysis highlighted an increased variant burden in CHD2, FLNA and TSC1 (P < 0.05) in Dravet syndrome compared with GEL SCN1A controls (Supplementary Fig. 11B) that was not significant after correction for multiple comparisons. This evidence concerns the gene CHD2 and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.