In 2006, Berkovic et al, showed that among a case series of children in whom vaccination had been implicated as a direct cause of the subsequent epileptic encephalopathy, 11 out of 14 children had Dravet syndrome due to SCN1A-mutations.[7] This showed that the epilepsy and retardation in these children was primarily due to a genetic defect and not to the vaccination. This evidence concerns the gene SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.