Controlling for the main genetic contributor of a genetic condition can allow additional genetic contributions to the phenotype to be discovered, as has been shown for example in Huntington’s disease.72,73 Here, we adopted the same approach to Dravet syndrome, exploring WGS from a small group of adults with Dravet syndrome due to variation in SCN1A. The gene discussed is SCN1A; the disease is encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy.