SCN1A and Epileptic encephalopathy: DS is a severe epileptic encephalopathy, most often resulting from de novo SCN1A mutations (Lorincz and Nusser, 2010), and typically begins in infancy with seizures provoked by fever, including status epilepticus cognitive impairment (Sugiura et al., 2012; Beck et al., 2019), and poor response to available antiepileptic drugs.