SCN1A and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: Some mutations in SCN1A that can cause epilepsy lead to defective folding of the encoded channel: Mutant channel insertion into a cell surface is temperature‐sensitive, for example, with increased insertion and current density at 30°C compared to 37°C.61 Mutations in SCN1A can cause the rare, severe developmental and epileptic encephalopathy Dravet syndrome.