STXBP1 and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: Although in about 85% of patients, a mutation of the SCN1A gene is present [9], other genes, such as but not limited to SCN1B [10], GABRA1 [11], STXBP1 [11], and HCN1 [12], have also been implicated in Dravet syndrome although with atypical presentations [13].