PCDH19 and encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy: Disruptions in the SCN9A, SCN2B, PCDH19, GABRG2, GABRA1, and STXBP1 genes can contribute to Dravet syndrome less frequently (the occurrence rate was estimated to be approximately 15.9–18% of the population).