HCN1 and Dravet syndrome: At the same time, several other genes have also been reported to cause DS-like phenotypes, including SCN2A, SCN8A, SCN9A, SCN1B, PCDH19, GABRA1, GABRG2, STXBP1, HCN1, CHD2, and KCNA2 [11] responding to other than DS treatment [12].