All the nine probands suffered from epilepsy with or without ID/DD and had no pathogenic variation found in other epilepsy candidate genes after trio-WES reanalysis, especially SCN1A or PCDH19. The variants found in this study included c.560 T > G (p.L187R), c.620_621insC (p.F207Ffs*39), c.13 G > T (p.E5X, 211), c.256 C > T (p.R86C), c.409 T > G (p.C137G), c.264delC (p.I88Ifs*46), c.410 G > T (p.C137F), c.332 G > C (p.R111P) and c.368-2 A > G in CSNK2B (NM_001320) (Table 1). Here, SCN1A is linked to epilepsy.