SCN1A and epilepsy: Eight of those (SCN1A, IQSEC2, STXBP1, CACNA1E, ARID1B, DDX3X, WHSC1, PHF21A) have been known to be responsible for NDDs associated with IDs or epilepsies.9, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29