Heron et al. (2002) reported that SCN2A gene was the major causative gene of benign familial neonatal-infantile epilepsy. At first, some researchers believed that missense variations tend to result in benign epilepsy, whereas truncation variations lead to severe and intractable epilepsy (Yamakawa, 2006). With the wide application of next-generation sequencing in clinical practice, SCN2A variants have been reported in severe early onset epileptic encephalopathy and most of them were de novo variants. This evidence concerns the gene SCN2A and genetic developmental and epileptic encephalopathy.