Introduction The gene SCN2A encodes sodium voltage-gated channel alpha subunit 2. We aimed to explore the genotype and phenotype of Chinese epileptic patients with SCN2A mutations.

Methods Epileptic patients who were detected with SCN2A mutations by targeted next-generation sequencing were collected．Clinical data of all patients and their family members were analyzed．

Results A total of 37 patients with SCN2A mutation were enrolled. Thirty-five SCN2A mutations were identified, including 31 missense mutations (88.6%), 2 in-frame deletion mutations, one frameshift mutation, and one nonsense mutation. Twenty-three SCN2A mutations were novel. Inherited mutations were confirmed in 10 cases and de novo mutations in the other 27 cases after validation in their parents. Three were diagnosed as benign familial neonatal-infantile epilepsy, five as benign familial infantile epilepsy, one as benign infantile epilepsy, one as febrile seizures plus, four as Ohtahara syndrome, seven as West syndrome, one as Dravet syndrome, 11 as unclassified early infantile epileptic encephalopathy, one as encephalopathy with infantile onset epilepsy, one as encephalopathy with childhood onset epilepsy, one as autism with epilepsy, one as intellectual disability with epilepsy.

Conclusions Missense mutation was the most common mutation type in Chinese epileptic patients with SCN2A mutations. De novo mutations are more common in patients with SCN2A mutations. SCN2A mutations could lead to a wide spectrum of epilepsy. We expanded the genotype and phenotype of SCN2A mutations.