Phenotypic and genetic spectrum in Chinese children with SCN8A-related disorders

•The phenotypic spectrum of SCN8A-related disorders in Chinese children ranged from severe developmental delay without epilepsy to severe DEE.•We found 50 patients who presented with severe developmental and epileptic encephalopathy (DEE, 70%), benign infantile epilepsy (BIE, 12%), developmental encephalopathy with epilepsy (16%), and severe developmental delay without epilepsy (2%).•All the variants were de novo missense with the exception of one splice site variant.•We reported three new variants, Asn1887Ser, Ile1605Thr, and Met1869Thr, which were associated with SCN8A-BIE.•Sodium channel blockers were effective in curing SCN8A-related disorders however may not be relevant to the mutant location.