Our report may provides evidence for the genetic etiology of CwG and expands the phenotypic and genetic spectrum of <i>SCN8A</i>-related disorders, which previously included severe developmental and epileptic encephalopathy (DEE) phenotype, benign epilepsy phenotype, spectrum of intermediate epilepsies, and patients with cognitive and/or behavioral disturbances without epilepsy. Here, SCN8A is linked to developmental and epileptic encephalopathy.