However, also gain‐of‐function (GoF) mutations in SCN1A, historically associated with familial hemiplegic migraine type 3, have recently been associated with encephalopathic phenotypes, including neonatal developmental and epileptic encephalopathy with movement disorder and arthrogryposis, and early infantile DEEs with/without movement disorder.5, 6. The gene discussed is SCN1A; the disease is movement disorder.