SCN1A and familial hemiplegic migraine: Advances in the clinical description and genetic diagnosis of many patients has allowed the classification of a broad spectrum of SCN1A-related disorders, including DS, myoclonic-atonic epilepsy (MAE), epilepsy of infancy with migrating focal seizures (EIMFS), early-infantile developmental and epileptic encephalopathy (EIDEE), GEFS+ and partial epilepsy with febrile seizure plus (PEFS+), as well as non-epileptic disorders such as familial hemiplegic migraine (FHM), autism spectrum disorders (ASD) and arthrogryposis [14,15,16,17,18].