SCN8A. In 2015, SCN8A has emerged as an important gene in epileptic encephalopathy. SCN8A encodes the voltage-gated sodium channel alpha subunit Nav1.6, and was first implicated in epileptic encephalopathy in 2012. Since then, approximately 100 cases of early-infantile epileptic encephalopathy caused by mutations of SCN8A have been identified, and the disorder has been designated EIEE13. Here is what you need to know about SCN8A in 2015.