Monarch Disease Ontology id MONDO_0012320 (migraine, familial hemiplegic, 3) is any familial or sporadic hemiplegic migraine in which the cause of the disease is a mutation in the SCN1A gene. Also known as: SCN1A familial or sporadic hemiplegic migraine, familial or sporadic hemiplegic migraine caused by mutation in SCN1A, migraine, familial hemiplegic, type 3.