Hemiplegic migraine and other monogenic migraine subtypes and syndromes

Hemiplegic migraine (HM) is a rare monogenic subtype of migraine with aura that includes reversible motor weakness and can be either familial or sporadic. Three genes have been associated with HM. Migraine can also be part of more elaborate monogenic syndromes. When the family history includes early-onset cerebrovascular diseases and dementia, the monogenic small-vessel diseases CADASIL, RVCL-S, and COL4A1-associated syndromes should be considered. The mitochondrial disease MELAS is also associated with migraine-like and stroke-like episodes, often with a progressive nature, hearing loss and short stature. Like familial HM type 1, EA2 and SCA-6 are associated with CACNA1A mutations. All three disorders can include episodic and progressive ataxia and imaging may reveal cerebellar atrophy. Episodic hemiplegia or quadriplegia also occurs in the rare disorder alternating hemiplegia of childhood, with an age at onset before 18 months and often in association with tonic/dystonic attacks and developmental delay.