Familial hemiplegic migraine (FHM) is a subtype of migraine with aura that includes hemiparesis (weakness of a limb) during episodes. The MHF was first described in 1910 by Clarke.
The prevalence of HCM is around 0.01%, with a male-female sex ratio of 1:3.
The disease is linked to a series of mutations in genes associated: CACNA1A SCN1A and ATP1A2, which encode ion transporters.
It appears as a pattern of autosomal dominant inheritance with 80% penetrance. There is a 50% chance that the child of an affected patient inherit the disease.
The MHF has a number of associated neurological symptoms that include visual disturbances, loss of feeling in limbs or face, difficulty speaking or disfragia, motor weakness, and aura located in the trunk or cerebral cortex. Symptoms may prologarse until days after the attack.