Familial Hemiplegic Migraine (FHM) is a rare type of migraine associated with genetic defects in ion-transporting proteins.


Clinical features:

(1) familial occurrence with autosomal dominant inheritance

(2) migraine with aura

(3) transient motor weakness and/or other aura symptoms


While neurological findings are often reversible over weeks or months, permanent neurologic deficits can occur.




Gene Mutated (Chromosome)

Protein Affected


CACNA1A (19p13)

pore-forming alpha1 subunit of the neuronal calcium channel Cav2.1


ATP1A2 (1q23.2)

alpha-2 subumit of the glial Na/K ATPase


SCN1A (2q24.3)

pore-forming alpha subunit of the voltage-gated sodium channel Nav1.1



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