Familial hemiplegic migraine: Probable linkage to chromosome 1 and genetic heterogeneity

Familial hemiplegic migraine (FHM) is an autosomal dominant form of migraine with aura. FHM is genetically heterogeneous. In about 50% of families FHM is caused by mutations in the CACNA1A gene on chromosome 19. Linkage to 1q31 e 1q21-23 has also been established. We observed two Italian families both unlinked to chromosome 19. In one family with probable linkage to chromosome 1q21-23, some affected members showed cerebellar signs, previously reported only in families linked to chromosome 19. Our families confirms the genetic heterogeneity of FHM.