Genes for familial hemiplegic migraine (FHM) and episodic ataxia type-2 (EA-2) have been mapped to chromosome 19p13. We characterized a brain- specific P/Q-type Ca2+ channel α1-subunit gene, CACNLIA4, covering 300 kb with 47 exons. Sequencing of all exons and their surroundings revealed polymorphic variations, including a (CA)(n)-repeat (D19S1150), a (CAG)(n)- repeat in the 3'-UTR, and different types of deleterious mutations in FHM and EA-2. In FHM, we found four different missense mutations in conserved functional domains. One mutation has occurred on two different haplotypes in unrelated FHM families. In EA-2, we found two mutations disrupting the reading frame. Thus, FHM and EA-2 can be considered as allelic channelopathies. A similar etiology may be involved in common types of migraine.,
Department of Virology

Ophoff, R., Terwindt, G., Vergouwe, Y., van Eijk, R., Oefner, P., Hoffman, S. M., … Frants, R. (1996). Familial hemiplegic migraine and episodic ataxia type-2 are caused by mutations in the Ca2+ channel gene CACNL1A4. Cell, 87(3), 543–552. doi:10.1016/S0092-8674(00)81373-2