Familial hemiplegic migraine: A ion channel disorder

At present, little information is available on the genetics of common migra ines, most likely to be considered a multifactorial disease. Recently, the CACNA1A gene encoding the brain-specific P/Q type calcium channel alpha (1) subunit, has been cloned and mutations in this gene, located on chromosome 19p13, have been shown to be involved in familial hemiplegic migraine (FHM ), a rare autosomal dominantly inherited subtype of migraine with aura. Bei ng part of the migraine spectrum, FHM represents a good model to study the genetics of more common forms of migraine. Different classes of mutations w ithin the CACNA1A gene have been associated with different diseases, thus i dentifying a new member among 'channelopathies'. Variable clinical expressi on and genetic heterogeneity of FHM will be discussed. (C) 2001 Elsevier Sc ience Inc.