Genetic testing may help in severe type of migraine

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - People who suffer from sporadic hemiplegic migraine (SHM) -- a rare, often severe subtype of migraine in which attacks are associated with a weakness affecting one side of the body -- may want to consider genetic testing, researchers suggest.

Their suggestion is based on a study in which they found "familial genes" for this type of migraine in people who did not have family members experiencing the problem.

"Normally one starts searching for genes only in families in which several family members have a disease," Dr. Michel D. Ferrari, from Leiden University Medical Center in the Netherlands, told Reuters Health. "This is the first study looking for genes in patients with a severe type of migraine but without similarly affected family members. The study shows that genes are important even in so called sporadic migraine patients."

Ferrari and colleagues performed genetic testing on 39 men and women with SHM. The study subjects, who had no known family members with this type of migraine, were screened for mutations in three genes that have been linked tohemiplegic migraine that runs in families: the CACNA1A gene, the ATPIA2 gene, and the SCN1A gene.

The researchers found variants of these three genes in 18 percent of the study subjects.

Ferrari noted that most people with SHM are "initially diagnosed with epilepsy, stroke or other disorders and are treated accordingly with non-effective medications that are associated with a high risk of side effects rather than with effective agents to treat migraine."

Genetic testing in people with this type of sporadic migraine may help to enable counseling and prevent unnecessary treatment with potentially harmful drugs, the researchers suggest.

SOURCE: Neurology, December 4, 2007.