WebMD Medical News
Laura J. Martin, MD
Aug. 30, 2010 -- Scientists have identified the first-ever genetic risk factor for common migraines.
People who have a specific change, or variation, in a section of DNA that helps control a brain chemical called glutamate have a significantly greater risk of developing migraines, researchers report in this week's issue of Nature Genetics.
The landmark achievement marks a significant step toward understanding the mysteries of migraines and could help pave the way for the development of new treatments for preventing the debilitating headaches.
The discovery is based on genetic data from more than 50,000 Europeans. A team of international researchers compared genetic data from migraine patients to people who did not have migraines. They found that patients with a variation on chromosome 8 between two genes called PGCP and MTDH/AEG-1 were significantly more likely to develop common migraines.
Researchers had previously linked genetic mutations to rare and extreme forms of migraine, but this is the first time they have identified one that leads to common forms of the headaches.
The newly identified genetic risk factor for common migraine is "rs1835740." The effect of this variation appeared to be stronger in people who have migraine with visual disturbances, called auras, than in people with migraine without auras.
"This is the first time we have been able to peer into the [genetic data] of many thousands of people and find genetic clues to understand common migraine," Aarno Palotie, MD, PhD, chair of the International Headache Genetics Consortium at the Wellcome Trust Sanger Institute, says in a news statement.
The particular migraine-related genetic variant disrupts the processes that help remove glutamate from nerve cell connections in the brain. Glutamate is a neurotransmitter, which sends messages to and from nerve cells in the brain.
The rs1835740 variant disrupts activities in certain cells that control a gene called EAAT2, which has been linked to other neurological disorders, including epilepsy. This gene normally helps clear glutamate from the brain's nerve cell junctions. But when the gene's activity is disrupted, levels of glutamate may build up.
The new study suggests that migraine attacks may be caused by a buildup of glutamate in the brain's nerve cell connections.
"Until now, no genetic link has been identified to suggest that glutamate accumulation in the brain could play a role in common migraine," Christian Kubisch of University of Ulm, Germany, says in a news release.
Preventing glutamate buildup at the brain's nerve cell junctions may help prevent migraine, researchers say.
Nearly 30 million Americans live with migraines, according to the National Headache Foundation. Women experience them three times more often than do men.
SOURCES:Anttila, V. Nature Genetics, published online Aug. 29, 2010.News release, Wellcome Trust Sanger Institute.News release, Nature Genetics.The National Headache Foundation web site: "Migraine."
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