Genetic Risk Factor for Migraine Discovered
Word that a genetic risk factor for common migraine has been discovered is good news for the tens of millions of Americans and millions more people around the world who suffer with this debilitating condition. Identification of such a risk factor could lead to new treatments to prevent migraine attacks.
Migraine is a disease, whose pain is caused by expansion of the cranial blood vessels, while inflammation of the tissue that surrounds the brain makes the pain worse. Unlike a headache, migraine can have many symptoms, including nausea, vomiting, auras, sensitivity to sound and light, difficultly with speech, and numbness. An estimated 36 million Americans suffer with migraine, representing about one in six women and one in twelve men.
It took studying 50,000 people to find Migrain's genetic risk factors
Identification of the first-known genetic risk factor for migraine was a collaborative effort among investigators from more than 40 centers around the world. After evaluating data from more than 50,000 people, the researchers found that individuals who have a specific DNA variant on chromosome 8 between two genes have a significantly higher risk for developing migraine.
This variant regulates levels of glutamate, a brain chemical that transports signals between nerve cells in the brain. Thus this new finding suggests that a buildup of glutamate in cell junctions (synapses) in the brain are involved in triggering migraine episodes, and that preventing such an accumulation of glutamate may lead to an effective treatment for this disease.
According to Dr. Aarno Palotie, chair of the International Headache Genetics Consortium at the Wellcome Trust Sanger Institute, which headed the study, “this discovery opens new doors to understand common human diseases.” It was the first time scientists have been able to examine the genomes of tens of thousands of people and “find genetic clues to understand common migraine,” explained Palotie.
That genome examination involved more than 3,000 individuals with migraine who attended a headache clinic, who were compared with more than 10,000 without migraine; and a second group of more than 3,000 migraine patients from headache clinics compared with more than 40,000 healthy people. The analysis revealed that a specific DNA variant appears to alter the activity of the gene MTDH/AEG-1 in cells, which regulates the activity of the EAAT2 gene. The EAAT2 protein removes glutamate from synapses in the brain.
Activity of the EAAT2 is familiar to scientists, who have previously found that it is involved in other neurological diseases, including schizophrenia, epilepsy, and different anxiety and mood disorders.
Additional research of the DNA variant and its impact on the genes that surround it is necessary. The study’s authors also want to expand their research subjects to include individuals with common migraine who are from the general population rather than just those attending headache clinics, because the latter are more likely to include people who have more severe migraine.
The road from discovering a genetic risk factor for migraine to introducing new treatments related to the discovery may take years, but it is a promising step toward relieving the suffering associated with the disease.
Anttila V et al. Nature Genetics 2010
MAGNUM: Migraine Awareness Group. A National Understanding of Migraine
Wellcome Trust Sanger Institute