New research shows that having a particular variation in a gene on chromosome 8 may increase the risk of migraines. Although it has long been believed that migraines have a genetic component to detect specific genes has been difficult, the researchers said.
The current study is among the first to identify a specific gene variant associated with increased risk of common types of migraines, such as those with and those without aura, although the relationship with migraine with aura was more intense, the study .
“We have found this relationship mainly with migraines with aura. We need more studies to see how far is this true for other forms of migraine,” said Aarno Palotie, lead study author and chairman of the International Consortium for Genetics of the Headache Wellcome Trust Sanger Institute in England. The report appears in the August 29 edition of Nature Genetics.
The researchers conducted a study of genome-wide association for more than 6,000 people who had been diagnosed with migraines and some 50,000 who did not have them, and found that suffering from migraine were more likely to have a variant of chromosome 8 between MTDH and PGCP genes.
The genes are related to the regulation of glutamate, a neurotransmitter, Palotie said. “When used in studies relating to the whole genome, often ends in an area for which you have no idea of what was done,” said Palotie. “In this case, we were lucky. Both genes are related to the balance of glutamate between the body and brain. We also know that one of these regulated genes related to an additional regulation of glutamate.”
Glutamate is a chemical substance or molecule that carries signals between neurons, Palotie said. The researchers speculate that the variant could do that glutamate accumulates in the synapses, although it is unclear why a change in glutamate levels contribute to migraines.
Nor is it known why it could trigger a headache among those with genetic susceptibility, he said. About 26 percent of those suffering from migraine in the study had the variant, while between 18 and 20 percent of the people who had migraines did. Although significant, migraines are a complex condition and many other genes and variants probably have to do.
“What this means is that there are many, many more genes that predispose to migraine,” said Palotie. “This is just discovering the tip of the iceberg.” About 17 percent of women and 8 percent of men suffer from migraines, according to background information in the article.
Although researchers have described in the past genetic mutations that cause rare forms of migraine, this is one of the first genetic risk factors associated with common forms of migraine, the researchers said. Dr. Kate Henry, associate professor of neurology at the Langone Medical Center New York University, called the findings important because they reveal information about the genetics of most common types of migraines.
“The belief is that between 70 and 80 percent of the risk of migraine is genetic, especially because we know that people with migraines often have relatives who also have it,” said Henry. “However, there was never a clear understanding of what was the specific gene.”
The hope is that a better understanding of genetics could open the door to treatments safer and more effective, said Henry. Medications such as triptans work for many who suffer from migraines, but not all, and may have side effects. Triptans may also have more risk for those with cardiovascular disease or risk factors for cardiovascular disease.
Between 12 and 18 percent of those with migraine have migraine with aura, including visual disturbances before the headache starts, and other warning signs that a migraine is imminent.
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