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Epilepsy and Migraine Genetically Linked
Researchers at Columbia University Medical Center in New York have discovered a shared genetic susceptibility to epilepsy and migraine. Findings published in Epilepsia, a journal of the International League Against Epilepsy, indicate that having a strong family history of seizure disorders increases the chance of having migraine with aura (MA).
Medical evidence has established that migraine and epilepsy often co-exist. Previous studies have found that people with epilepsy are substantially more likely than the general population to have migraine headache. However, it was not clear whether that comorbidity resulted from a shared genetic cause.
“Epilepsy and migraine are each individually influenced by genetic factors,” said lead author Dr. Melodie Winawer. “Our study is the first to confirm a shared genetic susceptibility to epilepsy and migraine in a large population of patients with common forms of epilepsy.”
In the new study, Winawer and her colleagues analyzed data collected from participants in the Epilepsy Phenome/Genome Project (EPGP) — a genetic study of epilepsy patients and families from clinical centers in the U.S., Canada, Argentina, Australia, and New Zealand. The new research examined one aspect of the EPGP: sibling and parent–child pairs with focal epilepsy or generalized epilepsy of an unknown cause. Most people with epilepsy have no family members affected by the disorder. EPGP was designed to look at those rare families that had more than one individual with epilepsy, in order to increase the chance of finding genetic causes.
An analysis of 730 participants with epilepsy in the EPGP study demonstrated that the prevalence of MA — when additional symptoms, such as blind spots or flashing lights, occur prior to headache pain — was substantially increased when several individuals in the same family had seizure disorders. Participants in the EPGP with epilepsy who had three or more close relatives with a seizure disorder were more than twice as likely to experience MA than were patients from families with fewer individuals with seizures. In other words, the stronger the genetic effect on epilepsy in the family, the higher the rates of MA. This result provides evidence of the existence of a gene or genes that cause both epilepsy and migraine, according to the study’s authors.
The identification of genetic contributions to the comorbidity of epilepsy with other disorders, such as MA, has implications for epilepsy patients. Prior research has shown that coexisting conditions impact the quality of life, treatment success, and mortality of epilepsy patients, with some experts suggesting that these comorbidities may have a greater effect on patients than the seizures themselves. In fact, comorbid conditions are emphasized in the National Institutes of Health Epilepsy Research Benchmarks and in a recent report on epilepsy from the Institute of Medicine.
“Our study demonstrates a strong genetic basis for migraine and epilepsy, because the rate of migraine is increased only in people who have close rather than distant relatives with epilepsy and only when three or more family members are affected,” Winawer said. “Further investigation of the genetics of groups of comorbid disorders and epilepsy will help to improve the diagnosis and treatment of these comorbidities, and will enhance the quality of life for those with epilepsy.”
Source: Wiley; January 7, 2013.