Five 'new' migraine risk genes identified

Five genetic regions not previously associated with migraine have been linked to the condition, according to an international group of researchers.

'This is the largest ever genetic study into migraines and highlights for the first time the possible genetic causes of what can be a devastating condition for many', said Dr Lydia Quaye from the Department of Twin Research at King's College London. 'By looking at almost 120,000 samples, we have been able to find genes associated with migraine and have pinpointed some mechanisms through which migraine occurs'.

Researchers from the International Headache genetics consortium, a multinational research collaboration studying genetic causes and background of headache and related disorders, pooled data from 29 different genome-wide association studies totalling more than 100,000 people. The researchers compared data from 23,285 people who suffer from migraines with data from 95,425 people who do not and were able to pinpoint regions of genetic variations that are more common in those affected by the condition.

The researchers identified 12 regions associated with migraine susceptibility, of which five were not previously associated with migraines. They also found that some of the regions were close to genes sensitive to oxidative stress, a biochemical process resulting in brain dysfunction which could be linked to migraine symptoms.

Migraine is one of the most common forms of brain disorder, affecting one in six people. It is thought to be caused by chemical changes in the brain and a drop in serotonin levels, but it is not known precisely why this occurs.

'Migraine and epilepsy are particularly difficult neural conditions to study; between episodes the patient is basically healthy so it's extremely difficult to uncover biochemical clues', said senior co-author Dr Aarno Palotie, from the Wellcome Trust Sanger Institute.

The study authors state their findings contribute to the understanding of migraine biology. Eight of the locations were close to genes known to play a role in brain circuitry and two were associated with maintaining healthy brain tissue, which may confirm the belief that these genes play a role in migraine risk.

One surprising finding was that no loci were found specifically in people who have migraine with aura, a type of migraine thought to be more strongly genetically determined. This could be due to greater variability in the genetic regions linked to migraine with aura, which makes them more difficult to detect, the authors suggest.

Dr Kári Stefánsson, President of deCODE genetics, said: 'The molecular mechanisms of migraine are poorly understood. The sequence variants uncovered through this meta-analysis could become a foothold for further studies to better understanding the pathophysiology of migraine'.