A team of scientists has identified a faulty gene responsible for debilitating headaches, giving people who suffer from migraines new hope that treatment may be improved.
The researchers, from the University of Oxford and a team in Canada, took DNA samples from migraine sufferers and their families.
According to the study, if a gene called Tresk is faulty, it triggers the pain nerves in the brain.
As a result, a severe headache is caused.
The scientists said the findings explain why people in the same family suffer from migraines.
And they added that the discovery of the gene could lead to new drugs that could switch off the pain.
Currently, around one in five people suffer from the neurological disorder.
Dr Zameel Cader, from the Medical Research Council's Functional Genomics Unit at the University of Oxford, said: "We have now made a major step forward in our understanding of why people suffer with migraine and how in certain cases, your family can literally give you a headache.
"Previous studies have identified parts of our DNA that increase the risk in the general population but have not found genes which can be directly responsible for common migraine.
"What we've found is that migraines seem to depend on how sensitive our nerves are in the pain centres of the brain.
"This finding should help lead to the key player which controls this excitability and will give us a real opportunity to find a new way to fight migraines and improve the quality of life for those suffering."
The study, published in Nature Medicine, was funded by the Medical Research Council, Genome Canada, Genome Quebec, Emerillon Therapeutics, the Wellcome Trust and Pfizer.