They found that those who suffered from migraines were much more likely to have a genetic variant known as a single nucleotide polymorphism (SNP).
The genetic variant, found between two normally occurring genes, allows the chemical glutamate, a neurotransmitter associated with migraine headaches, to build up.
Scientists say the discovery could lead to better treatments of migraine sufferers, but they add that there are several abnormal genes and environmental factors that may also trigger migraines.
The study is published online in this week's issue of Nature Genetics.
