PARIS (AFP) - Scientists have uncovered a trio of genes tied to migraine headaches, including one in which the link is exclusive to women, according to a study published Sunday. Migraines are acutely debilitating headaches - sometimes with an aura, in which patients have the impression of seeing through frosted glass - that strike up to 20 percent of the population. Scientists describe the condition, which is three to four times more common in women, as a brain disorder in which neurons, or brain cells, respond abnormally to stimuli. The precise cause it unknown, but inheritance is thought to play a significant role. To assess the genetic component, Markus Schuerks of Brigham and Womens Hospital in Boston coordinated an international sweep of genomes in 23,230 women, 5,122 of whom suffered from migraines.