The first genome-wide association study in patients with migraine without aura—the most common form of migraine—has revealed susceptibility loci for this disorder. Comparing genomes of 2,326 German and Dutch patients with those of 4,580 controls, the researchers identified single nucleotide polymorphisms associated with the disorder, which were then carried forward to replication studies in large, independent cohorts. Two susceptibilty loci were identified: one at 1q22, in the MEF2D gene, and one at 3p24, near the TGFBR2 gene.