Fig. 1

Flowchart showing the pipeline of the variant-phenotype association study. We determined the genotypes and phenotypes of patients with migraine using arrays and a questionnaire, respectively, and the patients were divided based on the onset age of migraine (AoM). In the first stratification, we selected 12-year-old as a limit to separate the patients based on their onset age of migraine into before and after 12-year-old groups in a phenotype association study. We also applied all the migraine cohorts to a quantitative trait association study. The results are shown in Table 2; Fig. 2. In the second stratification, we separated the samples from two studies into two groups based on the presence and absence of aura. The results of the quantitative trait association study in the second stratification are shown in Table 3; Fig. 3