BTBD9 and migraine disorder: A previous study identified 13 SNP markers at six RLS‐related loci (MEIS1, BTBD9, MAP2K5, PTPRD, TOX3, and an intergenic region on chromosome 2p14) in Caucasian populations, and the replication portion of the study indicated an association between rs2300478 in MEIS1 with a significantly increased risk of RLS in an Asian migraine cohort.2