PSMB7 and migraine disorder: Human genetic association studies investigating KCNB2 are rare: Besides a possible SNP-SNP interaction for the risk of migraine (KCNB2 SNP rs1431656 and a SNP mapping on the beta 2 subunit of the calcium dependent voltage channel; CACNB2, [28]), a GWAS identified KCNB2 as candidate gene for a risk factor in cardiovascular disease [29].