FHL5 and Cluster headache: Results: Four independent lead SNPs (r2 < 0.1) were identified in relation to cluster headache with genome-wide significance (p < 5 × 10-8) and notably large effect sizes, rs11579212 (odds ratio (OR) = 1.51, 95% CI 1.33-1.72 near RP11-815M8.1), rs6541998 (OR = 1.53, 95% CI 1.37-1.74 near MERTK), rs10184573 (OR = 1.43, 95% CI 1.26-1.61 near AC093590.1), and rs2499799 (OR = 0.62, 95% CI 0.54-0.73 near UFL1/FHL5), collectively explaining 7.2% of the total variance of cluster headache.