Quantile-quantile plot of the GWAS data. The quantile-quantile plot of the GWAS stroke association results is shown using ∼770 000 SNPs. The GWAS compared the 177 patients with stroke with the 335 control patients without stroke. The quantile-quantile plot showed good correlation between observed and expected P values, and no evidence of genomic inflation was found (mean λ = 1.07; median λ = 1.06).