Genome-wide association of anti-PF4/heparin antibodies in the discovery cohort (A) and replication cohort (B).P values were generated using linear regression adjusted for sex, age, and PCs 1 to 3 in an additive model. P values on the −log₁₀ scale are plotted on the left vertical axis, and the chromosomal position is plotted along the horizontal axis. The significance threshold of 5 × 10⁻⁸ is indicated by the solid red horizontal line, and the suggestive significance threshold of 1 × 10⁻⁴ is indicated by the dashed red line. Betas are indicated by dot color as described in the legend on the right.