Association of rs342293 with platelet expression and function. (A) Heatmap of mRNA expression for 6 genes within a 1-MB interval. VST-transformed signal intensities were median-normalized, and values were averaged across biologic replicates in erythroblasts (EB; n = 4), megakaryocytes (MK; n = 4), and platelets (n = 35, whereby expression values were averaged based on rs342293 genotype). Signal intensities obtained with platelets were normalized independently from the MK and EB samples. (B) Boxplots of associations between rs342293 genotype and mRNA levels in 35 platelet samples, shown for the 2 genes with expression above detection level (PIK3CG and PRKAR2B). (C) Association of rs342293 genotypes with measurements of platelet reactivity in the Platelet Function Cohort. (Top) Standardized residuals of logit transformed levels of P-selectin expression (left), and fraction of platelets binding fibrinogen (middle) or annexin V (right) in response to the collagen mimetic CRP-XL. (Bottom) P-selectin expression and fibrinogen binding in response to ADP. Horizontal bars indicate averages and error bars indicate 1 standard deviation.