Meta-analysis of genotype data. (A) MPL-mutated cases. (B) JAK2 exon 12 mutated cases. The plots show the odds ratio (OR) and 95% confidence interval (CI) within each patient subgroup compared their corresponding population controls. The combined data show the OR and CI derived by meta-analysis of all the data after confirmation of the comparability and homogeneity of the respective datasets. *The United Kingdom MPL and JAK2 exon 12 cohorts include 1 and 2 cases, respectively, of European origin from the United States.