JAK2 and myeloproliferative disorder: For each trait, we built a linear regression model with predictors that included the corresponding PGS (for example, PGSHGB), demographic variables (age and sex), JAK2 46/1 haplotype status (due to its influence on hematological traits23,24) and somatic mutation status for genes frequently (>20 patients) mutated in the MPN patient cohort (Fig. 2b).