We estimated the heritability of IS explained by the metaGRS, on the liability scale, using the R2 and partial R2 obtained from linear regression of the stroke outcomes on metaGRS (partial R2 was from linear regression adjusted for sex, age of assessment, genotyping chip, and 10 PCs). The estimates were converted to the liability scale54, assuming that the IS prevalence in UKB represents that of the general population (K = 0.008). Due to a lack of robust estimates of the heritability of stroke, we examined a range of plausible h2 values from 0.1 to 0.4, yielding estimates of explained heritability ranging from 7.7 to 1.8%, respectively (Supplementary Fig. 10).
