In the EUR sample, the SNP-based heritability (h2SNP) (i.e. proportion of variance in liability attributable to all measured SNPs) was estimated13 to be 0.24 (SE 0.007). Using the all ancestry primary GWAS as the discovery sample, polygenic risk score (PRS) analysis explained a median of 0.073 of variance in liability (SNPs with GWAS p<0.05), and 0.024 when restricted to genome-wide significant SNPs. For almost all cohorts, PRS had more explanatory power based on risk alleles derived from the larger combined ancestry GWAS than from the matched ancestry GWAS; given the ancestry specific sample sizes, unsurprisingly9, this effect was strongest for the non-EUR samples (Extended Data Figure 2 Supplementary Table 5).
