As numerous small studies contribute to PGC1.5 (24 EUA studies with N < 200 cases, Supplementary Table 3), we first investigated the contribution of small studies to the overall genetic signal and genetic similarity to the larger PGC1.5 cohorts. The combined subset of small studies showed significant overall heritability (h2SNP = 0.12, P = 0.046) and close to significant genetic correlation with large studies (rg = 0.45, P = 0.08), indicating a meaningful genetic contribution in aggregate.
