To evaluate the consistency of the causal estimate of all SNPs observed, the variability in the estimates obtained for each SNP was calculated and heterogeneity was only significant in association with IgA level and lower respiratory infections in previous GWAS studies (MR Egger, p = 0.0089 and inverse variance weighted, p = 0.016, Table S27) but none in our suggested model (Table S28). Here, CD79A is linked to respiratory tract infectious disorder.