Figure 5

Combined causal effect estimates (β = beta; coloured bars indicate the direction and magnitude of the effect; yellow bars, β > 0, blue bars, β < 0) of hArg with 122 systemic metabolic measures using summary-level data from previous meta-analyses of genome-wide association studies. For each metabolite, the summary-level data across the three hArg associated SNPs (GATM rs1153858, CPS1 rs1047891 and AGXT2 rs37369) was combined using weighted linear regression, and the heterogeneity in the causal effects from different individual variants was tested by Cochran’s Q statistic. All p-values for combined causal effects >0.05. A p-value of >0.05 from Cochran’s Q statistic indicates that there is no more heterogeneity between causal effects estimated using the variants individually than would be expected by chance. The numbers of individuals used to estimate SNP–metabolite associations vary between 8 905 and 24 924, depending on the metabolite.