Fig. 1

Study Design Overview. (a) A detailed flowchart illustrating the steps taken to assess the role of circulating metabolites as mediators in the effect of Probucol on Behçet’s disease. This includes the identification of genetic instruments and the evaluation of causal pathways. (b) A schematic representation of the two-step Mendelian randomization (MR) process, where the first step evaluates the association between Probucol (via ABCA1) and circulating metabolites, and the second step assesses the link between these metabolites and Behçet’s disease.