This multi-omics MR study links mitochondrial genes, particularly FXN, to urolithiasis risk. Although colocalization evidence was weak (PP.H4 = 0.0239) and replication in independent cohorts was not statistically significant, the multi−omics consistency across methylation, expression, and protein levels prioritizes FXN as a hypothesis−generating candidate for further investigation. Because all QTL data are blood− or plasma−derived, this study provides blood/plasma QTL−based genetic prioritization rather than kidney−specific causal inference.