Among them, 2,3-dihydroxy-2-methyl-butyrate levels exhibited a significant mediation effect linking the DCXR gene and BPH with a mediation proportion of 22.0%, and the level of 3-methyl-2-oxovalerate linking PUS1 and PCa with mediation proportion of 15.5%, sulfate levels mediated association between TRMU and prostatitis with 5.9% (Supplementary Table S22–24). The gene discussed is DCXR; the disease is posterior cortical atrophy.