Genome-wide Mendelian randomization implicates metabolism-related gene expression in inflammatory bowel disease in European populations

BACKGROUND: The impact of metabolism-related genes on inflammatory bowel disease remains unclear. This study aimed to identify the causal relationships between metabolism-related genes and inflammatory bowel disease. METHODS: We performed summary-data-based Mendelian randomization analysis to investigate the associations of metabolism-related genes with inflammatory bowel disease. RESULTS: In the first priority, genetically predicted SORD (CD: odds ratio [OR], 0.716, 95% confidence interval [CI], 0.647-0.791; UC: OR, 0.720, 95% CI, 0.647-0.802), NDUFB2 (CD: OR, 0.814, 95% CI, 0.765-0.866; UC: OR, 0.820, 95% CI, 0.778-0.864), HS2ST1 (CD: OR, 0.765, 95% CI, 0.687-0.853; UC: OR, 0.781, 95% CI, 0.711-0.859), and SDHC (CD: OR, 0.896, 95% CI, 0.857-0.936; UC: OR, 0.908, 95% CI, 0.874-0.943) expression were associated with decreased CD and UC risk. Conversely, genetically predicted higher expression of SRD5A3 (CD: OR, 1.175, 95% CI, 1.118-1.235; UC: OR, 1.134, 95% CI, 1.074-1.197), CDO1 (CD: OR, 1.202, 95% CI, 1.126-1.284; UC: OR, 1.264, 95% CI, 1.162-1.375), and FADS2 (CD: OR, 1.127, 95% CI, 1.072-1.184; UC: OR, 1.189, 95% CI, 1.114-1.268) were associated with increased CD and UC risk. In the second priority, we found MOCOS (OR: 1.174, 95% CI: 1.108-1.244) was presumptively associated with CD, the NAGA (OR: 0.812, 95% CI: 0.744-0.886) and ATP6V1D (OR: 1.236, 95% CI: 1.123-1.362) were associated with UC. CONCLUSION: This study provides genetic support for a potential causal relationship between metabolism-related genes and the risk of inflammatory bowel disease. Our findings should be interpreted with caution given the inherent limitations of Mendelian randomization analysis, and further research is warranted to validate these results.