AI Insight
This large-scale multi-ancestry genome-wide association study (GWAS) analyzed 125,992 IBD patients and over 1.2 million controls to identify 619 independent genetic risk signals for Crohn's disease and ulcerative colitis, including 374 previously unknown ones, collectively explaining 77-80% of SNP-based heritability. Fine-mapping and integrative genomic analyses — combining eQTL, pQTL, colocalization, and Mendelian randomization approaches — allowed researchers to pinpoint high-confidence causal variants and prioritize 664 candidate effector genes, 390 of which had not been previously linked to IBD. The study also revealed distinct biological mechanisms underlying CD versus UC, including subtype-specific enrichment in intestinal epithelial cell types for UC and stronger links to systemic inflammatory biomarkers for CD, as well as a potential causal role of low HDL cholesterol in Crohn's disease risk.
Why it matters
The identification of 390 newly implicated IBD genes and their cellular contexts provides a substantially expanded foundation for understanding disease mechanisms and offers concrete human-genetics-supported targets for drug development, potentially accelerating the design of more precise and subtype-specific therapies for patients with Crohn's disease or ulcerative colitis.
⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Inflammatory bowel diseases (IBD), principally Crohn’s disease (CD) and ulcerative colitis (UC), are common chronic disorders involving inflammation and often progressive tissue damage. Genome-wide association studies have mapped many risk signals, but the causal variants, effector genes and relevant cellular contexts remain difficult to resolve, limiting mechanistic interpretation and therapeutic translation. Here we performed a multi-ancestry GWAS meta-analysis of 125,992 individuals with IBD and more than 1.2 million controls, identifying 619 independent association signals (374 novel) at 420 IBD regions that account for 77-80% of SNP-based heritability. Fine-mapping resolved 81 high-confidence variants, 41 not previously reported. Although most signals were shared between CD and UC, 39% showed subtype specificity, with UC signals showing stronger enrichment in functional annotations from intestinal epithelial, secretory and enteroendocrine cells, and CD showing stronger genetic correlations with circulating inflammatory biomarkers, including C-reactive protein and glycoprotein acetylation. Latent causal modelling supported a causal effect of decreased high-density lipoprotein on CD risk. By integrating bulk and single-cell eQTL and pQTL resources using colocalisation and Mendelian randomisation, together with coding-variant evidence from exome sequencing, we prioritised 664 candidate effector genes across 341 signals, including 390 newly implicated IBD genes, revealing new biological mechanisms and candidate therapeutic targets supported by human genetics.
Source: Resolving inflammatory bowel disease risk variants to genes and cell types