Evaluation of causal relationships between genetic liability to inflammatory bowel disease and autism spectrum disorder by Mendelian randomization analysis

BACKGROUND: Emerging observational studies have indicated the association between autism spectrum disorder (ASD) and IBD, including Crohn's disease (CD) and ulcerative colitis (UC), whereas the causality remains unknown. METHODS: Summary-level data from large-scale genome-wide association (GWAS) studies of IBD and ASD were retrieved. Mendelian randomisation analyses were performed with a series of sensitivity tests. CONCLUSION: Our findings indicate genetic predisposition to ASD might not increase the risk of IBD, whereas genetic liability to IBD is associated with an increased risk of ASD. Further investigations using more powerful datasets are warranted.