AUTHOR=Liu Wei , Yan Hanlei , Jia Wanying , Huang Jingjing , Fu Zihao , Xu Wenyao , Yu Hui , Yang Weili , Pan Weikang , Zheng Baijun , Liu Yong , Chen Xinlin , Gao Ya , Tian Donghao TITLE=Association between gut microbiota and Hirschsprung disease: a bidirectional two-sample Mendelian randomization study JOURNAL=Frontiers in Microbiology VOLUME=Volume 15 - 2024 YEAR=2024 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1366181 DOI=10.3389/fmicb.2024.1366181 ISSN=1664-302X ABSTRACT=Background: Several studies have pointed to the critical role of gut microbiota (GM) and their metabolites in Hirschsprung disease (HSCR) pathogenesis. However, the detailed causal relationship between GM and HSCR remains unknown. Methods: In this study, we used two-sample Mendelian Randomization (MR) analysis to investigate the causal relationship between GM and HSCR, based on the MiBioGen Consortium's genome-wide association study (GWAS) and the GWAS Catalog's HSCR data. Reverse MR analysis was performed subsequently, and the sensitivity analysis, Cochran's Q test, Mendelian randomization pleiotropy residual sum, outlier (MR-PRESSO), and the MR-Egger intercept to analysis heterogeneity or horizontal pleiotropy. 16sRNA sequencing and targeted mass spectrometry were developed for initial validation. Results: In the forward MR analysis, inverse variance weighted estimates suggested that Eggerthella (OR: 2.66, 95%CI: 1.23-5.74, P = 0.01) was a risk factor for HSCR, while Peptococcus (OR: 0.37, 95%CI: 0.18-0.73, P=0.004), Ruminococcus2 (OR: 0.32, 95%CI: 0.11-0.91, P = 0.03), Clostridiaceae1(OR: 0.22, 95%CI: 0.06-0.78, P = 0.02), Mollicutes RF9 (OR: 0.27, 95%CI: 0.09-0.8, P = 0.02), Ruminococcaceae (OR: 0.16, 95%CI: 0.04-0.66, P = 0.01) and Paraprevotella (OR: 0.45, 95%CI: 0.21-0.98, P = 0.04) were protective factors for HSCR, which had no heterogeneity or horizontal pleiotropy. However, reverse MR analysis showed that HSCR (OR: 1.02, 95%CI: 1-1.03, P = 0.049) is the risk factor for Eggerthella. Furtherly, some of above microbiota and short-chain fatty acids (SCFAs) altered in HSCR, showing correlated. Conclusions: Our analysis established the relationship between specific GM and HSCR, identifying specific bacteria as protective or risk factors. Significant microbiota and SCFAs altered in HSCR, underlining the importance for further study and could provide new insights into the pathogenesis and treatment.