Gut microbiome in biliary atresia.

Biliary atresia (BA) is a progressive cholangiopathy of infancy and the leading cause of pediatric liver transplantation. Despite surgical intervention with the Kasai portoenterostomy, long-term outcomes remain poor, with many patients progressing to cirrhosis. Emerging evidence implicates the gut microbiota-a dynamic ecosystem crucial to immune development and liver homeostasis-in BA pathogenesis and clinical progression. This review synthesizes current literature on gut microbiota composition in BA before and after the Kasai procedure, highlighting consistent patterns of dysbiosis, including pathobiont expansion and depletion of beneficial microbes such as Bifidobacterium. The review explores associations between microbial profiles and clinical outcomes-highlighting potential mechanisms involving bile acid metabolism, microbial translocation, and immune modulation. Further understanding of gut-liver-microbiota interactions in BA may inform microbiome-targeted therapies to improve native liver survival.