Gut Microbiota and Metabolic Dysfunction-Associated Steatotic Liver Disease: From Dysbiosis to Metagenomic Insights and Therapeutic Perspectives.

Metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as the most common chronic liver disorder in the pediatric population, closely paralleling the global rise in childhood obesity. Increasing evidence highlights the gut-liver axis as a key contributor to MASLD pathogenesis, with gut microbiota dysbiosis influencing hepatic steatosis through multiple interconnected mechanisms, including increased intestinal permeability, endotoxemia, altered bile acid metabolism, and modulation of host energy homeostasis. In children, the characterization of microbiota signatures associated with MASLD remains challenging due to heterogeneity across studies, age-related microbial dynamics, and methodological variability. This review synthesizes current evidence regarding the role of the gut microbiota in pediatric MASLD, focusing on pathogenetic pathways, reported microbial patterns, and microbiota-targeted therapeutic strategies, while incorporating relevant mechanistic evidence from adult studies where pediatric data remain limited. Although several taxa have been repeatedly associated with pediatric MASLD, findings are not yet sufficiently consistent for clinical application. Interventions such as probiotics, prebiotics, and dietary modulation show promising but still preliminary results, with limited high-quality pediatric trials available. A deeper mechanistic understanding and standardized study designs are needed to clarify causality and to support microbiota-based precision approaches in pediatric MASLD management.