The brain-gut axis in autism spectrum disorder: from gastrointestinal dysfunction to neuroimmune mechanisms

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by social deficits and repetitive behaviors, often accompanied by gastrointestinal (GI) symptoms such as constipation, diarrhea, and abdominal pain. Emerging evidence highlights the gut-brain axis as a key pathway linking GI dysfunction to ASD pathophysiology. This review synthesizes current findings on the interplay among dietary patterns, gut microbiota dysbiosis, intestinal barrier dysfunction, and neuroimmune activation in ASD. We also discuss shared genetic vulnerabilities and environmental factors influencing both gut and brain function. Finally, we evaluate microbiota-targeted interventions, including probiotics and fecal microbiota transplantation, as potential therapeutic strategies. Understanding these mechanisms may inform personalized approaches to managing GI and behavioral symptoms in ASD.