Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by deficits in social communication and interaction, alongside restricted, and repetitive behaviors. Emerging evidence suggests that gut microbiota alterations may contribute to ASD pathogenesis via the gut-brain axis. However, many previous studies have not adequately controlled for confounding genetic and environmental variables. In this study, we examined the gut microbiota profiles of 19 children with ASD, 8 siblings with non-ASD, and 36 parents from 17 families, providing a unique design that minimized biases related to shared genetic and familial environments. Metagenomic sequencing revealed significant differences in gut microbiota diversity and composition between groups. Specifically, children with ASD had lower abundances of Bifidobacterium and higher abundances of both Bacteroides and Clostridium species compared to their siblings, with notable dysbiosis correlated to ASD-specific symptoms. These findings highlight the potential role of microbiota alterations in ASD pathogenesis and suggest familial microbiota traits influenced by both genetic and environmental factors. Further exploration of gut microbial therapies could offer promising avenues for ASD intervention.