Objectives/Goals: Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with unclear biological causes, potentially influenced by the gut-brain axis. This study sought to explore the infant gut microbiome to identify whether specific changes in the microbiota during early infancy are associated with later diagnosis of ASD. Methods/Study Population: Study participants included a subset of children from MARBLES (Markers of Autism Risk in Babies – Learning Early Signs), an ASD enriched-risk cohort study. Infant stool samples were collected from these children between 0 and 7 months of age. At 36 months of age, children were clinically classified as having ASD (n=42), or non-typically developing without ASD (Non-TD, n=16), or typically developing (TD, n=79). The fecal microbiome was investigated using 16S rRNA gene sequencing to evaluate whether the gut microbial composition during early infancy was associated with later neurodevelopmental diagnoses. Results/Anticipated Results: Overall, no significant differences in alpha diversity or beta diversity, or bacterial abundance, were found between groups of infants who developed ASD or Non-TD compared to those who went on to have TD. However, our findings highlight some early alterations in gut microbial composition during infancy that may relate to later neurodevelopmental outcomes. For example, infants who developed ASD showed slightly lower Veillonella and Flavonifractor levels, suggesting minor early microbial distinctions potentially linked to neurodevelopment. These differences are less pronounced than the effects of delivery mode or diet on the infant gut microbiome. Discussion/Significance of Impact: Although we found no significant differences in bacterial abundance in early infancy linked to later neurodevelopmental outcomes, our results highlight minor microbial shifts that align with findings in older children with ASD, which may indicate early gut microbiome dysbiosis, but further research is needed.
Sotelo-Orozco et al. (Wed,) studied this question.