Mapping the Geographical Distribution of the Mucosa-Associated Gut Microbiome in GI-Symptomatic Children with Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by cognitive, behavioral, and communication impairments. In the last few years, it has been proposed that alterations in the gut microbiota may contribute to an aberrant communication between the gut and brain in children with ASD. Consistent with this notion, several studies have demonstrated that children with ASD have an altered fecal microbiota compared to typically developing (TD) children. However, it is unclear where along the length of the gastrointestinal (GI) tract these alterations in microbial communities occur. Additionally, the variation between specific mucosa-associated communities remains unknown. To address this gap in knowledge of the microbiome associated with ASD, biopsies from the antrum, duodenum, ileum, ascending colon, and rectum of children with ASD and age- and sex-matched TD children were examined by 16s rRNA sequencing. We observed an overall elevated abundance of Bacillota and Bacteroidota and decreased abundance of Pseudomonadota in all GI tract regions of both male and female ASD children compared to TD children. Further analysis at the genera level revealed unique differences in the microbiome in the different regions of the GI tract in ASD children compared to TD children. We also observed sex-specific differences in the gut microbiota composition in children with ASD. These data indicate that the microbiota of ASD children is altered at multiple regions of the GI tract and that different anatomic locations have unique alterations in mucosa-associated bacterial genera.