Disentangling the relationship of gut microbiota, functional gastrointestinal disorders and autism: a case-control study on prepubertal Chinese boys

Emerging evidence of an altered gut microbiome in autism spectrum disorder (ASD) suggests a pathomechanism through the gut-brain axis despite the inconsistent microbiome profile reported across studies. One of the knowledge gaps in the existing ASD microbiota studies is the lack of systematic exploration of the role of comorbid functional gastrointestinal disorder (FGID) in the association of ASD and altered gut microbiome. Consequently, 92 ASD and 112 age-matched typically developing (TD) boys were profiled on general psychopathology, FGID status by Rome IV classification, and gut microbiota using 16S ribosomal RNA amplicon sequencing at the V4 hypervariable region. Compared to TD, a significant decrease in the within-sample abundance of taxa was observed in ASD, regardless of FGID status. The microbiota of ASD FGID+ and ASD FGID- clustered apart from the TD groups. The microbiota of ASD FGID+ also showed qualitative differences from that of ASD FGID- and had the highest-level Firmicutes: Bacteroidetes ratio, which was paralleled by elevated levels of anxiety and overall psychopathology. The altered gastrointestinal microbiota composition in ASD appeared to be independent of comorbid FGID. Further studies should address how FGID may mediate neuropsychiatric symptoms in ASD through inflammation along the microbiota-gut-brain axis.

Automated summary

Emerging evidence suggests an altered gut microbiome in autism spectrum disorder (ASD) through the gut-brain axis, despite inconsistent findings. This study highlights the lack of exploration of the role of comorbid functional gastrointestinal disorder (FGID) in the association between ASD and altered gut microbiome. The study found a significant decrease in within-sample abundance of taxa in ASD compared to typically developing (TD) individuals, regardless of FGID status. The composition of the gut microbiome in ASD with FGID displayed differences from ASD without FGID, along with higher levels of anxiety and overall psychopathology. Further research is needed to understand how FGID may impact neuropsychiatric symptoms in ASD through inflammation along the microbiota-gut-brain axis.