Childhood gut microbiome affects toddler’s social behaviour

The gut microbiome in early childhood may play a role in the development of autism spectrum disorder (ASD) at 3 years of age, a recent study has found.

To measure gut bacterial diversity, structure, taxa, and function, the researchers performed 16S ribosomal RNA gene and shotgun metagenomic sequencing across four timepoints: 6 weeks (n=166), 1 year (n=158), 2 years (n=129), and 3 years (n=140). The Social Responsiveness Scale (SRS-2) was used to evaluate ASD-related social behaviours at age 3 years.

Total SRS-2 T-scores were generally lower and had a narrower distribution than a nationally representative reference, suggesting better social behaviours. As was expected, the researchers documented increasing gut bacterial within-subject diversity across time points.

In general, higher within-subject diversity correlate with better SRS-2 T-scores across most time points, but none of the interactions achieved statistical significance. However, within-subject diversity at 6 weeks seemed to have a stronger magnitude of effect on SRS-2 T-scores at 3 years.

Looking at individual taxa, the researchers found that the relative abundance of specific groups likewise correlated significantly with social behaviours. For example, relative enrichment of the Coprococcus and Bifidobacterium genera at 2 years were significantly associated with worse social behaviour at 3 years of age.

Metagenomic data expanded this finding further. The abundance of Flavonifactor plautii at 6 weeks correlated with worse SRS-2 T-scores at 3 years, as did Ruminococcus torques and Eubacterium dolichum at 1 year.

“Further research is warranted to elucidate mechanisms and to determine whether features of the gut microbiome can be used to identify ASD during a vulnerable window during which time interventions can optimize neurodevelopmental outcomes,” the researchers said.