Urinary Uremic Toxin Signatures and the Metabolic Index of Gut Dysfunction (MIGD) in Autism Spectrum Disorder: A Stool-Phenotype-Stratified Analysis.

Researchers studied gut-related toxins in the urine of children with autism compared to typical children, looking at different stool types. They created a new measure called MIGD that combines several toxins. Children with autism who had hard stools showed different toxin patterns than those with loose stools, suggesting their gut bacteria work differently. This could help identify different types of gut problems in autism and guide personalized treatments.

This study examined five gut-derived uremic toxins in urine samples from 97 children with autism spectrum disorder (ASD) and 71 neurotypical controls, stratified by stool consistency patterns. Researchers developed a novel composite biomarker called the Metabolic Index of Gut Dysfunction (MIGD) combining four toxins. While individual metabolite levels showed no significant differences, analysis by stool phenotype revealed distinct patterns. ASD children with hard stools showed elevated levels suggesting phenolic fermentation dominance, while those with loose stools had lower MIGD values indicating enhanced indole metabolism.

The findings suggest MIGD may serve as a biomarker to stratify metabolic phenotypes in autism, linking urinary metabolite patterns to gut function.

MIGD may serve as a novel biomarker for stratifying metabolic phenotypes in ASD children, potentially guiding precision microbiota-targeted interventions. The link between stool consistency and urinary metabolite patterns could inform personalized gut health approaches in autism care.

Small sample size, cross-sectional design, and lack of longitudinal data limit generalizability. The study requires validation in larger cohorts. Stool phenotype stratification reduces subgroup sizes, potentially affecting statistical power.

Gut-derived uremic toxins may play a key role in neurodevelopmental conditions such as autism spectrum disorder (ASD) via host-microbe metabolic interactions. We evaluated five uremic toxins-p-cresyl sulfate (PCS), indoxyl sulfate (IS), trimethylamine N-oxide (TMAO), asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA)-in urine samples of 97 children with ASD and 71 neurotypical controls, stratified by Bristol Stool Chart (BSC) consistency types. Four of these toxins (PCS, IS, TMAO, ADMA) were integrated into a novel composite biomarker called the Metabolic Index of Gut Dysfunction (MIGD), while SDMA was measured as a complementary renal function marker. While individual metabolite levels showed no statistically significant differences, group-wise analysis by stool phenotype revealed distinct trends.

ASD children with hard stools (BSC 1-2) showed elevated PCS levels and the MIGD score (median 555.3), reflecting phenolic fermentation dominance with reduced indolic detoxification. In contrast, children with loose stools (BSC 6-7) had the lowest MIGD values (median 109.8), driven by higher IS and lower ADMA concentrations, suggestive of enhanced indole metabolism. These findings indicate that MIGD may serve as a novel biomarker to stratify metabolic phenotypes in ASD, linking urinary metabolite patterns to gut function. Further validation in larger and longitudinal cohorts is warranted to confirm its potential utility in precision microbiota-targeted interventions.