BackgroundChildren with autism spectrum disorder (ASD) commonly exhibit gut microbiota dysbiosis and metabolic abnormalities, yet the mechanisms linking these changes to clinical symptoms remain unclear.ObjectiveThis study employed a nested case–control design and multi-omics approaches to evaluate the effects of rehabilitation intervention on clinical symptoms and gut microbiota in children with ASD, identify distinct microbial-metabolic signatures, and explore their mechanistic links with sleep disorders and developmental abilities.MethodsWithin a prospectively established pediatric cohort (n = 45), we implemented a nested case–control design including 26 ASD children (18 males, 8 females; mean age 61.79 ± 11.15 months) and 19 age- and sex-matched healthy controls. All ASD participants received standardized rehabilitation therapy (2 h/day, 5 days/week for 6 months) comprising occupational therapy and cognitive-linguistic training. Primary outcomes included comprehensive clinical assessments [Griffiths Development Scales-Chinese (GDS-C), Children’s Sleep Habits Questionnaire (CSHQ), Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS)] and longitudinal multi-omics analysis (metagenomic sequencing and LC–MS-based metabolomics). Association analyses were performed with FDR correction (q < 0.05).ResultsFollowing the 6-month rehabilitation intervention, significant clinical improvements were observed in sleep quality (CSHQ total and subscores) and developmental performance (GDS-C). Multi-omics profiling revealed distinct biological signatures in ASD children compared to healthy controls, characterized by elevated Intestinibacter_bartlettii and reduced levels of ornithine and siderophore nonribosomal peptide biosynthesis. Crucially, correlation analysis demonstrated that, after FDR correction, ornithine levels were significantly positively correlated with multiple GDS-C developmental domains, while tyrosine was associated with parasomnias. These findings establish a potential mechanistic link where amino acid metabolism connects gut microbial shifts to clinical phenotypes.ConclusionThis study demonstrates that rehabilitation intervention synchronously ameliorates clinical symptoms and modulates the gut-metabolic profile in ASD. The identified associations between specific metabolites (ornithine and tyrosine) and clinical outcomes suggest a metabolic mechanism underlying the gut-brain axis, highlighting the potential of these metabolites as biomarkers for therapeutic monitoring. Further large-scale studies are needed to validate these findings.

