From mouth to mind: Investigating oral microbial contributions to autism spectrum disorder

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by persistent social communication challenges and restricted, repetitive patterns of behavior. ASD arises from both genetic and environmental influences. Growing evidence also points to microbial dysbiosis, especially in the gut and mouth, as a potential contributor to neurodevelopment and symptom patterns. While gut microbiome alterations have been well documented in ASD, the oral microbiota has received comparatively less attention, despite its established roles in systemic inflammation, immune regulation, and even neurological function. Understanding these microbial shifts may help identify early biomarkers and guide oral health interventions to improve outcomes in ASD populations. This narrative review synthesizes current knowledge on the relationship between oral microbiota dysbiosis and ASD, with three primary objectives: (1) to characterize oral microbiome alterations observed in individuals with ASD compared to neurotypical controls; (2) to explore potential mechanisms linking oral dysbiosis to core and comorbid ASD symptoms; and (3) to evaluate therapeutic strategies targeting the oral microbiome as potential interventions for ASD.