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. • Individuals with ASD consistently exhibit distinct oral microbiota dysbiosis across studies. • Periopathogenic taxa such as Porphyromonas and Tannerella are enriched in ASD populations. • Oral dysbiosis may trigger systemic inflammation through IL-6 and TNF-α signaling pathways. • Oral microbes generate neuroactive metabolites that can influence neurodevelopmental processes. • Experimental models show ASD-associated oral microbiota can induce ASD-like behaviors in mice. • Modulating the oral microbiome offers promising avenues for biomarkers and therapeutic strategies in ASD.
Burch et al. (2026) studied this question.