Common Gut Microbial Signatures in Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder

ABSTRACT The potential etiological and diagnostic values of the gut microbiota in children with neurodevelopmental disorders are encouraging but controversial. In particular, the composition and characteristics of the gut microbiota in autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) remain largely unidentified. Herein, we analyzed stool samples from 113 participants with a clinical diagnosis of ASD, 43 with ADHD, 8 with both ASD and ADHD, and 120 healthy controls between 2 and 11 years of age using 16S rRNA sequencing. We observed that clinical diagnosis, age, comorbidities, food sensitivities, and antibiotic use significantly affected the gut microbiota. The enriched genera in the control group were relatively common and dominant human gut bacteria, such as Bacteroides , Faecalibacterium , and Roseburia . The genera present in children with neurodevelopmental disorders showed greater heterogeneity, and the abundance of Bifidobacterium was consistently increased. We found 4899 deregulated microbial metabolic functions and revealed the formation of a divergent genus‐level network in patients. This analysis demonstrated that the gut microbial signatures efficiently discriminated patients from healthy participants in both the discovery (area under the curve [AUC]: 0.95–0.98) and validation (AUC: 0.69–0.74) sets. Importantly, although ASD and ADHD share several gut microbial characteristics, specific bacteria that contribute to the disease pathogenesis may have different metabolic functions.