Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social communication and interaction problems. The prevalence of ASD is increasing globally, with a higher ratio of males to females. Gastrointestinal symptoms are common in individuals with ASD, and gut microbiota has been implicated in the disorder's development. This study aimed to investigate the gut microbiota alteration in Thai individuals with ASD compared to healthy controls using 16S rRNA gene sequencing. The influence of gender and age on gut microbiota composition and function was also examined. A total of 65 ASD individuals and 30 neurotypical (NT) individuals were included in the analysis. The results revealed notable differences in gut microbiota composition between the ASD and NT groups, with variations observed in microbial richness and the presence of enriched microbial taxa. These differences were influenced by both gender and age. Fusobacteriota, Fusobacteriaceae, and Fusobacterium were found to be enriched in individuals with ASD. Furthermore, the study identified gender-related taxa, such as Bacteroides plebeius, enriched in ASD females. Age-related taxa, including Veillonella, known to be associated with poor oral hygiene, were also observed in ASD children. The analysis of differentially abundant pathways highlighted the enrichment of various metabolic pathways in individuals with ASD, including those related to endocrine-disrupting chemicals. These findings underscore the importance of considering gender and age when studying gut microbiota in ASD. They provide valuable insights into the potential role of gut microbiota dysbiosis in ASD pathogenesis and highlight the influence of environmental factors.