Childhood dysbiosis associated with autism and regressive autism: a systematic review

Abstract

Autism Spectrum Disorder (ASD) encompasses a heterogeneous set of early-onset neurodevelopmental conditions characterized by alterations in communication, social interaction, and behavior. Among these conditions, Regressive Autism (RA) stands out, in which children experience a loss of previously acquired skills and begin to manifest typical spectrum symptoms, generally within the first two years of life. Studies indicate that individuals with ASD frequently present significant gastrointestinal disorders associated with alterations in the gut microbiota, favoring the growth of potentially pathogenic microorganisms. In this context, this study aimed to analyze the relationship between the gut microbiota and the manifestation of autistic symptoms, as well as the impact of gastrointestinal disorders on the modulation of this microbiota from infancy. This is a systematic literature review, developed to identify current evidence on intestinal dysbiosis in children with ASD and RA, compared to neurotypical children. Studies that used randomized control groups (siblings or blood relatives) were included, in which genetic sequencing was performed to identify and compare gut microbiota bacteria. Analysis of the results revealed agreements and disagreements between the studies, indicating alterations in the microbiota of children with ASD compared to controls, except in studies with large cohorts or controls composed only of siblings. However, there was no consensus regarding specific taxa or bacterial proportions associated with ASD, highlighting the need for future research with more standardized methodologies for a better clinical, diagnostic, and therapeutic understanding of autism spectrum disorder.

Keywords: Autism Spectrum Disorder; regressive autism; dysbiosis; gut microbiota; gastrointestinal symptoms.