Study Finds Unique Gut Flora in Children with Autism

The traditional process for diagnosing autism heavily relies on a parent's description of their child's behavior and a professional's observations. This subjective approach leaves plenty of room for human error. Parents' concerns may skew their responses on questionnaires, providers may hold biases that lead to underdiagnosis in certain groups, and children may show widely varying symptoms depending on various factors.

Now, in a study published in Nature Microbiology, researchers have added strong evidence to the idea that the gut microbiome could help create more accurate autism diagnosis.

For decades, researchers have studied the human genome, medical histories, and brain scans for a reliable indicator of autism spectrum disorder, with limited success. Although the Food and Drug Administration has approved two diagnostic tests based on eye-tracking software, these require significant involvement from a psychiatrist.

The new study analyzed more than 1,600 stool samples from children aged 1 to 13 and discovered several distinct biological markers in the samples of autistic children. These unique traces of gut bacteria, fungi, viruses, and other microorganisms could serve as the basis of a diagnostic tool. Such a tool based on biomarkers could help professionals diagnose autism sooner, allowing children to access more effective treatments at a younger age.

In the past 15 years, some researchers have begun investigating whether stool samples, which provide a window into the trillions of fungi, bacteria, and viruses living in the intestines, might offer clearer diagnostic answers. Until now, most of those studies relied on small groups and often produced mixed results.

The idea that the gut microbiome might play a role in the development of autism remains controversial among researchers. However, the new study used machine learning to identify significant biological differences between the stool samples of autistic children and others.

Unlike past studies that focused mainly on intestinal bacteria, this research included other microorganisms in the gut, such as fungi, archaea, and viruses, as well as related metabolic processes. The scientists identified 31 biological signatures distinguishing the groups. They then tested these markers on an entirely new group of samples, successfully identifying which stool samples belonged to children with autism almost all the time.

While more research is needed to confirm that these biomarkers are valid indicators of autism, this study marks a significant step forward. If confirmed, these findings could revolutionize the way autism is diagnosed, leading to earlier and more accurate diagnoses and, ultimately, better outcomes for children with the disorder.

Reference: Su, Q., Wong, O.W.H., Lu, W. et al. Multikingdom and functional gut microbiota markers for autism spectrum disorder. Nat Microbiol (2024). https://doi.org/10.1038/s41564-024-01739-1