Research continues on the potential relationship between individuals with autism and gastrointestinal issues, such as constipation, diarrhea, bloating, and vomiting. Recently, researchers have begun to find links between microbial composition and neurodevelopmental disorders. A new study revealed that autism spectrum disorder is associated with specific changes in the composition and function of a wide range of gut microbiota. The findings pave the way for the development of a precise diagnostic test for this condition, according to New Atlas citing the journal Nature Microbiology.
**Stomach Bacteria as the Cause of the Affliction**
The researchers noted that the central role of the microbiome in regulating the gut-brain axis and impacting health has gained significant importance over the past decade. Previous research has linked gut bacteria composition to brain-related conditions such as depression, post-traumatic stress disorder, Alzheimer’s disease, and multiple sclerosis.
**A Complex Neurological Disorder**
New research conducted by Chinese University of Hong Kong found that changes in the composition and function of both bacterial and non-bacterial microorganisms are associated with autism spectrum disorder, a complex neurological condition that affects how a person interacts with others, communicates, learns, and behaves. While the cause of autism remains unknown, it is believed to result from a complex interaction of genetic and environmental factors. The study also showed that the gut communicates directly with the brain, potentially contributing to the development of autism spectrum disorder.
Researchers adopted this hypothesis and conducted a metagenomic analysis of stool samples from 1,627 children aged between one and 13 years. Metagenomics studies the structure and function of diverse genetically present organisms in a large sample, including bacteria, viruses, fungi, and archaea, which are single-celled organisms lacking a nucleus.
When researchers compared the changes in gut microbiota diversity between typically developing children and those with autism spectrum disorder, they found that children with autism exhibited a decrease in the diversity of archaea, bacteria, and viruses. The relative abundance of 80 out of 90 identified microbial types significantly decreased in children with autism compared to typically developing children. This discovery was particularly evident for bacterial communities, where 50 bacterial species were depleted in children with autism, with only one species enriched.
Researchers also found that microbial function was affected, showing changes in microbial genes and metabolic pathways in children with autism spectrum disorder.
**Microbial Panel and Accurate Diagnosis**
In light of the metagenomic information, researchers developed a microbial panel consisting of 31 markers, and a machine learning model was used to test it. The results revealed that the microbial panel accurately diagnosed autism spectrum disorder across various ages, genders, populations, and geographical locations, much better than using a single type of microorganism like bacteria.
The researchers indicated that the critical roles of non-bacterial microorganisms, such as archaea, fungi, and viruses, in the gut-brain axis had previously been recognized. In this study, a comprehensive multi-kingdom and functional microbiome analysis was conducted using over 1,600 genomes across five independent groups of children. It was shown that ancient, fungal, and viral species, as well as functional microbiome pathways, could also differentiate children with autism from those considered typical.
Additionally, it was demonstrated that the model based on the 31 multi-kingdom marker panel achieved high predictive values for diagnosing autism spectrum disorder. Researchers emphasized that their study paves the way for developing diagnostic tests for autism spectrum disorder in the future. They also noted the need for further studies to investigate the interaction between known genetic markers for autism spectrum disorder and microbiome panels to determine if diagnostic accuracy can be improved for earlier diagnosis of autism spectrum disorder.
