Link between autism and gut microorganisms discovered

A new study, the most detailed to date, has found a link between autism and the gut microbiome (the microorganisms that inhabit the digestive tract).

The findings, which show that children's gut microbiomes, including bacteria, fungi and viruses, may contribute to autism, could be used to diagnose the condition in the future, the researchers said.

Autism, also called autism spectrum disorder (ASD), is a lifelong developmental condition that affects the way a person communicates, interacts, and processes information.

The new analysis looked not only at the bacteria in the digestive tract, but also at the fungi and viruses that can be found there.

The team, led by researchers from the Chinese University of Hong Kong, developed a comprehensive test that reveals a link between changes in the composition of the entire gut microbiome and a diagnosis of autism spectrum disorder.

While this link is still unclear, the emerging evidence is providing new ways to diagnose and understand autism.

More evidence is gathering about the link between altered gut microbiome composition and autism, although the cause of the association has yet to be confirmed. But there’s still a lot we don’t know about how our gut microbiome—the microorganisms that live inside our digestive tract—affects our mood, our thoughts, and even our decision-making.

Previous research on the link between the microbiome and autism has focused only on differences in bacteria. To explore this phenomenon in more detail, gastroenterologist Siu Ng of the Chinese University of Hong Kong and colleagues expanded their focus to include the entire gut metagenome (the study of genetic material extracted directly from environmental samples).

They sequenced stool samples from 1,627 children, both with and without autism, and looked at all the different microbes that could be found in them.

This analysis revealed some striking differences in the microbiomes of children with autism.

They found that specific bacterial and non-bacterial components of the gut microbiome and their functions could contribute to autism spectrum disorder (ASD) in both male and female children.

Taking into account additional factors including diet, medications and other health conditions, they determined that a number of different components of the microbiome were altered in children with autism spectrum disorder.

The researchers identified 14 archaea, 51 bacteria, 7 fungi, 18 viruses, 27 microbial genes, and 12 metabolic pathways that differed between neurotypical children and children with autism.

In fact, the findings not only confirm the link between the gut and autism, but also provide a way forward in studying the mechanisms underlying autism, and testing it in children in a relatively straightforward and painless way.

The research paper was published in the journal Nature Microbiology.