Scientists have discovered a link between altered gut bacteria in children and autism and predict that stool samples could be used to speed up diagnosis.
The Hong Kong researchers’ findings suggest that specific components of the gut microbiome (microorganisms, including bacteria, fungi and viruses, that live in the digestive tracts of animals) could provide a new way to diagnose the disease.
Although the findings, published in the journal Nature Microbiology, are unprecedented, experts say they are excited because they could help reduce the “huge backlog” of people waiting for tests.
Autism, also known as autism spectrum disorder (ASD), is a lifelong developmental disorder that affects how a person communicates, interacts, and processes information.
Usually, no laboratory tests are needed to establish an autism diagnosis, only observation by a specialist is necessary. But in some cases, children must wait up to four years to get an autism diagnosis.
Dr Elizabeth Lund, an independent consultant in nutrition and gastrointestinal health, who was not involved in the study, said: “The idea that stool sample analysis could help with diagnosis is very exciting, as there is currently a huge backlog of children and adults waiting for assessment.
“The current process is very lengthy and there is a shortage of clinicians such as psychologists and psychiatrists trained to make a proper diagnosis.”
She added: “The researchers rightly point out that these data cannot tell whether the different microbiome is causing ASD or whether differences in diet or other environmental factors associated with children with ASD are leading to the observed differences.
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“However, in my opinion, the food preferences of people with ASD are so diverse that they are unlikely to result in a consistent difference in the gut microbiome.”
According to the National Autistic Society, more than one in 100 people are on the autistic spectrum and there are around 700,000 autistic adults and children in the UK.
Signs of autism in adults include not understanding how others are feeling, becoming anxious in social situations, having a strict routine, or appearing blunt without meaning to be.
Children with autism may avoid eye contact and not respond when called by name, among other symptoms.
Siew Ng, from the Chinese University of Hong Kong, and colleagues analyzed stool samples from 1,627 children aged 1 to 13, with and without ASD.
They found that specific bacterial and non-bacterial components of the gut microbiome and their functions could contribute to autism spectrum disorder (ASD) in male and female children.
Taking into account additional factors, including diet, medications and other health issues, they identified that a number of different components of the microbiome were altered in children with ASD.
The researchers created a model based on 31 different microbes and functions that made the diagnosis more accurate, compared to looking at just one component, such as bacteria.
Professor Bhismadev Chakrabarti, Director of Research at the University of Reading’s Autism Centre, who was not involved in the research, said: “What’s exciting about this study is that it opens up the possibility of studying specific biochemical pathways and how they impact different autistic characteristics.
“It could also provide new ways to detect autism, if microbial markers prove to enhance the ability of genetic and behavioral tests to detect autism.
“A future platform capable of combining simple genetic, microbial and behavioral assessments could help fill the detection gap.
“With the results of this study, the perspective through which we observe the microbiota in autism has definitely broadened.”