Researchers have now discovered that a simple stool sample may eventually prove to be instrumental in changing the way autism is diagnosed. Scientists at the Chinese University of Hong Kong discovered consistent differences in gut microbiomes between those with and without autism, thereby allowing for the future possibility of a faster and easier diagnostic method.
“Usually it takes three to four years to make a confirmed diagnosis for suspected autism, with most children diagnosed at six years old,” said Prof. Qi Su of the Chinese University of Hong Kong. The new microbiome biomarker panel, however, shows high performance in children under the age of four, potentially facilitating earlier diagnoses.
Over recent decades, the huge rise in autism rates is attributed in large part to increased awareness and broadened diagnostic criteria. On this count, approximately one in 100 people are now reckoned to reside somewhere on the spectrum of autism in many Western countries. Genetics has an enormous role to play, in 60-90% of all cases. Other risk factors include older parental age, birth complications, and environmental exposures of various sorts.
As people with autism are known to have much less bacterial diversity in their gut, it is still an open question whether this is an effect or cause. For that reason, Su and his co-authors sequenced stool samples of 1,627 children between one and 13 years, some of them autistic. They looked for bacteria, viruses, fungi, and archaea in the stools.
A Nature Microbiology study reveals profound differences in gut microbes among autistic children. They broadly found such differences to include 51 kinds of bacteria, 18 viruses, 14 archaea, seven fungi, and a dozen metabolic pathways. Machine learning can differentiate autistic children with an accuracy of up to 82% by 31 microbial marker-defined biological functions.
The study also pointed to disruptions in energy and neurodevelopment metabolic pathways in autistic children. “While genetic factors play a substantial role in autism, the microbiome could act as a contributing factor by modulating immune responses, neurotransmitter production, and metabolic pathways,” explained Su. In other words, the microbiome may contribute to the severity or manifestation of autism symptoms.
The potential results, if they bear out, could eventually lead to using diet or probiotics to create a more diverse microbiome in those with an autism diagnosis. “Ultimately, this broad scope increases the potential to develop more effective, noninvasive diagnostic tools and therapeutic strategies for autism,” Su added. The team is now conducting a clinical trial into whether stool samples can identify autistic children as young as one year old.
Dr. Dominic Farsi at King’s College London commented on the “great potential” that these findings may have for diagnostic practice, but again reiterated that further studies are called for in reproducibility before definitive claims can be made. Independent nutrition and gastrointestinal health consultant Dr. Elizabeth Lund said the idea of diagnosing this way, using stool samples, was “very exciting,” particularly against the backdrop of the current backlog in autism assessments.
It is an important advance in the gut microbiome-autism connection and provides a variety of new avenues for diagnosis and treatment. If that continues to bear out, this could be a game-changer for how autism gets detected and managed, and that could change the lives of millions of people and their families.