A new mouse study, which builds on findings from a previously unpublished study in humans, suggests that gene mutations found in both the brain and the gut could be the reason why so many people with autism suffer from gut issues.
The study, published in the journal Autism Research, confirms the existence of a suspected gut-brain nervous system link in autism and suggests a potential new target for treatments that might ease the behavioral issues commonly found in the disorder.
Chief Investigator Associate Professor Elisa Hill-Yardin from the Royal Melbourne Institute of Technology (RMIT) University in Australia, said that autism researchers have long been looking at the brain, and have only recently begun to look at the gut.
“We know the brain and gut share many of the same neurons and now for the first time we’ve confirmed that they also share autism-related gene mutations,” Hill-Yardin said. “Up to 90 percent of people with autism suffer from gut issues, which can have a significant impact on daily life for them and their families.”
“Our findings suggest these gastrointestinal problems may stem from the same mutations in genes that are responsible for brain and behavioural issues in autism. It’s a whole new way of thinking about it — for clinicians, families and researchers — and it broadens our horizons in the search for treatments to improve the quality of life for people with autism.”
The study reveals that a gene mutation that affects neuron communication in the brain — and was first identified as a cause of autism — also causes dysfunction in the gut.
The new research builds on previously unpublished clinical work from a landmark 2003 study of two brothers with autism, led by Swedish researchers and a French geneticist. The 2003 study was the first to identify a specific gene mutation as a cause of the neurodevelopmental disorder. The study had shown that this gene mutation affected communication by altering the “velcro” between neurons that keeps them in close contact.
Researchers in the Gut-Brain Axis team at RMIT have built on this clinical work with a series of studies on the function and structure of the gut in mice that have the same “velcro” gene mutation.
They team found this mutation affects:
- gut contractions;
- the number of neurons in the small intestine;
- the speed that food moves through the small intestine;
- responses to a critical neurotransmitter important in autism (well known in the brain but not previously identified to play any major role in the gut).
Collaborator Associate Professor Ashley Franks (La Trobe University) also found significant differences in the gut microbes of mice with the mutation and those without it, even though both groups were kept in identical environments.
While this specific “velcro” mutation is rare, it is one of more than 150 autism-related gene mutations that alter neuronal connections, Hill-Yardin said. “The link we’ve confirmed suggests a broader mechanism, indicating that the mutations that affect connections between neurons could be behind the gut problems in many patients.”
Source: RMIT University