The discovery confirms a gut-brain nervous system link in autism, opening a new direction in the search for potential treatments that could ease behavioural issues associated with autism by targeting the gut.
Chief Investigator Associate Professor Elisa Hill-Yardin, RMIT University, said scientists trying to understand autism have long been looking in the brain, but the links with the gut nervous system have only been recently explored.
“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% 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 autism gene and the gut-brain link
The study reveals a gene mutation that affects neuron communication in the brain, and was the first identified as a cause of autism, also causes dysfunction in the gut.
The research brings together new results from pre-clinical animal studies with previously unpublished clinical work from a landmark 2003 study led by Swedish researchers and a French geneticist.
The study of two brothers with autism by Professor Christopher Gillberg (University of Gothenburg), Professor Maria Råstam (Lund University) and Professor Thomas Bourgeron (Pasteur Institute) was the first to identify a specific gene mutation as a cause of the neurodevelopmental disorder.
This mutation affects communication by altering the “velcro” between neurons that keeps them in close contact.
While the 2003 study was focused on identifying the genetic basis for autism, Gillberg and Råstam also took detailed clinical notes of the brothers’ significant gastrointestinal problems.
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)