Q: Recent developments in autism research indicate which of the following is linked to autism?
- A breakdown in the signaling pathway
used by the neurotransmitter GABA
- Mutations in a gene called SCN2a
- The gut microbiome
- ✅ All of the above
Autism researchers have made tremendous progress in understanding the mechanisms of Autism Spectrum Disorder in the last few years. The findings offer optimism for new tests and therapies.
The Finding: SCN2a
Genetic research has led to tremendous breakthroughs in the understanding of risk factors for autism. Among them, a paper published earlier this year has shown that mutations in a gene called SCN2a can affect brain activity and are linked to autism.
What is SCN2a?
SCN2a codes for a channel that allows the passage of sodium ions across the neuronal membrane. One mutation makes the channels hyperactive and this is associated with infantile seizures. Another inactivates or diminishes the channels’ function. This slows transmission between neurons and is linked to autism. The resulting sluggish neurons and signaling imbalance may affect early brain development.
Why is this hopeful?
These findings are important since assessing the mutation and the affected channels’ function might lead to a test which could predict severity of symptoms. Certainly, it will stimulate further research into the gene and how it leads to general changes in brain function in early development and how these are tied to autism.
The Finding: GABA
Differences in the GABA signaling pathway have been linked to autism in genetic studies, animal models, post-mortem tissue examination and now in living humans.
What is GABA?
As an inhibitory neurotransmitter, GABA helps to suppress both perception and behavior. Altered GABA signaling helps explain why many people with autism have altered sensory processing. One study used binocular rivalry to test this. Researchers presented different images to participants’ right and left eyes. Our eyes naturally see slightly different images and our brain averages the two images to create a whole image. In this test, the images were dramatically different (like a horse in one eye and an apple in the other). To make sense of the image, control subjects simply suppressed one of the images (say, the horse) and saw the other (the apple). Subjects with autism could do this less well causing what they saw to shift frequently between the two images indicating a deficit in the GABA signaling pathway.
Why is this hopeful?
Right now, it is difficult to screen for autism in people without speech. But vision tests based on these findings may be able to detect autism earlier in life – even before speech develops. This would allow for earlier intervention when it is most effective.
The Finding: The Gut Microbiome
For years, scientists have been studying the relationship between the gut microbiome and autism. Indeed, gastrointestinal issues are a common symptom of autism. And children with autism have been found to have unusual species (not found in their unaffected siblings) or imbalances of gut bacteria.
What is the gut microbiome?
The gut microbiome refers to the composition of bacteria in the intestines. Awareness is increasing about the importance of the bidirectional gut-brain connection. Since the connection goes both ways, intestinal distress or imbalance can be the cause or the product of brain and behavioral issues. Scientists have looked at connections between the gut and many psychological symptoms and disorders. With regard to autism, one example is that researchers have found that the absence of a specific bacteria can cause social deficits in mice. They also found that adding that bacteria back into the guts of the affected mice reversed the behavioral symptoms.
Why is this hopeful?
This line of research may lead to procedures to restore proper microbial balance to treat behavioral impairments that accompany autism and even possible ways to reduce the risk of autism in the first place.
There is much hope for people who live on the autism spectrum. Research is making new strides monthly and new diagnostic tools and interventions will result. At iLs, we are encouraged regularly by stories we hear of our holistic family of tools helping to improve the quality of life for people who live with autism and their families.