Autism refers to a spectrum of different learning and behavioural conditions — autism spectrum disorder. The condition is characterized by inhibited verbal and non-verbal communication, and by problems with social interaction, such as restricted or repetitive behaviors. The causes of autism are unknown, although a combination of genetic and environmental factors are thought to come together.
Researchers have noted some people with autism are missing a gene called Shank3 — the gene is thought to be present but in an inactive state. This gene has a role in brain development, and those without the gene exhibit repetitive behavior and avoidance of social interactions — behaviours that fall on the autism spectrum.
Shank3 protein is found in synapses. These are the connections that allow neurons to communicate with each other. In the brain, the synapses are found in the part of the brain called the striatum. In some cases of autism, the density of neurons equipped to transmit signals is much smaller.
Based on a study using mice, researchers have shown that by switching the gene back on, the brain is able to re-wire and the symptoms of autism dissipate. The gene was switched back on by adding tamoxifen to the mice’s diet. On examining the brains of the mice, a greater concentration of neurons was seen in the striatum, when the mice that had the gene switched back on were compared with a control group.
Parallel studies showed that the earlier in life that the gene was switched back on the better the behaviour of the mice became.
This success has led to speculate as to whether the same effect can be seen with adults. Provided the human brain has equivalent “plasticity,” then the studies in mice might produce the same effects. If proven one day for people, modifications to the brains could be achieved through gene editing techniques.
The study was led by Professor Guoping Feng from the Massachusetts Institute of Technology. The results are published in the science journal Nature. The paper is titled “Adult restoration of Shank3 expression rescues selective autistic-like phenotypes.”
