Autism may be able to be reversed in the future, as neuroscientists have now been able to reverse symptoms of autism in mice.
Researchers at MIT were able to reverse some of the behavioral symptoms of autism in mice by turning on a gene. The findings suggest that treating autism may eventually be as simple as “flicking the switch” on certain genes. The results of the study may have big implications for future treatment of autism disorders.
Autism affects over 10 million people in the U.S., with roughly one in every 68 children being on the autism spectrum. As well, autism diagnoses have been increasing annually by over 10 percent.
There is no known cause for autism, although it is thought that a combination of genetic and environmental factors may contribute to the disorder.
Autism can have many symptoms. Some people with autism may only have difficulty with social behavior but can otherwise function completely normally. However, people with more severe cases of autism can have major behavioral problems, be unable to communicate, and require constant care and supervision.
Now, in a new study, neuroscientists have reversed some behavioral symptoms of autism in adult mice, including social avoidance and repetitive behavior. After turning on the Shank3 gene in mice, there was a sudden stop to certain autistic symptoms, with the mice becoming more social.
The Shank3 gene is missing in roughly one percent of people with autism. The gene is associated with brain development, and helps neurons to communicate with one another.
In previous studies, researcher Guoping Feng found that mice missing Shank3 or with defective Shank3 had damage in their brain. In fact, the synapses of their brain had a reduced density of dendritic spines, which help neurons transmit signals.
To perform the new study, the researchers genetically engineered mice with the Shank3 gene turned off. The gene could be turned back on using a medication.
Once the mice were between 2.5 to four months of age, making them young adults, the researchers turned the Shank3 gene back on.
Not only did some symptoms of autism completely reverse, but turning on the Shank3 gene also caused an increase in the density of dendritic spines within the brain. The result showed that the mice’s brain could make a dramatic recovery and that damage could be reversed.
However, the study also found that some symptoms in the mice could not be reversed. Even after turning on the Shank3 gene, the mice still suffered from anxiety and motor coordination issues. It is thought that these symptoms may be due to irreversible changes or damage in the brain.
If the Shank3 gene was turned on earlier in the mouse’s life, the researchers found that anxiety and motor coordination improved. This suggests that earlier treatment may be more effective for autism, and some symptoms may be permanent after a certain point.
The researchers are hoping that the results of the study will lead to new treatments for people with autism spectrum disorders.
Feng, Guoping, et al, “Adult restoration of Shank3 expression rescues selective autistic-like phenotypes,” Nature, 2016; doi: 10.1038/nature16971.
“What is Autism?” Autism Speaks, https://www.autismspeaks.org/what-autism.