Canadian scientists help unravel the cause of autism

Scott Sutherland

Austism seems to have taken the world by storm over the past ten years. The rate of diagnosis in Canada was 1 in 450 in 2003, whereas the most recent estimate out of the United States puts the number at 1 out of every 88 children. Whether that increase really indicates a massive growth in the number of people who fall on the spectrum of autism disorders or it means we've gotten better at diagnosing the illnesses is unclear.

What is clear, however, is that many Canadian children suffer from one of the more than 100 clincial disorders that make up the autism spectrum, and that just as many parents are eager to find more ways to help them.

There's good news today, then, from several Canadian science sources.

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In the first, a study published in The American Journal of Human Genetics, details the results of a project to analyze the entire DNA sequence — called 'whole genome sequencing' — of 32 Canadian families who are participants in the Autism Speaks Genetic Resource Exchange.

This study, which tested not only the people affected by autism but also their families, identified genetic variants in 50 percent of the families who participated. Standard sequencing, which looks only at the portion of DNA that holds instructions for making proteins, had only been able to identify autism-related gene changes 20 percent of the time.

Dr. Stephen Scherer, director of the Centre for Applied Genomics at the Hospital for Sick Children in Toronto, who led the study notes that: "The fact what we found notable genetic variants in 50 percent of the families reflects our new ability to apply genome sequencing to find spontaneous, or de novo, as well as inherited genetic variants often missed in other approaches."

He hopes that this would allow for earlier diagnosis of autism, particularly in siblings of autistic children.

Autism Speaks, the parent of this study, also reports that the testing provided other benefits to some of the 32 families involved, including alerting members of one family that they carried a gene change related to Fragile X syndrome. The organization, founded in 2005 and long-visible in the world of autism spectrum disorders (ASD), has been working on assembling a library of sequenced genomes for more than 2,000 families with two or more children on the autism spectrum since 2011.

Also making genetic news this week, another Canadian-led team has unraveled the RNA control code, critical to the process called gene expression — the way the genetic code in your DNA is translated for use in your cells. Working out of the University of Toronto, researchers feel they understand, for the first time, the "language of a code essential to gene processing," in a study published today in the journal Nature.

What they didn't expect to find was a possible explanation for some of the symptoms in children with autism. But, as it turns out, one of the proteins typically 'switched off' in the brains of ASD patients, RBFOX1, is also responsible for the activity of genes important for the function of nerve cells in the brain.

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In a UofT news release, one of the scientists involved in the study said: "This was a surprising finding, because we knew RBFOX2 controls gene expression, but had no idea it also stablizes RNA... It's a good example of the predictive opwer of the RNA control code, which we think will really open up the field of gene regulation."

The researchers are hopeful this new insight might lead to therapies for autism, as well as new pathways for research into other protiens that might play a role in other diseases.

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