Dual genetic tests may be best way to diagnose autism: Canadian study

A new Canadian study suggests the use of two newer genetic tests may be used to help better diagnose autism.

Characterized by impaired social, emotional and communications skills, various studies suggest autism affects approximately one per cent of the population. In the U.S., one in 68 children are now being diagnosed with the neurological condition.

The symptoms displayed by those who have the disorder vary, leading to the use of the term autism spectrum disorder, or ASD.

Doctors have traditionally relied on various standardized tests -- including observation of how a child learns -- to make an ASD diagnosis. But scientists believe the best confirmation may be in a child's DNA.

In a study published Tuesday in the Journal of the American Medical Association (JAMA), researchers from Toronto's Hospital for Sick Children found that the use of two diagnostic tests may help identify the genetic mutations potentially linked to ASD.

The study involved more than 250 unrelated children with a suspected ASD diagnosis, including Melissa Blundon's 12-year-old son, Owen, who showed outward signs of the disorder early in life.

"He was walking; he didn't talk," Blundon said.

Researchers used two genetic tests in the study:

All the children underwent CMA, while 95 also underwent WES.

The study found that when used individually, the tests identified ASD in approximately eight per cent of the children. The CMA showed 9.3 per cent of children had genetic mutations that could explain their autism, while the WES found 8.4 per cent of children had mutations could explain their disorder.

When the tests were used together, however, twice as many children received a molecular diagnosis.

"Sixteen per cent of the children had an ASD-related genetic finding," said Dr. Bridget Fernandez, with Memorial University of Newfoundland.

According to autism advocates, the use of both tests may allow for improved care in the future.

"Many children don't get diagnosed for many years, so with the genetic testing and the increased diagnosis, it will lead to better support for those kids affected by autism," said Shane Cunningham Boles, a development co-ordinator with Autism Ontario.

For mothers like Blundon, the genetic information helped her decide her son Owen was capable of going to school.

"I knew that he was smart enough," Blundon said. "Now he's developed into a lovely young man."

In Canada, only one of the genetic tests are available. But doctors say they will soon be offered to families.

With files from CTV News' medical correspondent Avis Favaro