Autism is a complex developmental disorder and diagnosing the disorder is also complex, which usually involve a combination of different rounds of behavioral tests. But according to a new study it has found that two genetic tests may aid doctors and parents to identify certain genetic mutations that are linked to the disorder. This provides a clear molecular diagnosis.
This information could potentially help parents who have one child with autism spectrum disorder identify whether any future children are at risk of developing the same disorder. Also this information can lead to the development of more personalized treatment plans.
For the study a team of investigators with the Hospital for Sick Children in Toronto, Canada, performed 2 new genetic tests on a group of 258 children who were already diagnosed with autism. This test was performed to understand how capable the tests are at spotting genetic mutations that may contribute to autism.
More than 9% of the 258 children received a molecular diagnosis from a test known as "chromosomal microarray analysis" or CMA. Around 8% received a diagnosis from a new diagnostic test known as "whole-exome sequencing" or WES. When the two tests were combined roughly 16% of families were provided with some genetic clues as the reason for their children to develop autism.
Though the number might be low, there is a significant range in the level of impairment associated with autism and likely many factors that contribute to its development both genetic or otherwise, said Stephen Scherer, director of the Center for Applied Genomics at the Hospital for Sick Children and an author on the study. Also among a subgroup of children with certain physical anomalies that are often linked to autism, the rate of molecular diagnoses was higher (37%).
"The first thing parents want to know is why autism came about in their kid, and 10 years ago, we couldn't tell them anything," Scherer said. "Now, for at least 15% [of parents], we can tell them something. That's really important."
Scherer said "parents' second question is often about whether any other children they have are at greater risk for autism. Because siblings share many genetic similarities, the new tests could provide parents with one child who received a molecular diagnosis a better understanding of that risk."
Judith Miles, a researcher with the Thompson Center for Autism and Neurodevelopmental Disorders in the Department of Child Health, University of Missouri Health Care, said that the new findings show that doctors who treat children with autism should help arrange for testing that may help provide additional information about whether genetic factors are at play.
"It is incontrovertible that precise diagnoses pave the way to better medical care, improved surveillance, better functional outcomes and informed genetic counseling," she said. "Children with ASD are often grouped together and the opportunity to provide patient-specific care is missed," Miles added.
Due to the much variability in the types of symptoms accompanying autism, it is indeed believed to stem from differences in genetic mutations. Scherer hopes that the clinicians will be able to use genetic testing to help classify autism into more specific subgroups, so children can receive more targeted treatment.
He added that the two tests are increasingly available in major medical centers, and that parents should feel empowered to ask for them after their child has undergone behavioral testing, but said that insurance coverage can be limited. "Awareness is the key," Scherer said. "Parents and doctors should know about these tests, because in 15 to 16 percent of families, they can add information that's really quite relevant."
The study was published in the Journal of the American Medical Association