Can a Blood Test Detect Autism Early?
A company has developed a simple blood test to identify most cases of autism—but determining if it really works is not so simple.
A company called SynapDx is hoping that a simple blood test will be able to identify most cases of autism in children much faster than current evaluations. At the Consumer Genetics Conference in Boston last week, SynapDx founder and CEO Stanley Lapidus said the company would soon begin evaluating the ability of its diagnostic test, which examines gene activity, to identify children with the disorder. While such a test would be of great value if successful, the concept is “risky,” says a company scientific adviser, because it’s not yet known whether there is a molecular signal for autism.
An estimated one of every 88 children in the United States was diagnosed with an autism spectrum disorder in 2008, according to the Centers for Disease Control and Prevention. Autism is referred to as a spectrum disorder because it is probably a mix of several different conditions. Those affected may exhibit a wide range of symptoms, from social awkwardness and unusual obsessions to significant language delays and intellectual disability. Although the cause of the disorder is not completely clear, researchers have identified both genetic and environmental factors (see, for example, “DNA Deletion Linked to Autism” and “New Thoughts on Autism”).
While there are no drug treatments available, behavioral therapy can help about 20 percent of patients, says Lapidus. But this therapy is most effective if it starts early, and diagnosis can take years. Only 20 percent of children are diagnosed by the age of three, he says, and a diagnosis is based on direct observation of the child as well as the parents’ reports about the child’s behavior. On average, parents first become concerned when their child is around 19 months old but don’t get a diagnosis until the child is four and a half.
“It’s a very long journey, and the length of that journey harms the outcomes,” Lapidus told the audience. “Every month, every year that your child is not diagnosed means the chance of behavioral therapy influencing the outcome is diminished.”
Lapidus hopes that SynapDx’s test will be able to identify the majority of children with autism spectrum disorders at a much younger age. The company will soon announce a 600-patient study that will test the current form of the assay against diagnoses made by today’s method of evaluation. Other groups are also working toward molecular tests for autism: for example, last month researchers at the University of Melbourne in Australia announced they had developed a genetic test that “correctly predicted ASD with more than 70 percent accuracy in people of central European descent.”
The company’s test is based on work from Children’s Hospital of Boston, says Lapidus. Researchers Isaac Kohane and Louis Kunkel have identified a molecular profile of 245 genes that are uniquely regulated in patients with autism spectrum disorders. A blood test based on the researchers’ work can identify autism with 85 percent accuracy, according to the hospital. The company has also licensed technology from autism researcher Valerie Hu of George Washington University. Hu’s team has identified gene activity differences in patients with autism spectrum disorders.
“At least four different groups have identified potential biomarkers,” says Dan Geschwind, director of the Center for Autism Research and Treatment at the University of California, Los Angeles, and a scientific advisor for SynapDx. But none of these groups, including his own, have proved that these biomarkers can prospectively distinguish autistic children from non-autistic children, he says.
“This whole proposition of looking for blood makers is not without significant risk,” he says. “It’s worth looking for, but it doesn’t mean that we will find them.”
The value of such biomarkers would be earlier diagnoses. “The earlier one can introduce interventions, the better,” says Hu. Right now, all interventions tend to be behavioral, she says, but her goal is to use gene activity profiles not only as a means of diagnosis but also to “understand the biology behind the autism in order to develop novel therapies.”
Still, the fact that doctors and researchers do not yet fully understand autism makes a test like this seem to be getting ahead of the research. “A molecular diagnostic at this point is worse than premature—it has the potential to be misleading,” says Jeanne Loring, a stem-cell researcher at Scripps Institute who studies the molecular basis of autism. “Autism is a spectrum disorder, with a lot of variations,” she says; she believes we need to understand those better before much more progress can be made.
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