Blood Test May Help Diagnose Autism

April 23, 2013, 10:41 a.m. ET

Blood Test May Help Diagnose Autism

By SHIRLEY S. WANG

To cut through some of the mystery of mental disorders, which are largely defined by how people behave, universities and medical-technology companies are seeking firmer biological clues lurking in blood and saliva.

The latest initiative is a clinical trial of a blood test that may distinguish between kids with autism and those with other developmental delays.

The 20-site, 660-patient study, expected to be launched Wednesday, is thought to the biggest multisite effort to date to study a biological marker for autism-spectrum disorders, which affect one in every 50 children in the U.S.

The test aims to speed the diagnosis of autism, a condition characterized by poor social interaction and repetitive behaviors that can be hard to recognize when a child is very young. The average age of diagnosis in the U.S. is about 4 years, older than is optimal, according to experts, because therapies are more effective when begun early.“Time is the enemy here in improving outcomes,” said Stan Lapidus, chief executive of SynapDx, the lab-services company in Lexington, Mass., that is sponsoring the trial. If children could get referred to specialists earlier, their prognosis may be improved, he said.

The search for biological markers, like proteins in blood, has the potential to transform the murky science of diagnosing mental disorders. Many diseases, including Alzheimer’s, Parkinson’s and schizophrenia, can be hard to diagnose using traditional, subjective, assessments of behavior. Patients may go undiagnosed or be misdiagnosed, delaying treatment. More-objective measures are needed, scientists say.

Researchers at the University of Washington in Seattle have demonstrated that two proteins that are elevated in Parkinson’s patients’ brains are detectable in the saliva of those patients, as well, raising the possibility of a saliva test for Parkinson’s disease.

“Many of us are trying to find biomarkers that can help us diagnose PD with more certainty and, in the long run, to diagnose it before symptoms kick in,” says James Leverenz, a professor of neurology, psychiatry and behavioral sciences who published this work in the journal Brain in 2011.

In January, researchers from the National Institute of Mental Health published findings in JAMA Psychiatry suggesting a possible biomarker that predicts the response to a fast-acting antidepressant, by imaging a particular part of the brain. Another effort to identify biomarkers to predict antidepressant response is under way by academic centers, including the University of Texas Southwestern Medical Center, Columbia University and Massachusetts General Hospital.

The new study is based on work from several academic groups suggesting that it may be possible to distinguish autism by looking at the numbers of particular molecules in the blood.

Isaac Kohane, a professor of pediatrics and health sciences and technology at Boston Children’s Hospital and Harvard Medical School, who led some of this work, said his team found a “substantial and persistent difference” in about 55 proteins that could identify about 75% of the children with autism. The accuracy is “not the best you’ve ever seen, but it may be good enough to start with,” said Dr. Kohane, who serves as a consultant to SynapDX but isn’t involved with their product.

Pilot data with 270 patients demonstrated the biomarker technology accurately distinguished 65% to 70% of the kids with autism from children with other developmental delays who were diagnosed by an expert, according to Mr. Lapidus of SynapDx, which licensed the basic discovery of how to detect autism from Boston Children’s Hospital.

Researchers caution that biomarkers aren’t going to replace a traditional diagnosis anytime soon.

Myriad Genetics Inc., MYGN +0.43% of Salt Lake City, which is also working on biomarkers, introduced a blood-based test for schizophrenia in 2010. The company said the 36-protein test, called VeriPsych, could distinguish between schizophrenia and other forms of psychotic behavior with 85% accuracy. But Myriad took it off the market because psychiatrists said they could do just as good a job diagnosing patients clinically.

“It was a pretty good example of the difference between clinical validity—the ability to discriminate between two clinical states—and clinical utility” or how useful the test was in the real world, said Richard Wenstrup, chief medical officer.