Researchers from Boston Children's Hospital have developed a new kind of genetic test to detect Autism Spectrum Disorders (ASD). Researchers say that the test shows that immunologic activity may help explain why brains of people with ASD develop differently than others.

The genetic test can help with early diagnosis of the condition in about two-thirds of the patients, even before any clear symptoms appear.

Researchers say that the new approach in finding markers for autism can even be a good way to start looking for possible treatments.

The study involved 66 male patients diagnosed with Autism Spectrum Disorder and 33 people without ASD. Participants' blood samples were analyzed for RNA signatures that reflect gene expression.

"Since brain biopsy isn't a viable option for research, we asked whether blood could serve as a proxy for gene expression in the brain. We found that it could, though we and others were initially skeptical," said Isaac Kohane, director of Boston Children's Hospital Informatics Program.

Researchers found 489 genes that had different gene activity pattern in people with ASD. The researchers then narrowed the group to 55 genes that were distinct in these people.

Researchers then tested their findings on a group of 102 people (male and female) with autism and 82 people without autism. The test had a classification accuracy of 68 percent.

The gene signature approach proposed by the researchers says that what we understand as autism can happen by different pathways.

"It's clear that no single mutation or even a single pathway is responsible for all cases. By looking at this 55-gene signature, which can capture disruptions in multiple pathways at once, we can say with about 70 percent accuracy, 'this child does not have autism,' or 'this child could be at risk,' putting him at the head of the queue for early intervention and evaluation. And we can do it relatively inexpensively and quickly," said Kohane.

In their studies, researchers classified people with ASD in four groups depending on the changes in biological pathway: synaptic pathways, specifically long-term potentiation pathways (memory and learning), neurotrophic pathways (signaling neurons to survive, develop and grow) and Immune/inflammatory pathways.

"In our sample, about half of the autism cases had some sort of alteration on immune pathways, synaptic pathways, or both," said Sek Won Kong, MD, of the Boston Children's Hospital Informatics Program and lead author of the study.

The study is published in the journal PLOS ONE.