In a new report, researchers describe their development of a novel blood test to identify gene-expression patterns distinctive to autism in infants and toddlers. The test, they say, has potential to be further developed for both diagnosing autism before full symptoms emerge and for guiding research on early treatments.
In analyzing the blood samples, the UCSD researchers went beyond conventional gene testing to look at patterns of gene expression. In other words, they looked at which genes were turned “on” or “off” in blood samples from 215 toddlers, 131 of whom had autism.
Overall, the two groups of toddlers showed significantly different patterns of gene-expression related to immune function (inflammation) and protein production. The altered protein patterns were concentrated in pathways known to be crucial to early brain development.
“This study is important for identifying biological pathways that are affected in autism,” comments Paul Wang, Autism Speaks’ head of medical research. “The findings reinforce the theory that inflammatory and immune pathways are involved in autism’s development, alongside disturbances in protein synthesis.” Dr. Wang and Autism Speaks were not involved in the study.
In their study, the UCSD investigators ran two related but slightly different blood analyses with two different groups of young boys, ages 1 to 4. They plan a future study with girls, once they’re able to recruit a sufficiently large group.
In the first analysis, a state-of-the art gene-expression screen proved 83 percent accurate in distinguishing 87 boys with autism from 55 age-matched boys without the disorder. In the second analysis, a slightly older test was 75 percent accurate in distinguishing 44 boys with autism from 29 without the disorder. This is about the same accuracy as current autism-screening tests based on behavioral differences.
“Given the small sample size, it’s not yet clear whether this type of testing can be helpful in screening the general population of children for autism,” Dr. Wang cautions. More promising, Dr. Wang says, is the potential for blood tests such as these to guide future autism treatments that target the distinct, underlying biology of each child’s challenges.
The UCSD team has begun larger studies using their new gene-expression screen with larger numbers of infants and toddlers.
Note: The lead and senior authors of the study – Tiziano Pramparo and Eric Courchesne – disclose that they have a pending patent application that includes data from their research.
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