UW study shows promise of quicker autism diagnosis

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Autistic children often engage in repetitive behavior.

Of all the developmental disorders in the United States, autism, collectively known as autistic spectrum disorder (ASD) is the most prevalent and fastest growing. More children will be diagnosed with ASD this year than with AIDS, diabetes, and cancer combined.

An estimated 8,000 to 12,000 children in Washington State have some form of autism.  According to the Centers for Disease Control and Prevention, an average of one in every 88 children in the U.S. has ASD. Without early intervention, say many experts, the outlook for children is significantly less hopeful.

Now University of Washington and Battelle scientists have evaluated a non-intrusive and inexpensive diagnostic laboratory test for identifying young children at risk of developing ASD. In a study, they found that the diagnostic approach spotted a large share of children with ASD.

As with many other diseases early detection can reduce the behavioral and social impacts associated with ASD. According to the latest statistics, about 75 to 86 percent of those children who receive early intervention services between the ages of 2 and 7 will develop some form of functional communication by age 9.

Health care practitioners currently use a variety of screening methods to evaluate children for developmental problems affecting children such as language. Until recently, however, diagnostic evaluation required a team of health professionals employing a range of behavioral tests such as game playing.

A group of neurodevelopmental brain disorders, autism is characterized by impaired social interactions, difficulty in speaking, and repetitive behavioral patterns. Other behavioral symptoms of ASD also can include anxiety, depression, learning disabilities, and sleep disorders.

Battelle Centers for Public Health Research and Evaluation scientists Nicholas Heyer and Diana Echeverria, and UW public health professor James Woods have identified a biochemical marker, based on highly elevated levels of porphyrins, which are organic chemicals found in urine.

In the current issue of the journal, Autism Research, Heyer, Echeverria, and Woods report that porphyrin levels are much higher in some children with autism than normally developing, or non-autistic, children of the same age. 

"Additionally, when children with ASD were compared with typically developing children, or children with other developmental disorders, these porphyrin biomarkers correctly identified thirty percent of ASD children without incorrectly identifying a single non-autistic child," said Woods, a professor in the UW School of Public Health's Department of Environmental and Occupational Health Sciences.

The significance of those biomarkers, according to Woods, is that they may enable health professionals to detect the risk of autism earlier, which would improve the chances for more successful treatment options for at-risk children. That research may have broader implications, Heyer added.

Early detection and intervention enhances the chances for children to develop normally, said Battelle researcher Heyer, who performed the statistical analysis for the study.  "Autism is a developmental condition.  Behavioral and educational intervention teaches kids to pick up on different cues, so they can develop more social interaction skills."

The UW and Battelle scientists tested 76 children between 2 and 12 years. Thirty-two children were in the neurotypically developing control group whereas 30 were diagnosed with ASD, and 14 had other other non-specified pervasive developmental disabilities.  "When all kids in the study were evaluated, approximately one-third of the kids were found to have much higher urinary porphyrin levels, and all of these were kids who had ASD," Woods said.

While disordered porphyrin metabolism among children with ASD has been previously reported, Woods said, "ours is the first systematic study to find out how those elevated porphyrin levels can be used to predict autism risk, and more importantly, they demonstrate that a large number of children with ASD have this characteristic.  This can narrow the focus for better intervention options."

While acknowledging that the findings must be validated by others in larger studies, Woods and his colleagues are convinced that this potential biomarker holds great promise for enhancing the quality of care for children at risk of ASD.

Beyond the age cohort of 2 to 12 year-old children that Battelle and UW scientists tested, Heyer is hopeful that future studies of younger children could yield even more significant results.  "If we can do that, it will have a huge impact on early detection of ASD," he said. "If we can reproduce the findings of our recent study, then that would mean better evaluation, care, and treatment."