January 15, 2013
Researchers Identify Autism-related Gene Variants
Lee Rannals for redOrbit.com — Your Unvierse Online
These CNVs are "high impact," and although they are individually rare, each one has a strong effect in raising an individual's risk for autism.
"Many of these gene variants may serve as valuable predictive markers," the study's corresponding author, Hakon Hakonarson, MD, PhD, director of the Center for Applied Genomics at The Children's Hospital of Philadelphia, said in a statement. "If so, they may become part of a clinical test that will help evaluate whether a child has an autism spectrum disorder."
The study builds on and extends previous gene research by Hakonarson and other scientists on autism spectrum disorders (ASDs), which is a group of childhood neurodevelopment disorders that cause impairments in verbal communication, social interaction and behavior.
Genetic researchers analyzed DNA from 55 individuals from Utah families with multiple members diagnosed with ASDs. They custom-designed a DNA array with probes for those 153 CNVs, as well as for another 185 CNVs previously reported to be associated with autism.
The team then analyzed the actual prevalence of all the CNVs in a larger sample set of 3,000 ASD cases and 6,000 control subjects previously gathered in studies by The Children's Hospital of Philadelphia.
They found 15 of the CNVs found in the family studies, in addition to nine other CNVs found by their custom array. The subjects with those variants had at least a two-fold increased risk of having an ASD, compared to controls.
The findings could be incorporated into clinical tests for evaluating children for ASDs, according to Hakonarson.
"These high-impact variants could be most useful in advising parents who already have one child with an ASD," Hakonarson said in another statement. "If a second child has delays in reaching developmental milestones, testing for these CNVs could help predict whether that child is also likely to develop an ASD."
He said the newly identified variants would need to be added to existing commercially available diagnostic array in current use.
Harkonarson added that the CNVs detected in the study occur in genes involved in neuronal development and signaling pathways.
"Many of these gene pathways active in ASDs overlap with those in other nervous system disorders, such as schizophrenia and epilepsy," he explained. "At the same time, our results are consistent with other studies suggesting that many different biological pathways, when disrupted, can lead to ASDs." Hakonarson concluded further research may help establish whether the CNVs reported in the current study may be categorized by how they contribute to specific clinical subtypes of ASDs.