Autism genomes add to disorder's mystery

Less than a third of siblings with autism shared the same DNA mutations in genes associated with the disorder, according to a new study that is the largest whole-genome sequencing for autism to date.

Canadian researchers sequenced whole genomes from 170 siblings with autism spectrum disorder and both their parents. They found that these sibling pairs shared the same autism-relevant gene variations only about 31% of the time, according to the study published online Monday in the journal Nature Medicine.

More than a third of the mutations believed to be relevant to autism arose in a seemingly random way, the study also found.

It isnt really autism; its autisms, said the studys lead investigator, Dr. Stephen W. Scherer, head of the Center for Applied Genomics, Genetics and Genome Biology at the Hospital for Sick Children in Toronto. In some cases, he added, its like lightning striking twice in the same family.

The results are part of 1,000 whole genomes that are being made available to researchers via a massive Google database that autism advocates hope will grow to 10 times that size by next year.

The effort, spearheaded by the research and advocacy group Autism Speaks, has been somewhat controversial from the start, with some questioning whether results from the relatively costly and time-consuming process will be too complicated or obscure to yield significant breakthroughs.

Indeed, researchers associated with the effort acknowledged that much of their data remain a mysterious ocean of jumbled, deleted or inserted DNA code, much of which is not located on areas of the genome that program the proteins that directly affect biological functions.

You might expect that youd see some commonalities in the mutations between kids in the same family, but thats actually not the case here, said Rob Ring, chief science officer of Autism Speaks. Were not really sure what might explain that at this time.

Said Scherer: Weve really just scratched the surface of this data.

Thats where Googles cloud-based data capabilities will come in, according to Ring and Scherer. Making these whole genomes potentially 10,000 of them available to any researcher could yield unexpected connections and order in data thatare the equivalent of more than 13 years of streaming high-definition television programming.

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Autism genomes add to disorder's mystery