Small Deletions, Duplications of DNA May Up Autism Risk
Two new studies have found more small deletions and duplications of DNA in individuals with autism than in controls. These variants may also affect the severity of the disorder.
The studies mined the sequences of exomes, the regions of the genome that code for proteins.
Autism is strongly genetic: Twin studies have estimated that some 50 to 90 percent of cases are caused by genetic factors. Yet all of the genetic studies of autism put together have identified less than half of these genes.
The new studies suggest that some of that missing heritability can be explained by small deletions and duplications of DNA — called copy number variations (CNVs).
"Now that there’s exome data on a substantial number of autism families, you can take advantage of the ability to detect CNVs in exons to find stuff that you couldn’t find before," notes Jonathan Sebat, associate professor of psychiatry at the University of California, San Diego, who was not involved in either study.
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