A gene-sequencing study of children with autism, described in an advance online publication in Nature Genetics on 15 May, offers a sneak peek at a technique which, combined with other approaches, may explain 40 to 50 percent of the genetic causes of the disorder within just a few years, proposes the study's lead investigator. This approach, says Evan Eichler of the University of Washington in Seattle, will potentially allow clinicians to "lift the hood on what has gone wrong in each individual child with autism," with the hope of ultimately devising individually-tailored drug therapies.
Autism spectrum disorders manifest themselves in a wide variety of ways, and researchers believe that they are highly genetically diverse, involving mutations in any of several hundred genes. While studies of twins suggest that as much as 90 percent of autism is genetically based, large-scale genetic screens over the last decade that searched for common genetic variants underlying the disorder have been disappointing. A growing body of evidence suggests that, especially in families with no prior history of the disorder, autism results not from the inheritance of an unfortunate combination of common gene variants, but from rare, spontaneous or de novo mutations in the egg or sperm.
Over the past few years, this theory has been supported by numerous microarray studies showing that children with spontaneous autism are more likely than their unaffected siblings to have de novo copy number variants, mutations in which a large chunk of DNA is duplicated or deleted.
Now, in work funded in part by the Simons Foundation, Brian O'Roak, a joint postdoc in Jay Shendure's and Eichler's labs at the University of Washington, has sequenced the exome the protein-coding regions of the genome of 20 families consisting of one child with an autism spectrum disorder and unaffected parents and siblings. In contrast to most previous studies, which had sufficient re
|Contact: Anastasia Greenebaum|