New Genetic Link to Autism Reported

By DAVID ARMSTRONGJanuary 10, 2008; Page D4 Researchers have identified a new genetic link to autism using recently developed gene-scanning technology that sorts through hundreds of thousands of genetic markers to pinpoint abnormalities.
Research teams in Boston and Chicago, publishing separate studies in different medical journals, independently identified a genetic variation -- in a region of the DNA called chromosome 16 -- that is associated with about 1% of all autism cases. The abnormality is often not inherited, the researchers found.
The identification of a genetic defect tied to the risk of developing autism isn't new. About 15% of autism cases have a known genetic cause, says David Miller, a researcher at Children's Hospital in Boston and a co-author of one of the studies.
Nonetheless, the discoveries related to chromosome 16 offer promising clues for future research. University of Chicago researchers, who published their results in Human Molecular Genetics, say the loss of a small portion of chromosome 16 results in a corresponding loss of 25 genes. At least three of those genes are thought to influence behavior, say the researchers, making them prime candidates for autism research.
"The hope is that eventually, if we can find genes that lead to brain mechanisms, we can think about treatment," said Fred Volkmar, an autism expert and director of the child study center at the Yale University School of Medicine, who wasn't involved in either study. He cautioned, however, that this work is "many steps down the road," and that the findings regarding chromosome 16 are only "one step in a very complicated puzzle we have to piece together."
About one in 150 children under the age of three is diagnosed with autism. Symptoms range from mild to profound, and include impaired social interaction, problems speaking or communicating, and unusual or repetitive behaviors.
In the second study, published yesterday in the online edition of the New England Journal of Medicine, researchers from a group of Boston hospitals and universities known as the Autism Consortium scanned DNA samples from more than 3,000 children and families to identify the link to chromosome 16.
The researchers took advantage of new technology that maps five to 10 times more genetic markers in the human genome than before, making it easier to identify specific abnormalities. Two companies -- Affymetrix Inc. and Agilent Technologies Inc. -- produce the DNA maps used by the Boston researchers. Using a laser scanner and complex computer algorithms, the researchers compared those DNA maps with samples taken from children with autism or suspected of having an autism-related disorder.