Scientists combing the human genome in recent years for autism-related DNA have uncovered dozens of genes related to the disorder and note that countless more genes have yet to be found.
New gene discoveries announced this year - including one just last week - are helping to shape a narrative that autism spectrum disorders are largely genetic conditions.
"A consensus is emerging that many of the individual genes associated with autism underlie a number of other brain disorders," said Dr. Joseph Buxbaum, director of the Seaver Autism Center at Mount Sinai School of Medicine in Manhattan, which is participating in the Autism Genome Project.
Genes related to autism, he said, have been found near those related to other complex brain conditions - attention-deficit/hyperactivity, obsessive compulsive and bipolar disorders.
Buxbaum was among the scientists who helped uncover six DNA flaws linked to autism spectrum disorders last summer. Examining DNA from 1,000 children with autism and 1,300 without the condition, project scientists identified clusters of mutations that were nearly 20 percent more common in children with autism.
"As we continue to uncover genetic mutations that can cause autism, we are gaining further insights that will lead to earlier diagnosis and better treatments," said Buxbaum, who also receives research support from the Simons Foundation. The multimillion-dollar nonprofit was founded by Long Island billionaire James Simons, whose daughter has Asperger syndrome, an autism spectrum disorder.
But genome project investigations are not the only autism-related gene searches under way.
"By no means is that the end of the story," said Dr. Anil Malhotra of the Feinstein Institute for Medical Research in Manhasset, who earlier this year isolated DNA that, when mutated, appears to cause schizophrenia in some people but autism in others.
Malhotra said as researchers continue to study the genetics of all complex neurobiological conditions, the work eventually will help explain why so many traits are shared from one condition to the next.
Another genetic question under study is why autism affects boys more frequently than girls. That answer could come within the next several months, said Dr. Michael Ronemus of Cold Spring Harbor Laboratory, where scientists are trying to unravel the disparity.
Yet, even as compelling DNA evidence emerges, experts say the findings will probably not extinguish the fiery debate about cause and effect. "Autism is a very controversial subject, especially among parent groups," said Dr. Eli Hatchwell, geneticist and founder of Population Diagnostics, a biotechnology firm in Melville and Oxford, England.
Hatchwell and his team are working on gene-based diagnostics for autism.
He predicts genetic research will ultimately define autism as at least 100 distinct conditions, each caused by their own mutations.
"There may be a small number of individuals who are reacting badly to something in the environment, but I don't believe that to be the case for everyone," Hatchwell said. "Autism is 90 percent genetic in my opinion."
Friday, December 10, 2010
Posted by BA Haller at 11:20 PM