Genes From Middle East Families Yield Autism Clues

Scientists look to DNA from Middle Eastern families to solve the autism mystery.

ByABC News
September 22, 2008, 4:54 PM

July 10, 2008— -- WASHINGTON (AP) - Harvard researchers have discovered half adozen new genes involved in autism that suggest the disorderstrikes in a brain that can't properly form new connections.

The findings also may help explain why intense educationprograms do help some autistic children - because certain genesthat respond to experience weren't missing, they were just stuck inthe "off" position.

"The circuits are there but you have to give it an extrapush," said Dr. Gary Goldstein of the Kennedy Krieger Institute inBaltimore, which wasn't involved in the gene hunt but is well-knownfor its autism behavioral therapy.

The genetics suggest that "what we're doing makes sense when wework with these little kids -- and work and work and work -- andsuddenly get through," he said.

But the study's bigger message is that autism is too strikinglyindividual to envision an easy gene test for it. Instead, patientsare turning out to have a wide variety, almost a custom set, ofgene defects.

"Almost every kid with autism has their own particular cause ofit," said Dr. Christopher Walsh, chief of genetics at Children'sHospital Boston, who led the research published in Friday's editionof the journal Science.

Autism spectrum disorders include a range of poorly understoodbrain conditions, from the mild Asperger's syndrome to more severeautism characterized by poor social interaction, impairedcommunication and repetitious behaviors.

It's clear that genes play a big role in autism, from studies oftwins and families with multiple affected children. But so far, thegenetic cause is known for only about 15 percent of autism cases,Walsh said.

So Walsh's team took a new tack. They turned to the Middle East,a part of the world with large families and a tendency for cousinsto marry, characteristics that increase the odds of finding raregenes. They recruited 88 families with cousin marriages and a highincidence of autism, from Jordan, Saudi Arabia, Kuwait, Oman,Pakistan, Qatar, Turkey and the United Arab Emirates. They comparedthe DNA of family members to search for what are called recessivemutations -- where mom and dad can be healthy carriers of a genedefect but a child who inherits that defect from both parents getssick.