Autism Cause: Brain Development Genes?
Genes Missing in Autism Needed for Learning-Triggered Brain Growth
"We still don't understand the underlying genetics for more than half the kids with autism, so we have a long way to go to understand that, and to understand what non-genetic factors might also contribute," Walsh says. "We know genetics is very, very important in autism, but we don't know whether it is the whole answer or not."
The Walsh team's findings are "really exciting," says Margaret A. Pericak-Vance, PhD, director of the Miami Institute for Human Genomics at the University of Miami School of Medicine. But she, too, notes that it's far from the end of the search for the causes of autism.
"Autism, even though it has a heritable component, is a complex disease that will take a lot of different approaches to decipher," Pericak-Vance tells WebMD. "It will not be one-stop shopping. We know there is no single major cause and no simple answer."
Pericak-Vance predicts that researchers scanning the entire human genome for autism clues will soon be announcing more "exciting" results.
Crucial to the Walsh team's findings was the collaboration of scientists in Jordan, Kuwait, Oman, Pakistan, Qatar, Saudi Arabia, Turkey, and the United Arab Emirates. These researchers enrolled 104 families in the study, including 88 families with marriages among cousins. That was an important factor, as rare or recessive genes occur twice as often in such families.
But also crucial was a chance meeting between Walsh, a geneticist, and fellow Children's Hospital Boston/Harvard researcher Michael E. Greenberg, PhD, a neuroscientist studying how the brain changes as it learns.
"When we talked to each other, we realized, gee, a lot of our genes that are involved in autism are also their genes that are involved in learning in the brain," Walsh says. "There is nothing more powerful in science than these kinds of serendipitous collisions between people working in related but somewhat distinct fields."
Walsh and colleagues report their findings in the July 11 issue of the journal Science.
(Just found out your child has autism? Come meet other parents who understand at WebMD's Autism Support Group.)