Researchers are hopeful of being able to treat autism which is not a disease but the result of a range of genetic and environmental factors. The study published in the journal Science, says that autism appears to be caused by faulty DNA combining with the physical and social environment of a child after birth. Through the identification of at least six new genes that appear to underlie autism, researchers feel treatment in some cases may be possible.

Autism, one of the more urgent health problems of today, which is marked by speech problems, social isolation and repetitive actions, is felt to be the result of mutations, which appear to disrupt genes important to the developing brain. These are turned on and off by activity of brain cells known as neurons that are stimulated by early childhood experiences. Studies have shown that genes probably contribute about 70 percent to a child's risk of developing autism.

A study by the Centers for Disease Control and Prevention last year reported that 1 in every 150 American children has an "autism spectrum disorder," a number that is growing.

The study, by Dr. Christopher Walsh and Dr. Eric Morrow of Harvard Medical School in Boston and colleagues suggests in theory that changing the experiences of autistic children, could change the course of the disease.

"The genes implicated in our study are ones that interact with the environment and are involved in how the brain converts what it sees from the environment. If we can activate those genes by other mechanisms, we might be able to help the kids," says Dr. Walsh, a neurologist and chief of genetics at Children's Hospital in Boston who headed the team.