POSTED: 5:53 p.m. PDT July 15, 2003

Micki Flowers
KIRO 7 Eyewitness News Health Reporter

A remarkable new finding could help calm the fears of parents worried about a link between autism and childhood vaccines.

No one knows exactly what causes autism, but a new study of head circumference in autistic children may give us a new diagnostic tool.

2-year-old Mario Fraser is mildly autistic. The disorder has many symptoms, including difficulty communicating and showing emotion.

"Being able to love and to be loved, and when they tell you that maybe your son won't be able to have this type of quality of life, it's devastating," said Mario's mother, Estella Fraser.

Early intervention can help. Now California researchers may have found a way to determine which children are at risk.

For a decade, researchers analyzed data from 48 autistic children. Brain scans confirmed a startling finding about their brains.

"We found that at birth, these infants have smaller head circumference than normal and then, a few months after birth, there was sudden and dramatic burst of growth so that by 6 to 14 months of age, head circumference is far larger than normal," said Dr. Eric Courchesne.

The researchers say more rapid brain growth was related to more severe symptoms of autism. They say the growth spurt occurs well before kids get certain vaccines.

MORE ON THIS STORY See the study in JAMA Autism Society of America

"Environmental events, such as MMR vaccines, cannot possibly cause these preceding brain growth abnormalities," Courchesne said.

An MRI caught Mario's brain growth early. Therapy is helping. His autistic symptoms have decreased.

"He's giving me kisses and he has 14 words and he's ... coming back," Estella Fraser said.

Findings could serve as an early warning signal of risk for autism, allowing for early intervention. The findings could also lead to further research on what causes the early brain overgrowth.