SEATTLE - University of Washington researchers are looking for infants with an older sibling with autism for a study on the developmental disorder.

The study will examine changes in children's brains and behavior that may signal the onset of autistic symptoms.

The infants are needed for the $13.25 million Infant Brain Imaging Study of the developmental disorder that affects one in every 150 youngsters.

Infants who have an older sibling with autism are at even greater risk for developing the disorder. One in 20 of these infants may develop autism.

The UW portion of the study is still looking for 84 six-month-old infants from California, Oregon, Washington, Montana, Idaho, Nevada and Alaska who have an older sibling who has been diagnosed with autism. It also needs 34 infants with typically developing older brothers or sisters.

Participants in the study will go through a preliminary screening interview, then a comprehensive developmental assessment and finally will have magnetic resonance imaging scans taken of their brains when they are 6, 12 and 24 months of age. Families can earn $225 for participating in the entire study. The study requires the imaging to be done in Seattle and money is available to cover the cost of travel for participants.

"This is the first study that will prospectively measure, in the same group of infants, both the onset of autistic symptoms and brain enlargement that may co-occur at the end of the first year of life in children with autism," said Dr. Stephen Dager, principal investigator of the study at the UW and interim director of the university's Autism Center.

Families interested in participating in the study or those that want more information should contact the intake coordinator for the UW's Autism Center at 800-994-9701 or ddrinfo@u.washington.edu. More information about the Infant Brain Imaging Study is available on the Web at http://ibis-network.org/default.html.