Narrator: This is Science Today. According to the Centers for Disease Control and Prevention, 1 out of 166 children in this country are affected with autism. Neurologist David Amaral, the research director of the M.I.N.D. Institute at the University of California, Davis, says there are three cardinal features of autism.

Amaral: The first and foremost is they have a problem having social interactions with other people. But there are two other features as well. One is impairment in communication and the third is repetitive behaviors. They'll either have repetitive motor behaviors or they'll say the same words over and over and over again.

Narrator: The M.I.N.D. Institute, which stands for Medical Investigation of Neurodevelopmental Disorders, is one of the nation's leading centers for autism research.

Amaral: We have a team that ranges all the way from molecular biology and genetics up to immunology, up to brain science, up to even treatment research. And what we hope is that by getting all this information on a large group of kids, things are going to start hanging together.

Narrator: For Science Today, I'm Larissa Branin.