The goal of our study is to increase our understanding of the timing and pattern of brain development in very young children with autism. This knowledge will help us to understand the underlying causes and brain mechanisms involved in autism and the relationship of those brain mechanisms to particular behaviors and psychological processes.

Autism is typically diagnosed at 3 years of age. Some children are brought to attention and receive a diagnosis even earlier at 2 years of age. Although some behavioral characteristics, qualitatively similar to the defining features of autism, can sometimes be observed at younger ages (for example at 12 months and later), typical features sufficient for a diagnosis of autism are not usually present before age 2 years.

While we do not know specifically what causes autism, twin and family studies have demonstrated that genetic factors play a significant role in many cases. This study examines younger siblings (brothers and sisters) of children with autism. Twin and family studies have shown that younger brothers and sisters of children with autism are at a higher risk of also developing autism than those children that do not have relatives with this condition. Therefore by studying younger brothers and sisters of children with autism, some of whom will be unfortunately diagnosed with autism at later ages, we have the opportunity to gain insights into the developing brain in autism at these early ages before a formal diagnosis is determined. While we understand the worries this idea may raise in some families the insights possible about the developing brain in autism, from such a study, are potentially extremely valuable.

In particular some children with autism have been shown to have overall brain overgrowth by age 2 years. One large study of head circumference by our group suggests that this overgrowth begins (on average) around 12 months of age. We therefore propose to conduct an MRI (Magnetic Resonance Imaging) brain scan of children at risk for autism (i.e., younger brothers and sisters of older autistic individuals) at around 3 months of age, with repeat scans through 24 months of age. In addition to targeting brothers and sisters of autistic individuals, we will use newly developed behavioral assessment tools and parental questionnaires to help us identify infants at risk for autism. Through the use of MRI technology we will capture images of the brain and perform sophisticated brain measurements. The data gathered in this study will provide important information regarding early brain development in autism, which may in turn provide clues that will eventually result in early rationale interventions (e.g., early behavioral or medication treatments) to improve outcomes for children with autism.