This grant provides support for an NIH Autism Center of Excellence (ACE) Network. Studying infants with Tuberous Sclerosis Complex (TSC), is a genetic disorder with a high prevalence of autism spectrum disorder (ASD). Because TSC can be diagnosed before or at the time of birth, there is the potential to develop better tools for early detection of ASD. This project will investigate whether longitudinal assessment of brain connectivity using magnetic resonance imaging (MRI) and electroencephalography (EEG) in children with TSC can identify an early biomarker of subsequent ASD in this genetic disease. This study will establish a consortium of five Children's Hospitals that are geographically-distributed throughout the United States to recruit TSC patients in the first year of life to test this hypothesis. State of the art imaging with 3 Tesla MRI scanners, advanced EEG technology, validated neurodevelopmental assessment tools, genetic analysis, and standardized clinical measures through age 36 months will be utilized. The clinical consortium will be supported by a centralized Data Coordinating Center with experience in another rare disease (neurofibro- matosis). Collaboration with Leadership Education in Neurodevelopmental and Related Disabilities (LEND) programs at each center will provide additional interdisciplinary research training and education expertise in ASD and TSC. As a result of the research outlined in this proposal, better understanding of brain connectivity and it relationship to ASD in TSC will pave the way for new interventions for this and related causes of ASD.