The Clinical Core (Core Unit C) will provide a full range of clinical services to the ACE. The services include recruitment, diagnosis and comprehensive behavioral assessments of participants for Projects I, II, and 111. Core personnel will provide assistance in outcome evaluations for Project I and data collection for Projects 11 and III and will maintain communications and support for participants and their families. In addition, Core C will provide advice and interpretation of available phenotyping information for the tissue samples that will be available for Project IV. The Core personnel includes highly qualified clinicians and researchers covering a range of professional expertise, as well as students and staff who will be trained in carrying out the assessments and fulfilling the goals of the Core and the Center. Because many of the participants to be recruited for the Center projects present with highly challenging behaviors and are difficult to test, a number of innovative approaches will be taken to maximize participants' success in completing the behavioral assessments, and then to tolerate and provide artifact-free data in the electrophysiological (Project 11) and neuroimaging (Project III) studies. Novel measures for assessing key behavioral domains (including movements and motor activity; autonomic arousal; vocal behavior; language) across different contexts will be included. The clinical core will provide detailed preparation and support for the staff and families that will be implemented through a secure on-line environment designed to deliver video-based training and foster communication and collaboration between the research programs and participating families. The primary goal is to ensure that high quality clinical and research data will be collected and that participants and their families find their involvement with our research center a supportive and satisfying experience.