The Emory ACE Clinical Assessment Core (CAC) is the locus for the recruitment, rigorous clinical characterization, management and care of participants in Projects I, II and III. The CAC objecfives include: Recruitment: to ensure that a sufficient number of subjects (including infants, their families, and appropriate controls) are recruited for each project in an efficient and ethical manner, with efforts to reduce attrition and maximize follow-through, making full use of the vast clinical resources available through the Marcus Autism Center, Children's Healthcare of Afianta, and Kids Health First; Clinical Characterization: to provide each Project with a well centralized, supported, and coordinated assessment protocol conducted and supervised by expert clinicians to ensure the accurate collecfion and management of diagnostic, assessment, genetic, and medical data, as well as independence between risk status and clinical ascertainment, and beh/veen clinical and experimental procedures; Clinical Care: to provide optimal clinical care including supports associated with children's risk status; Training & Reliability: to ensure achievement of high-level procedural and numerical reliability among the CAC clinicians, maintenance of achieved reliability, and correction of drift among staff; and Qualitv Control: to ensure investigator satisfaction and quality control of procedures by implementing a systematic framework for communication between investigators and the CAC through the use of both a web-based platform and regulariy scheduled meetings. We believe that outstanding research programs are seamlessly fied to outstanding clinical care programs, from which relevant hypotheses are derived and which become the ultimate laboratory for translational science and practice. RELEVANCE (See instructions): The needs of Projects I, II and III are substantial: participants are infants completing an intensive protocol from birth through the age of 36 months, with the possibility of up to 13 visits; and for the majority of them, their parents are aware of their risk status. The clinical characterization of infants & toddlers requires special expertise and experience. High levels of family support are required in order to address the families' needs, problem-solve logistics of visits, and ensure family safisfacfion and engagement.