CLINICAL TRANSLATIONAL CORE B Core B is the U54’s translational bridge, providing essential services that enable researchers to test their hypotheses in people with autism spectrum disorders, learning disabilities, genetic syndromes, or other IDDs. Translational research depends on successfully recruiting volunteers with disabilities into studies, and characterizing them in ways that shed light on the questions or treatments under study. Core B provides these important recruitment and phenotyping services, with more intensive support for basic science colleagues who are less familiar with the intricacies of human studies. At the same time, however, the core develops innovative resources that advance translational science in four, interrelated Aims: Aim 1. Develop and implement multi-faceted strategies for successfully recruiting families and individuals with IDDs into research. Aim 1 services integrate with Core A’s communication and education goals (A5.1, 5.2), and also advance a new, national IDD Sub-Registry of the CTSA-supported ResearchMatch. The IDD Sub-Registry stands to benefit other IDDRCs in our national network. Aim 2. Grow the IDDRC’s autism and Down syndrome clinical research registries, and State of TN epidemiological databases, in both number of registrants and phenotypic complexity. This Aim facilitates recruitment and unique data mining resources for complementary clinical and population-based IDD studies. Aim 3. Advance multi-method approaches to measure the complex phenotypes of individuals with IDDs in descriptive or treatment studies, including promising new assessments in Core C (C4.2.3) and the U54 Research Project. Using the REDCap platform, Aim 3 also builds a novel, annotated collection of outcome measures used in IDD trials or interventions; a step toward filling a gap in the field underscored by NICHD. Aim 4. Provide extensive consultative and coordinating services for basic scientists embarking on human, IDD translational studies, which necessarily entails work with all others in all U54 Cores. This Aim also helps both basic and clinical investigators navigate VUMC’s Clinical Trials Center, which provides efficient administrative trial support, but lacks expertise in IDDs that is instead provided by Core B. Core B’s scientific generativity stems from both the 26 highly productive Core B users leading 43 projects, and from the development of new, forward-thinking core resources. These new directions allow IDDRC investigators to leverage their discoveries into more optimal treatments or interventions that improve the lives of people with IDDs and their families.