Data Coordinating Center: B2B CHANGE Cohort - PROJECT ABSTRACT Congenital heart disease (CHD) occurs in approximately 40,000 infants in the United States each year. The National Heart, Lung, and Blood Institute (NLHBI) launched its Bench to Bassinet Program (B2B) in 2009 to overcome the major barriers in translational research, identify the causes of human CHD, and improve outcomes for individuals with CHD. Through the Congenital Heart Disease GEnetic NEtwork Study (CHD GENES), the B2B program has enrolled over 14,000 participants with CHD and 18,000 family members, conducting genomic sequencing to identify an estimated 25% of previously unexplained CHD cases. Despite these advances, critical gaps persist in our understanding of how genetic variants influence genotype- phenotype correlations and long-term outcomes in CHD. Although not initially designed as a longitudinal cohort, the NHLBI recognized the unique potential of the CHD GENES and directed the coordinating center (CC) to organize deep phenotyping and re-enrollment of a subset of participants for an in-person clinical assessment and to make the data available to the scientific community as the B2B Congenital Heart disease Advancing New understanding in GEnomics (CHANGE) Cohort. The new iteration of the CC is a unique, integrated combination of world-leading cardiovascular and clinical/translational research expertise, advanced infrastructure, outstanding operational support, and state-of-the-art technology. The specific aims are to: 1) Establish and maintain the B2B CHANGE Cohort, 2) Create a unique resource for CHD research by integrating new data sources with the existing clinical and genomic information maintained in the B2B DataHub (HeartsMart) and shared with NHLBI’s BioData Catalyst system, and 3) Ensure the CHD community has the necessary access, tools, and support to translate B2B data into improved health and quality of life for those affected by CHD. B2B CHANGE will be established using a multifaceted and patient-informed cohort outreach and engagement approach incorporating nationally recognized expert leadership and consultation and adaptation to local contexts as appropriate. Innovative clinical assessments and technical advancements to HeartsMart will expand and enrich existing phenotyping approaches, extend the duration of follow-up, and allow for new biological sample acquisition for future mechanistic and translational studies. Through resources including HeartsMart and BioData Catalyst, and extensive outreach, education, and engagement, the CC will ensure the CHD community has access to this vital resource to support rigorous, independently funded, investigator-initiated ancillary studies. The B2B CC has provided excellence in administrative support and coordination for the B2B program for the previous two funding cycles and will continue to be a successful partner with site investigators, the NHLBI, and the CHD community, leading the coordination of knowledge and data for this important cardiovascular research effort.