Abstract The chromosome 18 cohort with hemizygous deletions of chromosome 18 who manifest a multitude of structural birth defects bring an expanded opportunity to the Gabrielle Miller Kids First Pediatric Research Program (GMKF) (Project number (HD107271-01). This cohort, with known and varied genetic contributors to those birth defects, will contribute valuable data toward understanding the underlying molecular gene contributors of a variety of a number of structural birth defects. However, our current phenotypic database lacks important details about the associated endophenotypes and the outcomes of any treatments. We have a wealth of data in the existing scanned medical records, survey and questionnaire answers and from our on-site clinical evaluation records. Additionally we have longstanding relationships with the participating families and can follow up to verify, get new details, and clarify information. We propose to expand the scope of the curated data elements, map Human Phenotype Ontology (HPO) terms to those data elements thereby increasing the value of the data available to the research community. Our plan to enhance the depth and scope of the phenotype data is to first reevaluate all the existing records adding additional data elements where necessary to the database. This evaluation will generate a report for the families detailing the information we have and the dates the information was gathered. We will ask the families for any updated information focusing on evaluation and treatment outcomes for any of the structural birth defects as well as any cancer diagnoses. The enhanced dataset will be standardized by the mapping of the Human Phenotype Ontology (HPO) terms to the data elements. The outcome of this project will be to increase the accessibility and quality of these data to the broader research community as these phenotype data are integrated with the genomic data generated by the GMKF program.