Introduction: Leigh syndrome (LS) is a rare, severe neurometabolic disorder and a type of primary mitochondrial disease. The Cure Mito Foundation is a nonprofit foundation founded in 2018 by parents of affected children. The organization's mission is to unite the global LS community to accelerate patient-centered research, treatments, and cures. Cure Mito has launched a global patient registry for Leigh syndrome in September 2021 to better understand the disease, facilitate clinical trials recruitment, and build a strong global community. Objectives: Patient data is collected in registries for getting a real-world view of patient reported outcomes, and to improve the understanding of the disease. Establishment of interoperability of therapies. The project described here has been undertaken to establish such interoperability for Leigh syndrome patient registry data.Methods: Establishing interoperability consisted of assessment of all data elements and collected data, alignment of data elements and variables with CDASH domains and variables, terminology alignment, data transformation, and compliance assessment. Results: Data assessment has been done, domain map has been developed, and data has been converted to CDASH standard.Conclusion: Cure Mito Foundation and Sumptuous Data Sciences, LLC completed a project focused on interoperability of Leigh syndrome patient registry data with CDISC standards, converting the data to CDASH standards, with SDTM conversion in progress. This project is a key milestone for all stakeholders who collect real world data in rare diseases.