Currently, a dataset of approximately 15,000 patients affected by various rare diseases has their genetic variants mapped to the human genome version GRCh37. However, to enhance precision and relevance, there's an essential need to remap these variants to the latest version, GRCh38, for a comprehensive genomic analysis. This project aims to bridge this gap and improve the accuracy of variant mapping in the context of rare diseases. By leveraging cutting-edge genomics techniques, the study aims to uncover novel genetic insights that might be obscured in the previous version. The project is a vital component of all Rare Diseases cohorts in BioResource, which aims to decipher underlying genetic factors in challenging cases. This endeavor holds the potential to empower clinicians in offering informed guidance to affected families, enabling early detection, prevention strategies, and improved management.