Prion diseases such as Creutzfeldt–Jakob disease (CJD) are rare and rapidly progressive. This project will support a major global genetic study by funding and coordinating the safe extraction of high-quality DNA from existing blood and brain samples held in centres around the world, so that as many sites as possible can contribute on an equal footing. The goal is to assemble around 10,000 samples for analysis, with a partner organisation providing large-scale DNA sequencing and returning the resulting data to participating scientists. , We know that making progress depends on researchers pooling samples internationally and joining forces together. By increasing both the number and diversity of samples, the study aims to identify genetic factors that influence who develops CJD and how it progresses, generating biological clues that could ultimately inform better diagnostics and, in time, more targeted treatments.