RARE-X: A patient-driven approach for collecting symptom and patient-reported outcome data in rare diseases.

Abstract

Innovation in rare disease research is constrained by limited access to reliable and accessible patient data. Accurate characterization of many conditions requires infrastructure that captures population diversity. Existing efforts are often disease specific, investigators led, with limited data sharing. The RARE-X platform was developed to address these limitations by enabling patient-reported data collection and supporting broader data access. RARE-X is a disease-agnostic platform designed to capture symptoms and patient-reported outcomes using a shared survey structure. Participants across conditions complete a core set of surveys, enabling standardized data collection and cross-disease comparisons. The platform supports global participation, enables longitudinal data capture, and provides data access to researchers through an established request process. Since its launch, and at the time of this report, RARE-X has enrolled 7493 participants from 93 countries, including 3857 patients and 3636 caregivers or siblings, across 74 rare disease communities supported by more than 120 Patient Advocacy Groups. Sixty-three percent are US-based and 37% international. Data are used in research applications, community reporting, and computational analyses. RARE-X addresses limitations of traditional registries by enabling standardized, cross-disease data collection, stakeholder input and data sharing, with the potential to inform therapeutic development and advance rare disease research.