Executive summary Investment in rare diseases represents a multitrillion- dollar opportunity to improve lives, strengthen economies and advance science. However, around 95% of rare diseases have no treatment authorized by a major regulatory agency, leaving most patients without effective treatment and so placing a heavy burden on families and caregivers. This paper explores the case for greater societal investment in rare diseases and the central role of data in assessing need, measuring impact and enabling progress. These investments generate impact across three key dimensions: –Human health: Improving diagnosis, treatment and understanding of rare diseases can directly enhance quality of life and outcomes for more than 300 million people worldwide. –Socioeconomic resilience: Reducing the impact of rare diseases can lower healthcare costs and strengthens economic productivity, benefiting the wider circle of more than 1 billion people whose lives are touched by these conditions, including families and caregivers. –Scientific and medical progress: Insights and technologies pioneered in rare diseases often spill over into more common conditions, driving scientific discovery and innovation across healthcare. The paper also provides a practical roadmap to strengthen rare disease data systems worldwide, with five key recommendations: –Define and track a minimum dataset across countries to standardize data collection processes and expand the global knowledge base on rare diseases –Strengthen patient engagement in data collection to maximize the quality, breadth and utility of patient registries and other key datasets –Improve newborn screening and diagnostic capacity to enable earlier detection, better prevalence estimates and more efficient care –Enable trusted data sharing across health systems by aligning standards, governance and safeguards to make data more usable while protecting privacy –Use AI and digital tools to address evidence gaps, turning scattered information into structured, actionable insights These strategies are broadly applicable across healthcare systems, although implementation will vary based on socioeconomic and cultural factors. In all contexts, success depends on tailoring the roadmap to local realities while ensuring alignment with international standards. Public, private and philanthropic actors all have roles to play, independently or in partnership. Those who benefit – patients, families, health systems, employers, payers, governments and industry – are the same stakeholders who can invest, and each realizes gains in health, productivity and innovation. Landmark policy actions, including the recent resolutions on rare diseases from the United Nations (2021)3 and World Health Assembly (2025),4 have placed rare diseases firmly on the global health agenda. There is an opportunity for countries and health systems to act decisively, using this roadmap to convert global recognition into national and local progress. Rare diseases matter to all of us. While individually rare, they are collectively common, and their impacts are felt across every part of society. The call to action is clear: invest in rare diseases, with data as the foundation. This will improve lives, strengthen economies and accelerate innovation across healthcare.Investment in rare disease data systems will benefit society and the economy, drive medical progress and improve the health and life outcomes of more than 300 million people. Making Rare Diseases Count: How Better Data Can Unlock a Multitrillion-Dollar Opportunity 4

Making Rare Diseases Count 2026