Making Rare Diseases Count 2026

Prader-Willi syndrome (PWS) is a rare neurodevelopmental disorder that causes developmental delays, intellectual disability and a spectrum of complex medical and behavioural challenges. Among the most debilitating features is hyperphagia, a chronic and insatiable hunger that often leads to life-threatening weight gain and severe anxiety. The impact on families is profound. A 2018 study found caregiver impact in PWS exceeded that reported in dementia, Alzheimer’s disease and traumatic brain injury.26 Building a high-impact registry for novel insights To better understand and address the real-world challenges of PWS, the Foundation for Prader-Willi Research (FPWR) launched a patient registry in 2015. Hosted on the US National Organization for Rare Disorders (NORD) IAMRARE platform, the registry collects structured data on symptoms, medications, developmental milestones and other aspects of patient and caregiver experience. By 2025, over 2,200 participants had completed more than 60,000 surveys. Most participants are from the United States, but the dataset covers dozens of countries. While this represents only a fraction of the estimated 350,000 individuals living with PWS globally, the dataset has proven large and diverse enough to generate meaningful, actionable insights for the community.The registry has enabled peer-reviewed publications and clinical insights that have helped shape best practices.27 These findings have supported clinician education, informed research priorities and helped guide FPWR’s strategic decisions. For example, registry data revealed that many PWS cases in the US are still not diagnosed until after the first year of life, evidence that has informed FPWR’s investments in newborn screening. Supporting regulatory engagement and therapeutic breakthroughs FPWR has also made use of registry data to strengthen its engagement with regulators and policy-makers. During meetings with the US Food and Drug Administration (FDA), structured evidence from the registry added analytical depth to caregiver and patient testimonials, helping translate lived experience into quantifiable patterns of disease impact and unmet need. More notably, registry insights played a key role in the 2025 FDA approval of DCCR (diazoxide choline extended-release) tablets.28 This is the first therapy approved specifically to treat hyperphagia in PWS. It represents the culmination of years of collective effort (see Figure 8) and the beginning of a new chapter in PWS care. FPWR continues to advance its registry infrastructure. New platforms allow expert clinicians to contribute structured clinical observations to complement patient-reported data. The foundation also recently launched a registry for Schaaf-Yang syndrome, a condition with close genetic and phenotypic overlap with PWS. Additionally, FPWR is collaborating with peer organizations to broaden participation in under-represented populations, aiming to make its data even more inclusive and globally representative. Figure 8 – Timeline of PWS community milestones, 1956–present Source: Foundation for Prader-Willi ResearchCASE STUDY 1 Harnessing registry data to advance PWS therapies PWS first recognized as a distinct medical condition.1956 Genetic cause of PWS first identified on chromosome 15.1981 Prader-Willi Syndrome Association USA (PWSA USA) incorporated.1977 International Prader-Willi Syndrome Organisation (IPWSO) founded.1991 Foundation for Prader-Willi Research (FPWR) founded.2003 FDA approves recombinant human growth hormone for PWS.2000 FPWR makes venture philanthropy investment in DCCR.2014 Top-line phase 3 clinical trial results for DCCR reported.2020 FPWR launches Global PWS Registry on NORD’s IAMRARE platform.2015 FPWR, PWSA USA and IPWSO co-host EL–PFDD meeting with FDA.2023 FDA approves DCCR for treatment of hyperphagia in PWS.2025 Making Rare Diseases Count: How Better Data Can Unlock a Multitrillion-Dollar Opportunity 16