Rare Disease Day takes place on the last day of February each year — in 2026 this is Saturday 28 February — to raise awareness and accelerate change for people living with a rare disease and their families.
Within ECTS, the Rare Bone Disease Action Group (RBDAG) works to connect clinicians and researchers across Europe, translate emerging evidence into practice, and build collaborative projects that can move the field forward.
Last year we announced the launch of a condition specific registry for Melorheostosis, a collaborative effort of the ECTS RBDAG and ERN BOND experts. This year we are proud to highlight the publication of the dataset,Developing a standard dataset in the European registries for rare endocrine and bone conditions—a Melorheostosis dataset. Orphanet J Rare Dis 20, 331 (2025).
Why this matters: Melorheostosis is an ultra-rare sclerosing bone dysplasia (estimated prevalence ~1 in 1,100,000), with fragmented clinical data and no widely adopted standards of care. A shared dataset is a key step toward harmonized real-world evidence, natural history studies, and ultimately evidence-informed guidance. Through an expert consensus process over ~12 months (including voting rounds and teleconferences), an initial long list of variables was refined to 44 unique data elements, structured under headings such as general information, clinical features, genetics, fractures, surgery, and medication. Pain and mobility capture were standardised using agreed patient-reported measures (e.g., VAS in adults; Wong-Baker in children; BPI-SF). The group also designed the module to be feasible in routine care—reported testing suggested <10 minutes for complete entry. Since activation in January 2023, the registry module had collected ~18–20 cases from two countries at the time of writing, already enabling descriptive summaries (age, anatomical distribution, symptom burden). This is infrastructure-building with immediate clinical relevance: the dataset provides a common language for centres to collaborate, compare practice, and accelerate research in an otherwise data-scarce condition. (EuRREB)
Our ECTS/ERN BOND Rare Bone Disease webinar program for 2026 is being finalised, Achondroplasia (February the 12th) will be the first webinar this year and we are already preparing the program for 2027.
Another key RBDAG priority this year is an ECTS board–approved survey on initiation of treatment in adults with Osteogenesis Imperfecta (OI) (“who is treated when?”).
The aim is to capture cross ECTS and ERN BOND—how treatment is initiated, what drives decisions (e.g., fractures, DXA, biomarkers), and where uncertainty remains—with planned launches during the ECTS conference in Girona (April 2026) and a second launch at ERN BOND GA (Oslo, May 2026), followed by summer analysis.
The ECTS RBDAG would like to call upon members to:
- Participate in the planned OI survey If you manage adult OI patients (or work in a centre seeing them). Please contribute—your practice patterns are exactly the “real-world data” we need to identify consensus, gaps, and priorities for future studies and education.
- If you have suggestions for webinars in 2027 please let us know
- For both the OI survey and the webinars please send an email to n.m.appelman-dijkstra@lumc.nl