Introduction: The European Registry for Rare Bone and Mineral Conditions (EuRR-Bone) was founded to support the needs of the bone and endocrine community by facilitating the collaboration between patients, health care professionals and researchers across Europe. It is closely linked to the European Reference Networks on rare bone and endocrine conditions. This is an open access platform  that in collaboration with the EuRRECa project (European Registries for Rare Endocrine Conditions) provides two different tools: a Core Registry and an electronic reporting tool (e-REC). The core registry collects a set of core data elements and longitudinal clinician and patient reported outcomes.

Objective: To describe the activity of the EuRR-Bone Core Registry between April 2020 and October 2021.

Methods: Core Registry clinical contributors are invited to register new and existing cases of bone and mineral conditions seen in their centres. A core data set and a condition group data set collect information regarding demographics and diagnosis. Patient access and participation in the platform is possible.

Results: A total of 166 records have been entered in the registry. 10 centres from 9 countries have participated. In the mineral group of conditions 120 cases have been entered with genetic hyperparathyroidism (28%), X-linked hypophosphataemia (15%) and iPPSD2 (former PHP1A) (7%) being the most reported. In the bone dysplasia group 46 cases have been registered, polyostotic fibrous dysplasia (3%) and hypophosphatasia (3%) were the most reported. Regarding patient participation, 35 patients have declared they would like access to the registry but only 10 have an active account.

Conclusion: The Core Registry is a platform that allows clinician and patient participation. Currently, the records have been entered by a small number of centres in Europe and beyond. Dissemination of the project among the bone and mineral community are necessary to increase participation of health professionals, researchers and patients while supporting their needs.