Supplementary Material for: The CrescNet Registry Achondroplasia Module: Real-World Demographic Data and Clinical Outcomes in Untreated and Vosoritide-Treated Individuals

Introduction: Achondroplasia is a rare skeletal dysplasia characterized by severe disproportionate short stature. Vosoritide is currently the only approved therapy. The CrescNet registry is a network of primary and specialized pediatric tertiary centers that aims to improve early detection of growth disorders in Europe. In 2021, an achondroplasia-specific data collection module was set up within CrescNet to enhance data collection among children with achondroplasia and assess the impact of interventions. Here, we describe the module setup and report preliminary real-world outcomes of vosoritide treatment over 3 years.Methods: The module was established in 10 of 11 countries participating in CrescNet. Achondroplasia-specific data were collected, including developmental milestones, interventions (such as limb-lengthening surgery, treatment with vosoritide and growth hormone), complications, and health-related quality of life, alongside standard anthropometric measurements (eg height, weight, etc). Pseudonymized data were sent to the CrescNet central database, Leipzig University Hospital, Germany, for analysis by age and treatment status.Results: As of May 2025, 486 participants from 32 tertiary centers were enrolled. Data from 73 untreated and 186 vosoritide-treated individuals with genetically documented achondroplasia were analyzed. In vosoritide-treated individuals, mean height standard deviation score, referenced to an untreated European achondroplasia population, significantly increased from baseline at 1, 2, and 3 years after vosoritide initiation (P≤0.0001).Conclusions: The module facilitates the collection of real-world data to improve understanding of the natural history of achondroplasia and outcomes associated with interventions. Growth data from vosoritide-treated individuals were consistent with clinical trial findings and published real-world data. Longer-term follow-up is ongoing.