MAScINSIGHT: A Real-World Data Study to Deepen Knowledge and Management of McCune-Albright Syndrome - Study Protocol for an Observational Study within OHDSI

Introduction McCune-Albright syndrome (MAS) is a rare congenital disorder affecting endocrine, skeletal and dermatological systems. MAS is often coded as fibrous dysplasia (FD) in routine health data, which includes other conditions and does not allow precise identification. This coding gap complicates reliable epidemiological estimates and clinical characterization. The study MAScINSIGHT aims to address this by investigating MAS features within FD-coded cohorts. Methods and analysis MAScINSIGHT is a retrospective observational study using a federated network of data in the OMOP Common Data Model. Routine data from multiple sites will be analyzed within a federated setting to assess endocrine abnormalities and treatment patterns in patients with FD or MAS. Ethics and dissemination Analyses will be performed locally at the data partner, with only aggregate statistics made available and centrally analyzed. The study protocol was approved by the ethics committee (reference number: 2026-18760-retrospektiv). Findings will be disseminated through open-access publications and patient-oriented reports.