The Development of a European Registry for Facial Dysostosis Syndromes: A Delphi-Guided Approach.

Facial dysostosis syndromes (FDS) are rare congenital conditions that significantly impact facial function and appearance. At the time of this writing, standardised monitoring protocols for FDS are lacking, hampering research, and evidence-based care. Thus, a comprehensive dataset was developed within the European Reference Network for Rare and Complex Craniofacial Anomalies (ERN CRANIO). Candidate data elements were identified through a systematic literature review (1985-2024) and supplemented with elements from existing ERN CRANIO datasets and expert panel suggestions. A Delphi survey was then conducted among 61 clinicians and 3 patient representatives to assess each element's relevance and reliability using a 9-point Likert scale. A subsequent hybrid consensus meeting with the expert panel shaped the final dataset, ensuring comprehensive coverage, avoiding overlap, and determining the appropriate timing for data collection. Of 200 data elements that entered the Delphi voting, 98 were strongly recommended, 102 scored neutral, and none were strongly discouraged. Ultimately, 110 elements were included, organised into 2 levels: Level 1, comprising exclusively patient-reported and parent-reported outcome measures; and Level 2, encompassing patient characteristics, treatment information, clinical outcomes, and imaging/diagnostics. This newly developed dataset marks the first international registry for FDS, offering considerable potential for collaborative research, cross-centre comparisons, and substantial improvements in care for patients with FDS worldwide. Real-world implementation will be essential to evaluate its feasibility and guide further refinements.