The Gender Incongruence module in the European Registries for Rare Endocrine & Bone Conditions (EuRREB): first results, current insights and future directions.

Objective: Healthcare for transgender and gender diverse (TGD) adolescents varies across countries, therefore a specific module dedicated to gender incongruence (GI) within the European Registries for Rare Endocrine & Bone Conditions (EuRREB) was developed to understand this variation. Additionally, this project aims to facilitate longitudinal data collection through international, multicenter collaborations with the ultimate scope of refining current guidelines.

Methods: The module consists of five sections covering general information, including the presence of mental health comorbidities, and specific information on gonadal hormone suppression (GHS), gender-affirming hormone (GAH) therapy, fertility preservation, gender-affirming surgery (GAS), and eventual stop of treatments.

Results: As of December 2024, five centers from four European countries (Belgium, Poland, Switzerland, and the Netherlands) had started to report cases in the registry. Preliminary findings highlight the existence of some differences among centers, often consequence of differences in national regulations and healthcare policies, e.g. reimbursement criteria. Importantly, mental health comorbidities were commonly reported among TGD adolescents from all centers, emphasizing the need for comprehensive psychological assessment and targeted psychological care. While currently still at an early stage, this longitudinal data collection will offer insights in important long-term outcomes such as uptake of surgical or reproductive options, or detransition, in large cohorts.

Conclusion: The data collected so far highlight the importance of wide multicenter data collection in advancing knowledge on the care of TGD adolescents. Expanding this registry and fostering international collaboration will be crucial in standardizing protocols, improving care, and guiding evidence-based recommendations for TGD youth.