Background
This study presents the development and first results of the Gender Incongruence (GI) module within EuRREB. The module was designed to collect standardized, multicentre data on individuals with gender incongruence (GI) across Europe. It includes five key domains: general and mental health data, gonadal hormone suppression, gender-affirming hormone therapy, fertility preservation, and gender-affirming surgery or treatment discontinuation. As of late 2024, five European centres in Belgium, Poland, Switzerland, and the Netherlands had begun contributing cases. Early findings show significant variations in clinical practices – such as age at treatment initiation and choice of hormone formulations – reflecting national regulations and healthcare contexts. Mental health comorbidities were also found to be common among transgender and gender diverse adolescents in care. This first EuRREB dataset on gender incongruence provides an essential foundation for future longitudinal studies on treatment outcomes, fertility, and long-term wellbeing. The initiative marks an important step toward harmonising care practices and improving evidence-based management for transgender and gender diverse individuals across Europe.
Objective
Healthcare for transgender and gender-diverse (TGD) adolescents varies across countries; therefore, a specific module dedicated to gender incongruence within the European Registries for Rare Endocrine & Bone Conditions (EuRREB) was developed to understand this variation. In addition, this project aims to facilitate longitudinal data collection through international, multicenter collaborations with the ultimate goal of refining current guidelines.
Methods
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 as a 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 into 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.
Overview Publication
| Title | The Gender Incongruence module in the European Registries for Rare Endocrine and Bone Conditions (EuRREB): first results, current insights and future directions |
| Date | October 3rd, 2025 |
| Issue name | Endocrine Connections |
| Issue number | Volume 14, 10 (2025) |
| DOI | 10.1530/EC-25-0401 |
| Authors | |
| Citation | Wiepjes CM, Kersseboom R, Jeśka K, Nicolino M, van den Berg S, Turan S, Hauschild M, Flück CE, Krone N. |
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