New EuRREB Publication: Gender Incongruence Module
We are pleased to share the publication of a new EuRREB article: “The Gender Incongruence module in the European Registries for Rare Endocrine & Bone Conditions (EuRREB): first results, current insights and future directions” now available in Endocrine Connections, 3 October 2025. Read the full publication here.
This study presents the development and first results of the Gender Incongruence (GI) module within the 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.
What is next
The GI module will continue to expand with additional centres joining across Europe. Upcoming work will focus on longitudinal data collection to assess outcomes of gender-affirming treatments, fertility preservation, and potential detransition, aiming to inform future clinical guidelines and policy.
Citation
Claahsen-van der Grinten HL, Wiepjes CM, Kersseboom R, Jeśka K, Nicolino M, van den Berg S, Turan S, Hauschild M, Flück CE, Krone N, et al. (2025). The Gender Incongruence module in the European Registries for Rare Endocrine and Bone Conditions (EuRREB): first results, current insights and future directions. Endocrine Connections. DOI: 10.1530/EC-25-0401.