Differences or (biomedically) Disorders of Sex Development (DSD) constitute a group of rare to very rare congenital conditions affecting the development of the genito-urinary tract and in most instances also the endocrine-reproductive system. DSDs are caused by chromosomal, molecular genetic and endocrine aberrations, which in turn modulate the sexual phenotype of an individual. Several distinct entities, like congenital adrenal hyperplasia (CAH), affect also other organ functions, mostly adrenal or kidney, but also complex syndromes are described.

The exact aetiopathogenesis remains unknown in the majority of the cases. For some conditions, the molecular diagnosis can be achieved in almost 90% of the cases, while in many others like complete gonadal dysgenesis it may be below 20%. It should also be highlighted that the molecular study of DSD can also provide novel insights into the aetiology of other much more common reproductive disorders such as male and/or female.

Research on rare conditions requires a structured approach towards linking expert research insights of various specialities with relevant patient data and promotion of clinical centres of reference. The relative scarcity of people with rare conditions and their overall distribution implies that international collaboration between clinical and research networks is crucial in order to develop new knowledge and tools for diagnosis and treatment. The participants who developed this Action believe it is mandatory that the international research community works together on these issues in a manner that is inclusive of all interested stakeholders and includes academics, clinicians, small to medium enterprises (SMEs), and patient organisations from both COST and non-COST countries. The main motivation of this COST Action is to link up researchers from various specialities at all levels of experience to expedite scientific exchange in order to harmonise research and diagnostic approaches as well as clinical management. This will encourage and nurture European support networks for DSD.

If you are interested in DSD research, please consult information on the achievements of the working groups.