Orphanet offers a range of freely accessible services:
(1) an inventory of rare diseases and a classification of diseases elaborated using existing published expert classifications;
(2) an encyclopaedia of rare diseases in English and French, progressively translated into Dutch, German, Italian, Spanish, Polish, Portuguese, and Czech;
(3) an inventory of orphan drugs at all stages of development;
Orphanet datasets are available for research purposes at www.orphadata.org. Orphadata provides the scientific community with comprehensive, quality data sets related to rare diseases and orphan drugs from the Orphanet knowledge base, in reusable formats. Orphanet produces ORDO, the Orphanet Rare Diseases Ontology, and HOOM, the HPO-ORDO Ontological Module. Orphadata, part of the French node of ELIXIR, is an Elixir Core Data Resource. Orphanet and ORDO are IRDIRC Recognized Resources.