The Orphanet nomenclature is used to code the diagnosis of rare diseases with an identifier, the ORPHAcode, in order to facilitate data collection, research and analysis. Several European countries have already adopted the ORPHAcode to identify rare diseases in their Health Information Systems, as shown by the recent inventory Implementation of rare disease patient coding across member states, produced in the framework of the RD-ACTION Joint Action (2015-2018). In order to improve the collection of information on rare diseases, and to share standardised and consistent information at European level, the RD-ACTION codification workpackage published a series of documents (Specifications for an integrated coding application with Orphacodes, Standard procedure and guide for the coding with Orphacodes, Recommendation for routine maintenance of codification resources for rare diseases) to provide recommendations and tools to facilitate the use of ORPHAcodes in Health Information Systems.

The objective of creating a toolset for coding is to provide the computable information necessary to achieve implementation of ORPHAcodes in Health Information Systems, and ensure easier and accurate coding. The files are limited to codification needs and are delivered annually (July), accompanied by descriptive documentation. Previous versions are stored and a log of changes are made available to ensure traceability. In the future, in order to facilitate the interrogation of the nomenclature, Orphanet will provide (Decembre 2019) an API (Application Program Interface).

Orphanet Nomenclature files for coding

In order to allow the implementation of the Orphanet nomenclature in Health Information Systems, Orphanet provides a set of files available on xml format. It includes:

  • the Orphanet nomenclature file,

  • the Orphanet – ICD-10 cross-referencing file,

  • a directory containing the Orphanet classifications files.

Download ORPHAnomenclature files for coding

These files are generated and made available at least once a year, in July, in 9 different languages: Czech, Dutch, English, French, German, Italian, Polish, Portuguese and Spanish.

They go with a description aiming to help users in the implementation process. Each file is described in details and the minimal information to allow data sharing, statistical reporting and interoperability is made explicit. After reading this documentation, if you still have questions, you can visit our Github Tracker issue.

The previous versions as well as the related change logs remain accessible and downloadable in GitHub. Idem for the differential produced between the current version and the n-1 version.

According to the recommandations delivered by the European RD-Action Joint Action Recommendation for routine maintenance of codification resources for rare diseases, the minimal information to allow data sharing and statistical reporting is the list of clinical entities defined by a definite diagnosis (disorder level of the Orphanet nomenclature or Aggregation level) and their proposed mapping to ICD-10 for interoperability. This minimal information is included in the « Master file ». You can easily find this data set in the Orphanet nomenclature files, according to the description available in ORPHA nomenclature xml files content.


The API is available here.

The API facilitates the implementation of the Orphanet nomenclature in Health Information Systems, and enables customised queries for specific use cases.

Orphanet Datavisualisation tool

The Orphanet Datavisualisation tool, is available here.

This tool is based on the API data and available in all API languages. It allows to search for clinical entities (groups of disorders, disorders, sub-types), displays the corresponding data (present in the API) and allows browsing through the different branches of the corresponding classification.

Find out more info about the tool here.

If you have any questions about tools, you can post an issue on our Github Tracker issue.