The HPO itself does not describe individual disease entities but, rather, the phenotypic abnormalities associated with them. It is currently being developed using information from OMIM mainly, as well as from other medical information sources such as ORPHANET or DECIPHER. The combination of HPO together with the ORPHANET disease classification represents a promising resource for automated rare disease classification.
Several tools have been developed to be used by clinicians in order to optimize the exploitation of the HPO. Phenotips, PhenomeCentral, and Phenomizer are some tools currently available. All of them focus on providing assistance in diagnosis, but they offer different possibilities: