HPO

The Human Phenotype Ontology (HPO) provides a structured vocabulary of phenotypic abnormalities — over 17,000 terms organised under root concepts like 'Abnormality of the nervous system' or 'Abnormality of head or neck'. Each term has a textual definition, synonyms, cross-references and a position in the polyhierarchy.

The complementary HPO Annotations dataset maps each disease (OMIM, Orphanet, DECIPHER) to its characteristic phenotypes with frequency, onset and modifier metadata. HPO is the de facto standard for deep phenotyping in clinical genetics and is embedded in diagnostic pipelines like Exomiser, LIRICAL and the GA4GH Phenopackets schema. Monthly releases, CC BY 4.0.