RGD uses the Human Disease Ontology (DO, https://disease-ontology.org/) for disease curation across species. RGD automatically downloads each new release of the ontology on a monthly basis. Some additional terms which are required for RGD's curation purposes but are not currently covered in the official version of DO have been added. As corresponding terms are added to DO, these custom terms are retired and the DO terms substituted in existing annotations and subsequently used for curation.
A condition characterized by the presence of rudimentary THYROID tissue at the base of the TONGUE. It is due to failed embryonic development and migration of thyroid tissue to its normal location. The lingual thyroid usually cannot maintain adequate hormone production thereby resulting in HYPOTHYROIDISM.