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 retinitis pigmentosa characterized by mild to moderate rod-cone dystrophy with onset in the second or third decade of life. Patients have constricted visual fields with macular sparing and show mildly reduced visual acuity with mild to high myopia that has_material_basis_in compound heterozygous mutation in the CC2D2A gene on chromosome 4p15. (DO)