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.
An autosomal dominant cerebellar ataxia that is characterized by late-onset ataxia, dysarthria and horizontal nystagmus, has_material_basis_in repeat expansion mutation in the BEAN1 gene. (DO)