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 multiple mitochondrial dysfunctions syndrome that is characterized by progressive neurologic deterioration beginning in early infancy, with affected individuals having no psychomotor development and early-onset seizures with neurologic decline and spasticity, and has_material_basis_in autosomal recessive inheritance of homozygous mutation in the iron-sulfur cluster assembly 1 gene on chromosome 9q21. (DO)