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 recessive intellectual developmental disorder that is characterized by global developmental delay with hypotonia and mildly delayed walking, impaired intellectual development with poor or absent speech, and mildly dysmorphic features and that has_material_basis_in homozygous mutation in the NAA20 gene on chromosome 20p11. (DO)