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 non-syndromic X-linked intellectual disability characterized by mild to moderate intellectual disability in males and mild intellectual disability in females, in addition males are relatively short with a large head and have a highly arched palate, square face, prominent ears, and large testicular volumes that has_material_basis_in hemizygous or heterozygous mutation in a region on chromosome Xp22.3. (DO)