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 syndromic X-linked intellectual disability characterized by delayed psychomotor development, mild to moderate intellectual disability, and a wide range of additional congenital anomalies that has_material_basis_in heterozygous mutation in the USP9X gene on chromosome Xp11.4. (DO)