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.
Characterized by global developmental delay with poor overall growth, variably impaired intellectual development, learning difficulties, distal skeletal anomalies, and dysmorphic facies. Caused by heterozygous mutation in the H4C9 gene on chromosome 6p21.