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.
Term:
Developmental Delay, Language Impairment, and Ocular Abnormalities
A disease characterized by delayed acquisition of skills particularly affecting speech and language development, although many patients show mild motor delay. Caused by heterozygous mutation in the ARPC4 gene on chromosome 3p25.