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.
This disease is an autosomal recessive disorder characterized by a specific anomaly of extraocular muscle movements involving the oculomotor nerve (cranial nerve III) and the abducens nerve (cranial nerve VI). Affected individuals show ptosis as well as elevation of the eyelid on ipsilateral abduction. The features indicate abnormal innervation of extraocular muscles and suggest synkinesis of the oculomotor and abducens nerves.