Monarch Disease Ontology entry MONDO_0009072 (Dandy-Walker syndrome) can be described as follows. Dandy-Walker malformation (DWM) is the association of three signs: hydrocephalus, partial or complete absence of the cerebellar vermis, and posterior fossa cyst contiguous with the fourth ventricle, presenting early in life with hydrocephalus, bulging occiput and posterior fossa signs such as cranial nerve palsies, nystagmus and ataxia. Also known as: Dandy Walker Malformation, Dandy-Walker syndrome, Isolated cases, atresia of foramina of Magendie and Luschka.