Rare diseases · Sign or symptom
Dilated fourth ventricle
HP:0002198
What it means
An abnormal dilatation of the fourth cerebral ventricle.
Rare diseases that can present with this15
Common30–79%
10- Ataxia-telangiectasia-like disorder
- Autosomal recessive cutis laxa type 2A
- Congenital muscular dystrophy with cerebellar involvement
- Isolated Dandy-Walker malformation
- Lissencephaly due to TUBA1A mutation
- Machado-Joseph disease type 1
- Machado-Joseph disease type 2
- Machado-Joseph disease type 3
- Orofaciodigital syndrome type 14
- Severe X-linked intellectual disability, Gustavson type
Sometimes5–29%
3The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Enlarged fourth ventricle
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.