Rare diseases · Sign or symptom
Hydrocephalus
Too much cerebrospinal fluid in the brain
HP:0000238
What it means
Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation.
Hydrocephalus results from an imbalance between the rate of production of cerebrospinal fluid (CSF), mainly in the choroid plexus, and its reabsorption in the subarchnoid space over brain and spinal cord.
In everyday care
Most people with this sign do not have a rare disease — it appears in common conditions far more often. These general reference pages cover the same topic:
Rare diseases that can present with this207
Very common80–99%
34- Absent radius-anogenital anomalies syndrome
- Aminopterin/methotrexate embryofetopathy
- Autosomal recessive malignant osteopetrosis
- Axial mesodermal dysplasia spectrum
- Biemond syndrome type 2
- BRESEK syndrome
- Congenital hydrocephalus
- Craniofacial conodysplasia
- Craniosynostosis-Dandy-Walker malformation-hydrocephalus syndrome
- Craniosynostosis-hydrocephalus-Arnold-Chiari malformation type I-radioulnar synostosis syndrome
- Ectodermal dysplasia-intellectual disability-central nervous system malformation syndrome
- Fried syndrome
- Gómez-López-Hernández syndrome
- Hydrocephalus-costovertebral dysplasia-Sprengel anomaly syndrome
- Hydrocephalus with stenosis of the aqueduct of Sylvius
- Hydrocephaly-tall stature-joint laxity syndrome
- Hydrolethalus
- Intellectual disability-cataracts-calcified pinnae-myopathy syndrome
- Isolated Dandy-Walker malformation
- Isolated rhombencephalosynapsis
- L1 syndrome
- Lhermitte-Duclos disease
- Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome
- Muscle-eye-brain disease
- Muscular hypertrophy-hepatomegaly-polyhydramnios syndrome
- Papillary tumor of the pineal region
- Papilloma of choroid plexus
- Pineocytoma
- Tetraamelia-multiple malformations syndrome
- Tetrasomy 5p syndrome
- VACTERL with hydrocephalus
- Walker-Warburg syndrome
- Xeroderma pigmentosum-Cockayne syndrome complex
- X-linked dominant chondrodysplasia, Chassaing-Lacombe type
Common30–79%
44- 3C syndrome
- 6p22microdeletion syndrome
- Adams-Oliver syndrome
- Amniotic band syndrome
- Atypical teratoid rhabdoid tumor
- Aymé-Gripp syndrome
- B3GALT6-related spondylodysplastic Ehlers-Danlos syndrome
- Cobblestone lissencephaly without muscular or ocular involvement
- Congenital muscular dystrophy, Fukuyama type
- Congenital muscular dystrophy with cerebellar involvement
- Craniofacial dysplasia-short stature-ectodermal anomalies-intellectual disability syndrome
- Craniotelencephalic dysplasia
- Crouzon syndrome-acanthosis nigricans syndrome
- Diabetic embryopathy
- Diencephalic syndrome
- Dural sinus malformation with arteriovenous shunt
- Edinburgh malformation syndrome
- Focal facial dermal dysplasia type IV
- Frontal encephalocele
- Hemoglobin Bart's fetalis syndrome
- Holoprosencephaly-postaxial polydactyly syndrome
- Hurler syndrome
- Isotretinoin-like syndrome
- Kabuki syndrome
- Knobloch syndrome
- Lethal omphalocele-cleft palate syndrome
- Megalencephaly-capillary malformation-polymicrogyria syndrome
- MEND syndrome
- Methylmalonic acidemia with homocystinuria
- Monosomy 9q22.3 syndrome
- Multiple sulfatase deficiency
- Neurocutaneous melanocytosis
- Non-syndromic bilambdoid and sagittal craniosynostosis
- Noonan syndrome-like disorder with loose anagen hair
- Oculocerebral hypopigmentation syndrome, Preus type
- Oculocerebrocutaneous syndrome
- Otopalatodigital syndrome type 2
- Oxoglutaric aciduria
- PEHO syndrome
- Pelvis-shoulder dysplasia
- Peters plus syndrome
- Pfeiffer syndrome type 2
- Port-wine nevi-mega cisterna magna-hydrocephalus syndrome
- Proteus-like syndrome
The 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: Hydrocephaly · Nonsyndromal hydrocephalus
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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.