Rare diseases · Sign or symptom
Gliosis
HP:0002171
What it means
Gliosis is the focal proliferation of glial cells in the central nervous system.
Gliosis generally occurs as a response to tissue damage. Gliosis appears bright on T2 scans upon magnetic resonance imaging, unlike encephalomalacia which follows CSF signal on all sequences. Glial cells, the non-neuronal component of the central nervous system, are divided into microglia and macroglia. The latter are in turn divided into astrocytes, oligodendrocytes, and ependymal cells. The astrocytes and the microglia are the glial cells predominantly responsible for tissue response to injury.
Rare diseases that can present with this21
Common30–79%
10- Cockayne syndrome
- Early-onset progressive leukoencephalopathy-central nervous system calcification-deafness-visual impairment syndrome
- Familial acute necrotizing encephalopathy
- Frontotemporal dementia with motor neuron disease
- Leigh syndrome
- Primary non-essential cutis verticis gyrata
- Progressive supranuclear palsy
- Pyruvate dehydrogenase E1-alpha deficiency
- Sporadic Creutzfeldt-Jakob disease
- Tay-Sachs disease
Sometimes5–29%
8- Alacrimia-choreoathetosis-liver dysfunction syndrome
- Cerebrotendinous xanthomatosis
- DYRK1A-related intellectual disability syndrome due to 21q22.13q22.2 microdeletion
- Gabriele-de Vries syndrome
- Hemimegalencephaly
- Hereditary late-onset Parkinson disease
- Huntington disease-like 1
- X-linked intellectual disability-short stature-overweight 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: Cerebral gliosis · Excess astrocytes in brain
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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.