Rare diseases · Sign or symptom
Truncal ataxia
Instability or lack of coordination of central trunk muscles
HP:0002078
What it means
Truncal ataxia is a sign of ataxia characterized by instability of the trunk. It usually occurs during sitting.
Truncal ataxia is generally caused by midline damage to the cerebellar vermis and associated pathways. Patients with truncal ataxia may not be able to sit or stand without support.
Rare diseases that can present with this31
Very common80–99%
7- Autosomal recessive cerebellar ataxia due to STUB1 deficiency
- Autosomal recessive cerebellar ataxia-movement disorder syndrome
- Autosomal recessive cerebellar ataxia-psychomotor delay syndrome
- Autosomal recessive congenital cerebellar ataxia due to GRID2 deficiency
- Christianson syndrome
- Spinocerebellar ataxia type 36
- Urocanic aciduria
Common30–79%
16- Adult-onset autosomal recessive cerebellar ataxia
- Autosomal recessive ataxia due to PEX10 deficiency
- Autosomal recessive cerebellar ataxia due to CWF19L1 deficiency
- CACH syndrome
- Cerebellar ataxia, Cayman type
- Dentatorubral pallidoluysian atrophy
- Episodic ataxia type 5
- Intellectual disability-hyperkinetic movement-truncal ataxia syndrome
- Neurodegeneration due to 3-hydroxyisobutyryl-CoA hydrolase deficiency
- Spectrin-associated autosomal recessive cerebellar ataxia
- Spinocerebellar ataxia type 19/22
- Spinocerebellar ataxia type 26
- Spinocerebellar ataxia type 27A
- Spinocerebellar ataxia type 37
- Wiedemann-Rautenstrauch syndrome
- X-linked non progressive cerebellar ataxia
Sometimes5–29%
5The 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: Trunk ataxia
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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.