Rare diseases · Sign or symptom

Ataxia

HP:0001251

What it means

Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).

Ataxia can be differentiated into dyssynergy, asynergy, dysmetria (hypometria, hypermetria), dysdiadochokinesis, gait ataxia, truncal ataxia, limb ataxia, and dysarthria). Note: This term does not include sensory ataxia.

Rare diseases that can present with this406

Very common80–99%

78

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: Cerebellar ataxia

Ataxia

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This 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.