Rare diseases · Sign or symptom
Ankle clonus
Abnormal rhythmic movements of ankle
HP:0011448
What it means
Clonus is an involuntary tendon reflex that causes repeated flexion and extension of the foot. Ankle clonus is tested by rapidly flexing the foot upward.
Ankle clonus is generally caused by corticospinal disease.
Rare diseases that can present with this27
Common30–79%
9- Adult-onset autosomal recessive cerebellar ataxia
- Autosomal dominant spastic paraplegia type 3
- Autosomal dominant spastic paraplegia type 4
- Autosomal recessive spastic paraplegia type 35
- Autosomal recessive spastic paraplegia type 5A
- Dystonia-parkinsonism-hypermanganesemia syndrome
- Mohr-Tranebjaerg syndrome
- X-linked spastic paraplegia type 34
- Xq21microdeletion syndrome
Sometimes5–29%
14- Allan-Herndon-Dudley syndrome
- Autosomal recessive ataxia, Beauce type
- Autosomal recessive cerebellar ataxia due to STUB1 deficiency
- Autosomal recessive spastic paraplegia type 20
- Autosomal recessive spastic paraplegia type 76
- Autosomal spastic paraplegia type 18
- Combined oxidative phosphorylation defect type 39
- Infantile Krabbe disease
and 6 more in this range
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
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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.