Rare diseases · Sign or symptom
Myoclonic absence seizure
HP:0011150
What it means
Myoclonic absence seizure is a type of generalized non-motor (absence) seizure characterized by an interruption of ongoing activities, a blank stare and rhythmic three-per-second myoclonic movements, causing ratcheting abduction of the upper limbs leading to progressive arm elevation, and associated with 3 Hz generalized spike-wave discharges on the electroencephalogram. Duration is typically 10-60 s. Whilst impairment of consciousness may not be obvious the ILAE classified this seizure as a generalized non-motor seizure in 2017.
Rare diseases that can present with this3
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: Myoclonic absence · Myoclonic absences
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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.