Rare diseases · Sign or symptom
Seizure
HP:0001250
What it means
A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
A type of electrographic seizure has been proposed in neonates which does not have a clinical correlate, it is electrographic only. The term epilepsy is not used to describe recurrent febrile seizures. Epilepsy presumably reflects an abnormally reduced seizure threshold.
In everyday care
Most people with this sign do not have a rare disease — it appears in common conditions far more often. These general reference pages cover the same topic:
Rare diseases that can present with this1046
Always100%
9- Cortical dysgenesis with pontocerebellar hypoplasia due to TUBB3 mutation
- Early infantile developmental and epileptic encephalopathy
- FADD-related immunodeficiency
- Pyridoxine-dependent-developmental and epileptic encephalopathy
- RFT1-CDG
- Spinal muscular atrophy-progressive myoclonic epilepsy syndrome
- STT3A-CDG
- STT3B-CDG
- X-linked microcephaly-growth retardation-prognathism-cryptorchidism syndrome
Very common80–99%
71- 1q41q42microdeletion syndrome
- 2q23.1microdeletion syndrome
- 3-hydroxy-3-methylglutaryl-CoA synthase deficiency
- 3-methylglutaconic aciduria type 4
- 5q14.3microdeletion syndrome
- 6q terminal deletion syndrome
- 9q33.3q34.11microdeletion syndrome
- Adenylosuccinate lyase deficiency
- AICA-ribosiduria
- Alexander disease
- ALG11-CDG
- ALG1-CDG
- ALG9-CDG
- Alpha-N-acetylgalactosaminidase deficiency type 1
- Alpha-N-acetylgalactosaminidase deficiency type 3
- Amelocerebrohypohidrotic syndrome
- Angelman syndrome
- Angelman syndrome due to maternal 15q11q13 deletion
- Arthrogryposis multiplex congenita-whistling face syndrome
- Atypical Rett syndrome
- Autosomal recessive cerebellar ataxia-epilepsy-intellectual disability syndrome due to TUD deficiency
- Bangstad syndrome
- Baraitser-Winter cerebrofrontofacial syndrome
- Beta-mannosidosis
- Beta-mercaptolactate cysteine disulfiduria
- Bilateral frontoparietal polymicrogyria
- Bilateral polymicrogyria
- Carbamoyl-phosphate synthetase 1 deficiency
- Carnitine palmitoyl transferase 1A deficiency
- Cataract-nephropathy-encephalopathy syndrome
- CK syndrome
- Classic glucose transporter type 1 deficiency syndrome
- CNTNAP2-related developmental and epileptic encephalopathy
- Corpus callosum agenesis-abnormal genitalia syndrome
- Corpus callosum agenesis-neuronopathy syndrome
- Craniosynostosis-hydrocephalus-Arnold-Chiari malformation type I-radioulnar synostosis syndrome
- Cutaneous mastocytosis-deafness-microtia syndrome
- Cutis marmorata telangiectatica congenita
- DDOST-CDG
- Dermotrichic syndrome
- Developmental and epileptic encephalopathy with spike-wave activation in sleep
- Developmental delay-language impairment-dopa responsive dystonia-parkinsonism syndrome due to 2q24 microdeletion
- Distal deletion 19p syndrome
- Distal deletion 1q syndrome
- DPM1-CDG
- Early-onset autosomal dominant Alzheimer disease
- Early-onset epilepsy-intellectual disability-brain anomalies syndrome
- Early-onset seizures-distal limb anomalies-facial dysmorphism-global developmental delay syndrome
- EAST syndrome
- Encephalocraniocutaneous lipomatosis
- Encephalopathy due to sulfite oxidase deficiency
- Epilepsy-microcephaly-skeletal dysplasia syndrome
- Epilepsy-telangiectasia syndrome
- Epiphyseal dysplasia-hearing loss-dysmorphism syndrome
- Familial cerebral cavernous malformation
- Familial isolated hypoparathyroidism
- Foix-Chavany-Marie syndrome
- Folinic acid-responsive seizures
- Galactosialidosis
- Glycine encephalopathy
- Glycogen storage disease due to glucose-6-phosphatase deficiency
- Griscelli syndrome type 1
- Grubben-de Cock-Borghgraef syndrome
- Guanidinoacetate methyltransferase deficiency
- Hemimegalencephaly
- Hereditary neurocutaneous malformation
- Hernández-Aguirre Negrete syndrome
- Hirschsprung disease-ganglioneuroblastoma syndrome
- Holocarboxylase synthetase deficiency
- Houge-Janssens syndrome type 2
- HSD10 disease, neonatal type
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, and Orphanet separately records 14 diseases where this sign is specifically absent. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Epilepsy · Epileptic seizure · Seizures
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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.