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ORPHA:98818Disease
Also called Acquired epileptic aphasia · LKS
What it is
A rare form of epileptic encephalopathy with spike-wave activation in sleep (EE-SWAS) characterized by various combinations of acquired cognitive, language, behavioral, and motor deficits associated with marked spike- and- wave activation in sleep. In Landau-Kleffner syndrome (LKS), receptive language is mainly affected, with an acquired auditory verbal agnosia.
Key facts
- Prevalence
- 1-9 / 1 000 000 (Japan)
- Age of onset
- Childhood
- Inheritance
- Autosomal dominant, Unknown
- Classified as
- Disease
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Signs and symptoms
Very common80–99%
8Common30–79%
12- Attention deficit hyperactivity disorder
- Atypical behavior
- Autistic behavior
- Bilateral tonic-clonic seizure with generalized onset
- Developmental regression
- EEG with frontal focal spikes
- EEG with generalized epileptiform discharges
- EEG with temporal focal spikes
- Focal motor seizure
- Generalized non-motor (absence) seizure
- Social and occupational deterioration
- Speech articulation difficulties
Sometimes5–29%
22- Aggressive behavior
- Anxiety
- Atypical absence seizure
- Bilateral tonic-clonic seizure
- Depression
- Difficulty standing
- Emotional lability
- Focal impaired awareness seizure
and 14 more in this range
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
Gene
ICD-10 codes
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Benefit programs to look at
Programs whose eligibility touches the same ICD-10 categories. Eligibility is decided by the administering agency, never by this page.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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