Landau-Kleffner syndrome
Findings
No curated finding names Landau-Kleffner syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
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, receptive language is mainly affected, with an acquired auditory verbal agnosia.
Definition from the Mondo Disease Ontology (MONDO:0009509), read 2026-09-29. CC BY 4.0.
Features
44 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- AphasiaHPOHP:0002381
- Very frequent (80% to 99% of cases)
- Continuous spike and waves during slow sleepHPOHP:0031491
- Very frequent (80% to 99% of cases)
- Interictal EEG abnormalityHPOHP:0025373
- Very frequent (80% to 99% of cases)
- Language impairmentHPOHP:0002463
- Very frequent (80% to 99% of cases)
- Loss of speechHPOHP:0002371
- Very frequent (80% to 99% of cases)
- SeizureHPOHP:0001250
- Very frequent (80% to 99% of cases)
- Speech apraxia
Show the remaining 32
- Developmental regressionHPOHP:0002376
- Frequent (30% to 79% of cases)
- EEG with frontal focal spikesHPOHP:0012015
- Frequent (30% to 79% of cases)
- EEG with generalized epileptiform dischargesHPOHP:0011198
- Frequent (30% to 79% of cases)
- EEG with temporal focal spikesHPOHP:0012018
- Frequent (30% to 79% of cases)
- Focal motor seizureHPOHP:0011153
- Frequent (30% to 79% of cases)
- Generalized non-motor (absence) seizureHPOHP:0002121
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- GRIN2AHGNC:4585
- Definitive · G2P · Autosomal dominant · 2020
- Strong · Ambry Genetics · Autosomal dominant · 2019
- Strong · Labcorp Genetics (formerly Invitae) · Autosomal dominant · 2023
- Supportive · Orphanet · Autosomal dominant · 2021
Where it sits
Other names
2 names
Resolves to: Landau-Kleffner syndrome
- Also called
- acquired epileptic aphasiaLKS