Landau-Kleffner Syndrome

Mendelian MONDO:0009509 Pathograph 7 Show in embeddings browser childhood-onset epilepsy syndrome GRIN2A-related complex neurodevelopmental disorder

Landau-Kleffner syndrome (LKS), or acquired epileptic aphasia, is a rare childhood epileptic encephalopathy in which previously normal children (onset typically ages 3-6 years) lose acquired language skills, most prominently receptive language (auditory verbal agnosia), in association with continuous or near-continuous spike-and-wave discharges activated during slow-wave sleep (electrical status epilepticus in sleep, ESES/CSWS). LKS sits within the epilepsy-aphasia spectrum (EAS) together with rolandic epilepsy and the syndrome of continuous spike-and-wave during slow-wave sleep (CSWSS). About 20% of EAS cases (including LKS) are caused by pathogenic variants in GRIN2A, which encodes the GluN2A subunit of the NMDA glutamate receptor.

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4
Pathophys.
7
Phenotypes
7
Pathograph
1
Genes
7
Medical Actions
1
References
1
Deep Research
⚙

Pathophysiology

4
GRIN2A/NMDA Receptor Dysfunction
In approximately 20% of LKS/epilepsy-aphasia spectrum cases, de novo or inherited pathogenic variants in GRIN2A alter the function of the GluN2A (NR2A) subunit of the NMDA glutamate receptor. Disrupted NMDA receptor signaling perturbs excitatory glutamatergic neurotransmission and synaptic plasticity in cortical neurons, providing the molecular substrate for the epileptic encephalopathy.
Cortical glutamatergic neuron CL:0000679
NMDA receptor (ionotropic glutamate receptor) signaling GO:0035235 ⚠ ABNORMAL Glutamatergic synaptic transmission GO:0035249 ⚠ ABNORMAL
Downstream
Perisylvian and Hippocampal Structural Anomalies NMDA-receptor (GluN2A) dysfunction perturbs development of perisylvian speech-language networks and the hippocampus.
Sleep-Activated Epileptiform Activity and ESES/CSWS Altered NMDA-receptor (GluN2A) signaling produces a hyperexcitable cortical/subcortical substrate that gives rise to sleep-activated epileptiform activity.
Show evidence (2 references)
PMID:23933820 SUPPORT Human Clinical
"about 20% of cases of LKS, CSWSS and electroclinically atypical rolandic epilepsy often associated with speech impairment can have a genetic origin sustained by de novo or inherited mutations in the GRIN2A gene (encoding the N-methyl-D-aspartate (NMDA) glutamate receptor α2 subunit, GluN2A)"
Establishes GRIN2A/NMDA receptor (GluN2A) dysfunction as the molecular basis in a substantial subset of LKS.
PMID:23933818 SUPPORT Human Clinical
"We report the first monogenic cause, to our knowledge, for EAS. GRIN2A mutations are restricted to this group of cases"
Identifies GRIN2A as the first monogenic cause of epilepsy-aphasia syndromes, of which LKS is the prototype.
Sleep-Activated Epileptiform Activity and ESES/CSWS
Pathological hyperexcitability produces marked activation of focal, typically perisylvian/centrotemporal, spike-and-wave discharges during non-REM (slow-wave) sleep, reaching continuous or near-continuous spike and waves during slow sleep (electrical status epilepticus in sleep, ESES/CSWS). This sleep-potentiated epileptiform activity in language cortex is thought to disrupt the maturation and function of language networks during a critical developmental window.
Cortical glutamatergic neuron CL:0000679
Membrane depolarization / neuronal hyperexcitability GO:0051899 ↑ INCREASED
Downstream
Language Regression Sleep-activated epileptiform activity in speech cortex drives the acquired language regression.
Show evidence (2 references)
PMID:8595482 SUPPORT Human Clinical
"It is thought to be the result of an epileptogenic lesion arising in speech cortex during a critical period of development."
Supports the model that an epileptogenic focus in speech cortex during a developmental critical period drives the language disorder.
PMID:31149903 SUPPORT Human Clinical
"RE is part of a single and continuous spectrum of childhood epilepsies and epileptic encephalopathies with acquired cognitive, behavioral and speech and/or language impairment, known as the epilepsy-aphasia spectrum (EAS)"
Frames LKS within the epilepsy-aphasia spectrum in which sleep- activated epileptiform activity produces acquired language and cognitive impairment.
Language Regression
Sleep-activated epileptiform disruption of perisylvian language cortex produces acquired loss of previously developed language, characteristically beginning with impaired auditory verbal comprehension (auditory verbal agnosia) and progressing to broader receptive and expressive language loss, sometimes with associated behavioral and cognitive regression.
Show evidence (1 reference)
PMID:23933818 SUPPORT Human Clinical
"Epilepsy-aphasia syndromes (EAS) are a group of rare, severe epileptic encephalopathies of unknown etiology with a characteristic electroencephalogram (EEG) pattern and developmental regression particularly affecting language."
Supports the core LKS phenotype of developmental regression preferentially affecting language.
Perisylvian and Hippocampal Structural Anomalies
Structural MRI in individuals with pathogenic GRIN2A variants and epilepsy-aphasia syndromes shows altered development of classical speech-language networks: increased cortical thickness/volume in perisylvian regions (posterior Broca's area, superior temporal region) and reduced left hippocampal volume, indicating that NMDA-receptor dysfunction perturbs speech-language network development.
Regulation of synaptic plasticity GO:0048167 ⚠ ABNORMAL
superior temporal gyrus UBERON:0002769 hippocampal formation UBERON:0002421
Show evidence (1 reference)
PMID:38715655 SUPPORT Human Clinical
"Anomalies in perisylvian regions, with largest differences in Broca's area, suggest an altered development of classical speech-language networks in GRIN2A-related EAS."
Structural MRI in GRIN2A-variant individuals demonstrates perisylvian and hippocampal anomalies consistent with disrupted speech-language network development.
⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Landau-Kleffner Syndrome Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
●

Phenotypes

7
Nervous System 4
Acquired Aphasia Aphasia HP:0002381
Course: PROGRESSIVE
Show evidence (1 reference)
PMID:23933820 SUPPORT Human Clinical
"Acquired epileptic aphasia (Landau-Kleffner syndrome, LKS) and continuous spike and waves during slow-wave sleep syndrome (CSWSS) represent rare and closely related childhood focal epileptic encephalopathies of unknown etiology."
Defines LKS as an acquired epileptic aphasia, supporting acquired loss of language as the defining phenotype.
Seizures Seizure HP:0001250
Show evidence (1 reference)
PMID:27683935 SUPPORT Human Clinical
"Epilepsy features include seizure onset usually between ages three and six years, focal epilepsy with language and/or global developmental regression"
GeneReviews documents seizures with onset between ages 3-6 years in the GRIN2A/LKS phenotype.
Developmental Regression Developmental regression HP:0002376
Show evidence (1 reference)
PMID:27683935 SUPPORT Human Clinical
"focal epilepsy with language and/or global developmental regression"
GeneReviews documents language and/or global developmental regression in the GRIN2A/LKS phenotype.
Behavioral and Neuropsychiatric Problems Atypical behavior HP:0000708
Show evidence (1 reference)
PMID:31149903 SUPPORT Human Clinical
"epileptic encephalopathies with acquired cognitive, behavioral and speech and/or language impairment"
Supports acquired behavioral impairment as part of the LKS/epilepsy- aphasia spectrum phenotype.
Other 3
Auditory Verbal Agnosia Auditory agnosia HP:5200410
Show evidence (1 reference)
PMID:28134012 SUPPORT Human Clinical
"This aphasia takes the form of an auditory agnosia; in contrast to the language deficit in electrical status epilepticus in sleep, where there is a primarily expressive aphasia with intact comprehension, children with Landau-Kleffner syndrome may appear to be unconscious of spoken words, or..."
Supports auditory verbal agnosia ("word deafness") as the characteristic receptive language deficit in LKS.
Continuous Spike and Waves During Slow Sleep (ESES/CSWS) Continuous spike and waves during slow sleep HP:0031491
Show evidence (2 references)
PMID:27683935 SUPPORT Human Clinical
"electroencephalogram (EEG) abnormalities, including continuous spike-and-wave discharges in sleep or very active centrotemporal discharges"
GeneReviews documents continuous spike-and-wave discharges in sleep as a characteristic EEG abnormality of the GRIN2A/LKS phenotype.
PMID:31149903 SUPPORT Human Clinical
"the epileptic Encephalopathy related to Status Epilepticus during slow Sleep syndrome (ESES)"
Supports the electrical-status-epilepticus-in-sleep electrographic pattern central to LKS and the broader spectrum.
EEG with Centrotemporal Focal Spike Waves EEG with centrotemporal focal spike waves HP:0012557
Show evidence (1 reference)
PMID:27683935 SUPPORT Human Clinical
"continuous spike-and-wave discharges in sleep or very active centrotemporal discharges"
GeneReviews documents very active centrotemporal discharges as part of the EEG spectrum in GRIN2A-related disorders including LKS.
🧬

Genetic Associations

1
GRIN2A pathogenic variants (De novo or inherited pathogenic GRIN2A variants cause ~20% of LKS and epilepsy-aphasia spectrum cases)
Gene: GRIN2A hgnc:4585 relationship_type: CAUSATIVE
Autosomal dominant
Show evidence (2 references)
PMID:23933820 SUPPORT Human Clinical
"about 20% of cases of LKS, CSWSS and electroclinically atypical rolandic epilepsy often associated with speech impairment can have a genetic origin sustained by de novo or inherited mutations in the GRIN2A gene"
Quantifies the GRIN2A contribution (~20%) to LKS and related EAS disorders.
PMID:23933818 SUPPORT Human Clinical
"all four families presented with EAS, accounting for 9% of epilepsy-aphasia cases"
Independent cohort confirming GRIN2A variants segregating in epilepsy-aphasia spectrum families.
💊

Medical Actions

7
Corticosteroids / ACTH
Action: Pharmacotherapy NCIT:C15986
Agent: corticosteroid CHEBI:50858
Corticosteroids (and ACTH) are widely used to suppress the sleep-activated epileptiform activity and promote language recovery in LKS, particularly when started early.
Mechanism Target:
INHIBITS Sleep-Activated Epileptiform Activity and ESES/CSWS — Corticosteroids suppress the sleep-activated epileptiform activity (ESES), reducing the spike-wave index that drives cognitive/language decline.
Show evidence (1 reference)
PMID:36970534 SUPPORT Human Clinical
"In (D)EE-SWAS (nine studies, 126 patients), 64% of patients showed an improvement either in the EEG or in their language/cognition following various steroid treatment regimes."
Documents corticosteroid-driven EEG (epileptiform activity) improvement in DEE-SWAS including LKS, supporting that steroids act on the sleep-activated epileptiform mechanism.
Show evidence (2 references)
PMID:29128194 SUPPORT Human Clinical
"Steroid treatment was most successful in improving cognitive performance."
A retrospective cohort of children with electrical status epilepticus in sleep (the electrographic substrate of LKS) found steroid treatment most successful in improving cognition, supporting corticosteroid use.
PMID:36970534 SUPPORT Human Clinical
"In (D)EE-SWAS (nine studies, 126 patients), 64% of patients showed an improvement either in the EEG or in their language/cognition following various steroid treatment regimes."
A systematic review quantifies corticosteroid response in DEE-SWAS (which includes LKS), with 64% showing EEG or language/cognitive improvement.
Antiseizure Medication
Action: Pharmacotherapy NCIT:C15986
Anti-seizure medications are used to control clinical seizures; some conventional agents may worsen ESES, so agent selection is important. Note: a 2020 Cochrane review found no randomized trial evidence to support or refute pharmacological treatment for CSWS/LKS.
Show evidence (1 reference)
PMID:33174224 PARTIAL Human Clinical
"There was no evidence from trials to support or refute the use of pharmacological treatment for continuous spike-wave during slow wave sleep syndrome or Landau-Kleffner syndrome."
A Cochrane systematic review documents the absence of randomized trial evidence for pharmacotherapy in LKS/CSWS, contextualizing the empirical basis of antiseizure drug use.
Benzodiazepines
Action: Pharmacotherapy NCIT:C15986
Agent: benzodiazepine CHEBI:22720
High-dose benzodiazepines (e.g., diazepam, clobazam) are among the most frequently used first-line therapies for the sleep-activated epileptiform activity (ESES/CSWS) underlying LKS and the epilepsy-aphasia spectrum. In a multicenter cohort, benzodiazepines were associated with greater odds of clinical improvement than other antiseizure medications.
Mechanism Target:
INHIBITS Sleep-Activated Epileptiform Activity and ESES/CSWS — Benzodiazepines suppress the sleep-activated epileptiform activity (ESES/CSWS) that drives the cognitive and language decline.
Show evidence (1 reference)
PMID:33484700 SUPPORT Human Clinical
"children had a greater odds of clinical improvement with benzodiazepines (OR 3.32, 95%CI 1.57-7.04, P = .002) or steroids (OR 4.04, 95%CI 1.41-11.59, P = .01) than with ASMs"
A multicenter retrospective CSWS cohort found benzodiazepines superior to other antiseizure medications for clinical improvement, supporting their use against the sleep-activated epileptiform mechanism.
Show evidence (1 reference)
PMID:33484700 SUPPORT Human Clinical
"Benzodiazepines and ASMs are the most frequent initial therapy prescribed for CSWS in the US. Our data suggests that ASMs are inferior to benzodiazepines and steroids and support earlier use of these therapies."
A multicenter collaboration documents benzodiazepines as a common first-line CSWS/LKS therapy with outcomes superior to other antiseizure medications.
L-serine (NMDAR coagonist, GRIN2A loss-of-function)
Action: Pharmacotherapy NCIT:C15986
Agent: L-serine CHEBI:17115
In individuals with GRIN2A loss-of-function/null variants, treatment with the NMDAR coagonist L-serine has been associated with improvements in behavior, development, EEG, and/or seizure frequency. CAUTION: in gain-of-function (NMDAR-activating) missense variants, NMDAR agonists/ activators such as L-serine should be avoided as they may worsen symptoms.
Mechanism Target:
RESTORES GRIN2A/NMDA Receptor Dysfunction — In GRIN2A loss-of-function variants, the NMDAR coagonist L-serine pharmacologically restores deficient NMDA-receptor signaling.
Show evidence (1 reference)
PMID:27683935 SUPPORT Human Clinical
"treatment with the N-methyl-D-aspartate receptor (NMDAR) coagonist L-serine was associated with improvements in behavior, development, EEG features, and/or seizure frequency"
GeneReviews documents L-serine acting as an NMDAR coagonist to address deficient NMDA-receptor signaling in GRIN2A loss-of-function variants.
Show evidence (1 reference)
PMID:27683935 SUPPORT Human Clinical
"treatment with the N-methyl-D-aspartate receptor (NMDAR) coagonist L-serine was associated with improvements in behavior, development, EEG features, and/or seizure frequency"
GeneReviews documents L-serine as a targeted therapy for GRIN2A loss-of-function variants.
Speech and Language Therapy
Action: speech therapy MAXO:0000930
Significant speech and language deficits require ongoing therapy from a speech-language pathologist.
Show evidence (1 reference)
PMID:27683935 SUPPORT Human Clinical
"Significant speech and language deficits require therapy from a speech-language pathologist."
GeneReviews recommends speech-language therapy as supportive care.
Multiple Subpial Transection
Action: surgical procedure MAXO:0000004
A surgical technique that interrupts horizontal intracortical fibers to abolish the capacity of speech cortex to generate seizures while preserving normal cortical function; used in selected drug-resistant LKS with a demonstrable unilateral epileptogenic focus. Evidence for benefit over the natural history is mixed.
Show evidence (2 references)
PMID:8595482 SUPPORT Human Clinical
"we have treated 14 children with aphasia, seizures and a severely abnormal EEG by multiple subpial transection of the epileptogenic cortex. Seven of the 14 patients (50%) have recovered age-appropriate speech"
Original case series describing multiple subpial transection with language recovery in selected LKS patients.
PMID:26337264 PARTIAL Human Clinical
"there is insufficient evidence to suggest that multiple subpial transection provides additional benefits over and above the mixed recovery often seen in LKS and related regressive epilepsies"
A controlled comparison tempering the benefit of multiple subpial transection, indicating outcomes comparable to non-surgical patients.
Genetic Counseling
Action: Genetic Counseling NCIT:C15240
Recommended for families given autosomal dominant inheritance of GRIN2A-related LKS.
Show evidence (1 reference)
PMID:27683935 SUPPORT Human Clinical
"GRIN2A-related disorders are inherited in an autosomal dominant manner."
Autosomal dominant inheritance (with ~50% de novo) per GeneReviews is the basis for offering genetic counseling to families.
{ }

Source YAML

click to show 
name: Landau-Kleffner Syndrome
creation_date: "2026-06-04T00:00:00Z"
category: Mendelian
disease_term:
  preferred_term: Landau-Kleffner syndrome
  term:
    id: MONDO:0009509
    label: Landau-Kleffner syndrome
parents:
- childhood-onset epilepsy syndrome
- GRIN2A-related complex neurodevelopmental disorder
description: >
  Landau-Kleffner syndrome (LKS), or acquired epileptic aphasia, is a rare
  childhood epileptic encephalopathy in which previously normal children (onset
  typically ages 3-6 years) lose acquired language skills, most prominently
  receptive language (auditory verbal agnosia), in association with continuous
  or near-continuous spike-and-wave discharges activated during slow-wave sleep
  (electrical status epilepticus in sleep, ESES/CSWS). LKS sits within the
  epilepsy-aphasia spectrum (EAS) together with rolandic epilepsy and the
  syndrome of continuous spike-and-wave during slow-wave sleep (CSWSS). About
  20% of EAS cases (including LKS) are caused by pathogenic variants in GRIN2A,
  which encodes the GluN2A subunit of the NMDA glutamate receptor.

references:
- reference: PMID:27683935
  title: "GRIN2A-Related Disorders."
  tags:
  - GeneReviews

pathophysiology:
- name: GRIN2A/NMDA Receptor Dysfunction
  description: >
    In approximately 20% of LKS/epilepsy-aphasia spectrum cases, de novo or
    inherited pathogenic variants in GRIN2A alter the function of the GluN2A
    (NR2A) subunit of the NMDA glutamate receptor. Disrupted NMDA receptor
    signaling perturbs excitatory glutamatergic neurotransmission and
    synaptic plasticity in cortical neurons, providing the molecular substrate
    for the epileptic encephalopathy.
  cell_types:
  - preferred_term: Cortical glutamatergic neuron
    term:
      id: CL:0000679
      label: glutamatergic neuron
  biological_processes:
  - preferred_term: NMDA receptor (ionotropic glutamate receptor) signaling
    term:
      id: GO:0035235
      label: ionotropic glutamate receptor signaling pathway
    modifier: ABNORMAL
  - preferred_term: Glutamatergic synaptic transmission
    term:
      id: GO:0035249
      label: synaptic transmission, glutamatergic
    modifier: ABNORMAL
  downstream:
  - target: Perisylvian and Hippocampal Structural Anomalies
    description: >-
      NMDA-receptor (GluN2A) dysfunction perturbs development of perisylvian
      speech-language networks and the hippocampus.
    evidence:
    - reference: PMID:38715655
      reference_title: Perisylvian and Hippocampal Anomalies in Individuals With Pathogenic GRIN2A Variants.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Patients with pathogenic variants in GRIN2A offer an opportunity to
        interrogate the impact of glutamate receptor dysfunction on brain
        development.
      explanation: >-
        Links GRIN2A glutamate-receptor dysfunction to altered speech-language
        network brain development.
  - target: Sleep-Activated Epileptiform Activity and ESES/CSWS
    description: >-
      Altered NMDA-receptor (GluN2A) signaling produces a hyperexcitable
      cortical/subcortical substrate that gives rise to sleep-activated
      epileptiform activity.
    evidence:
    - reference: PMID:33420383
      reference_title: >-
        Voltage-independent GluN2A-type NMDA receptor Ca(2+) signaling promotes
        audiogenic seizures, attentional and cognitive deficits in mice.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        voltage-independent glutamate-gated signaling of GluN2A-containing NMDA
        receptors is associated with NMDAR-dependent audiogenic seizures due to
        hyperexcitable midbrain circuits
      explanation: >-
        A Grin2a gene-targeted mouse model demonstrates that altered GluN2A NMDA
        receptor signaling produces a hyperexcitable, seizure-prone substrate,
        supporting the link from GRIN2A dysfunction to epileptiform activity.
  evidence:
  - reference: PMID:23933820
    reference_title: GRIN2A mutations in acquired epileptic aphasia and related childhood focal epilepsies and encephalopathies with speech and language dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      about 20% of cases of LKS, CSWSS and electroclinically atypical
      rolandic epilepsy often associated with speech impairment can have a
      genetic origin sustained by de novo or inherited mutations in the
      GRIN2A gene (encoding the N-methyl-D-aspartate (NMDA) glutamate
      receptor α2 subunit, GluN2A)
    explanation: >-
      Establishes GRIN2A/NMDA receptor (GluN2A) dysfunction as the
      molecular basis in a substantial subset of LKS.
  - reference: PMID:23933818
    reference_title: GRIN2A mutations cause epilepsy-aphasia spectrum disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We report the first monogenic cause, to our knowledge, for EAS.
      GRIN2A mutations are restricted to this group of cases
    explanation: >-
      Identifies GRIN2A as the first monogenic cause of epilepsy-aphasia
      syndromes, of which LKS is the prototype.

- name: Sleep-Activated Epileptiform Activity and ESES/CSWS
  description: >
    Pathological hyperexcitability produces marked activation of focal,
    typically perisylvian/centrotemporal, spike-and-wave discharges during
    non-REM (slow-wave) sleep, reaching continuous or near-continuous spike
    and waves during slow sleep (electrical status epilepticus in sleep,
    ESES/CSWS). This sleep-potentiated epileptiform activity in language
    cortex is thought to disrupt the maturation and function of language
    networks during a critical developmental window.
  cell_types:
  - preferred_term: Cortical glutamatergic neuron
    term:
      id: CL:0000679
      label: glutamatergic neuron
  biological_processes:
  - preferred_term: Membrane depolarization / neuronal hyperexcitability
    term:
      id: GO:0051899
      label: membrane depolarization
    modifier: INCREASED
  downstream:
  - target: Language Regression
    description: >-
      Sleep-activated epileptiform activity in speech cortex drives the acquired
      language regression.
    evidence:
    - reference: PMID:8595482
      reference_title: Landau-Kleffner syndrome. Treatment with subpial intracortical transection.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Landau-Kleffner syndrome (LKS) is an acquired epileptic aphasia
        occurring in childhood and associated with a generally poor prognosis
        for recovery of speech.
      explanation: >-
        Characterizes LKS as an acquired epileptic aphasia, supporting the
        causal link from the epileptogenic activity in speech cortex to the
        acquired language regression.
  evidence:
  - reference: PMID:8595482
    reference_title: Landau-Kleffner syndrome. Treatment with subpial intracortical transection.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      It is thought to be the result of an epileptogenic lesion arising in
      speech cortex during a critical period of development.
    explanation: >-
      Supports the model that an epileptogenic focus in speech cortex during
      a developmental critical period drives the language disorder.
  - reference: PMID:31149903
    reference_title: Update on the genetics of the epilepsy-aphasia spectrum and role of GRIN2A mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      RE is part of a single and continuous spectrum of childhood
      epilepsies and epileptic encephalopathies with acquired cognitive,
      behavioral and speech and/or language impairment, known as the
      epilepsy-aphasia spectrum (EAS)
    explanation: >-
      Frames LKS within the epilepsy-aphasia spectrum in which sleep-
      activated epileptiform activity produces acquired language and
      cognitive impairment.

- name: Language Regression
  description: >
    Sleep-activated epileptiform disruption of perisylvian language cortex
    produces acquired loss of previously developed language, characteristically
    beginning with impaired auditory verbal comprehension (auditory verbal
    agnosia) and progressing to broader receptive and expressive language loss,
    sometimes with associated behavioral and cognitive regression.
  evidence:
  - reference: PMID:23933818
    reference_title: GRIN2A mutations cause epilepsy-aphasia spectrum disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Epilepsy-aphasia syndromes (EAS) are a group of rare, severe
      epileptic encephalopathies of unknown etiology with a characteristic
      electroencephalogram (EEG) pattern and developmental regression
      particularly affecting language.
    explanation: >-
      Supports the core LKS phenotype of developmental regression
      preferentially affecting language.

- name: Perisylvian and Hippocampal Structural Anomalies
  description: >
    Structural MRI in individuals with pathogenic GRIN2A variants and
    epilepsy-aphasia syndromes shows altered development of classical
    speech-language networks: increased cortical thickness/volume in
    perisylvian regions (posterior Broca's area, superior temporal region)
    and reduced left hippocampal volume, indicating that NMDA-receptor
    dysfunction perturbs speech-language network development.
  locations:
  - preferred_term: superior temporal gyrus
    term:
      id: UBERON:0002769
      label: superior temporal gyrus
  - preferred_term: hippocampal formation
    term:
      id: UBERON:0002421
      label: hippocampal formation
  biological_processes:
  - preferred_term: Regulation of synaptic plasticity
    term:
      id: GO:0048167
      label: regulation of synaptic plasticity
    modifier: ABNORMAL
  evidence:
  - reference: PMID:38715655
    reference_title: Perisylvian and Hippocampal Anomalies in Individuals With Pathogenic GRIN2A Variants.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Anomalies in perisylvian regions, with largest differences in Broca's
      area, suggest an altered development of classical speech-language
      networks in GRIN2A-related EAS.
    explanation: >-
      Structural MRI in GRIN2A-variant individuals demonstrates perisylvian and
      hippocampal anomalies consistent with disrupted speech-language network
      development.

phenotypes:
- name: Acquired Aphasia
  category: Neurological
  description: >
    Progressive loss of previously acquired language, with receptive language
    most affected, followed by deterioration of expressive language. This
    acquired epileptic aphasia is the defining feature of LKS.
  phenotype_term:
    preferred_term: Acquired aphasia
    term:
      id: HP:0002381
      label: Aphasia
    clinical_course: PROGRESSIVE
  evidence:
  - reference: PMID:23933820
    reference_title: GRIN2A mutations in acquired epileptic aphasia and related childhood focal epilepsies and encephalopathies with speech and language dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Acquired epileptic aphasia (Landau-Kleffner syndrome, LKS) and
      continuous spike and waves during slow-wave sleep syndrome (CSWSS)
      represent rare and closely related childhood focal epileptic
      encephalopathies of unknown etiology.
    explanation: >-
      Defines LKS as an acquired epileptic aphasia, supporting acquired loss
      of language as the defining phenotype.

- name: Auditory Verbal Agnosia
  category: Neurological
  description: >
    Impaired recognition/comprehension of spoken language ("word deafness")
    with a normal audiogram. The receptive deficit is often the earliest and
    most prominent feature and may initially be mistaken for deafness.
  phenotype_term:
    preferred_term: Auditory verbal agnosia (word deafness)
    term:
      id: HP:5200410
      label: Auditory agnosia
  evidence:
  - reference: PMID:28134012
    reference_title: "Treatment of Epileptic Encephalopathies: Current State of the Art."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This aphasia takes the form of an auditory agnosia; in contrast to the
      language deficit in electrical status epilepticus in sleep, where there is
      a primarily expressive aphasia with intact comprehension, children with
      Landau-Kleffner syndrome may appear to be unconscious of spoken words, or
      effectively deaf.
    explanation: >-
      Supports auditory verbal agnosia ("word deafness") as the characteristic
      receptive language deficit in LKS.

- name: Continuous Spike and Waves During Slow Sleep (ESES/CSWS)
  category: Neurological
  description: >
    Continuous or near-continuous spike-and-wave discharges activated during
    slow-wave sleep, the electroencephalographic hallmark of LKS and the
    epilepsy-aphasia spectrum. Discharges are frequently focal/centrotemporal
    and markedly potentiated by sleep.
  phenotype_term:
    preferred_term: Continuous spike and waves during slow sleep
    term:
      id: HP:0031491
      label: Continuous spike and waves during slow sleep
  evidence:
  - reference: PMID:27683935
    reference_title: GRIN2A-Related Disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      electroencephalogram (EEG) abnormalities, including continuous
      spike-and-wave discharges in sleep or very active centrotemporal
      discharges
    explanation: >-
      GeneReviews documents continuous spike-and-wave discharges in sleep as
      a characteristic EEG abnormality of the GRIN2A/LKS phenotype.
  - reference: PMID:31149903
    reference_title: Update on the genetics of the epilepsy-aphasia spectrum and role of GRIN2A mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the epileptic Encephalopathy related to Status Epilepticus during slow
      Sleep syndrome (ESES)
    explanation: >-
      Supports the electrical-status-epilepticus-in-sleep electrographic
      pattern central to LKS and the broader spectrum.

- name: EEG with Centrotemporal Focal Spike Waves
  category: Neurological
  description: >
    Focal spike-and-wave discharges in the centrotemporal (perisylvian)
    regions, overlapping electroclinically with rolandic epilepsy.
  phenotype_term:
    preferred_term: EEG with centrotemporal focal spike waves
    term:
      id: HP:0012557
      label: EEG with centrotemporal focal spike waves
  evidence:
  - reference: PMID:27683935
    reference_title: GRIN2A-Related Disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      continuous spike-and-wave discharges in sleep or very active
      centrotemporal discharges
    explanation: >-
      GeneReviews documents very active centrotemporal discharges as part of
      the EEG spectrum in GRIN2A-related disorders including LKS.

- name: Seizures
  category: Neurological
  description: >
    Most children with LKS have clinical epileptic seizures, which may be
    focal or generalized; seizures are often infrequent and can precede or
    follow the onset of language regression.
  phenotype_term:
    preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
  evidence:
  - reference: PMID:27683935
    reference_title: GRIN2A-Related Disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Epilepsy features include seizure onset usually between ages three and
      six years, focal epilepsy with language and/or global developmental
      regression
    explanation: >-
      GeneReviews documents seizures with onset between ages 3-6 years in the
      GRIN2A/LKS phenotype.

- name: Developmental Regression
  category: Neurological
  description: >
    Beyond language, some children show broader developmental, global, or
    cognitive regression, contributing to the encephalopathic nature of the
    disorder.
  phenotype_term:
    preferred_term: Developmental regression
    term:
      id: HP:0002376
      label: Developmental regression
  evidence:
  - reference: PMID:27683935
    reference_title: GRIN2A-Related Disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      focal epilepsy with language and/or global developmental regression
    explanation: >-
      GeneReviews documents language and/or global developmental regression
      in the GRIN2A/LKS phenotype.

- name: Behavioral and Neuropsychiatric Problems
  category: Neurological
  description: >
    Children frequently develop behavioral disturbances including
    hyperactivity, inattention, aggression, and autistic-like features,
    which often accompany the language regression.
  phenotype_term:
    preferred_term: Behavioral / neuropsychiatric disturbance
    term:
      id: HP:0000708
      label: Atypical behavior
  evidence:
  - reference: PMID:31149903
    reference_title: Update on the genetics of the epilepsy-aphasia spectrum and role of GRIN2A mutations.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      epileptic encephalopathies with acquired cognitive, behavioral and
      speech and/or language impairment
    explanation: >-
      Supports acquired behavioral impairment as part of the LKS/epilepsy-
      aphasia spectrum phenotype.

genetic:
- name: GRIN2A pathogenic variants
  gene_term:
    preferred_term: GRIN2A
    term:
      id: hgnc:4585
      label: GRIN2A
  association: >-
    De novo or inherited pathogenic GRIN2A variants cause ~20% of LKS and
    epilepsy-aphasia spectrum cases
  relationship_type: CAUSATIVE
  inheritance:
  - name: Autosomal dominant
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
    de_novo_rate: >-
      Approximately 50% of GRIN2A-related disorders arise from a de novo
      variant; the remainder are inherited from an affected parent.
    evidence:
    - reference: PMID:27683935
      reference_title: GRIN2A-Related Disorders.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        GRIN2A-related disorders are inherited in an autosomal dominant
        manner.
      explanation: >-
        GeneReviews documents autosomal dominant inheritance of
        GRIN2A-related disorders including LKS.
  notes: >-
    GRIN2A encodes the GluN2A subunit of the NMDA glutamate receptor. Variants
    include null/loss-of-function, missense (loss- or gain-of-function), and
    deletions; functional class has therapeutic implications.
  evidence:
  - reference: PMID:23933820
    reference_title: GRIN2A mutations in acquired epileptic aphasia and related childhood focal epilepsies and encephalopathies with speech and language dysfunction.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      about 20% of cases of LKS, CSWSS and electroclinically atypical
      rolandic epilepsy often associated with speech impairment can have a
      genetic origin sustained by de novo or inherited mutations in the
      GRIN2A gene
    explanation: >-
      Quantifies the GRIN2A contribution (~20%) to LKS and related EAS
      disorders.
  - reference: PMID:23933818
    reference_title: GRIN2A mutations cause epilepsy-aphasia spectrum disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      all four families presented with EAS, accounting for 9% of
      epilepsy-aphasia cases
    explanation: >-
      Independent cohort confirming GRIN2A variants segregating in
      epilepsy-aphasia spectrum families.

treatments:
- name: Corticosteroids / ACTH
  description: >-
    Corticosteroids (and ACTH) are widely used to suppress the sleep-activated
    epileptiform activity and promote language recovery in LKS, particularly
    when started early.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: corticosteroid
      term:
        id: CHEBI:50858
        label: corticosteroid
  target_mechanisms:
  - target: Sleep-Activated Epileptiform Activity and ESES/CSWS
    treatment_effect: INHIBITS
    description: >-
      Corticosteroids suppress the sleep-activated epileptiform activity (ESES),
      reducing the spike-wave index that drives cognitive/language decline.
    evidence:
    - reference: PMID:36970534
      reference_title: "Corticosteroids in childhood epilepsies: A systematic review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        In (D)EE-SWAS (nine studies, 126 patients), 64% of patients showed an
        improvement either in the EEG or in their language/cognition following
        various steroid treatment regimes.
      explanation: >-
        Documents corticosteroid-driven EEG (epileptiform activity) improvement
        in DEE-SWAS including LKS, supporting that steroids act on the
        sleep-activated epileptiform mechanism.
  evidence:
  - reference: PMID:29128194
    reference_title: >-
      Treatment of electrical status epilepticus in sleep: Clinical and EEG
      characteristics and response to 147 treatments in 47 patients.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Steroid treatment was most successful in improving cognitive
      performance.
    explanation: >-
      A retrospective cohort of children with electrical status epilepticus
      in sleep (the electrographic substrate of LKS) found steroid treatment
      most successful in improving cognition, supporting corticosteroid use.
  - reference: PMID:36970534
    reference_title: "Corticosteroids in childhood epilepsies: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In (D)EE-SWAS (nine studies, 126 patients), 64% of patients showed an
      improvement either in the EEG or in their language/cognition following
      various steroid treatment regimes.
    explanation: >-
      A systematic review quantifies corticosteroid response in DEE-SWAS
      (which includes LKS), with 64% showing EEG or language/cognitive
      improvement.

- name: Antiseizure Medication
  description: >-
    Anti-seizure medications are used to control clinical seizures; some
    conventional agents may worsen ESES, so agent selection is important.
    Note: a 2020 Cochrane review found no randomized trial evidence to support
    or refute pharmacological treatment for CSWS/LKS.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
  evidence:
  - reference: PMID:33174224
    reference_title: Pharmacological treatment for continuous spike-wave during slow wave sleep syndrome and Landau-Kleffner Syndrome.
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      There was no evidence from trials to support or refute the use of
      pharmacological treatment for continuous spike-wave during slow wave
      sleep syndrome or Landau-Kleffner syndrome.
    explanation: >-
      A Cochrane systematic review documents the absence of randomized trial
      evidence for pharmacotherapy in LKS/CSWS, contextualizing the empirical
      basis of antiseizure drug use.

- name: Benzodiazepines
  description: >-
    High-dose benzodiazepines (e.g., diazepam, clobazam) are among the most
    frequently used first-line therapies for the sleep-activated epileptiform
    activity (ESES/CSWS) underlying LKS and the epilepsy-aphasia spectrum. In a
    multicenter cohort, benzodiazepines were associated with greater odds of
    clinical improvement than other antiseizure medications.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: benzodiazepine
      term:
        id: CHEBI:22720
        label: benzodiazepine
  target_mechanisms:
  - target: Sleep-Activated Epileptiform Activity and ESES/CSWS
    treatment_effect: INHIBITS
    description: >-
      Benzodiazepines suppress the sleep-activated epileptiform activity
      (ESES/CSWS) that drives the cognitive and language decline.
    evidence:
    - reference: PMID:33484700
      reference_title: "Treatment Practices and Outcomes in Continuous Spike and Wave during Slow Wave Sleep: A Multicenter Collaboration."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        children had a greater odds of clinical improvement with benzodiazepines
        (OR 3.32, 95%CI 1.57-7.04, P = .002) or steroids (OR 4.04, 95%CI
        1.41-11.59, P = .01) than with ASMs
      explanation: >-
        A multicenter retrospective CSWS cohort found benzodiazepines superior
        to other antiseizure medications for clinical improvement, supporting
        their use against the sleep-activated epileptiform mechanism.
  evidence:
  - reference: PMID:33484700
    reference_title: "Treatment Practices and Outcomes in Continuous Spike and Wave during Slow Wave Sleep: A Multicenter Collaboration."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Benzodiazepines and ASMs are the most frequent initial therapy
      prescribed for CSWS in the US. Our data suggests that ASMs are inferior
      to benzodiazepines and steroids and support earlier use of these
      therapies.
    explanation: >-
      A multicenter collaboration documents benzodiazepines as a common
      first-line CSWS/LKS therapy with outcomes superior to other antiseizure
      medications.

- name: L-serine (NMDAR coagonist, GRIN2A loss-of-function)
  description: >-
    In individuals with GRIN2A loss-of-function/null variants, treatment with
    the NMDAR coagonist L-serine has been associated with improvements in
    behavior, development, EEG, and/or seizure frequency. CAUTION: in
    gain-of-function (NMDAR-activating) missense variants, NMDAR agonists/
    activators such as L-serine should be avoided as they may worsen symptoms.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: L-serine
      term:
        id: CHEBI:17115
        label: L-serine
  target_mechanisms:
  - target: GRIN2A/NMDA Receptor Dysfunction
    treatment_effect: RESTORES
    description: >-
      In GRIN2A loss-of-function variants, the NMDAR coagonist L-serine
      pharmacologically restores deficient NMDA-receptor signaling.
    evidence:
    - reference: PMID:27683935
      reference_title: GRIN2A-Related Disorders.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        treatment with the N-methyl-D-aspartate receptor (NMDAR) coagonist
        L-serine was associated with improvements in behavior, development,
        EEG features, and/or seizure frequency
      explanation: >-
        GeneReviews documents L-serine acting as an NMDAR coagonist to address
        deficient NMDA-receptor signaling in GRIN2A loss-of-function variants.
  evidence:
  - reference: PMID:27683935
    reference_title: GRIN2A-Related Disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      treatment with the N-methyl-D-aspartate receptor (NMDAR) coagonist
      L-serine was associated with improvements in behavior, development,
      EEG features, and/or seizure frequency
    explanation: >-
      GeneReviews documents L-serine as a targeted therapy for GRIN2A
      loss-of-function variants.

- name: Speech and Language Therapy
  description: >-
    Significant speech and language deficits require ongoing therapy from a
    speech-language pathologist.
  treatment_term:
    preferred_term: speech therapy
    term:
      id: MAXO:0000930
      label: speech therapy
  evidence:
  - reference: PMID:27683935
    reference_title: GRIN2A-Related Disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Significant speech and language deficits require therapy from a
      speech-language pathologist.
    explanation: >-
      GeneReviews recommends speech-language therapy as supportive care.

- name: Multiple Subpial Transection
  description: >-
    A surgical technique that interrupts horizontal intracortical fibers to
    abolish the capacity of speech cortex to generate seizures while
    preserving normal cortical function; used in selected drug-resistant LKS
    with a demonstrable unilateral epileptogenic focus. Evidence for benefit
    over the natural history is mixed.
  treatment_term:
    preferred_term: surgical procedure
    term:
      id: MAXO:0000004
      label: surgical procedure
  evidence:
  - reference: PMID:8595482
    reference_title: Landau-Kleffner syndrome. Treatment with subpial intracortical transection.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      we have treated 14 children with aphasia, seizures and a severely
      abnormal EEG by multiple subpial transection of the epileptogenic
      cortex. Seven of the 14 patients (50%) have recovered age-appropriate
      speech
    explanation: >-
      Original case series describing multiple subpial transection with
      language recovery in selected LKS patients.
  - reference: PMID:26337264
    reference_title: Outcome following multiple subpial transection in Landau-Kleffner syndrome and related regression.
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      there is insufficient evidence to suggest that multiple subpial
      transection provides additional benefits over and above the mixed
      recovery often seen in LKS and related regressive epilepsies
    explanation: >-
      A controlled comparison tempering the benefit of multiple subpial
      transection, indicating outcomes comparable to non-surgical patients.

- name: Genetic Counseling
  description: >-
    Recommended for families given autosomal dominant inheritance of
    GRIN2A-related LKS.
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:27683935
    reference_title: GRIN2A-Related Disorders.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      GRIN2A-related disorders are inherited in an autosomal dominant
      manner.
    explanation: >-
      Autosomal dominant inheritance (with ~50% de novo) per GeneReviews is the
      basis for offering genetic counseling to families.
📚

References & Deep Research

References

1
PMID:27683935
GRIN2A-Related Disorders.
No top-level findings curated for this source.

Deep Research

1
Falcon ▸
Disease Characteristics Research Template
Edison Scientific Literature 36 citations 2026-06-04T09:44:32.193147

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

  • Disease Name: Landau-Kleffner Syndrome
  • MONDO ID: (if available)
  • Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Landau-Kleffner Syndrome covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

  • What is the disease? Provide a concise overview.
  • What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
  • What are the common synonyms and alternative names?
  • Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

  • Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
  • Risk Factors:

    Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases

  • Genetic risk factors (causal variants, susceptibility loci, modifier genes)
  • Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
  • Protective Factors:

    Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases

  • Genetic protective factors (protective variants, modifier alleles)
  • Environmental protective factors (diet, lifestyle, exposures that reduce risk)
  • Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

    Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

  • Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

    Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene

  • Pathogenic Variants:
  • Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
  • Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
  • Variant type/class (missense, frameshift, nonsense, splice-site, structural)
  • Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
  • Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
  • Functional consequences (loss of function, gain of function, dominant negative)
  • Modifier Genes: Genes that modify disease severity or expression
  • Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

    Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

  • Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

    Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases

  • Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

    Search first: CDC databases, WHO, PubMed, NHANES

  • Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

    Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

  • Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

    Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc

  • Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

    Search first: Gene Ontology (GO), Reactome, KEGG, PubMed

  • Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

    Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold

  • Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

    Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA

  • Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

    Search first: ImmPort, Immunome Database, IEDB, Gene Ontology

  • Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

    Search first: PubMed, Gene Ontology, Reactome

  • Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

    Search first: BRENDA, UniProt, KEGG, OMIM, PubMed

  • Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Molecular Profiling (if available):
  • Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
  • Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
  • Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
  • Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
  • Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
  • Advanced Technologies (if applicable):
  • Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
  • Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
  • Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
  • Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

  • Organ Level:
  • Primary organs directly affected
  • Secondary organ involvement (complications, secondary effects)
  • Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

    Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT

  • Tissue and Cell Level:
  • Specific tissue types affected (epithelial, connective, muscle, nervous)
  • Specific cell populations targeted (with Cell Ontology terms)

    Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB

  • Subcellular Level:
  • Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

    Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas

  • Localization:
  • Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
  • Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

  • Onset:
  • Typical age of onset (congenital, pediatric, adult, geriatric)
  • Onset pattern (acute, subacute, chronic, insidious)

    Search first: OMIM, Orphanet, HPO, PubMed

  • Progression:
  • Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
  • Progression rate (rapid, slow, variable)
  • Disease course pattern (episodic, relapsing-remitting, progressive, stable)
  • Disease duration (self-limited, chronic lifelong)

    Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM

  • Patterns:
  • Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
  • Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

  • Epidemiology:
  • Prevalence (cases per 100,000 at given time)
  • Incidence (new cases per 100,000 per year)

    Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries

  • For Genetic Etiology:
  • Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
  • Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
  • Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
  • Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
  • Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
  • Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
  • Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
  • Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
  • Population Demographics:
  • Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
  • Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
  • Geographic distribution of specific variants
  • Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
  • Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

  • Clinical Tests:
  • Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
  • Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
  • Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
  • Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
  • Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
  • Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
  • Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
  • Genetic Testing:

    Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen

  • Overview of recommended genetic testing approach
  • Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
  • Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
  • Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
  • Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
  • Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
  • Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
  • FISH > Search first: ClinVar, cytogenetics databases, PubMed
  • Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
  • Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
  • Omics-Based Diagnostics (if applicable):
  • RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
  • Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
  • Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
  • Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
  • Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
  • Clinical Criteria:
  • Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
  • Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
  • Screening:
  • Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

  • Survival and Mortality:
  • Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
  • Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
  • Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
  • Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
  • Morbidity and Function:
  • Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
  • Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
  • Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
  • Disease Course:
  • Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
  • Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
  • Prediction:
  • Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
  • Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

  • Pharmacotherapy:
  • Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
  • Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
  • Advanced Therapeutics:
  • Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
  • Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
  • RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
  • Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
  • Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
  • Surgical and Interventional:
  • Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
  • Supportive and Rehabilitative:
  • Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
  • Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
  • Experimental:
  • Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
  • Treatment Outcomes:
  • Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
  • Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
  • Treatment Strategy:
  • Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
  • Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
  • Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

  • Prevention Levels:
  • Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
  • Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
  • Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
  • Immunization: Vaccine strategies (if applicable)

    Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database

  • Screening and Early Detection:
  • Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
  • Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
  • Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
  • Behavioral Interventions: Lifestyle modifications to reduce risk

    Search first: CDC, WHO, behavioral intervention databases, Cochrane Library

  • Counseling: Genetic counseling (risk assessment, family planning guidance)

    Search first: NSGC resources, ACMG guidelines, GeneReviews

  • Public Health:
  • Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
  • Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
  • Prophylaxis: Preventive medications or procedures

    Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

  • Taxonomy: Species affected (with NCBI Taxon identifiers)

    Search first: NCBI Taxonomy

  • Breed: Specific breeds affected (with VBO identifiers if applicable)

    Search first: VBO (Vertebrate Breed Ontology)

  • Gene: Orthologous genes in other species (with NCBI Gene IDs)

    Search first: NCBI Gene

  • Natural Disease:
  • Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
  • Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
  • Comparative Biology:
  • Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
  • Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
  • Transmission (if applicable):
  • Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
  • Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

  • Model Types:
  • Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
  • Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
  • Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
  • Genetic Models:
  • Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
  • Model Characteristics:
  • Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
  • Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
  • Applications:
  • Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
  • Resources:
  • Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

  • Cite primary literature (PMID preferred) for all mechanistic and clinical claims
  • Prioritize recent reviews and landmark papers
  • Include direct quotes from abstracts where possible to support key statements
  • Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Landau–Kleffner Syndrome (LKS): Disease Characteristics Research Report (2026-06-04)

Target disease

  • Disease name: Landau–Kleffner syndrome (LKS)
  • Category: Typically considered within the epilepsy–aphasia spectrum / developmental and epileptic encephalopathies with spike-wave activation in sleep (EE-SWAS/DEE-SWAS). (strehlow2024grin2arelateddisorders pages 3-5, strehlow2024grin2arelateddisorders pages 1-3)
  • MONDO ID: Not extractable from the retrieved sources in this tool run (no MONDO/OMIM/Orphanet/MeSH/ICD identifiers were present in the captured texts).

1. Disease information

Overview (current understanding)

Landau–Kleffner syndrome is a rare childhood epileptic encephalopathy characterized by acquired receptive and expressive aphasia—often presenting as auditory verbal agnosia (“word deafness”)—with sleep-activated epileptiform EEG abnormalities; seizures are common but not obligatory. (magalhaes2022onesilencedifferent pages 1-2, motta2022landaukleffnersyndromea pages 1-2)

Synonyms / alternative names

  • Acquired epileptic aphasia / acquired aphasia-epilepsy syndrome (nariai2018treatmentofepileptic pages 8-9)
  • Often discussed within epilepsy–aphasia spectrum disorders and alongside CSWS/ESES/EE-SWAS. (krey2024genetikundgenetische pages 2-3, moresco2020pharmacologicaltreatmentfor pages 5-6)

Key identifiers (as available here)

  • Open Targets disease entity: Landau–Kleffner syndrome EFO_1001010 (Open Targets internal/EFO identifier in returned record). (OpenTargets Search: Landau-Kleffner syndrome)
  • ClinicalTrials.gov condition label(s): “Landau-Kleffner Syndrome”, often paired with “CSWS/ESES”. (NCT02904265 chunk 1, NCT03024827 chunk 1)

Evidence provenance

The information summarized here comes from aggregated disease-level resources (systematic reviews, scoping reviews, GeneReviews-like GRIN2A disorder summary, Cochrane review) and aggregated case-series evidence; some case-report-derived statements are also present in the systematic review corpus. (motta2022landaukleffnersyndromea pages 5-6, moresco2020pharmacologicaltreatmentfor pages 7-10, strehlow2024grin2arelateddisorders pages 1-3)

2. Etiology

Disease causal factors

Core causal model (electroclinical): LKS is strongly associated with sleep-potentiated epileptiform activity (SWAS/ESES/CSWS pattern) that disrupts language networks and yields acquired aphasia/auditory agnosia. (nariai2018treatmentofepileptic pages 8-9, moresco2020pharmacologicaltreatmentfor pages 4-5)

Genetic contributions: LKS is within the epilepsy–aphasia spectrum in which pathogenic variants in GRIN2A are a major established monogenic contributor. (strehlow2024grin2arelateddisorders pages 1-3, strehlow2024grin2arelateddisorders pages 17-19)

Other proposed contributors: Etiology is often described as unclear/multifactorial, with hypotheses including autoimmune mechanisms and infectious triggers (e.g., HSV, Toxoplasma) in some cases/reviews. (motta2022landaukleffnersyndromea pages 2-3)

Risk factors

  • Genetic: Pathogenic GRIN2A variants (dominant/monoallelic) are associated with epilepsy–aphasia syndromes including LKS. (strehlow2024grin2arelateddisorders pages 1-3, OpenTargets Search: Landau-Kleffner syndrome)
  • Male predominance is reported in aggregated LKS case data. (motta2022landaukleffnersyndromea pages 5-6, magalhaes2022onesilencedifferent pages 1-2)

Protective factors

No specific protective genetic variants or environmental protective factors were identified in the retrieved sources.

Gene–environment interactions

Not directly supported by the retrieved sources. Reviews mention autoimmune/infectious hypotheses, but do not provide explicit gene–environment interaction evidence for LKS. (motta2022landaukleffnersyndromea pages 2-3)

3. Phenotypes (with suggested HPO terms)

Core phenotype set

1) Acquired aphasia / language regression - Description: Rapid or progressive loss of language (weeks–months) with prominent receptive deficit (auditory agnosia), often with normal audiogram; expressive deficits may follow. (papatheodorou2024howencephalopathyimpacts pages 2-3, magalhaes2022onesilencedifferent pages 1-2) - Age of onset: Typically 3–8 years; broader reported range 18 months–14 years. (magalhaes2022onesilencedifferent pages 1-2, motta2022landaukleffnersyndromea pages 2-3) - Suggested HPO: - Aphasia (HP:0002385) - Loss of speech (HP:0002371) - Language regression (HP:0002376)

2) Auditory verbal agnosia (“word deafness”) / impaired speech comprehension - Description: Child may appear “effectively deaf” to speech (auditory agnosia). (nariai2018treatmentofepileptic pages 8-9) - Suggested HPO: - Auditory agnosia (HP:0008551) - Abnormality of speech comprehension (HP:0002189)

3) Seizures (variable; not obligatory) - Frequency: Two-thirds in one review; in pooled case data, seizures were present in ~80.35% of cases with seizure-status described. (magalhaes2022onesilencedifferent pages 1-2, motta2022landaukleffnersyndromea pages 5-6) - Seizure–aphasia timing (243 cases): seizures preceded aphasia 32.51% (79/243), followed aphasia 43.21% (105/243), and 18.52% (45/243) had no seizures. (motta2022landaukleffnersyndromea pages 5-6) - Suggested HPO: - Seizure (HP:0001250) - Focal seizures (HP:0007359) (if specified)

4) Behavioral and cognitive comorbidities - Frequency: In pooled 243 cases, 69.96% (170/243) had additional symptoms including behavioral and mood changes. (motta2022landaukleffnersyndromea pages 5-6) - Examples: irritability, aggressiveness, attention-deficit disorder, hyperkinesis, autistic behaviors. (nariai2018treatmentofepileptic pages 8-9, motta2022landaukleffnersyndromea pages 5-6) - Suggested HPO: - Behavioral abnormality (HP:0000708) - Attention deficit (HP:0000736) - Autistic behavior (HP:0000729)

Quality-of-life impact

Direct QoL instrument data (e.g., EQ-5D, PedsQL) specific to LKS were not found in the retrieved sources; however, persistent communication impairment into adulthood is reported in follow-up literature. (papatheodorou2024howencephalopathyimpacts pages 9-10)

4. Genetic / molecular information

Causal / high-confidence genes

GRIN2A (NMDA receptor GluN2A subunit) - Evidence type: human genetic association; epilepsy–aphasia spectrum disorders including LKS. (strehlow2024grin2arelateddisorders pages 17-19, strehlow2024grin2arelateddisorders pages 1-3) - Key primary literature explicitly cited with PMIDs in retrieved GeneReviews excerpt: - “GRIN2A mutations cause epilepsy-aphasia spectrum disorders” (Carvill 2013 PMID: 23933818). (strehlow2024grin2arelateddisorders pages 17-19) - “GRIN2A mutations in acquired epileptic aphasia …” (Lesca 2013 PMID: 23933820). (strehlow2024grin2arelateddisorders pages 17-19) - Inheritance: autosomal dominant; about 50% de novo among GRIN2A-related disorders. (strehlow2024grin2arelateddisorders pages 1-3) - Variant classes: missense, nonsense, splice-site, small deletions/insertions reported in GRIN2A-related disorders. (strehlow2024grin2arelateddisorders pages 3-5, strehlow2024grin2arelateddisorders pages 1-3)

Other genetic findings (less specific / broader spectrum) - GRIN2B: implicated in related phenotypes; cited with Endele 2010 PMID: 20890276 in the GRIN2A disorders excerpt. (strehlow2024grin2arelateddisorders pages 17-19) - 16p13 deletions including GRIN2A: reported (Reutlinger 2010 PMID: 20384727). (strehlow2024grin2arelateddisorders pages 17-19)

Disease–target association resource summary

Open Targets reports a strong association between LKS and GRIN2A and provides a list of supporting PMIDs (including 23933818, 23933820, 30544257, 38538865, etc.) and an allelic requirement indicating monoallelic involvement. (OpenTargets Search: Landau-Kleffner syndrome)

Functional consequences / mechanistic genetics

GRIN2A-related disorder guidance emphasizes that some variants have loss-of-function/null effects, others gain-of-function (activating) effects, and that this distinction may guide precision therapy (e.g., avoid NMDAR agonists such as L-serine in GOF; consider L-serine in LOF/null; use NMDAR blockers cautiously depending on functional class). (strehlow2024grin2arelateddisorders pages 1-3, krey2024genetikundgenetische pages 2-3)

Modifier genes / epigenetics / chromosomal abnormalities

No specific modifier genes or epigenetic signatures were identified in the retrieved sources. Chromosomal abnormality evidence is limited to reported 16p13 deletions including GRIN2A. (strehlow2024grin2arelateddisorders pages 17-19)

5. Environmental information

The retrieved sources do not support specific environmental toxins, lifestyle factors, or infectious agents as consistent causal triggers. Reviews mention possible infectious/autoimmune hypotheses (HSV, Toxoplasma) but without strong causal epidemiologic evidence in the extracted text. (motta2022landaukleffnersyndromea pages 2-3)

6. Mechanism / pathophysiology

Core causal chain (electroclinical model)

1) Sleep potentiates epileptiform discharges (SWAS/ESES/CSWS), with near-continuous spike–wave activity during NREM sleep in some definitions. (moresco2020pharmacologicaltreatmentfor pages 4-5, papatheodorou2024howencephalopathyimpacts pages 2-3) 2) Abnormal discharges disrupt language network function/plasticity, producing impaired access to previously established receptive/expressive language and neurocognitive regression. (moresco2020pharmacologicaltreatmentfor pages 4-5, nariai2018treatmentofepileptic pages 8-9) 3) Clinical manifestations include auditory verbal agnosia and aphasia, with behavioral/cognitive sequelae. (nariai2018treatmentofepileptic pages 8-9, motta2022landaukleffnersyndromea pages 5-6)

A mechanistic framing from ESES literature suggests that sleep-related network consolidation may be repeatedly disrupted (“spikes” undoing normal network “work”), contributing to persistent deficits. (nariai2018treatmentofepileptic pages 8-9)

Circuit-level mechanisms (sleep activation)

A 2024 sleep–epilepsy review proposes that SWAS/ESES sleep activation may reflect abnormal hyperactivation of the thalamic oscillatory circuit and altered inhibitory dynamics (shift from GABA-A to GABA-B-mediated postsynaptic inhibition). (krutoshinskaya2024thereciprocalrelationship pages 5-7)

Molecular mechanisms

  • NMDA receptor dysfunction (via GRIN2A variants) is a key molecular mechanism for a subset of patients, linking glutamatergic synaptic signaling to epilepsy–aphasia syndromes. (strehlow2024grin2arelateddisorders pages 17-19, strehlow2024grin2arelateddisorders pages 1-3)

Neuroanatomical/network correlates

LKS EEG abnormalities are often localized to temporal/perisylvian regions around the Sylvian fissure (language network). (magalhaes2022onesilencedifferent pages 2-4, motta2022landaukleffnersyndromea pages 2-3)

Structural MRI studies in GRIN2A-related epilepsy–aphasia syndromes show anomalies in perisylvian speech-language regions (e.g., posterior Broca’s area and superior temporal regions) and reduced left hippocampal volume, suggesting altered development of speech-language networks in this genetic subgroup. (thompsonlake2024perisylvianandhippocampal pages 1-2)

Suggested ontology annotations

  • GO (biological process):
  • synaptic transmission, glutamatergic (GO:0035249)
  • learning or memory (GO:0007611)
  • regulation of synaptic plasticity (GO:0048167)
  • sleep / regulation of sleep (GO:0030431 / GO:0060113) (mechanistic context: sleep-activated discharges)
  • CL (cell types; hypothesized):
  • cortical pyramidal neuron (e.g., CL:0000540)
  • GABAergic interneuron (e.g., CL:0000617)
  • thalamic neuron (generic thalamic relay neuron; relevant to thalamocortical oscillations) (krutoshinskaya2024thereciprocalrelationship pages 5-7)

7. Anatomical structures affected

  • Primary system: Central nervous system, particularly networks supporting speech/language.
  • Localization evidence: Temporal and perisylvian regions around the Sylvian fissure on EEG; Wernicke/Broca involvement is discussed in reviews/case localizations. (magalhaes2022onesilencedifferent pages 2-4, motta2022landaukleffnersyndromea pages 2-3)
  • UBERON suggestions:
  • temporal lobe (UBERON:0001871)
  • cerebral cortex (UBERON:0000956)
  • superior temporal gyrus (UBERON:0002290) (linked via posterior STG activation in LKS recovery studies) (papatheodorou2024howencephalopathyimpacts pages 12-13)

8. Temporal development

  • Onset: Typically ages 3–8 (some sources: 2–8); range 18 months–14 years. (magalhaes2022onesilencedifferent pages 1-2, nariai2018treatmentofepileptic pages 8-9)
  • Course: Sudden or gradual language regression; seizures may be absent or infrequent; spontaneous resolution before adolescence can occur but persistent language deficits are common in some. (magalhaes2022onesilencedifferent pages 1-2)

9. Inheritance and population

Epidemiology

  • Incidence: Japanese epidemiologic estimate reported as ~1 per 1,000,000 (e.g., ages 5–14). (magalhaes2022onesilencedifferent pages 1-2, motta2022landaukleffnersyndromea pages 2-3)
  • Share of childhood epilepsy: One systematic review summary reports LKS accounts for ~0.2% of childhood epilepsy cases (as stated in the review narrative). (motta2022landaukleffnersyndromea pages 1-2)

Inheritance (for genetic subgroup)

For GRIN2A-related disorders that include LKS: autosomal dominant; ~50% de novo. (strehlow2024grin2arelateddisorders pages 1-3)

Sex ratio

Aggregated cases show male predominance (e.g., “1.4 times more” male than female in one pooled dataset). (motta2022landaukleffnersyndromea pages 5-6)

10. Diagnostics

Core diagnostic tests

EEG (sleep recording is essential): - Diagnostic emphasis on sleep EEG to capture SWAS/ESES features; epileptiform discharges can become continuous during non-REM sleep. (magalhaes2022onesilencedifferent pages 2-4, papatheodorou2024howencephalopathyimpacts pages 2-3) - A commonly cited classical criterion for ESES/CSWS is ≥85% of NREM/slow-wave sleep occupied by spike–wave complexes; some studies use spike–wave index thresholds ≥25% or >50% for clinical relevance. (nariai2018treatmentofepileptic pages 8-9)

MRI: Often normal in LKS, but focal lesions may occur in a minority and should be excluded (e.g., vascular lesions, tumors, inflammatory lesions, demyelination, cortical atrophy). (motta2022landaukleffnersyndromea pages 2-3, magalhaes2022onesilencedifferent pages 1-2)

Genetic testing

  • Epilepsy gene panels including GRIN2A are used in workup; diagnosis of GRIN2A-related disorder is by finding a heterozygous pathogenic variant. (magalhaes2022onesilencedifferent pages 2-4, strehlow2024grin2arelateddisorders pages 1-3)

Differential diagnosis (examples mentioned)

  • Selective mutism and other primary emotional/anxiety disorders can mimic presentation; diagnostic difficulty is emphasized. (magalhaes2022onesilencedifferent pages 2-4)

11. Outcome / prognosis

Short- and long-term outcomes

A systematic review summarizing 243 published cases reported: - Partial regression: 58.02% (141/243) - Total regression: 41.98% (102/243) - Improved without therapy: 3.29% (8 cases) with “total improvement” defined as ≥50% seizure reduction and ≥50% aphasia improvement / conversational autonomy. (motta2022landaukleffnersyndromea pages 5-6)

Adult language outcomes vary widely; across multiple follow-up studies summarized in a 2024 scoping review, groups had subsets with normal/mild outcomes and smaller subsets with severe persistent impairment (e.g., severe impairment counts of 2/13 and 4/8 in example cohorts). (papatheodorou2024howencephalopathyimpacts pages 9-10)

12. Treatment

Evidence base caveat (critical)

A 2020 Cochrane review concluded there was no eligible RCT evidence for pharmacologic therapy for CSWS/LKS as of its search, stating: - “We identified no trials that matched our inclusion criteria” and - “There was no evidence from trials to support or refute the use of pharmacological treatment … [and] well-designed randomised controlled trials are needed.” (moresco2020pharmacologicaltreatmentfor pages 10-11, moresco2020pharmacologicaltreatmentfor pages 1-4)

Commonly used real-world therapies (with evidence summaries)

1) Corticosteroids / ACTH (immunomodulatory therapy) - 2023 systematic review: in (D)EE-SWAS including LKS, 81/126 (64%) improved in EEG or language/cognition across nine heterogeneous studies. (becker2023corticosteroidsinchildhood pages 2-4) - In one cited study: 6/6 LKS improved with oral prednisolone 1–2 mg/kg/day for 6 months (in the review’s summary of Chen et al.). (becker2023corticosteroidsinchildhood pages 2-4) - Relapse is common in some series (e.g., relapse in 14/21 responders in one SWAS cohort; relapse reported in 17/25 in three studies in a broader synthesis). (becker2023corticosteroidsinchildhood pages 2-4, becker2023corticosteroidsinchildhood pages 4-5) - MAXO suggestions: corticosteroid therapy; adrenocorticotropic hormone therapy.

2) Benzodiazepines - In a multicenter retrospective CSWS cohort (not LKS-specific): compared with ASMs, benzodiazepines had higher odds of physician-noted clinical improvement (OR 3.32), and steroids OR 4.04; steroids had greater EEG improvement than ASMs (OR 3.36). (baumer2021treatmentpracticesand pages 1-2) - MAXO suggestions: benzodiazepine therapy.

3) Anti-seizure medications (ASMs) - Several reviews describe valproate and others as commonly used; some ASMs (carbamazepine, phenytoin, phenobarbital; also oxcarbazepine, vigabatrin) may worsen discharges and are discouraged. (magalhaes2022onesilencedifferent pages 1-2, nariai2018treatmentofepileptic pages 8-9) - MAXO suggestions: antiseizure medication therapy.

4) IVIG - Used in practice in some reports (dosing regimens described in differential diagnosis review) but evidence is inconsistent; one review excerpt notes IVIG attempted “without success” in ESES context. (magalhaes2022onesilencedifferent pages 1-2, nariai2018treatmentofepileptic pages 8-9) - MAXO suggestions: intravenous immunoglobulin therapy.

5) Ketogenic diet - Suggested in selected cases and in broader ESES/CSWS literature; high-quality LKS-specific outcome data were not captured in the retrieved excerpts. (magalhaes2022onesilencedifferent pages 1-2, nariai2018treatmentofepileptic pages 8-9) - MAXO suggestions: ketogenic diet therapy.

6) Surgical options (including multiple subpial transection, MST) - Systematic-review summaries and ESES surgical reviews describe MST historically used, but outcomes vary and evidence is inconsistent. (wang2020surgicalmanagementof pages 2-3, magalhaes2022onesilencedifferent pages 1-2) - A pooled case review reported surgery performed in 19.34% (47/243) cases and suggested higher total regression rates in surgically treated vs conservative cases within the limitations of case-report literature. (motta2022landaukleffnersyndromea pages 5-6) - MAXO suggestions: epilepsy surgery; multiple subpial transection.

Precision/targeted approaches (recent genetic-era developments)

For GRIN2A-related disorders (which include LKS phenotypes), variant-function-guided therapy has been proposed: - Consider L-serine for GRIN2A loss-of-function/null variants; avoid NMDAR agonists/activators in gain-of-function missense variants; use NMDAR blockers (memantine, ketamine, dextromethorphan) cautiously depending on functional class. (strehlow2024grin2arelateddisorders pages 1-3, krey2024genetikundgenetische pages 2-3)

13. Prevention

No primary prevention strategies are established for idiopathic LKS. Secondary prevention focuses on early detection of sleep-activated epileptiform activity and timely therapy to reduce EEG burden, as earlier onset/longer duration predicts poorer outcomes. (nariai2018treatmentofepileptic pages 8-9)

14. Other species / natural disease

No naturally occurring LKS analogs in non-human species were identified in the retrieved sources.

15. Model organisms

A rat model of frequent focal interictal spikes during neurodevelopment is described as relevant to cognitive/behavioral comorbidities seen in syndromes such as LKS/CSWS; ACTH modestly improved attention deficits in the model without changing spike activity, supporting a neurodevelopmental impact of epileptiform activity beyond seizures. (moresco2020pharmacologicaltreatmentfor pages 10-11)

Recent developments and latest research (prioritized 2023–2024)

1) Corticosteroids evidence synthesis (2023): systematic review quantified response/relapse rates in EE-SWAS/LKS and highlighted need for controlled trials. URL: https://doi.org/10.3389/fneur.2023.1142253 (published Mar 2023). (becker2023corticosteroidsinchildhood pages 1-2, becker2023corticosteroidsinchildhood pages 2-4) 2) GRIN2A precision management guidance (2024): autosomal dominant inheritance with ~50% de novo and variant-function-guided recommendations (L-serine vs caution with NMDAR modulators). (strehlow2024grin2arelateddisorders pages 1-3) 3) Neuroimaging in GRIN2A epilepsy–aphasia spectrum (2024): perisylvian and hippocampal structural anomalies in pathogenic GRIN2A carriers. URL: https://doi.org/10.1212/nxg.0000000000200129 (published Apr 2024). (thompsonlake2024perisylvianandhippocampal pages 1-2) 4) Language outcomes in adulthood (2024): scoping review summarizes variable adult language outcomes and cognitive–linguistic correlations. URL: https://doi.org/10.3390/medicina60101635 (published Oct 2024). (papatheodorou2024howencephalopathyimpacts pages 2-3, papatheodorou2024howencephalopathyimpacts pages 9-10)

Clinical trials and real-world implementations (ClinicalTrials.gov)

  • NCT02904265 “Efficacy Study of Acetazolamide Versus Diazepam in Continuous Spike and Wave/Landau-Kleffner Syndrome” (Mayo Clinic). Phase 2/3; randomized open-label; terminated for lack of enrollment; enrollment 3; start Sep 2016; completion Jul 26, 2019; results first posted Jun 11, 2020. (NCT02904265 chunk 1)
  • NCT03024827 CARE-E: cannabidiol-enriched cannabis oil in children with refractory epileptic encephalopathy; conditions list includes LKS/CSWS; Phase 1 dose escalation; start 2017-04-26; estimated completion 2023-12-31; enrollment 20; outcomes include safety labs, EEG, seizure frequency logs, QOLCE. (NCT03024827 chunk 1)
  • NCT01335425 observational case-control study of rolandic epilepsy/ESES/LKS and language impairment correlations; completed; enrolled 47; start Oct 2010; completion Dec 2013. (NCT01335425 chunk 1)

Visual evidence

A figure summarizing corticosteroid regimens across pediatric epilepsy syndromes (including (D)EE-SWAS) is available from Becker & Kaindl 2023 and supports the diversity of steroid protocols used in practice. (becker2023corticosteroidsinchildhood media 270f7cc0)

Notable limitations of this report (due to retrieval constraints)

  • Formal OMIM/Orphanet/MeSH/MONDO/ICD identifiers were not present in retrieved texts during this tool run, so they cannot be provided with citations here.
  • Many LKS treatment claims remain based on heterogeneous retrospective series; high-quality RCT evidence is limited/absent per Cochrane review (searched to Sept 2020). (moresco2020pharmacologicaltreatmentfor pages 10-11)

References

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  3. (magalhaes2022onesilencedifferent pages 1-2): P Magalhães, M Marques, and V Martins. One silence, different clinical pictures: landau kleffner syndrome: differential diagnosis. Unknown journal, 2022.

  4. (motta2022landaukleffnersyndromea pages 1-2): Giovana Cássia de Almeida Motta, Letícia Goes, Pedro Henrique Simm Pires de Aguiar, Fernando Furtado Santos, César Cozar Pacheco, Paulo Roberto Franceschini, and Paulo Henrique Pires de Aguiar. Landau-kleffner syndrome: a systematic review and two illustrative cases. Revista Chilena de Neurocirugía, 47:67-73, Apr 2022. URL: https://doi.org/10.36593/revchilneurocir.v47i2.250, doi:10.36593/revchilneurocir.v47i2.250. This article has 5 citations.

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  8. (OpenTargets Search: Landau-Kleffner syndrome): Open Targets Query (Landau-Kleffner syndrome, 1 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.

  9. (NCT02904265 chunk 1): Katherine C. Nickels. Efficacy Study of Acetazolamide Versus Diazepam in Continuous Spike and Wave/Landau-Kleffner Syndrome. Mayo Clinic. 2016. ClinicalTrials.gov Identifier: NCT02904265

  10. (NCT03024827 chunk 1): Richard Huntsman. Cannabidiol in Children With Refractory Epileptic Encephalopathy. University of Saskatchewan. 2017. ClinicalTrials.gov Identifier: NCT03024827

  11. (motta2022landaukleffnersyndromea pages 5-6): Giovana Cássia de Almeida Motta, Letícia Goes, Pedro Henrique Simm Pires de Aguiar, Fernando Furtado Santos, César Cozar Pacheco, Paulo Roberto Franceschini, and Paulo Henrique Pires de Aguiar. Landau-kleffner syndrome: a systematic review and two illustrative cases. Revista Chilena de Neurocirugía, 47:67-73, Apr 2022. URL: https://doi.org/10.36593/revchilneurocir.v47i2.250, doi:10.36593/revchilneurocir.v47i2.250. This article has 5 citations.

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  13. (moresco2020pharmacologicaltreatmentfor pages 4-5): Luca Moresco, Matteo Bruschettini, Maria Grazia Calevo, and Laura Siri. Pharmacological treatment for continuous spike-wave during slow wave sleep syndrome and landau-kleffner syndrome. The Cochrane database of systematic reviews, 11:CD013132, Nov 2020. URL: https://doi.org/10.1002/14651858.cd013132.pub2, doi:10.1002/14651858.cd013132.pub2. This article has 19 citations.

  14. (strehlow2024grin2arelateddisorders pages 17-19): V Strehlow, KA Myers, and AT Morgan. Grin2a-related disorders. Unknown journal, 2024.

  15. (motta2022landaukleffnersyndromea pages 2-3): Giovana Cássia de Almeida Motta, Letícia Goes, Pedro Henrique Simm Pires de Aguiar, Fernando Furtado Santos, César Cozar Pacheco, Paulo Roberto Franceschini, and Paulo Henrique Pires de Aguiar. Landau-kleffner syndrome: a systematic review and two illustrative cases. Revista Chilena de Neurocirugía, 47:67-73, Apr 2022. URL: https://doi.org/10.36593/revchilneurocir.v47i2.250, doi:10.36593/revchilneurocir.v47i2.250. This article has 5 citations.

  16. (papatheodorou2024howencephalopathyimpacts pages 2-3): Ioanna Papatheodorou, Stavroula Stavrakaki, Vasiliki Koukoulioti, Martha Spilioti, and Vasileios Kimiskidis. How encephalopathy impacts language ability: a scoping review of the linguistic abilities of adults with developmental and epileptic encephalopathy. Medicina, 60:1635, Oct 2024. URL: https://doi.org/10.3390/medicina60101635, doi:10.3390/medicina60101635. This article has 4 citations.

  17. (papatheodorou2024howencephalopathyimpacts pages 9-10): Ioanna Papatheodorou, Stavroula Stavrakaki, Vasiliki Koukoulioti, Martha Spilioti, and Vasileios Kimiskidis. How encephalopathy impacts language ability: a scoping review of the linguistic abilities of adults with developmental and epileptic encephalopathy. Medicina, 60:1635, Oct 2024. URL: https://doi.org/10.3390/medicina60101635, doi:10.3390/medicina60101635. This article has 4 citations.

  18. (krutoshinskaya2024thereciprocalrelationship pages 5-7): Yana Krutoshinskaya, Kelly Coulehan, Galyna Pushchinska, and Rebecca Spiegel. The reciprocal relationship between sleep and epilepsy. Journal of Personalized Medicine, 14:118, Jan 2024. URL: https://doi.org/10.3390/jpm14010118, doi:10.3390/jpm14010118. This article has 33 citations.

  19. (magalhaes2022onesilencedifferent pages 2-4): P Magalhães, M Marques, and V Martins. One silence, different clinical pictures: landau kleffner syndrome: differential diagnosis. Unknown journal, 2022.

  20. (thompsonlake2024perisylvianandhippocampal pages 1-2): Daisy G.Y. Thompson-Lake, Frederique J. Liegeois, Ruth O. Braden, Graeme D. Jackson, Samantha J. Turner, Lottie Morison, Michael Hildebrand, Ingrid E. Scheffer, and Angela T. Morgan. Perisylvian and hippocampal anomalies in individuals with pathogenic grin2a variants. Neurology Genetics, Apr 2024. URL: https://doi.org/10.1212/nxg.0000000000200129, doi:10.1212/nxg.0000000000200129. This article has 2 citations.

  21. (papatheodorou2024howencephalopathyimpacts pages 12-13): Ioanna Papatheodorou, Stavroula Stavrakaki, Vasiliki Koukoulioti, Martha Spilioti, and Vasileios Kimiskidis. How encephalopathy impacts language ability: a scoping review of the linguistic abilities of adults with developmental and epileptic encephalopathy. Medicina, 60:1635, Oct 2024. URL: https://doi.org/10.3390/medicina60101635, doi:10.3390/medicina60101635. This article has 4 citations.

  22. (moresco2020pharmacologicaltreatmentfor pages 10-11): Luca Moresco, Matteo Bruschettini, Maria Grazia Calevo, and Laura Siri. Pharmacological treatment for continuous spike-wave during slow wave sleep syndrome and landau-kleffner syndrome. The Cochrane database of systematic reviews, 11:CD013132, Nov 2020. URL: https://doi.org/10.1002/14651858.cd013132.pub2, doi:10.1002/14651858.cd013132.pub2. This article has 19 citations.

  23. (moresco2020pharmacologicaltreatmentfor pages 1-4): Luca Moresco, Matteo Bruschettini, Maria Grazia Calevo, and Laura Siri. Pharmacological treatment for continuous spike-wave during slow wave sleep syndrome and landau-kleffner syndrome. The Cochrane database of systematic reviews, 11:CD013132, Nov 2020. URL: https://doi.org/10.1002/14651858.cd013132.pub2, doi:10.1002/14651858.cd013132.pub2. This article has 19 citations.

  24. (becker2023corticosteroidsinchildhood pages 2-4): Lena-Luise Becker and Angela M. Kaindl. Corticosteroids in childhood epilepsies: a systematic review. Frontiers in Neurology, Mar 2023. URL: https://doi.org/10.3389/fneur.2023.1142253, doi:10.3389/fneur.2023.1142253. This article has 29 citations and is from a peer-reviewed journal.

  25. (becker2023corticosteroidsinchildhood pages 4-5): Lena-Luise Becker and Angela M. Kaindl. Corticosteroids in childhood epilepsies: a systematic review. Frontiers in Neurology, Mar 2023. URL: https://doi.org/10.3389/fneur.2023.1142253, doi:10.3389/fneur.2023.1142253. This article has 29 citations and is from a peer-reviewed journal.

  26. (baumer2021treatmentpracticesand pages 1-2): Fiona M. Baumer, Nancy A. McNamara, Anthony L. Fine, Elia Pestana-Knight, Renée A. Shellhaas, Zihuai He, Daniel H. Arndt, William D. Gaillard, Sarah A. Kelley, Margot Nagan, Adam P. Ostendorf, Nilika S. Singhal, Laura Speltz, and Kevin E. Chapman. Treatment practices and outcomes in continuous spike and wave during slow wave sleep: a multicenter collaboration. May 2021. URL: https://doi.org/10.1016/j.jpeds.2021.01.032, doi:10.1016/j.jpeds.2021.01.032. This article has 38 citations.

  27. (wang2020surgicalmanagementof pages 2-3): Shelly Wang, Alexander G. Weil, George M. Ibrahim, Aria Fallah, Brandon Korman, John Ragheb, Sanjiv Bhatia, and Michael Duchowny. Surgical management of pediatric patients with encephalopathy due to electrical status epilepticus during sleep (eses). Epileptic disorders : international epilepsy journal with videotape, 22:39-54, Feb 2020. URL: https://doi.org/10.1684/epd.2020.1129, doi:10.1684/epd.2020.1129. This article has 17 citations.

  28. (becker2023corticosteroidsinchildhood pages 1-2): Lena-Luise Becker and Angela M. Kaindl. Corticosteroids in childhood epilepsies: a systematic review. Frontiers in Neurology, Mar 2023. URL: https://doi.org/10.3389/fneur.2023.1142253, doi:10.3389/fneur.2023.1142253. This article has 29 citations and is from a peer-reviewed journal.

  29. (NCT01335425 chunk 1): René Besseling. The Rolandic Epilepsy/ESES/Landau-Kleffner Syndrome and Correlation With Language Impairment Study. Maastricht University Medical Center. 2010. ClinicalTrials.gov Identifier: NCT01335425

  30. (becker2023corticosteroidsinchildhood media 270f7cc0): Lena-Luise Becker and Angela M. Kaindl. Corticosteroids in childhood epilepsies: a systematic review. Frontiers in Neurology, Mar 2023. URL: https://doi.org/10.3389/fneur.2023.1142253, doi:10.3389/fneur.2023.1142253. This article has 29 citations and is from a peer-reviewed journal.

Artifacts

## Context ID: pqac-00000030 The document does not contain a specific table or figure solely dedicated to treatment outcomes or SWAS/ESES criteria. However, Fig