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ORPHA:98818

Landau-Kleffner syndrome

medium confidenceDisorder

Also known as: Acquired epileptic aphasia · LKS

Publications

20,903

97.1th percentile

Trials

1

Interventional, condition-specific

Researchers

1,041

Distinct authors in sample

Gene link

GRIN2A

Definitive

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare form of epileptic with spike-wave activation in sleep (EE-SWAS) characterized by various combinations of acquired cognitive, language, behavioral, and motor deficits associated with marked spike- and- wave activation in sleep. In Landau-Kleffner syndrome (LKS), receptive language is mainly affected, with an acquired auditory verbal agnosia.

How rare: 1-9 / 1 000 000 — roughly one to nine people per million. In a city the size of Kolkata, perhaps a few dozen.

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Additional Mondo synonyms (1)

acquired epileptic aphasia

Research stages

Trial readiness signals

Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”

4/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedPresent

    Definitive — GRIN2A

  2. LiteraturePresent

    20,903 matched papers (10,389 in last 10 years) Source

  3. Phenotype characterisedPresent

    44 HPO annotations (e.g. Seizure; Aphasia; Generalized non-motor (absence) seizure) Source

  4. Animal modelNot found

    No Alliance genotype “model of” associations via Monarch for these Mondo IDs

  5. Orphan designationNot found

    No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source

  6. Interventional trialPresent

    1 matched on ClinicalTrials.gov

Biology

Genes and phenotypes

Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.

Do we know what causes it?

Yes — we know a specific gene responsible (GRIN2A).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

44

Associated phenotypes · MONDO:0009509

  • Seizure
  • Aphasia
  • Generalized non-motor (absence) seizure
  • EEG with generalized epileptiform discharges
  • EEG with temporal focal spikes

Showing 5 of 44 — open Monarch for the full list.

Animal models (Monarch / Alliance)

None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.

Monarch fetch 2026-07-29

Therapies

Designations, candidates, and chemicals

FDA OOPD and EMA orphan designations, Open Targets clinical candidates, and CTD chemical associations via MyDisease.info. These never change the interventional-trial headline.

Orphan designation (FDA · EMA)

No designation matched this disease via UMLS or preferred name on the FDA OOPD mirror or EMA orphan register. Absence here is not proof that none exists under another wording.

Open Targets candidates

2

Drugs / clinical candidates · MONDO_0009509

CTD chemicals (MyDisease.info)

No CTD chemical associations returned for this Mondo ID.

Literature

Is anyone studying this?

20,903

20,903 papers — among the better-studied rare conditions, though still a fraction of common-disease literature (breast cancer: over 700,000). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

20,903 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 59 (publications denominator n=3967).

10,389 in the last 10 years · medium confidence · 97.1th percentile (publications denominator)

Phrase hits: 1,226 · MeSH hits: 29

Open Europe PMC search

Who's working on it?

1,041

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Posar A5 papers · 2024

    IRCCS Institute of Neurological Sciences of Bologna, Child Neurology and Psychiatry Unit, Bologna, Italy.

    Papers in Europe PMC
  2. 02
    Scheffer IE5 papers · 2025

    Epilepsy Research Centre, Austin Health, The University of Melbourne, Melbourne, Victoria, Australia.

    Papers in Europe PMC
  3. 03
    Visconti P5 papers · 2024

    IRCCS Institute of Neurological Sciences of Bologna, Child Neurology and Psychiatry Unit, Bologna, Italy.

    Papers in Europe PMC
  4. 04
    Hirsch E4 papers · 2022

    Fédération de Médecine Translationnelle (FMTS), Strasbourg, France, INSERM UMR_SU1119, Strasbourg, France.

    Papers in Europe PMC
  5. 05
    Soto-Insuga V4 papers · 2026

    Hospital Infantil Universitario Niño Jesús, 28009 Madrid, España.

    Papers in Europe PMC
  6. 06
    Zhang Y4 papers · 2025

    Department of Pediatrics, Peking University First Hospital, Beijing, China. Electronic address: zhangyhdr@126.com.

    Papers in Europe PMC
  7. 07
    Bhatia S3 papers · 2025

    Division of Neurosurgery, Department of Surgery, Nicklaus Children's Hospital, Miami, USA.

    Papers in Europe PMC
  8. 08
    Furley K3 papers · 2026

    Monash Children's Hospital, Melbourne, Australia; Department of Paediatrics, Monash University, Melbourne, Australia. Electronic address: kirsten.furley1@monash.edu.

    Papers in Europe PMC
  9. 09
    Gaitanis J3 papers · 2023

    Hasbro Children's Hospital, The Warren Alpert Medical School of Brown University, Providence, RI 02903, USA.

    Papers in Europe PMC
  10. 10
    González-Alguacil E3 papers · 2026

    Hospital Infantil Universitario Niño Jesús, 28009 Madrid, España.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

1

interventional trials for this specific condition

1 interventional trial matched this specific condition name; none in our sample are currently recruiting.

Data as of 11 September 2026 · last trial check 28 July 2026

1 interventional trial — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 80.1th percentile).

medium confidence · 80.1th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

1 interventional trials matched after quoted-phrase search and title/condition post-filter.

No currently recruiting studies in the matched set. Open the same search on ClinicalTrials.gov.

Observational and natural-history studies

1 observational study matches this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.

None of the matched observational studies is currently listed as recruiting.

Open the complete matched search on ClinicalTrials.gov

Other registries (secondary)

Broader net from EU CTIS, ISRCTN, and ICTRP when available — deduped against ClinicalTrials.gov IDs already counted above. Dual-model LLM relevance gates what we keep. These rows are not added to the interventional headline.

raw 1 · after dedupe 1 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 1 · dropped 0 · fetched 2026-07-30

Source notes: ictrp: Error: ICTRP public search unavailable (WHO portal is SPA-only; SOAP needs partnership). Tried: https://apps.who.int/tri

No secondary-registry studies passed dual-model relevance for this condition name (after dedupe).

Uncertain / not reviewed (1)

Where to find support

Condition-specific patient organisations, when Orphanet lists them, are on the disease’s Orphanet page. We also link umbrella groups that support undiagnosed and ultra-rare families.

Orphanet entry for Landau-Kleffner syndrome — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.

Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.

How we counted this

Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.

("Landau-Kleffner syndrome" OR "Acquired epileptic aphasia") OR (MESH:"Landau-Kleffner Syndrome") OR ("GRIN2A" OR "GRIN2A syndrome" OR "GRIN2A-related")

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Landau-Kleffner Syndrome

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"Landau-Kleffner syndrome" OR "Acquired epileptic aphasia"

Interventional trials matched via: both (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 1 interventional · 1 observational · 0 expanded access. Only interventional studies enter the trial headline.

Query health: ok — strategies attempted: phrase, mesh; with hits: phrase, mesh

Run this search on ClinicalTrials.gov

Synonyms dropped by stoplist: LKS

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • 1 synonym(s) dropped by stoplist (may under-count)
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-27T05:26:18.906Z