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ORPHA:33543

Kleine-Levin syndrome

high confidenceDisorder

Publications

870

80.4th percentile

Trials

1

Interventional, condition-specific

Researchers

810

Distinct authors in sample

Gene link

—

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

Kleine-Levin syndrome (KLS) is a rare neurological disorder of unknown origin characterised by relapsing-remitting episodes of hypersomnia in association with cognitive and behavioural disturbances.

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.

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 identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    870 matched papers (388 in last 10 years) Source

  3. Phenotype characterisedPresent

    39 HPO annotations (e.g. Confusion; Amplification of sexual behavior; Photophobia) Source

  4. Animal modelNot found

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

  5. Orphan designationPartial

    1 EMA designation (none yet with FDA orphan-indication approval) — e.g. Lithium carbonate 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?

Not yet — the cause hasn't been pinned down in GenCC.

No strong gene–disease assertion joined for this Orphanet entity.

Phenotypes (Monarch / HPO)

39

Associated phenotypes · MONDO:0007863

  • Confusion
  • Amplification of sexual behavior
  • Photophobia
  • Apathy
  • Abnormal speech pattern

Showing 5 of 39 — 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)

1

Designation · no FDA orphan-indication approval yet

  • EMA Lithium carbonateTreatment of Kleine Levin syndrome · 16/08/2023 · PositiveEMA designation

Sources: FDA OOPD · EMA orphan designations

Open Targets candidates

No drugs or clinical candidates returned for this Mondo ID on Open Targets.

CTD chemicals (MyDisease.info)

1 associated chemical. Therapeutic evidence is listed first when present — not a treatment recommendation.

  • Isotretinoin · marker/mechanism

MyDisease.info · MONDO:0007863

Literature

Is anyone studying this?

870

870 papers have been published on this condition. That is a real research literature — still far smaller than common diseases (breast cancer: over 700,000 papers). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

870 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).

388 in the last 10 years · high confidence · 80.4th percentile (publications denominator)

Phrase hits: 870 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

810

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
    Dauvilliers Y50 papers · 2026

    National Reference Centre for Orphan Diseases, Narcolepsy, Idiopathic Hypersomnia, Sleep Unit, Department of Neurology, Gui-de-Chauliac Hospital, CHU Montpellier, University of Montpellier, INM INSERM, Montpellier, France.

    Papers in Europe PMC
  2. 02
    Barateau L39 papers · 2026

    National Reference Center for Orphan Diseases, Narcolepsy, Idiopathic Hypersomnia and Kleine-Levin Syndrome, Department of Neurology, Gui-de-Chauliac Hospital, Centre Hospitalier Universitaire (CHU) de Montpellier, Montpellier, France.

    Papers in Europe PMC
  3. 03
    Plazzi G18 papers · 2026

    IRCCS, Istituto delle Scienze Neurologiche di Bologna, UOC Clinica Neurologica, Bologna, Italy.

    Papers in Europe PMC
  4. 04
    Arnulf I16 papers · 2026

    Service des pathologies du sommeil, Centre National de Reference des Hypersomnies Rares, Hôpitaux Universitaires Pitié-Salpêtrière, Sorbonne Université, 47-83 boulevard de l'Hôpital, 75651 Paris Cedex 13, France. Electronic address: isabelle.arnulf@aphp.fr.

    Papers in Europe PMC
  5. 05
    Chenini S16 papers · 2026

    Sleep-Wake Disorders Unit, Department of Neurology, Gui-de-Chauliac Hospital, CHU, Montpellier, France.

    Papers in Europe PMC
  6. 06
    Jaussent I16 papers · 2026

    Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, Montpellier, France.

    Papers in Europe PMC
  7. 07
    Pizza F15 papers · 2026

    Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.

    Papers in Europe PMC
  8. 08
    Lecendreux M13 papers · 2025

    AP-HP, Pediatric Sleep Center, CHU Robert-Debré, Paris, France.

    Papers in Europe PMC
  9. 09
    Leu-Semenescu S8 papers · 2025

    From the Sleep Disorders Unit (A.L., E.G., C.C., S.L.-S., I.A.), National Reference Center for Narcolepsy, Hypersomnia and Kleine-Levin Syndrome, Brain Research Institute (CRICM, UPMC, Paris 6; Inserm UMR_S 975; CNRS UMR 7225), Sorbonne University Paris; Sleep Medicine and Respiratory Disease Center (L.P.-D.), Competence Center for Narcolepsy, Hypersomnia and Kleine-Levin Syndrome, Hospices Civils de Lyon, France; and Center for Investigation and Research in Sleep (A.O.R.), Lausanne University Hospital and Lausanne University, Switzerland.

    Papers in Europe PMC
  10. 10
    Lopez R8 papers · 2026

    Department of Neurology, Sleep-Wake Disorders Center, Hôpital Gui-de-Chauliac, Montpellier, France; National Reference Network for Narcolepsy, Montpellier, France.

    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

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).

high 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

General rare disease registries you may be eligible for

These studies enroll across many rare conditions. They are not counted as evidence that anyone is studying this specific disease.

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 0 · after dedupe 0 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 0 · dropped 0 · fetched 2026-07-29

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).

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 Kleine-Levin 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.

"Kleine-Levin syndrome"

Run this search on Europe PMC

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

"Kleine-Levin syndrome"

Interventional trials matched via: phrase (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; with hits: phrase

Run this search on ClinicalTrials.gov

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-26T23:37:19.564Z