RARE DISEASERESEARCH ATLAS
Open navigation menu

ORPHA:261494

Kleefstra syndrome

low confidenceDisorder

Publications

2,633

Trials

0

Interventional, condition-specific

Researchers

1,379

Distinct authors in sample

Gene link

EHMT1

Definitive

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare genetic, syndrome characterized by , childhood , severe expressive speech delay, autism spectrum disorder, and a distinctive facial appearance with a spectrum of additional clinical features.

How rare: <1 / 1 000 000 — fewer than one in a million. In a city the size of Kolkata, that might mean on the order of fifteen people.

Orphanet entry

Cross-references

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

Additional Mondo synonyms (6)

9Q- syndrome · 9q-syndrome · 9q34 deletion syndrome · 9q34.3 microdeletion syndrome · chromosome 9Q34.3 deletion syndrome · chromosome 9q deletion syndrome

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

No matched interventional trial, but a gene association and an animal model are on record — often described as translation-ready / stalled at the clinical step.

  1. Gene identifiedPresent

    Definitive — EHMT1

  2. LiteraturePresent

    2,633 matched papers (1,970 in last 10 years) Source

  3. Phenotype characterisedPresent

    277 HPO annotations (e.g. Everted lower lip vermilion; Malar flattening; Coarse facial features) Source

  4. Animal modelPresent

    3 genotype models (Mus musculus) Source

  5. Orphan designationNot found

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

  6. Interventional trialNot found

    No matched interventional trial under our ClinicalTrials.gov rules

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 (EHMT1).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

277

Associated phenotypes · MONDO:0012455

  • Everted lower lip vermilion
  • Malar flattening
  • Coarse facial features
  • Anteverted nares
  • Delayed speech and language development

Showing 5 of 277 — open Monarch for the full list.

Animal models (Monarch / Alliance)

3

Model associations linked to this Mondo ID

Monarch fetch 2026-07-27

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

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

CTD chemicals (MyDisease.info)

No CTD chemical associations returned for this Mondo ID.

Literature

Is anyone studying this?

2,633

2,633 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.

2,633 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).

1,970 in the last 10 years · low confidence

Phrase hits: 751 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,379

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

Who's working on it?

No interventional trial matched this name; these authors publish on it in the sampled literature — a practical starting point for contact.

  1. 01
    Kleefstra T24 papers · 2026

    Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud university medical center, Nijmegen, The Netherlands.

    Papers in Europe PMC
  2. 02
    Bouman A13 papers · 2026

    Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.

    Papers in Europe PMC
  3. 03
    Rots D10 papers · 2026

    Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands.

    Papers in Europe PMC
  4. 04
    Sadikovic B9 papers · 2026

    Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, Ontario, Canada.

    Papers in Europe PMC
  5. 05
    Srivastava S8 papers · 2026

    Department of Neurology, Boston Children's Hospital, Boston, MA, USA.

    Papers in Europe PMC
  6. 06
    Kerkhof J7 papers · 2026

    Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, Ontario, Canada.

    Papers in Europe PMC
  7. 07
    Kummeling J7 papers · 2026

    Department of Human Genetics, Donders Institute for Brain, Cognition and Behavior, Radboud university medical center, Nijmegen, The Netherlands.

    Papers in Europe PMC
  8. 08
    Negwer M6 papers · 2026

    Department of Human Genetics and Department of Cognitive Neuroscience, Radboudumc, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, Netherlands.

    Papers in Europe PMC
  9. 09
    Banka S5 papers · 2026

    Division of Evolution, Infection & Genomics, School of Biological Sciences, Faculty of Biology, Medicine & Health, The University of Manchester, Manchester M13 9PL, UK.

    Papers in Europe PMC
  10. 10
    Barrero MJ5 papers · 2026

    Institute of Rare Diseases Research (IIER), Spanish National Institute of Health Carlos III (ISCIII), Madrid, Spain.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

0

interventional trials for this specific condition

No interventional trial testing a treatment matched this specific condition name on ClinicalTrials.gov (observational studies and pan-disease registries are listed separately when present).

Data as of 9 September 2026 · last trial check 9 September 2026

No matched interventional trials. This is true for 77.2% of diseases in the trials denominator (5501 of 7126). Here are the researchers publishing on it.

low confidence · 38.6th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

No interventional trial testing a treatment was found for this specific condition name on ClinicalTrials.gov.

See who's working on it — people publishing on this disease are often the practical next contact when no trial is listed.

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 2026-07-27

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 Kleefstra 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.

("Kleefstra syndrome" OR "9Q- syndrome" OR "9q-syndrome" OR "9q34 deletion syndrome" OR "9q34.3 microdeletion syndrome" OR "chromosome 9Q34.3 deletion syndrome" OR "chromosome 9q deletion syndrome") OR ("EHMT1" OR "EHMT1 syndrome" OR "EHMT1-related")

Run this search on Europe PMC

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

"Kleefstra syndrome" OR "9Q- syndrome" OR "9q-syndrome" OR "9q34 deletion syndrome" OR "9q34.3 microdeletion syndrome" OR "chromosome 9Q34.3 deletion syndrome" OR "chromosome 9q deletion syndrome"

Study-type breakdown: 0 interventional · 0 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 short or not clearly distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus
  • Publication count (2633) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-26T02:19:37.775Z