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ORPHA:85279

KDM5C-related syndromic X-linked intellectual disability

low confidenceDisorder

Also known as: Claes-Jensen syndrome

Query health: suspect — Only one of 2 strategies returned hits (phrase).

Publications

3,214

Trials

0

Interventional, condition-specific

Researchers

1,193

Distinct authors in sample

Gene link

KDM5C

Definitive

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare multiple anomalies/ syndrome characterized by mild to severe intellectual deficit associated with variable clinical manifestations including spasticity, cryptorchidism, maxillary hypoplasia, alopecia areata, , short stature, impaired speech, and behavioral problems.

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 (7)

MRXSCJ · MRXSJ · intellectual developmental disorder, X-linked syndromic, Claes-Jensen type, X-linked recessive · intellectual disability, X-linked, syndromic, Claes-Jensen type · mental retardation, X-linked, syndromic, Claes-Jensen type · syndromic X-linked intellectual disability Claes-Jensen type · syndromic X-linked intellectual disability JARID1C-related

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 — KDM5C

  2. LiteraturePresent

    3,214 matched papers (2,582 in last 10 years) Source

  3. Phenotype characterisedPresent

    85 HPO annotations (e.g. Upslanted palpebral fissure; Brachydactyly; Severe intellectual disability) Source

  4. Animal modelPresent

    1 genotype model (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 (KDM5C).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

85

Associated phenotypes · MONDO:0010355

  • Upslanted palpebral fissure
  • Brachydactyly
  • Severe intellectual disability
  • Progressive spastic paraplegia
  • Pain insensitivity

Showing 5 of 85 — open Monarch for the full list.

Animal models (Monarch / Alliance)

1

Model associations linked to this Mondo ID

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

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?

3,214

3,214 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.

3,214 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).

2,582 in the last 10 years · low confidence

Phrase hits: 98 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,193

Distinct author names in 98 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
    Sadikovic B28 papers · 2026

    Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner's Road E, London, ON, N6A 5W9, Canada. bekim.sadikovic@lhsc.on.ca.

    Papers in Europe PMC
  2. 02
    Kerkhof J17 papers · 2026

    Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner's Road E, London, ON, N6A 5W9, Canada.

    Papers in Europe PMC
  3. 03
    Aref-Eshghi E14 papers · 2022

    Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner's Road E, London, ON, N6A 5W9, Canada.

    Papers in Europe PMC
  4. 04
    Levy MA13 papers · 2025

    Department of Pathology and Laboratory Medicine, Western University, 800 Commissioner's Road E, London, ON, N6A 5W9, Canada.

    Papers in Europe PMC
  5. 05
    McConkey H10 papers · 2025

    Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON, N6A 5W9, Canada.

    Papers in Europe PMC
  6. 06
    Alders M8 papers · 2025

    Amsterdam UMC, Department of Clinical Genetics, Genome Diagnostics laboratory Amsterdam, Reproduction & Development, University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands. m.alders@amsterdamumc.nl.

    Papers in Europe PMC
  7. 07
    Stevenson RE8 papers · 2022

    Greenwood Genetic Center, 106 Gregor Mendel Cir, Greenwood, SC, 29646, USA.

    Papers in Europe PMC
  8. 08
    Haghshenas S7 papers · 2024

    Verspeeten Clinical Genome Centre, London Health Science Centre, London, ON N6A 5W9, Canada.

    Papers in Europe PMC
  9. 09
    Iwase S7 papers · 2023

    Department of Human Genetics, University of Michigan, 5815 Medical Science II, Ann Arbor, MI 48109, USA.

    Papers in Europe PMC
  10. 10
    Lin H7 papers · 2021

    b Molecular Genetics Laboratory, Molecular Diagnostics Division , London Health Sciences Centre , London , ON , Canada . Children's Health Research Institute , London , ON , Canada.

    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 11 September 2026 · last trial check 11 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 2026-07-30

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).

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 KDM5C-related syndromic X-linked intellectual disability — 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.

("KDM5C-related syndromic X-linked intellectual disability" OR "Claes-Jensen syndrome" OR "MRXSCJ" OR "MRXSJ" OR "intellectual developmental disorder, X-linked syndromic, Claes-Jensen type, X-linked recessive" OR "intellectual disability, X-linked, syndromic, Claes-Jensen type" OR "mental retardation, X-linked, syndromic, Claes-Jensen type" OR "syndromic X-linked intellectual disability Claes-Jensen type" OR "syndromic X-linked intellectual disability JARID1C-related") OR (MESH:"Mental Retardation, X-Linked, Syndromic, Jarid1c-Related") OR ("KDM5C" OR "KDM5C syndrome" OR "KDM5C-related")

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Mental Retardation, X-Linked, Syndromic, Jarid1c-Related

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

"KDM5C-related syndromic X-linked intellectual disability" OR "Claes-Jensen syndrome" OR "MRXSCJ" OR "MRXSJ" OR "intellectual developmental disorder, X-linked syndromic, Claes-Jensen type, X-linked recessive" OR "intellectual disability, X-linked, syndromic, Claes-Jensen type" OR "mental retardation, X-linked, syndromic, Claes-Jensen type" OR "syndromic X-linked intellectual disability Claes-Jensen type" OR "syndromic X-linked intellectual disability JARID1C-related" OR "Mental Retardation, X-Linked, Syndromic, Jarid1c-Related"

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

Query health: suspect — strategies attempted: phrase, mesh; 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
  • Publication count (3214) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-27T02:51:51.555Z