RARE DISEASERESEARCH ATLAS
Open navigation menu

ORPHA:1444

Ring chromosome 20 syndrome

low confidenceDisorder

Also known as: Ring 20 · Ring chromosome 20

Publications

1,271

Trials

0

Interventional, condition-specific

Researchers

1,102

Distinct authors in sample

Gene link

—

Readiness

2/6

Stages with a signal

Clinical definition (Orphanet)

A rare chromosomal disorder, characterized by childhood onset drug resistant with typical electroencephalographic findings (EEG), mild to severe 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 (2)

ring chromosome 20 syndrome · ring chromosome type 20

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.”

2/6 stages with a signal

Research-stage checklist from open sources (GenCC, literature, Monarch when enriched, ClinicalTrials.gov). Not a prognosis or care recommendation.

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    1,271 matched papers (620 in last 10 years) Source

  3. Phenotype characterisedPresent

    12 HPO annotations (e.g. Short attention span; Intellectual disability; Specific learning disability) 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 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?

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

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

Phenotypes (Monarch / HPO)

12

Associated phenotypes · MONDO:0015436

  • Short attention span
  • Intellectual disability
  • Specific learning disability
  • Neurodevelopmental delay
  • EEG abnormality

Showing 5 of 12 — 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

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?

1,271

1,271 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.

1,271 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).

620 in the last 10 years · low confidence

Phrase hits: 1,271 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,102

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
    Canevini MP12 papers · 2026

    Epilepsy Centre, San Paolo Hospital, Health Science Department, University of Milano, Italy; Department of Medicine, Surgery and Dentistry, Faculty of Medicine and Surgery, University of Milano, Milano, Italy.

    Papers in Europe PMC
  2. 02
    Vignoli A11 papers · 2020

    Epilepsy Centre, San Paolo Hospital, Health Science Department, University of Milano, Italy.

    Papers in Europe PMC
  3. 03
    Myers KA6 papers · 2026

    Departments of Pediatrics and Neurology & Neurosurgery, Montreal Children's Hospital, McGill University, Montreal, Quebec, Canada.

    Papers in Europe PMC
  4. 04
    Meletti S5 papers · 2026

    Department of Neuroscience, NOCSAE Hospital, University of Modena e Reggio Emilia, Modena, Italy. stefano.meletti@unimore.it

    Papers in Europe PMC
  5. 05
    Dalla Bernardina B4 papers · 2016

    Department of Life and Reproduction Sciences, University of Verona, Verona, Italy.

    Papers in Europe PMC
  6. 06
    Darra F4 papers · 2016

    Department of Life and Reproduction Sciences, University of Verona, Verona, Italy.

    Papers in Europe PMC
  7. 07
    Mastrangelo M4 papers · 2016

    Pediatric Neurology Unit, V. Buzzi Hospital, A.O. ICP, Milano, Italy.

    Papers in Europe PMC
  8. 08
    Ruggieri A4 papers · 2015

    Department of Biomedical Sciences, Metabolism and Neuroscience, University of Modena and Reggio Emilia, NOCSE Hospital, Modena, Italy.

    Papers in Europe PMC
  9. 09
    Scheffer IE4 papers · 2025

    Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia.

    Papers in Europe PMC
  10. 10
    Zhang J4 papers · 2026

    College of Bioengineering, Jiuquan Vocational and Technical University, Jiuquan 735000, China.

    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 40 · after dedupe 40 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 40 · 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).

Uncertain / not reviewed (40)

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 Ring chromosome 20 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.

"Ring chromosome 20 syndrome" OR "Ring 20" OR "Ring chromosome 20" OR "ring chromosome type 20"

Run this search on Europe PMC

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

"Ring chromosome 20 syndrome" OR "Ring 20" OR "Ring chromosome 20" OR "ring chromosome type 20"

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 multi-word and distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus
  • Publication count (1271) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-26T17:22:48.166Z