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ORPHA:820

Sneddon syndrome

low confidenceDisorder

Also known as: Ehrmann-Sneddon syndrome · Livedo racemosa-cerebrovascular accident syndrome · Livedo reticularis-cerebrovascular accident syndrome

Publications

3,760

Trials

0

Interventional, condition-specific

Researchers

1,042

Distinct authors in sample

Gene link

ADA2

Moderate

Readiness

3/6

Stages with a signal

Clinical definition (Orphanet)

Sneddon's syndrome (SS) is a rare non-inflammatory thrombotic vasculopathy characterized by the combination of cerebrovascular disease with livedo racemosa.

How rare: How common this is has not been clearly measured.

Orphanet entry

Cross-references

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

Additional Mondo synonyms (2)

livedo racemosa-cerebrovascular accident syndrome · livedo reticularis-cerebrovascular accident 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.”

3/6 stages with a signal

No matched interventional trial; the gene is known and literature exists — preclinical or natural-history work may still be the practical next step.

  1. Gene identifiedPresent

    Moderate — ADA2

  2. LiteraturePresent

    3,760 matched papers (2,219 in last 10 years) Source

  3. Phenotype characterisedPresent

    75 HPO annotations (e.g. Cerebral cortical atrophy; Headache; Motor delay) 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?

Probably — there is moderate evidence for ADA2.

GenCC classification: Moderate.

Phenotypes (Monarch / HPO)

75

Associated phenotypes · MONDO:0008436

  • Cerebral cortical atrophy
  • Headache
  • Motor delay
  • Aortic regurgitation
  • Focal-onset seizure

Showing 5 of 75 — 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?

3,760

3,760 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.

3,760 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).

2,219 in the last 10 years · low confidence

Phrase hits: 452 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,042

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
    Bersano A4 papers · 2026

    Cerebrovascular Unit, IRCCS Foundation Neurological Institute "C. Besta", Via Celoria 11, Milan 20133, Italy. Electronic address: anna.bersano@gmail.com.

    Papers in Europe PMC
  2. 02
    Llamas-Velasco M4 papers · 2022

    Department of Dermatology, Hospital Universitario de la Princesa, Madrid, Spain.

    Papers in Europe PMC
  3. 03
    Frijns CJM3 papers · 2024

    Department of Neurology and Neurosurgery, University Medical Centre, Room G03.232, PO Box 85500, 3508 GA, Utrecht, The Netherlands. c.j.m.frijns@umcutrecht.nl.

    Papers in Europe PMC
  4. 04
    Kappelle LJ3 papers · 2024

    Department of Neurology and Neurosurgery, University Medical Centre, Room G03.232, PO Box 85500, 3508 GA, Utrecht, The Netherlands.

    Papers in Europe PMC
  5. 05
    Kraemer M3 papers · 2021

    Department of Neurology, Alfried Krupp Hospital, Alfried-Krupp-Strasse 21, 45130 Essen, Germany.

    Papers in Europe PMC
  6. 06
    Ni J3 papers · 2026

    Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.

    Papers in Europe PMC
  7. 07
    Starmans NLP3 papers · 2024

    Department of Neurology and Neurosurgery, University Medical Centre, Room G03.232, PO Box 85500, 3508 GA, Utrecht, The Netherlands.

    Papers in Europe PMC
  8. 08
    van Dijk MR3 papers · 2024

    Department of Pathology, University Medical Centre Utrecht, Utrecht, The Netherlands.

    Papers in Europe PMC
  9. 09
    Yao M3 papers · 2026

    Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.

    Papers in Europe PMC
  10. 10
    Zelger BG3 papers · 2022

    Department of Pathology, Medical University Innsbruck, Innsbruck, Austria.

    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. 3 observational studies did — shown below because natural-history and cohort work can be an important step toward a trial.

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.

Observational and natural-history studies

3 observational studies match 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.

Recruiting or not-yet-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 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 Sneddon 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.

("Sneddon syndrome" OR "Ehrmann-Sneddon syndrome" OR "Livedo racemosa-cerebrovascular accident syndrome" OR "Livedo reticularis-cerebrovascular accident syndrome") OR ("ADA2" OR "ADA2 syndrome" OR "ADA2-related")

Run this search on Europe PMC

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

"Sneddon syndrome" OR "Ehrmann-Sneddon syndrome" OR "Livedo racemosa-cerebrovascular accident syndrome" OR "Livedo reticularis-cerebrovascular accident syndrome"

Study-type breakdown: 0 interventional · 3 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 (3760) is extremely high with unknown/missing prevalence — treat as possible over-matching, not proven research intensity

Ingested 2026-07-26T15:32:21.755Z