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ORPHA:420556

Visual snow syndrome

high confidenceDisorder

Publications

245

70.7th percentile

Trials

6

Interventional, condition-specific

Researchers

656

Distinct authors in sample

Gene link

—

Readiness

3/6

Stages with a signal

Clinical definition (Orphanet)

Visual snow syndrome is a rare neurologic disease characterized by persistent continuous bilateral visual experience of flickering snow-like dots throughout the visual field in association with other visual (including palinopsia, enhanced entopic phenomena, nyctalopia, photophobia and photopsia) and non-visual (migraine with or without aura, tinnitus and occasionally tremor) symptoms.

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.”

3/6 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

    245 matched papers (234 in last 10 years) Source

  3. Phenotype characterisedPresent

    24 HPO annotations (e.g. Photophobia; Nyctalopia; Entoptic phenomenon) 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 trialPresent

    6 matched on ClinicalTrials.gov (3 recruiting in sample)

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)

24

Associated phenotypes · MONDO:0018486

  • Photophobia
  • Nyctalopia
  • Entoptic phenomenon
  • Postural instability
  • Irritability

Showing 5 of 24 — 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?

245

245 papers have ever been published on this condition (under this name). For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

245 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).

234 in the last 10 years · high confidence · 70.7th percentile (publications denominator)

Phrase hits: 245 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

656

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
    Schankin CJ30 papers · 2026

    Department of Neurology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland.

    Papers in Europe PMC
  2. 02
    Puledda F17 papers · 2026

    Headache Group, Department of Basic and Clinical Neuroscience, NIHR-Wellcome Trust King's Clinical Research Facility, King's College Hospital, King's College London, London, UK.

    Papers in Europe PMC
  3. 03
    Goadsby PJ15 papers · 2025

    Headache Group, Department of Basic and Clinical Neuroscience, NIHR-Wellcome Trust King's Clinical Research Facility, King's College Hospital, King's College London, London, UK.

    Papers in Europe PMC
  4. 04
    Fielding J14 papers · 2025

    Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia.

    Papers in Europe PMC
  5. 05
    White OB13 papers · 2025

    Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia.

    Papers in Europe PMC
  6. 06
    Klein A10 papers · 2026

    Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.

    Papers in Europe PMC
  7. 07
    Straube A10 papers · 2025

    Department of Neurology, Ludwig Maximilian University of Munich, Großhadern University Hospital, Munich, Germany.

    Papers in Europe PMC
  8. 08
    Eren OE9 papers · 2025

    Department of Neurology, University Hospital, LMU Munich, Munich, Germany; Department of Neurology, Inselspital, University Hospital Bern, Switzerland; Department of Ophthalmology, University of Tübingen.

    Papers in Europe PMC
  9. 09
    Fraser CL9 papers · 2024

    Faculty of Health and Medicine, Save Sight Institute, The University of Sydney, Sydney, NSW, Australia.

    Papers in Europe PMC
  10. 10
    McKendrick AM9 papers · 2026

    From the Department of Neuroscience (E.J.S., M.C., P.F., O.B.W., J.F.), Central Clinical School, Monash University, Melbourne; and Department of Optometry & Vision Sciences (A.M.M.) and Department of Medicine, Royal Melbourne Hospital (O.B.W.), The University of Melbourne, Australia.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

6

interventional trials for this specific condition

6 interventional trials matched this specific condition name; 3 currently recruiting in our sample.

Data as of 11 September 2026

6 interventional trials — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 90.1th percentile).

high confidence · 90.1th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

6 interventional trials matched after quoted-phrase search and title/condition post-filter.

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 3 · after dedupe 3 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 3 · 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).

Uncertain / not reviewed (3)

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 Visual snow 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.

"Visual snow syndrome"

Run this search on Europe PMC

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

"Visual snow 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: 6 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 multi-word and distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-27T15:47:41.001Z