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ORPHA:93338

Polysyndactyly

low confidenceDisorder

Also known as: PPD4 · Preaxial polydactyly type 4

Publications

8,620

Trials

1

Interventional, condition-specific

Researchers

1,339

Distinct authors in sample

Gene link

GLI3

Strong

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

Polysyndactyly or PPD4 is a form of preaxial polydactyly of fingers, a limb syndrome, characterized by the presence of a thumb showing the mildest degree of duplication, being broad, bifid or with radially deviated distal phalanx. Syndactyly of various degrees of third-and-fourth fingers is occasionally present.

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 (3)

polydactyly, preaxial type 4 · polydactyly, preaxial, type IV · preaxial polydactyly type 4

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

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedPresent

    Strong — GLI3

  2. LiteraturePresent

    8,620 matched papers (4,963 in last 10 years) Source

  3. Phenotype characterisedPresent

    5 HPO annotations (e.g. 3-4 finger cutaneous syndactyly; Dysplastic distal thumb phalanges with a central hole; Preaxial polydactyly) 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

    1 matched on ClinicalTrials.gov

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 (GLI3).

GenCC classification: Strong.

Phenotypes (Monarch / HPO)

5

Associated phenotypes · MONDO:0008272

  • 3-4 finger cutaneous syndactyly
  • Dysplastic distal thumb phalanges with a central hole
  • Preaxial polydactyly
  • Duplication of thumb phalanx
  • 1-5 toe syndactyly

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?

8,620

8,620 papers — among the better-studied rare conditions, though still a fraction of common-disease literature (breast cancer: over 700,000). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

8,620 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).

4,963 in the last 10 years · low confidence

Phrase hits: 1,019 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,339

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
    van Nieuwenhoven CA5 papers · 2022

    Department of Plastic and Reconstructive Surgery and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.

    Papers in Europe PMC
  2. 02
    Ahmad W3 papers · 2025

    Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, Islamabad, Pakistan.

    Papers in Europe PMC
  3. 03
    Baas M3 papers · 2021

    Department of Plastic and Reconstructive Surgery and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.

    Papers in Europe PMC
  4. 04
    Cai L3 papers · 2020

    BGI-Guangzhou Medical Laboratory, BGI-Shenzhen, Guangzhou, China.

    Papers in Europe PMC
  5. 05
    de Klein A3 papers · 2022

    Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.

    Papers in Europe PMC
  6. 06
    Galjaard RH3 papers · 2022

    Department of Clinical Genetics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.

    Papers in Europe PMC
  7. 07
    Hovius SER3 papers · 2019

    Department of Plastic and Reconstructive Surgery and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.

    Papers in Europe PMC
  8. 08
    Najmabadi H3 papers · 2024

    Kariminejad - Najmabadi Pathology & Genetics Center, Tehran, Iran. hnajm12@yahoo.com.

    Papers in Europe PMC
  9. 09
    Potuijt JWP3 papers · 2022

    Department of Plastic and Reconstructive Surgery and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. j.potuijt@erasmusmc.nl.

    Papers in Europe PMC
  10. 10
    Ren J3 papers · 2020

    Department of Health Management, School of Medicine, Hangzhou Normal University, No. 2318 Yuhangtang Road, Hangzhou, 311121, Zhejiang Province, China.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

1

interventional trials for this specific condition

1 interventional trial matched this specific condition name; none in our sample are currently recruiting.

Data as of 11 September 2026 · last trial check 28 July 2026

1 interventional trial — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 80.1th percentile).

low confidence · 80.1th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

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

No currently recruiting studies in the matched set. Open the same 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 2026-07-30

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 Polysyndactyly — 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.

("Polysyndactyly" OR "Preaxial polydactyly type 4" OR "polydactyly, preaxial type 4" OR "polydactyly, preaxial, type IV") OR ("GLI3" OR "GLI3 syndrome" OR "GLI3-related")

Run this search on Europe PMC

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

"Polysyndactyly" OR "Preaxial polydactyly type 4" OR "polydactyly, preaxial type 4" OR "polydactyly, preaxial, type IV"

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: 1 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

Synonyms dropped by stoplist: PPD4

Confidence reasoning

  • Preferred label is short or not clearly distinctive
  • 1 synonym(s) dropped by stoplist (may under-count)
  • "Polysyndactyly" also appears on ORPHA:93403
  • Publication count (8620) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-27T04:17:17.028Z