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ORPHA:2498

Syndactyly type 8

low confidenceDisorder

Also known as: Fusion of metacarpals 4 and 5

Publications

1,112

Trials

0

Interventional, condition-specific

Researchers

730

Distinct authors in sample

Gene link

FGF16

Strong

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare non-syndromic syndactyly characterized by unilateral or bilateral fusion of the 4th and 5th metacarpals with no other associated abnormalities. Patients present shortened 4th and 5th metacarpals with excessive separation between their distal ends, resulting in marked ulnar deviation of the little finger and an inability to bring the 5th finger in parallel with the other fingers.

Orphanet entry

Cross-references

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

Additional Mondo synonyms (4)

FGF16 non-syndromic syndactyly · fusion of metacarpals 4 and 5 · metacarpal 4-5 fusion, X-linked recessive · non-syndromic syndactyly caused by mutation in FGF16

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 specific-condition interventional trial, but broader-category trials exist — discuss eligibility with a clinician.

  1. Gene identifiedPresent

    Strong — FGF16

  2. LiteraturePresent

    1,112 matched papers (742 in last 10 years) Source

  3. Phenotype characterisedPresent

    4 HPO annotations (e.g. Short 5th metacarpal; Clinodactyly of the 5th finger; 4-5 metacarpal synostosis) 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 trialPartial

    None under the specific name; 5 for broader category syndactyly

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 (FGF16).

GenCC classification: Strong.

Phenotypes (Monarch / HPO)

4

Associated phenotypes · MONDO:0010669

  • Short 5th metacarpal
  • Clinodactyly of the 5th finger
  • 4-5 metacarpal synostosis
  • 2-3 toe cutaneous 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?

1,112

1,112 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.

1,112 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).

742 in the last 10 years · low confidence

Phrase hits: 113 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

730

Distinct author names in 113 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
    Horie M4 papers · 2022

    Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan.

    Papers in Europe PMC
  2. 02
    Ohno S4 papers · 2022

    Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan.

    Papers in Europe PMC
  3. 03
    Tabery HM3 papers · 2000

    University of Lund, Department of Ophthalmology, Malmö General Hospital, Sweden.

    Papers in Europe PMC
  4. 04
    Alderete JF2 papers · 2009
    Papers in Europe PMC
  5. 05
    Fukuyama M2 papers · 2022

    Department of Cardiovascular Medicine, Shiga University of Medical Science, Seta-Tsukinowa, Otsu, Shiga, 520-2192, Japan.

    Papers in Europe PMC
  6. 06
    Kavak RP2 papers · 2020

    University of Health Sciences, Dışkapı Yıldırım Beyazıt Training and Research Hospital, Department of Radiology, Ankara, Turkey.

    Papers in Europe PMC
  7. 07
    Keramatipour M2 papers · 2019

    Department of Medical Genetics, Tehran University of Medical Sciences, Tehran, Iran.

    Papers in Europe PMC
  8. 08
    Li Y2 papers · 2023

    School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.

    Papers in Europe PMC
  9. 09
    Liu Y2 papers · 2023

    School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.

    Papers in Europe PMC
  10. 10
    Makiyama T2 papers · 2022

    Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.

    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). 5 trials are registered for syndactyly, the broader category — shown separately because they may or may not enrol this specific subtype.

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.

5 interventional trials matched syndactyly, the broader category — listed below. Those studies are not counted in the condition-specific total.

Broader category: syndactyly

5

Interventional trials for the parent category, exclusive of NCT IDs already counted above. Eligibility for this subtype is not guaranteed.

Worth raising with a clinician. How we count trials.

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 Syndactyly type 8 — 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.

("Syndactyly type 8" OR "Fusion of metacarpals 4 and 5" OR "Fusion of the metacarpals 4 and 5" OR "FGF16 non-syndromic syndactyly" OR "metacarpal 4-5 fusion, X-linked recessive" OR "non-syndromic syndactyly caused by mutation in FGF16") OR ("FGF16" OR "FGF16 syndrome" OR "FGF16-related")

Run this search on Europe PMC

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

"Syndactyly type 8" OR "Fusion of metacarpals 4 and 5" OR "Fusion of the metacarpals 4 and 5" OR "FGF16 non-syndromic syndactyly" OR "metacarpal 4-5 fusion, X-linked recessive" OR "non-syndromic syndactyly caused by mutation in FGF16"

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

Parent-category trials query:

"syndactyly"

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 (1112) is extremely high with unknown/missing prevalence — treat as possible over-matching, not proven research intensity

Ingested 2026-07-26T20:21:43.707Z