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ORPHA:3269

Isolated radio-ulnar synostosis

low confidenceDisorder

Also known as: Isolated congenital radioulnar fusion

Publications

6,668

Trials

1

Interventional, condition-specific

Researchers

1,033

Distinct authors in sample

Gene link

SMAD6, ZMAT2

Limited

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

radioulnar synostosis is a rare bone disorder that may be isolated or associated with other disorders and that is characterized by failure of segmentation of the radius and ulna during embryological development, causing limited rotational movements of the forearm, which may lead to difficulties with some activities of daily living.

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 (3)

radioulnar fusion · radioulnar synostosis · radioulnar synostosis (disease)

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

    Limited — SMAD6, ZMAT2

  2. LiteraturePresent

    6,668 matched papers (4,070 in last 10 years) Source

  3. Phenotype characterisedPresent

    33 HPO annotations (e.g. Abnormal morphology of the radius; Abnormal morphology of ulna; Wrist pain) 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 (1 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?

Possibly — only limited evidence so far for SMAD6, ZMAT2.

GenCC classification: Limited.

Phenotypes (Monarch / HPO)

33

Associated phenotypes · MONDO:0017985

  • Abnormal morphology of the radius
  • Abnormal morphology of ulna
  • Wrist pain
  • Dislocated radial head
  • Congenital hip dislocation

Showing 5 of 33 — 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?

6,668

6,668 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.

6,668 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).

4,070 in the last 10 years · low confidence

Phrase hits: 1,182 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,033

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
    Yang Y11 papers · 2026

    The Laboratory of Genetics and Metabolism, Institute of Pediatric Medicine of Hunan Province, Hunan Children's Hospital, Hengyang Medical School, University of South China, Changsha, China.

    Papers in Europe PMC
  2. 02
    Shen F8 papers · 2026

    The Laboratory of Genetics and Metabolism, Institute of Pediatric Medicine of Hunan Province, Hunan Children's Hospital, Hengyang Medical School, University of South China, Changsha, China.

    Papers in Europe PMC
  3. 03
    Chen S7 papers · 2024

    Department of Hand Surgery, Beijing Ji Shui Tan Hospital, Beijing, China.

    Papers in Europe PMC
  4. 04
    Zheng Y7 papers · 2026

    The Laboratory of Genetics and Metabolism, Institute of Pediatric Medicine of Hunan Province, Hunan Children's Hospital, Hengyang Medical School, University of South China, Changsha, China.

    Papers in Europe PMC
  5. 05
    Zhu G7 papers · 2026

    Department of orthopedics, Hunan Children's Hospital, Hengyang Meical School, University of South China, Changsha, China.

    Papers in Europe PMC
  6. 06
    Deng M5 papers · 2026

    Institute of Pediatrics, South China University, Department of Medical Genetics, Hunan Provincial Children's Hospital, Changsha, Hunan 410007, China. yongjia727@aliyun.com.

    Papers in Europe PMC
  7. 07
    Liu L5 papers · 2024

    Department of Hand Surgery, Beijing Ji Shui Tan Hospital, Beijing, China.

    Papers in Europe PMC
  8. 08
    Luo Z5 papers · 2026

    The Laboratory of Genetics and Metabolism, Institute of Pediatric Medicine of Hunan Province, Hunan Children's Hospital, Hengyang Medical School, University of South China, Changsha, China.

    Papers in Europe PMC
  9. 09
    Wang H5 papers · 2026

    Pediatrics Research Institute, the Affiliated Children's Hospital of Xiangya School of Medicine, Central South University (Hunan Children's Hospital), Changsha, China; Department of Medical Genetics, The Affiliated Children's Hospital of Xiangya School of Medicine (Hunan Children's Hospital), Central South University, Changsha, China.

    Papers in Europe PMC
  10. 10
    Xu J5 papers · 2026

    Department of Orthopedics, Shenzhen Children's Hospital, Shenzhen, 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; 1 currently recruiting in our sample. 1 trial are registered for synostosis, the broader category — shown separately because they may or may not enrol this specific subtype.

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.

Broader category: synostosis

1

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 Isolated radio-ulnar synostosis — 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.

("Isolated radio-ulnar synostosis" OR "Isolated congenital radioulnar fusion" OR "radioulnar fusion" OR "radioulnar synostosis" OR "radioulnar synostosis (disease)") OR ("SMAD6" OR "SMAD6 syndrome" OR "SMAD6-related" OR "ZMAT2" OR "ZMAT2 syndrome" OR "ZMAT2-related")

Run this search on Europe PMC

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

"Isolated radio-ulnar synostosis" OR "Isolated congenital radioulnar fusion" OR "radioulnar fusion" OR "radioulnar synostosis" OR "radioulnar synostosis (disease)"

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.

Parent-category trials query:

"synostosis"

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 (6668) is extremely high with unknown/missing prevalence — treat as possible over-matching, not proven research intensity

Ingested 2026-07-26T22:42:43.904Z