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ORPHA:647916

Conjoined twins

low confidenceDisorder

Also known as: Siamese twins

Publications

2,822

Trials

1

Interventional, condition-specific

Researchers

996

Distinct authors in sample

Gene link

—

Readiness

2/6

Stages with a signal

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.”

2/6 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

    2,822 matched papers (816 in last 10 years) Source

  3. Phenotype characterisedNot checked

    Not yet enriched from Monarch / HPO

  4. Animal modelNot checked

    Not yet enriched from Monarch / Alliance

  5. Orphan designationNot checked

    FDA/EMA orphan-drug designation not enriched yet

  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?

Not yet — the cause hasn't been pinned down in GenCC.

No strong gene–disease assertion joined for this Orphanet entity.

Phenotypes (Monarch / HPO)

Not enriched in this build — Monarch phenotype joins were not run for this record.

Animal models (Monarch / Alliance)

Not enriched in this build.

Literature

Is anyone studying this?

2,822

2,822 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=5449) is 41.

2,822 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 41 (publications denominator n=5449).

816 in the last 10 years · low confidence

Phrase hits: 2,822 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

996

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
    Segal NL7 papers · 2026

    Department of Psychology, California State University, Fullerton, California, USA.

    Papers in Europe PMC
  2. 02
    Boer LL5 papers · 2023

    Department of Imaging, Section Anatomy and Museum for Anatomy and Pathology, Radboud University, Medical Center, Nijmegen, Netherlands.

    Papers in Europe PMC
  3. 03
    Oostra RJ5 papers · 2023

    Department of Medical Biology, Sections Clinical Anatomy & Embryology, Amsterdam University Medical Centers, Location Academic Medical Center, University of Amsterdam, Netherlands.

    Papers in Europe PMC
  4. 04
    Al Rabeeah AA4 papers · 2025

    King Salman Humanitarian Aid and Relief Center, Riyadh 11672, Saudi Arabia. Electronic address: alrabeeah.a@ksrelief.org.

    Papers in Europe PMC
  5. 05
    Al Namshan MK3 papers · 2026

    King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia.

    Papers in Europe PMC
  6. 06
    Ruano R3 papers · 2026

    Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology & Reproductive Sciences, University of Miami Leonard M. Miller School of Medicine, Miami, FL, USA.

    Papers in Europe PMC
  7. 07
    Adugna NB2 papers · 2026
    Papers in Europe PMC
  8. 08
    Akiyama Y2 papers · 2025

    Division of Research and Treatment for Oral Maxillofacial Congenital Anomalies, Aichi Gakuin University, Nagoya, Aichi, Japan.

    Papers in Europe PMC
  9. 09
    Al Aujan AA2 papers · 2025

    Department of Pediatrics, King Abdullah Specialized Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia.

    Papers in Europe PMC
  10. 10
    Al Khalaf HA2 papers · 2025

    Department of Pediatrics, King Abdullah Specialized Children's Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia.

    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.

Data as of 27 July 2026

1 interventional trial — more than 73% of diseases in the trials denominator have none at all (5114 of 7003; this disease is at the 76.8th percentile).

low confidence · 76.8th 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.

Observational and natural-history studies

1 observational study matches 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.

None of the matched observational studies is currently listed as recruiting.

Open the complete matched search on ClinicalTrials.gov

Where to find support

We do not yet link condition-specific patient organisations. These umbrella groups support undiagnosed and ultra-rare families:

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.

"Conjoined twins" OR "Siamese twins"

Run this search on Europe PMC

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

"Conjoined twins" OR "Siamese twins"

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 · 1 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
  • Publication count (2822) is extremely high with unknown/missing prevalence — treat as possible over-matching, not proven research intensity

Ingested 2026-07-27T19:49:42.236Z