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ORPHA:36412

Hypocomplementemic urticarial vasculitis

high confidenceDisorder

Also known as: Anti-C1q vasculitis · Mac Duffie hypocomplementemic urticarial vasculitis · Mac Duffie syndrome · McDuffie hypocomplementemic urticarial vasculitis · McDuffie syndrome

Query health: suspect — Only one of 2 strategies returned hits (phrase).

Publications

952

90.5th percentile

Trials

0

Interventional, condition-specific

Researchers

1,206

Distinct authors in sample

Gene link

—

Readiness

2/6

Stages with a signal

Clinical definition (Orphanet)

A rare immune complex-mediated small vessel vasculitis characterized by urticaria and hypocomplementemia (low C3, C4 and/or C1q), and usually associated with circulating anti-C1q autoantibodies. Arthritis, pulmonary disease, ocular inflammation are common systemic manifestations.

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 (1)

anti-C1q vasculitis

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

No specific-condition interventional trial, but broader-category trials exist — discuss eligibility with a clinician.

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    952 matched papers (524 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 trialPartial

    None under the specific name; 195 for broader category vasculitis

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?

952

952 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.

952 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).

524 in the last 10 years · high confidence · 90.5th percentile (publications denominator)

Phrase hits: 952 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,206

Distinct author names in 200 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
    Terrier B5 papers · 2022

    Assistance Publique-Hôpitaux de Paris, Département de Médecine Interne, Centre de Référence National pour les maladies auto-immunes systémiques rares, Hôpital Cochin.

    Papers in Europe PMC
  2. 02
    Belot A4 papers · 2026

    The International Center of Research in Infectiology, Lyon University, INSERM U1111, CNRS UMR 5308, ENS, UCBL, Lyon, France. alexandre.belot@chu-lyon.fr.

    Papers in Europe PMC
  3. 03
    Jachiet M4 papers · 2022

    Department of Dermatology, Saint-Louis Hospital, Paris, France.

    Papers in Europe PMC
  4. 04
    Tusseau M4 papers · 2026

    The International Center of Research in Infectiology, Lyon University, INSERM U1111, CNRS UMR 5308, ENS, UCBL, Lyon, France.

    Papers in Europe PMC
  5. 05
    Gonçalo M3 papers · 2025

    Dermatology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.

    Papers in Europe PMC
  6. 06
    Khan S3 papers · 2025

    Department of Radiology, Institute of Neurological Sciences, Queen Elizabeth University Hospital, Glasgow, United Kingdom.

    Papers in Europe PMC
  7. 07
    Moranne O3 papers · 2026

    Service de Nephrologie-Dialyse-Apherese, Hôpital Universitaire Carémeau Nimes, IDESP Université de Montpellier, France.

    Papers in Europe PMC
  8. 08
    Romagnani P3 papers · 2024

    Nephrology Unit, Anna Meyer Children Hospital and University of Florence, University of Florence, Florence, Italy.

    Papers in Europe PMC
  9. 09
    Zhu Y3 papers · 2026

    The Affiliated Changsha Central Hospital, Center of Tuberculosis Diagnosis and Treatment, Hengyang Medical School, University of South China, Changsha, Hunan, People's Republic of China.

    Papers in Europe PMC
  10. 10
    Abdwani R2 papers · 2025

    Child Health Department, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman.

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

Data as of 27 July 2026

No matched interventional trials. This is true for 73% of diseases in the trials denominator (5114 of 7003). Here are the researchers publishing on it.

high confidence · 36.5th 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.

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

Broader category: vasculitis

195

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.

Recruiting under the broader category

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.

"Hypocomplementemic urticarial vasculitis" OR "Anti-C1q vasculitis" OR "Mac Duffie hypocomplementemic urticarial vasculitis" OR "Mac Duffie syndrome" OR "McDuffie hypocomplementemic urticarial vasculitis" OR "McDuffie syndrome"

Run this search on Europe PMC

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

"Hypocomplementemic urticarial vasculitis" OR "Anti-C1q vasculitis" OR "Mac Duffie hypocomplementemic urticarial vasculitis" OR "Mac Duffie syndrome" OR "McDuffie hypocomplementemic urticarial vasculitis" OR "McDuffie syndrome" OR "immune complex mediated vasculitis"

Recall-expansion terms: immune complex mediated vasculitis

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

Parent-category trials query:

"vasculitis"

Query health: suspect — strategies attempted: phrase, recall-expansion; 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 2026-07-26T23:54:35.555Z