ORPHA:280133
Complement component 3 deficiency
Also known as: C3 deficiency
Clinical definition (Orphanet)
Complement component 3 deficiency is a rare, genetic, primary immunodeficiency characterized by susceptibility to infection (mainly by gram negative bacteria) due to extremely low C3 plasma levels. Patients typically present recurrent episodes of sinusitis, tonsillitis, and/or otitis, as well as upper and lower respiratory tract infections (including pneumonia) and skin infections, such as erythema multiforme. Autoimmune disease resembling systemic lupus erythematosus and mesangiocapillary or membranoproliferative glomerulonephritis may develop, resulting in renal failure.
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.
Is anyone studying this?
1,065
1,065 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=183) is 38.
1,065 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 38 (publications denominator n=183).
577 in the last 10 years · low confidence
Is a treatment being tested?
1
trials for this specific condition
1 interventional trial matched this specific condition name; none in our sample are currently recruiting.
Data as of 26 July 2026
1 interventional trial — more than 59.2% of diseases in the trials denominator have none at all (151 of 255; this disease is at the 65.3th percentile).
low confidence · 65.3th percentile (trials denominator)
Do we know what causes it?
Yes — we know a specific gene responsible (C3).
GenCC classification: Definitive.
Who's working on it?
1,176
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.
- 01Hwang DY8 papers · 2025
Department of Biomaterials Science (BK21 FOUR Program), College of Natural Resources and Life Science/Life and Industry Convergence Research Institute, Pusan National University, Miryang, South Korea.
Papers in Europe PMC - 02Kim JE8 papers · 2025
Department of Biomaterials Science (BK21 FOUR Program), College of Natural Resources and Life Science/Life and Industry Convergence Research Institute, Pusan National University, Miryang, South Korea.
Papers in Europe PMC - 03Li Y8 papers · 2026
Department of Immunology, Nanjing Medical University, Nanjing, China.
Papers in Europe PMC - 04Yang Y8 papers · 2025
From the Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, China.
Papers in Europe PMC - 05Wang H6 papers · 2026
Department of Day Surgery Center, The First Hospital of Lanzhou University, Lanzhou, Gansu, China.
Papers in Europe PMC - 06Wu X6 papers · 2026
Department of Neurology, Minhang Hospital Fudan University Shanghai China.
Papers in Europe PMC - 07Atkinson JP5 papers · 2026
Division of Rheumatology, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri, USA.
Papers in Europe PMC - 08Chen Y5 papers · 2023
Institute of Reproductive Medicine, Medical School, Nantong University, Nantong, China.
Papers in Europe PMC - 09Choi YJ5 papers · 2022
Department of Biomaterials Science (BK21 FOUR Program), College of Natural Resources and Life Science/Life and Industry Convergence Research Institute, Pusan National University, Miryang, South Korea.
Papers in Europe PMC - 10Isaac L5 papers · 2025
Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil. Electronic address: louisaac@icb.usp.br.
Papers in Europe PMC
Recruiting interventional trials
Trials testing a treatment 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.
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 2026-07-26This 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 below but are not added to the query string.
"Complement component 3 deficiency" OR "C3 deficiency" OR "C3 classic complement early component deficiency" OR "classic complement early component deficiency caused by mutation in C3"
MeSH descriptor terms unioned into the query: Complement Component 3 Deficiency, Autosomal Recessive
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Complement component 3 deficiency" OR "C3 deficiency" OR "C3 classic complement early component deficiency" OR "classic complement early component deficiency caused by mutation in C3" OR "Complement Component 3 Deficiency, Autosomal Recessive" OR "C3" OR "classic complement early component deficiency" OR "complement deficiency"
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.
Cross-references (from Mondo): MESH:C565169 OMIM:613779 UMLS:C3151071 NCIT:C9468
Query health: ok — strategies attempted: phrase, mesh, recall-expansion; with hits: phrase, recall-expansion
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 (1065) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity