ORPHA:420728
Combined oxidative phosphorylation defect type 20
Also known as: COXPD20
Publications
441
79.1th percentile
Trials
0
Interventional, condition-specific
Researchers
119
Distinct authors in sample
Gene link
VARS2
Strong
Readiness
3/6
Stages with a signal
Clinical definition (Orphanet)
A rare oxidative phosphorylation disorder characterized by variable combination of psychomotor delay, , muscle weakness, , microcephaly, and mild facial features. Variable types of structural brain anomalies have also been reported. Biochemical studies typically show decreased activity of complexes (mainly complex I).
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.
Cross-references
Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.
- MONDO:0014397
- OMIM:615917
- UMLS:C4014660
Additional Mondo synonyms (3)
VARS2 combined oxidative phosphorylation deficiency · combined oxidative phosphorylation deficiency caused by mutation in VARS2 · combined oxidative phosphorylation deficiency type 20
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.”
3/6 stages with a signal
No matched interventional trial; the gene is known and literature exists — preclinical or natural-history work may still be the practical next step.
- Gene identifiedPresent
Strong — VARS2
- LiteraturePresent
441 matched papers (353 in last 10 years) Source
- Phenotype characterisedPresent
21 HPO annotations (e.g. Progressive external ophthalmoplegia; Hypotonia; Ataxia) Source
- Animal modelNot found
No Alliance genotype “model of” associations via Monarch for these Mondo IDs
- Orphan designationNot found
No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source
- Interventional trialNot found
No matched interventional trial under our ClinicalTrials.gov rules
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 (VARS2).
GenCC classification: Strong.
Phenotypes (Monarch / HPO)
21
Associated phenotypes · MONDO:0014397
- Progressive external ophthalmoplegia
- Hypotonia
- Ataxia
- Respiratory insufficiency
- Ptosis
Showing 5 of 21 — 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?
441
441 papers have ever been published on this condition (under this name). For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.
441 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).
353 in the last 10 years · medium confidence · 79.1th percentile (publications denominator)
Phrase hits: 18 · MeSH hits: 0
Who's working on it?
119
Distinct author names in 18 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.
- 01Antonellis A2 papers · 2022
Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, United States; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, United States. Electronic address: antonell@umich.edu.
Papers in Europe PMC - 02Abu Diab A1 paper · 2019
Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
Papers in Europe PMC - 03Adrião M1 paper · 2018
Department of Pediatrics, Centro Hospitalar São João (CHSJ), Porto, Portugal.
Papers in Europe PMC - 04Ahmad B1 paper · 2025
Department of Paediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China.
Papers in Europe PMC - 05Alonso I1 paper · 2018
UnIGENe and Centre for Predictive and Preventive Genetics (CGPP), Institute of Molecular and Cellular Biology (IBMC), University of Porto, Porto, Portugal.
Papers in Europe PMC - 06
- 07Banin E1 paper · 2019
Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
Papers in Europe PMC - 08Baruffini E1 paper · 2021
Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy.
Papers in Europe PMC - 09
- 10Beg AA1 paper · 2017
Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States.
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).
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.
medium 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.
See who's working on it — people publishing on this disease are often the practical next contact when no trial is listed.
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 2026-07-30
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 Combined oxidative phosphorylation defect type 20 — check Associations / patient organisations on that page.
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 on the overview but are not added to the query string.
("Combined oxidative phosphorylation defect type 20" OR "COXPD20" OR "VARS2 combined oxidative phosphorylation deficiency" OR "combined oxidative phosphorylation deficiency caused by mutation in VARS2" OR "combined oxidative phosphorylation deficiency type 20") OR ("VARS2" OR "VARS2 syndrome" OR "VARS2-related")ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Combined oxidative phosphorylation defect type 20" OR "COXPD20" OR "VARS2 combined oxidative phosphorylation deficiency" OR "combined oxidative phosphorylation deficiency caused by mutation in VARS2" OR "combined oxidative phosphorylation deficiency type 20"
Study-type breakdown: 0 interventional · 0 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 (441) is high for prevalence class "<1 / 1 000 000" — confidence capped at medium
Ingested 2026-07-27T15:49:34.927Z