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ORPHA:477684

Combined oxidative phosphorylation defect type 26

medium confidenceDisorder

Also known as: COXPD26

Publications

281

69.8th percentile

Trials

0

Interventional, condition-specific

Researchers

34

Distinct authors in sample

Gene link

TRMT5

Strong

Readiness

3/6

Stages with a signal

Clinical definition (Orphanet)

A rare oxidative phosphorylation disorder characterized by a highly variable which may present as exercise intolerance with prominent exertional dyspnea, muscle weakness, spasticity, and , but without cognitive impairment or cardiac involvement, or as global , growth retardation, , and spasticity. Hypertrophic , optic atrophy, , and facial features have also been reported in the more severe . Serum lactate may be elevated, and muscle biopsy shows myopathic features and variably decreased activity of respiratory chain complexes.

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.

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Additional Mondo synonyms (3)

TRMT5 combined oxidative phosphorylation deficiency · combined oxidative phosphorylation deficiency caused by mutation in TRMT5 · combined oxidative phosphorylation deficiency type 26

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.

  1. Gene identifiedPresent

    Strong — TRMT5

  2. LiteraturePresent

    281 matched papers (221 in last 10 years) Source

  3. Phenotype characterisedPresent

    39 HPO annotations (e.g. Poor speech; Delayed CNS myelination; Cytochrome C oxidase-negative muscle fibers) 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 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 (TRMT5).

GenCC classification: Strong.

Phenotypes (Monarch / HPO)

39

Associated phenotypes · MONDO:0014684

  • Poor speech
  • Delayed CNS myelination
  • Cytochrome C oxidase-negative muscle fibers
  • Lactic acidosis
  • Babinski sign

Showing 5 of 39 — 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?

281

281 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.

281 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).

221 in the last 10 years · medium confidence · 69.8th percentile (publications denominator)

Phrase hits: 6 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

34

Distinct author names in 6 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
    Li Y2 papers · 2024

    Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China.

    Papers in Europe PMC
  2. 02
    Alsentzer E1 paper · 2025

    Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA.

    Papers in Europe PMC
  3. 03
    Bai Z1 paper · 2022

    Pediatric Intensive Care Unit, Children's Hospital of Soochow University, Suzhou, Jiangsu Province, 215025, P.R. China.

    Papers in Europe PMC
  4. 04
    Bian P1 paper · 2023

    Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, China.

    Papers in Europe PMC
  5. 05
    Brady L1 paper · 2017

    From McMaster University (M.A.T., L.B.), Hamilton; and McGill University (M.T.), Montreal, Canada.

    Papers in Europe PMC
  6. 06
    Cao M1 paper · 2024

    Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China.

    Papers in Europe PMC
  7. 07
    Chai J1 paper · 2023

    Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, China.

    Papers in Europe PMC
  8. 08
    Chen H1 paper · 2022

    Pediatric Intensive Care Unit, Children's Hospital of Soochow University, Suzhou, Jiangsu Province, 215025, P.R. China.

    Papers in Europe PMC
  9. 09
    Guo A1 paper · 2024

    Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China.

    Papers in Europe PMC
  10. 10
    Huang S1 paper · 2022

    Pediatric Intensive Care Unit, Children's Hospital of Soochow University, Suzhou, Jiangsu Province, 215025, P.R. China.

    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 26 — 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.

("Combined oxidative phosphorylation defect type 26" OR "COXPD26" OR "TRMT5 combined oxidative phosphorylation deficiency" OR "combined oxidative phosphorylation deficiency caused by mutation in TRMT5" OR "combined oxidative phosphorylation deficiency type 26") OR ("TRMT5" OR "TRMT5 syndrome" OR "TRMT5-related")

Run this search on Europe PMC

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

"Combined oxidative phosphorylation defect type 26" OR "COXPD26" OR "TRMT5 combined oxidative phosphorylation deficiency" OR "combined oxidative phosphorylation deficiency caused by mutation in TRMT5" OR "combined oxidative phosphorylation deficiency type 26"

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 (281) is high for prevalence class "<1 / 1 000 000" — confidence capped at medium

Ingested 2026-07-27T17:07:53.052Z