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ORPHA:139485

Autosomal recessive ataxia due to ubiquinone deficiency

low confidenceDisorder

Also known as: ARCA2 · Autosomal recessive ataxia due to coenzyme Q10 deficiency · Autosomal recessive cerebellar ataxia type 2 · Autosomal recessive spinocerebellar ataxia type 9 · SCAR9

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

Publications

563

Trials

0

Interventional, condition-specific

Researchers

1,130

Distinct authors in sample

Gene link

COQ8A

Definitive

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

This syndrome is characterised by childhood-onset and cerebellar atrophy.

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 (4)

autosomal recessive ataxia due to coenzyme Q10 deficiency · autosomal recessive cerebellar ataxia type 2 · autosomal recessive spinocerebellar ataxia type 9 · coenzyme Q10 deficiency, primary, type 4

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.”

4/6 stages with a signal

No matched interventional trial, but a gene association and an animal model are on record — often described as translation-ready / stalled at the clinical step.

  1. Gene identifiedPresent

    Definitive — COQ8A

  2. LiteraturePresent

    563 matched papers (480 in last 10 years) Source

  3. Phenotype characterisedPresent

    48 HPO annotations (e.g. Generalized tonic seizure; Increased circulating lactate concentration; Increased CSF lactate) Source

  4. Animal modelPresent

    1 genotype model (Mus musculus) Source

  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 (COQ8A).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

48

Associated phenotypes · MONDO:0012784

  • Generalized tonic seizure
  • Increased circulating lactate concentration
  • Increased CSF lactate
  • Decreased level of coenzyme Q10 in skeletal muscle
  • Increased intramyocellular lipid droplets

Showing 5 of 48 — open Monarch for the full list.

Animal models (Monarch / Alliance)

1

Model associations linked to this Mondo ID

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?

563

563 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=3967) is 59.

563 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).

480 in the last 10 years · low confidence

Phrase hits: 176 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,130

Distinct author names in 176 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
    Anheim M6 papers · 2023

    Service de neurologie, hôpital de Hautepierre, 1, avenue Molière, 67000 Strasbourg, France; Fédération de médecine translationnelle, 67000 Strasbourg, France.

    Papers in Europe PMC
  2. 02
    Koenig M6 papers · 2023

    Institut Universitaire de Recherche Clinique, Laboratoire de Génétique de Maladies Rares EA7402, Laboratoire de Génétique Moléculaire, University Hospital, Université de Montpellier, Montpellier, France.

    Papers in Europe PMC
  3. 03
    Tranchant C6 papers · 2023

    Service de neurologie, hôpital de Hautepierre, 1, avenue Molière, 67000 Strasbourg, France; Fédération de médecine translationnelle, 67000 Strasbourg, France. Electronic address: christine.tranchant@chru-strasbourg.fr.

    Papers in Europe PMC
  4. 04
    Drouot N5 papers · 2015

    Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/Université de Strasbourg UMR7104, INSERM U964, Illkirch, France. drouot@igbmc.fr.

    Papers in Europe PMC
  5. 05
    Ashizawa T4 papers · 2020

    Department of Neurology, Center for Movement Disorders and Neurorestoration College of Medicine, McKnight Brain Institute, University of Florida, 1149 South Newell Drive, L3-100, Gainesville, FL 32611, USA. Electronic address: tetsuo.ashizawa@neurology.ufl.edu.

    Papers in Europe PMC
  6. 06
    Fey PD4 papers · 2020

    Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA.

    Papers in Europe PMC
  7. 07
    Puccio H4 papers · 2025

    Département de Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U596, CNRS UMR 7104, 67400 Illkirch, France; Université de Strasbourg, 67081 Strasbourg, France; Chaire de Génétique Humaine, Collège de France, 67404 Illkirch, France. Electronic address: hpuccio@igbmc.fr.

    Papers in Europe PMC
  8. 08
    Quinzii CM4 papers · 2020

    Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA.

    Papers in Europe PMC
  9. 09
    Bertini E3 papers · 2026

    1Department of Neurosciences, Bambino Gesù Hospital, via della Torre di Palidoro, Fiumicino, Rome, Italy.

    Papers in Europe PMC
  10. 10
    Delannoy S3 papers · 2016

    ANSES Food Safety Laboratory, Platform IdentyPath, Université Paris-Est, Maisons-Alfort, France.

    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.

low 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.

General rare disease registries you may be eligible for

These studies enroll across many rare conditions. They are not counted as evidence that anyone is studying this specific disease.

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 Autosomal recessive ataxia due to ubiquinone deficiency — 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.

("Autosomal recessive ataxia due to ubiquinone deficiency" OR "ARCA2" OR "Autosomal recessive ataxia due to coenzyme Q10 deficiency" OR "Autosomal recessive cerebellar ataxia type 2" OR "Autosomal recessive spinocerebellar ataxia type 9" OR "SCAR9" OR "coenzyme Q10 deficiency, primary, type 4") OR (MESH:"Spinocerebellar Ataxia, Autosomal Recessive 9") OR ("COQ8A" OR "COQ8A syndrome" OR "COQ8A-related")

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Spinocerebellar Ataxia, Autosomal Recessive 9

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

"Autosomal recessive ataxia due to ubiquinone deficiency" OR "ARCA2" OR "Autosomal recessive ataxia due to coenzyme Q10 deficiency" OR "Autosomal recessive cerebellar ataxia type 2" OR "Autosomal recessive spinocerebellar ataxia type 9" OR "SCAR9" OR "coenzyme Q10 deficiency, primary, type 4" OR "Spinocerebellar Ataxia, Autosomal Recessive 9"

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

Query health: suspect — strategies attempted: phrase, mesh; 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 (563) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-27T07:38:01.577Z