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ORPHA:97

Familial paroxysmal ataxia

low confidenceDisorder

Also known as: Episodic ataxia type 2

Publications

5,204

Trials

2

Interventional, condition-specific

Researchers

1,298

Distinct authors in sample

Gene link

CACNA1A

Definitive

Readiness

5/6

Stages with a signal

Clinical definition (Orphanet)

A form of episodic (EA) characterized by paroxysmal episodes of lasting hours, with interictal nystagmus and mildly .

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 (3)

CACNA1A hereditary episodic ataxia · episodic ataxia type 2 · hereditary episodic ataxia caused by mutation in CACNA1A

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.”

5/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedPresent

    Definitive — CACNA1A

  2. LiteraturePresent

    5,204 matched papers (3,321 in last 10 years) Source

  3. Phenotype characterisedPresent

    30 HPO annotations (e.g. Paresthesia; Abnormal vestibular function; Progressive cerebellar ataxia) Source

  4. Animal modelPresent

    3 genotype models (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 trialPresent

    2 matched on ClinicalTrials.gov (1 recruiting in sample)

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 (CACNA1A).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

30

Associated phenotypes · MONDO:0007163

  • Paresthesia
  • Abnormal vestibular function
  • Progressive cerebellar ataxia
  • Muscle weakness
  • Cerebellar vermis atrophy

Showing 5 of 30 — open Monarch for the full list.

Animal models (Monarch / Alliance)

3

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

1

Drugs / clinical candidates · MONDO_0007163

CTD chemicals (MyDisease.info)

1 associated chemical · 20 pathways. Therapeutic evidence is listed first when present — not a treatment recommendation.

  • Acetazolamide · therapeutic

Pathways: MAPK signaling pathway; Calcium signaling pathway; Synaptic vesicle cycle; Retrograde endocannabinoid signaling; Glutamatergic synapse; Cholinergic synapse; Serotonergic synapse; GABAergic synapse

MyDisease.info · MONDO:0007163

Literature

Is anyone studying this?

5,204

5,204 papers — among the better-studied rare conditions, though still a fraction of common-disease literature (breast cancer: over 700,000). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

5,204 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).

3,321 in the last 10 years · low confidence

Phrase hits: 873 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,298

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.

  1. 01
    Boesch S9 papers · 2026

    Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria. sylvia.boesch@i-med.ac.at.

    Papers in Europe PMC
  2. 02
    Indelicato E9 papers · 2026

    Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria.

    Papers in Europe PMC
  3. 03
    Helbig I6 papers · 2025

    Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.

    Papers in Europe PMC
  4. 04
    Kim S6 papers · 2026

    Department of Neurology, Seoul National University Hospital, Seoul, Korea.

    Papers in Europe PMC
  5. 05
    Lusk L6 papers · 2025

    Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.

    Papers in Europe PMC
  6. 06
    Nachbauer W6 papers · 2026

    Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria.

    Papers in Europe PMC
  7. 07
    Amprosi M5 papers · 2026

    Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Anichstrasse 35, 6020, Innsbruck, Austria.

    Papers in Europe PMC
  8. 08
    Hommersom MP5 papers · 2026

    Department of Human Genetics, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands.

    Papers in Europe PMC
  9. 09
    Kim HJ5 papers · 2026

    Biomedical Research Institute, Seoul National University Bundang Hospital, Seongnam, Korea. hyojungkim.kor@gmail.com.

    Papers in Europe PMC
  10. 10
    van Bokhoven H5 papers · 2026

    Department of Human Genetics, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

2

interventional trials for this specific condition

2 interventional trials matched this specific condition name; 1 currently recruiting in our sample.

Data as of 11 September 2026 · last trial check 28 July 2026

2 interventional trials — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 84.5th percentile).

low confidence · 84.5th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

2 interventional trials matched after quoted-phrase search and title/condition post-filter.

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 1 · after dedupe 1 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 1 · dropped 0 · fetched 2026-07-29

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).

Uncertain / not reviewed (1)

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 Familial paroxysmal ataxia — 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.

("Familial paroxysmal ataxia" OR "Episodic ataxia type 2" OR "CACNA1A hereditary episodic ataxia" OR "hereditary episodic ataxia caused by mutation in CACNA1A") OR ("CACNA1A" OR "CACNA1A syndrome" OR "CACNA1A-related")

Run this search on Europe PMC

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

"Familial paroxysmal ataxia" OR "Episodic ataxia type 2" OR "CACNA1A hereditary episodic ataxia" OR "hereditary episodic ataxia caused by mutation in CACNA1A"

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: 2 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 (5204) is extremely high with unknown/missing prevalence — treat as possible over-matching, not proven research intensity

Ingested 2026-07-26T12:24:48.107Z