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ORPHA:98773

Spinocerebellar ataxia type 21

low confidenceDisorder

Also known as: SCA21

Publications

595

Trials

0

Interventional, condition-specific

Researchers

833

Distinct authors in sample

Gene link

TMEM240

Definitive

Readiness

3/6

Stages with a signal

Clinical definition (Orphanet)

Spinocerebellar type 21 (SCA21) is a very rare subtype of type I cerebellar (ADCA type I). It is characterized by slowly cerebellar , mild cognitive impairment, postural and/or resting tremor, bradykinesia, and rigidity.

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 (1)

spinocerebellar ataxia type 21

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

    Definitive — TMEM240

  2. LiteraturePresent

    595 matched papers (355 in last 10 years) Source

  3. Phenotype characterisedPresent

    45 HPO annotations (e.g. Progressive cerebellar ataxia; Intermittent microsaccadic pursuits; Atypical behavior) 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 (TMEM240).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

45

Associated phenotypes · MONDO:0011833

  • Progressive cerebellar ataxia
  • Intermittent microsaccadic pursuits
  • Atypical behavior
  • Dysarthria
  • Rigidity

Showing 5 of 45 — 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?

595

595 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.

595 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).

355 in the last 10 years · low confidence

Phrase hits: 133 · MeSH hits: 2

Open Europe PMC search

Who's working on it?

833

Distinct author names in 135 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
    Ashizawa T5 papers · 2018

    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
  2. 02
    Sablonnière B5 papers · 2020

    2 Institut National de la Santé et de la Recherche Médicale, INSERM U837, and Université de Lille Nord de France, F-59045, Lille, France 4 Pôle de Biochimie et Biologie moléculaire, Centre de Biologie-Pathologie, Centre Hospitalier Régional et Universitaire de Lille, F-59037, Lille, France bernard.sablonniere@inserm.fr.

    Papers in Europe PMC
  3. 03
    Hirai H4 papers · 2022

    Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, 3-39-22, Gunma, 371-8511, Japan.

    Papers in Europe PMC
  4. 04
    Santorelli FM4 papers · 2026

    Molecular Medicine Unit, IRCCS Fondazione Stella Maris, 56018 Pisa, Italy.

    Papers in Europe PMC
  5. 05
    Camargo CHF3 papers · 2025

    Neurological Diseases Group Graduate Program of Internal Medicine, Hospital de Clínicas, Federal University of Parana Curitiba Parana Brazil.

    Papers in Europe PMC
  6. 06
    Destée A3 papers · 2014

    3 Département de Neurologie, Centre Hospitalier Régional et Universitaire de Lille, F-59037, Lille, France.

    Papers in Europe PMC
  7. 07
    Devos D3 papers · 2014

    3 Département de Neurologie, Centre Hospitalier Régional et Universitaire de Lille, F-59037, Lille, France.

    Papers in Europe PMC
  8. 08
    Fogel BL3 papers · 2020

    Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA. bfogel@ucla.edu

    Papers in Europe PMC
  9. 09
    Fujioka S3 papers · 2013

    Department of Neurology at Mayo Clinic, 4500 San Pablo Road Cannaday Bldg 2-E, Jacksonville, FL 32224, USA.

    Papers in Europe PMC
  10. 10
    Hung CS3 papers · 2025

    Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, Republic of 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.

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 Spinocerebellar ataxia type 21 — 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.

("Spinocerebellar ataxia type 21" OR "SCA21") OR (MESH:"Spinocerebellar ataxia 21") OR ("TMEM240" OR "TMEM240 syndrome" OR "TMEM240-related")

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Spinocerebellar ataxia 21

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

"Spinocerebellar ataxia type 21" OR "SCA21" OR "Spinocerebellar ataxia 21"

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

Query health: ok — strategies attempted: phrase, mesh; with hits: phrase, mesh

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 (595) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-27T05:23:21.394Z