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ORPHA:100

Ataxia-telangiectasia

high confidenceDisorder

Also known as: Louis-Bar syndrome

Publications

36,216

98.4th percentile

Trials

27

Interventional, condition-specific

Researchers

1,598

Distinct authors in sample

Gene link

ATM

Definitive

Readiness

6/6

Stages with a signal

Clinical definition (Orphanet)

A rare cerebellar due to a DNA repair defect characterized by neurological impairment with cerebellar syndrome, oculocutaneous telangiectasia, defects in B and T cell-mediated immunity, and increased susceptibility to malignancies (mainly lymphoid neoplasms). High sensitivity to ionizing radiation limits patient treatments.

How rare: 1-5 / 10 000 — about one to five people per ten thousand (still uncommon, but less ultra-rare).

Orphanet entry

Cross-references

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

Additional Mondo synonyms (3)

ataxia - telangiectasia · ataxia telangiectasia · ataxia telangiectasia syndrome

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.”

6/6 stages with a signal

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

  1. Gene identifiedPresent

    Definitive — ATM

  2. LiteraturePresent

    36,216 matched papers (18,991 in last 10 years) Source

  3. Phenotype characterisedPresent

    84 HPO annotations (e.g. Conjunctival telangiectasia; Non-Hodgkin lymphoma; Hodgkin lymphoma) Source

  4. Animal modelPresent

    13 genotype models (Mus musculus, Danio rerio, Rattus norvegicus) Source

  5. Orphan designationPresent

    2 FDA · 2 EMA designations (2 FDA orphan-indication approvals) — e.g. N-Acetyl-Leucine Source

  6. Interventional trialPresent

    27 matched on ClinicalTrials.gov (2 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 (ATM).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

84

Associated phenotypes · MONDO:0008840

  • Conjunctival telangiectasia
  • Non-Hodgkin lymphoma
  • Hodgkin lymphoma
  • Sinusitis
  • Chronic diarrhea

Showing 5 of 84 — open Monarch for the full list.

Animal models (Monarch / Alliance)

13

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)

4

Designations · 2 with FDA orphan-indication approval

  • FDA N-Acetyl-LeucineAtaxia Telangiectasia · 2018-10-02 · Not FDA Approved for Orphan Indication
  • FDA betamethasoneAtaxia Telangiectasia · 2015-10-07 · Not FDA Approved for Orphan Indication
  • EMA acetylleucineTreatment of ataxia telangiectasia · 11/01/2019 · PositiveEMA designation
  • EMA Dexamethasone sodium phosphate encapsulated in human autologous erythrocytesTreatment of ataxia telangiectasia · 17/07/2013 · WithdrawnEMA designation

Sources: FDA OOPD · EMA orphan designations

Open Targets candidates

5

Drugs / clinical candidates · MONDO_0008840

CTD chemicals (MyDisease.info)

2 associated chemicals · 58 pathways. Therapeutic evidence is listed first when present — not a treatment recommendation.

  • Quercetin · therapeutic
  • Iron · marker/mechanism

Pathways: Platinum drug resistance; Homologous recombination; NF-kappa B signaling pathway; FoxO signaling pathway; Cell cycle; p53 signaling pathway; Apoptosis; HTLV-I infection

MyDisease.info · MONDO:0008840

Literature

Is anyone studying this?

36,216

36,216 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.

36,216 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).

18,991 in the last 10 years · high confidence · 98.4th percentile (publications denominator)

Phrase hits: 36,216 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,598

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
    Dineen RA8 papers · 2026

    Radiological Sciences, Mental Health and Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK.

    Papers in Europe PMC
  2. 02
    Willemsen MAAP6 papers · 2026

    Department of Pediatric Neurology, Amalia Children's Hospital, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.

    Papers in Europe PMC
  3. 03
    Leuzzi V5 papers · 2026

    Department of Neurosciences and Mental Health, La Sapienza University, Rome, Italy.

    Papers in Europe PMC
  4. 04
    Schubert R5 papers · 2025

    Department for Children and Adolescents, University Hospital Frankfurt, Goethe University, Frankfurt, Germany.

    Papers in Europe PMC
  5. 05
    Coman D4 papers · 2026

    Queensland Children's Hospital, 501 Stanley Street, South Brisbane, Australia.

    Papers in Europe PMC
  6. 06
    Roeleveld N4 papers · 2026

    Department of IQ Health, Radboud University Medical Center, Nijmegen, Netherlands.

    Papers in Europe PMC
  7. 07
    Stray-Pedersen A4 papers · 2026

    Habilitation Unit, Sanderud, Innlandet Hospital Trust, Brumunddal, Norway.

    Papers in Europe PMC
  8. 08
    van Os NJH4 papers · 2026

    Department of Pediatric Neurology, Amalia Children's Hospital, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.

    Papers in Europe PMC
  9. 09
    Weemaes CMR4 papers · 2026

    Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands.

    Papers in Europe PMC
  10. 10
    Alfayomy AM3 papers · 2026

    Department of Medicinal Chemistry, Institute of Pharmacy, Martin-Luther-University of Halle-Wittenberg, 06120, Halle (Saale), Germany; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Al-Azhar University, Assiut, 71524, Egypt.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

27

interventional trials for this specific condition

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

Data as of 11 September 2026

27 interventional trials — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 95.7th percentile).

high confidence · 95.7th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

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

Observational and natural-history studies

11 observational studies match this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.

Recruiting or not-yet-recruiting

Open the complete matched search on ClinicalTrials.gov

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 48 · after dedupe 47 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 47 · 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 (47)

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 Ataxia-telangiectasia — 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.

("Ataxia-telangiectasia" OR "Louis-Bar syndrome" OR "ataxia - telangiectasia" OR "ataxia telangiectasia" OR "ataxia telangiectasia syndrome")

Run this search on Europe PMC

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

"Ataxia-telangiectasia" OR "Louis-Bar syndrome" OR "ataxia - telangiectasia" OR "ataxia telangiectasia" OR "ataxia telangiectasia syndrome"

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: 27 interventional · 11 observational · 1 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

Ingested 2026-07-26T12:25:11.883Z