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ORPHA:363432

Autosomal recessive congenital cerebellar ataxia due to GRID2 deficiency

low confidenceSubtype of disorder

Also known as: Autosomal recessive congenital cerebellar ataxia due to ionotropic glutamate receptor delta-2 subunit deficiency · SCAR18

Query health: suspect — Source fetch failed for trials.

Publications

2,044

Trials

—

Interventional, condition-specific

Researchers

224

Distinct authors in sample

Gene link

GRID2

Strong

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare, genetic, slowly neurodegenerative disease resulting from GRID2 deficiency characterized by motor, speech and cognitive delay, , truncal and appendicular , and eye movement abnormalities (tonic upgaze, nystagmus, oculomotor apraxia). Intention tremor may also be associated. Brain imaging reveals cerebellar atrophy with cerebellar flocculus particularly affected.

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 (7)

GRID2 autosomal recessive cerebellar ataxia - pyramidal signs - nystagmus - oculomotor apraxia syndrome · GRID2 autosomal recessive cerebellar ataxia-pyramidal signs-nystagmus-oculomotor apraxia syndrome · autosomal recessive cerebellar ataxia - pyramidal signs - nystagmus - oculomotor apraxia syndrome caused by mutation in GRID2 · autosomal recessive cerebellar ataxia-pyramidal signs-nystagmus-oculomotor apraxia syndrome caused by mutation in GRID2 · autosomal recessive congenital cerebellar ataxia due to ionotropic glutamate receptor delta-2 subunit deficiency · autosomal recessive spinocerebellar ataxia type 18 · spinocerebellar ataxia, autosomal recessive type 18

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

Research-stage checklist from open sources (GenCC, literature, Monarch when enriched, ClinicalTrials.gov). Not a prognosis or care recommendation.

  1. Gene identifiedPresent

    Strong — GRID2

  2. LiteraturePresent

    2,044 matched papers (1,311 in last 10 years) Source

  3. Phenotype characterisedPresent

    32 HPO annotations (e.g. Abnormal speech pattern; Brain atrophy; Cognitive impairment) Source

  4. Animal modelPresent

    2 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 trialNot checked

    Trial fetch failed or incomplete

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 (GRID2).

GenCC classification: Strong.

Phenotypes (Monarch / HPO)

32

Associated phenotypes · MONDO:0014530

  • Abnormal speech pattern
  • Brain atrophy
  • Cognitive impairment
  • Limb ataxia
  • Truncal ataxia

Showing 5 of 32 — open Monarch for the full list.

Animal models (Monarch / Alliance)

2

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?

2,044

2,044 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.

2,044 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).

1,311 in the last 10 years · low confidence

Phrase hits: 39 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

224

Distinct author names in 39 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
    Beaudin M2 papers · 2019

    Axe Neurosciences, CHU de Québec-Université Laval, Québec, QC, Canada.

    Papers in Europe PMC
  2. 02
    De Michele G2 papers · 2023

    Department of Neurosciences, Reproductive and Odontostomatological Sciences, Federico II University, Naples, Italy.

    Papers in Europe PMC
  3. 03
    Durr A2 papers · 2023

    Institut du Cerveau-Paris Brain Institute (ICM), AP-HP, INSERM, CNRS, University Hospital Pitié-Salpêtrière, Sorbonne Université, Paris, France.

    Papers in Europe PMC
  4. 04
    Kuo SH2 papers · 2022

    Department of Neurology, Columbia University, New York, NY 10032, USA. emorymkpan@ntu.edu.tw sk3295@columbia.edu.

    Papers in Europe PMC
  5. 05
    Pan MK2 papers · 2022

    Department of Medical Research, National Taiwan University Hospital, Taipei City 10002, Taiwan. emorymkpan@ntu.edu.tw sk3295@columbia.edu.

    Papers in Europe PMC
  6. 06
    Reis A2 papers · 2020

    Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg FAU, Erlangen, Germany.

    Papers in Europe PMC
  7. 07
    Rouleau GA2 papers · 2019

    McGill University, Montreal, QC, Canada.

    Papers in Europe PMC
  8. 08
    Abdollahimajd F1 paper · 2021

    Skin Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

    Papers in Europe PMC
  9. 09
    Alihoseini MR1 paper · 2021

    Laser and Plasma Research Institute, Shahid Beheshti University, G.C., P.O. Box 19839-6941, Tehran, Iran.

    Papers in Europe PMC
  10. 10
    Allen J1 paper · 2026

    Department of Surgery, University of Auckland, Auckland, New Zealand.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

—

interventional trials for this specific condition

We could not load trial data for this condition right now.

Data as of 11 September 2026 · last trial check 31 July 2026

low confidence

Recruiting interventional trials

From the matched ClinicalTrials.gov set

Trial data could not be loaded for this build. This is not the same as finding zero interventional trials.

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 congenital cerebellar ataxia due to GRID2 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 congenital cerebellar ataxia due to GRID2 deficiency" OR "Autosomal recessive congenital cerebellar ataxia due to ionotropic glutamate receptor delta-2 subunit deficiency" OR "SCAR18" OR "GRID2 autosomal recessive cerebellar ataxia - pyramidal signs - nystagmus - oculomotor apraxia syndrome" OR "GRID2 autosomal recessive cerebellar ataxia-pyramidal signs-nystagmus-oculomotor apraxia syndrome" OR "autosomal recessive cerebellar ataxia - pyramidal signs - nystagmus - oculomotor apraxia syndrome caused by mutation in GRID2" OR "autosomal recessive cerebellar ataxia-pyramidal signs-nystagmus-oculomotor apraxia syndrome caused by mutation in GRID2" OR "autosomal recessive spinocerebellar ataxia type 18" OR "spinocerebellar ataxia, autosomal recessive type 18") OR ("GRID2" OR "GRID2 syndrome" OR "GRID2-related")

Run this search on Europe PMC

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

"Autosomal recessive congenital cerebellar ataxia due to GRID2 deficiency"

Query health: suspect — strategies attempted: phrase; with hits: phrase

Run this search on ClinicalTrials.gov

Source errors: trials: Error: HTTP 400 for https://clinicaltrials.gov/api/v2/studies?query.cond=%22Autosomal%20recessive%20congenital%20cerebellar%20ataxia%20due%20to%20GRID2%20deficiency%22%20OR%20%22Autosomal%20recessive%20congenital%20cerebellar%20ataxia%20due%20to%20ionotropic%20glutamate%20receptor%20delta-2%20subunit%20deficiency%22%20OR%20%22SCAR18%22%20OR%20%22GRID2%20autosomal%20recessive%20cerebellar%20ataxia%20-%20pyramidal%20signs%20-%20nystagmus%20-%20oculomotor%20apraxia%20syndrome%22%20OR%20%22GRID2%20autosomal%20recessive%20cerebellar%20ataxia-pyramidal%20signs-nystagmus-oculomotor%20apraxia%20syndrome%22%20OR%20%22autosomal%20recessive%20cerebellar%20ataxia%20-%20pyramidal%20signs%20-%20nystagmus%20-%20oculomotor%20apraxia%20syndrome%20caused%20by%20mutation%20in%20GRID2%22%20OR%20%22autosomal%20recessive%20cerebellar%20ataxia-pyramidal%20signs-nystagmus-oculomotor%20apraxia%20syndrome%20caused%20by%20mutation%20in%20GRID2%22%20OR%20%22autosomal%20recessive%20spinocerebellar%20ataxia%20type%2018%22%20OR%20%22spinocerebellar%20ataxia%2C%20autosomal%20recessive%20type%2018%22&format=json&pageSize=100&countTotal=true

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 (2044) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-27T14:34:58.510Z