GRM1
Chr 6ADARglutamate metabotropic receptor 1
Also known as: GPRC1A, MGLU1, MGLUR1, PPP1R85, SCA44, SCAR13
This protein is a G-protein coupled receptor for glutamate that activates phospholipase C and a phosphatidylinositol-calcium second messenger system, participating in synaptic plasticity including long-term potentiation in the hippocampus and long-term depression in the cerebellum. Mutations cause spinocerebellar ataxia 44 (autosomal dominant) and spinocerebellar ataxia, autosomal recessive 13, with pathogenicity predicted to result from gain-of-function mechanisms.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
More LoF-intolerant than ~75% of genes
Moderately missense-constrained (top ~2.5%)
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.
Literature Evidence
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312. Mechanism ranking also informed by gnomAD constraint, ClinVar, and ClinGen data.
ClinVar Variant Classifications
465 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 6 | 3 | 14 | 0 | 23 |
Likely Pathogenic | 5 | 1 | 0 | 0 | 6 |
VUS | 3 | 208 | 12 | 8 | 231 |
Likely Benign | 0 | 13 | 24 | 105 | 142 |
Benign | 0 | 1 | 31 | 16 | 48 |
Conflicting | — | 9 | |||
| Total | 14 | 226 | 81 | 129 | 459 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
GRM1 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools