GPR21
Chr 9G protein-coupled receptor 21
This gene encodes a G-protein-coupled receptor that activates Gq signaling pathways and mobilizes calcium in response to extracellular stimuli, though its specific ligand remains unknown. Mutations in GPR21 cause autosomal recessive spastic paraplegia with intellectual disability and seizures, typically presenting in early childhood. The gene shows relatively low constraint to loss-of-function variation.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Mild missense constraint
This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). Both the Badonyi & Marsh prediction and the broader genomic evidence point to gain-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.
Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
86 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 | 0 | 0 | 28 | 0 | 28 |
Likely Pathogenic | 0 | 0 | 1 | 0 | 1 |
VUS | 0 | 48 | 5 | 0 | 53 |
Likely Benign | 0 | 3 | 0 | 0 | 3 |
Benign | 0 | 0 | 0 | 1 | 1 |
| Total | 0 | 51 | 34 | 1 | 86 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
GPR21 · 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