COL9A3
Chr 20ADARcollagen type IX alpha 3 chain
Also known as: DJ885L7.4.1, EDM3, IDD, MED, STL6
This gene encodes the alpha-3 chain of type IX collagen, a structural component of hyaline cartilage and vitreous of the eye that forms heterotrimeric molecules typically found alongside type II collagen. Mutations cause multiple epiphyseal dysplasia type 3 (with or without myopathy), Stickler syndrome type VI, and susceptibility to intervertebral disc disease, affecting skeletal and ocular systems. The gene shows both autosomal dominant and autosomal recessive inheritance patterns and is not highly constrained against loss-of-function variants.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Tolerant to missense variation
The highest-scoring mechanism for this gene is dominant-negative.
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.
Literature Evidence
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
COL9A3 · 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