COL9A2
Chr 1ARADcollagen type IX alpha 2 chain
Also known as: DJ39G22.4, EDM2, MED, STL5
The protein is a structural component of hyaline cartilage and vitreous of the eye, forming one of three alpha chains of type IX collagen. Mutations cause multiple epiphyseal dysplasia and Stickler syndrome type V, affecting skeletal development and potentially vision. The gene shows both autosomal recessive and autosomal dominant inheritance patterns and is moderately constrained against loss-of-function variants.
Limited evidence — not for standalone diagnostic reporting
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Mild missense constraint
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.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
COL9A2 · 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