COL9A3

Chr 20ADAR

collagen type IX alpha 3 chain

Also known as: DJ885L7.4.1, EDM3, IDD, MED, STL6

NCBI Gene: 1299 ENSG00000092758 UniProt: Q14050 OMIM: 120270

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.

GeneReviews OMIM ResearchSummary from RefSeq, OMIM, UniProt

This gene encodes one of the three alpha chains of type IX collagen, the major collagen component of hyaline cartilage. Type IX collagen, a heterotrimeric molecule, is usually found in tissues containing type II collagen, a fibrillar collagen. Mutations in this gene are associated with multiple epiphyseal dysplasia type 3. [provided by RefSeq, Jan 2010]

GeneReviews OMIM ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

{Intervertebral disc disease, susceptibility to}MIM #603932

Epiphyseal dysplasia, multiple, 3, with or without myopathyMIM #600969

Stickler syndrome, type VIMIM #620022

UniProtMultiple epiphyseal dysplasia 3

UniProtStickler syndrome 6

Clinical highlights

Gene-disease validity (ClinGen)

Stickler syndrome · ARDefinitivesufficient evidence for diagnostic panels

Interpreting a novel variant

Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.

Active trials

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

0.75

LOEUF

Multiple*

Mechanism· G2P

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GeneReview available — COL9A3