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COL2A1

collagen type II alpha 1 chain

The COL2A1 gene provides the genetic blueprint for assembling the alpha-1(II) chain, a foundational component of type II collagen, which is essential for the structural integrity of cartilage and other connective tissues. COL2A1 encodes the alpha-1(II) chain, a core constituent of type II collagen, a crucial protein that imparts structure and resilience to connective tissues throughout the human body.

Chromosome 12q13.11 Autosomal dominant HGNC:2200
COL2A1 12q13.11 p arm q arm 12

COL2A1 is located on the long (q) arm of chromosome 12, at band 12q13.11. Arm ratio per GRCh38 - banding schematic.

Explore chromosome 12 in the library →

Available at Jeen Health

Clinical tests that include this

KNOVA NIPT
COL2A1 is 1 of 56 genes on this panel
Prenatal NIPT screening (trisomies, microdeletions, single-gene conditions)

Overview

The COL2A1 gene directs the production of the alpha-1(II) chain, which serves as the fundamental building block of type II collagen. This type of collagen is a primary structural protein responsible for providing both strength and resilience to various connective tissues, particularly cartilage. Its widespread presence highlights its importance in the formation and maintenance of joints, the eyes, and the inner ear.

Cartilage is a resilient material that constitutes a large proportion of the skeleton in foetal and infant development. While most of this cartilage is eventually replaced by bone, it persists in critical areas such as joint surfaces, the nose, and the external ears. Hyaline cartilage, a specific form rich in type II collagen, is especially important in growth plates, where new bone is generated. Beyond skeletal structures, type II collagen is also a significant component of the vitreous humour in the eye and the nucleus pulposus of spinal discs.

What the gene does

The primary function of the COL2A1 gene is to provide instructions for synthesising the alpha-1(II) chain, a monomeric component of type II collagen. This protein is critical for forming the robust, fibrous network characteristic of connective tissues. Inside cells, three individual alpha-1(II) chains wind around one another to form a procollagen molecule with a triple-helix configuration. These procollagen molecules then undergo enzymatic modifications within the cell.

Once processed, the modified molecules exit the cell and align themselves into elongated fibrillar structures. These fibrils then attach to one another in a lattice pattern, creating an organised mesh-like network within the extracellular matrix. This cross-linking process is essential for generating the exceptionally strong and mature type II collagen fibres that provide structural support and mechanical resistance to tissues. In this way, COL2A1 is indispensable for the normal development and functional integrity of cartilage, contributing to proper joint articulation, eye structure, and inner ear function.

Video: Genetics 101

Chromosome location

The COL2A1 gene is situated on the long arm of chromosome 12, specifically residing at band 12q13.11. This chromosomal location positions the gene within a region broadly associated with various genetic traits. The gene provides instructions for a protein that is 1487 amino acids in length.

Protein structure

The COL2A1 protein, the alpha-1(II) chain, exhibits a complex molecular architecture essential for its role in collagen formation. It contains a VWFC domain spanning amino acids 32-90, which is typically involved in binding and protein-protein interactions. A significant portion of the protein is classified as a Disordered region, from amino acids 97-1237, suggesting structural flexibility that may be important for its assembly and interaction with other molecules. The characteristic Triple-helical region, crucial for forming the collagen fibril, extends from amino acids 201-1214. Following this, a Nonhelical region (C-terminal) is located between amino acids 1215-1241. Finally, the protein features a Fibrillar collagen NC1 domain from amino acids 1253-1487, which plays a role in the trimerisation and processing of procollagen molecules.

Domain map · 1,487 amino acids
VWFC (32–90)Triple-helical region (201–1214)Nonhelical region (C-terminal) (1215–1241)Fibrillar collagen NC1 (1253–1487)VWFC32–90Triple-helical region201–1214Fibrillar collagen NC11253–14871~7441,487
Domain - independent functional unit
Region - functional region
🧬 Explore 3D structure on AlphaFold
UniProt:P02458Length:1,487 aaStructure:AlphaFold

Key variants

Genetic variations within the COL2A1 gene can encompass a wide range of types, including single nucleotide changes, insertions, deletions, and larger rearrangements. These variations can alter the fundamental structure or stability of the alpha-1(II) chain, impacting the formation and function of type II collagen. The clinical consequences of these variants depend on their specific nature and location within the gene, often leading to a spectrum of skeletal and connective tissue abnormalities.

3,498
Total variants catalogued in ClinVar
View all on ClinVar →
1,105 Pathogenic / Likely pathogenic 835 Uncertain significance 1,289 Benign / Likely benign 269 Conflicting or other

Sample of pathogenic variants

10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.

Variant (HGVS) Protein change Classification Evidence Associated condition
c.100T>C
single nucleotide variant
 p.Cys34Arg Pathogenic/Likely pathogenic ★★☆☆ not provided
c.1023+1G>A
single nucleotide variant
 - Pathogenic ★★☆☆ not provided
c.1023+3_1023+6del
Deletion
 - Pathogenic/Likely pathogenic ★★☆☆ not provided
c.1024-2A>C
single nucleotide variant
 - Pathogenic ★★☆☆ COL2A1-related disorder
c.1030C>T
single nucleotide variant
 p.Arg344Ter Pathogenic ★★☆☆ not provided
c.1034G>A
single nucleotide variant
 p.Gly345Asp Pathogenic ★★☆☆ Spondylometaphyseal dysplasia - Sutcliffe type
c.1043G>A
single nucleotide variant
 p.Gly348Asp Pathogenic/Likely pathogenic ★★☆☆ not provided
c.1105G>C
single nucleotide variant
 p.Gly369Arg Pathogenic ★★☆☆ not provided
c.1132G>A
single nucleotide variant
 p.Gly378Ser Pathogenic/Likely pathogenic ★★☆☆ not provided
c.115C>T
single nucleotide variant
 p.Gln39Ter Pathogenic ★★☆☆ not provided

Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.

Associated conditions

Pathogenic variants in the COL2A1 gene are linked to a number of inherited conditions primarily affecting skeletal development and connective tissue. These include Kniest dysplasia, which manifests with short stature, joint issues, and sensory problems. Another associated condition is Spondyloepimetaphyseal dysplasia (Strudwick), characterised by disproportionate short stature and skeletal malformations. Spondyloepiphyseal dysplasia congenita also results from COL2A1 variants, leading to short stature and specific visual complications. Additionally, Stickler syndrome type I, a disorder affecting collagen, involves widespread effects on the eyes, ears, and joints due to COL2A1 changes.

  • Kniest dysplasia
    Skeletal
    AD
  • Spondyloepimetaphyseal dysplasia (Strudwick)
    Skeletal
    AD
    Dedicated page coming soon
  • Spondyloepiphyseal dysplasia congenita
    Skeletal
    AR
    Dedicated page coming soon
  • Stickler syndrome type I
    Connective Tissue
    AD
    Dedicated page coming soon

Inheritance pattern

Conditions caused by pathogenic COL2A1 variants typically follow autosomal dominant inheritance.

♀ Affected parent 1 altered copy ♂ Unaffected parent 2 typical copies Affected Unaffected Unaffected Affected Affected Carrier Unaffected Circles = females · Squares = males

Each child has a 50% chance of inheriting the pathogenic variant, regardless of sex.

UK clinical status

In the UK, the COL2A1 gene is actively assessed for its role in several conditions through the NHS Genomic Medicine Service, as indicated by its inclusion in multiple Green RAG-rated PanelApp panels. These include panels for Bilateral congenital or childhood onset cataracts (R31), Clefting, DDG2P, Foetal anomalies (R21), Limb disorders, Monogenic hearing loss (R67), Retinal disorders (R32), Skeletal dysplasia (R104), and Stickler syndrome (R45). A Green RAG rating signifies that there is sufficient evidence for routine clinical testing of this gene for these specified conditions.

Green-listed
High evidence · clinically actionable in NHS testing
Included in NHS GMS signed-off panels
Bilateral congenital or childhood onset cataracts · R31 NHS GMS → Fetal anomalies · R21 NHS GMS → Monogenic hearing loss · R67 NHS GMS → Retinal disorders · R32 NHS GMS → Skeletal dysplasia · R104 NHS GMS → Stickler syndrome · R45 NHS GMS → Clefting NHS GMS → DDG2P NHS GMS →
NHS Genomic Medicine Service Jeen carrier screening

Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory

Diet & lifestyle considerations

Research suggests that generally maintaining a balanced diet rich in vitamins and minerals, alongside regular, moderate exercise, contributes to overall skeletal health. While no specific lifestyle interventions are known to prevent conditions associated with COL2A1 variants, supporting general well-being can be beneficial for managing symptoms of connective tissue disorders. Avoiding activities that place excessive strain on affected joints may also be recommended by healthcare professionals.

Supplement considerations

There is no conclusive scientific evidence to suggest that specific dietary supplements can prevent or treat conditions caused by COL2A1 gene variants. Some individuals with connective tissue disorders may explore supplements like glucosamine or chondroitin, or discuss vitamin D or calcium with their physician. However, these are not a substitute for established medical treatments. Discuss any potential supplement use with a healthcare provider to ensure safety and appropriateness.

Frequently asked questions

What is the primary function of the COL2A1 gene?

The COL2A1 gene provides instructions for making the alpha-1(II) chain, which is a fundamental component of type II collagen. This collagen is crucial for giving strength and structure to cartilage and other connective tissues throughout the body.

Which body parts are most affected by COL2A1 variants?

Variants in the COL2A1 gene primarily affect parts of the body rich in type II collagen, including cartilage, joints, the eyes (vitreous humour), and the inner ear, leading to skeletal and connective tissue disorders.

Is COL2A1 associated with a specific type of collagen?

Yes, COL2A1 is specifically responsible for producing a key chain of type II collagen, which is most abundant in cartilage, particularly hyaline cartilage found in joints and growth plates.

Are there any lifestyle changes that can help with COL2A1-related conditions?

While no specific lifestyle changes can prevent COL2A1-related conditions, a generally healthy lifestyle with a balanced diet and moderate exercise can support overall musculoskeletal health. Always consult a healthcare provider for personalised advice.

Where is the COL2A1 gene located?

The COL2A1 gene is located on chromosome 12, specifically at position 12q13.11.

References

  1. Kannu P, Bateman J, Savarirayan R. Clinical phenotypes associated with type II collagen mutations. Journal of paediatrics and child health. 2012. PMID: 21332586
  2. Kannu P, Bateman JF, Randle S. Premature arthritis is a distinct type II collagen phenotype. Arthritis and rheumatism. 2010. PMID: 20131279
  3. Su P, Li R, Liu S. Age at onset-dependent presentations of premature hip osteoarthritis, avascular necrosis of the femoral head, or Legg-Calvé-Perthes disease in a single family, consequent upon a p.Gly1170Ser mutation of COL2A1. Arthritis and rheumatism. 2008. PMID: 18512791
  4. Miyamoto Y, Matsuda T, Kitoh H. A recurrent mutation in type II collagen gene causes Legg-Calvé-Perthes disease in a Japanese family. Human genetics. 2007. PMID: 17394019
  5. Hoornaert KP, Marik I, Kozlowski K. Czech dysplasia metatarsal type: another type II collagen disorder. European journal of human genetics : EJHG. 2007. PMID: 17726487
  6. Zankl A, Neumann L, Ignatius J. Dominant negative mutations in the C-propeptide of COL2A1 cause platyspondylic lethal skeletal dysplasia, torrance type, and define a novel subfamily within the type 2 collagenopathies. American journal of medical genetics. Part A. 2005. PMID: 15643621
  7. Richards AJ, Meredith S, Poulson A. A novel mutation of COL2A1 resulting in dominantly inherited rhegmatogenous retinal detachment. Investigative ophthalmology & visual science. 2005. PMID: 15671297
  8. Nishimura G, Haga N, Kitoh H. The phenotypic spectrum of COL2A1 mutations. Human mutation. 2005. PMID: 15895462
  9. Prockop DJ. Type II collagen and avascular necrosis of the femoral head. The New England journal of medicine. 2005. PMID: 15930417
  10. Liu YF, Chen WM, Lin YF. Type II collagen gene variants and inherited osteonecrosis of the femoral head. The New England journal of medicine. 2005. PMID: 15930420
  11. Zankl A, Zabel B, Hilbert K. Spondyloperipheral dysplasia is caused by truncating mutations in the C-propeptide of COL2A1. American journal of medical genetics. Part A. 2004. PMID: 15316962
  12. Donoso LA, Edwards AO, Frost AT. Clinical variability of Stickler syndrome: role of exon 2 of the collagen COL2A1 gene. Survey of ophthalmology. 2003. PMID: 12686304
  13. Go SL, Maugeri A, Mulder JJ. Autosomal dominant rhegmatogenous retinal detachment associated with an Arg453Ter mutation in the COL2A1 gene. Investigative ophthalmology & visual science. 2003. PMID: 12939326
  14. Mortier GR, Weis M, Nuytinck L. Report of five novel and one recurrent COL2A1 mutations with analysis of genotype-phenotype correlation in patients with a lethal type II collagen disorder. Journal of medical genetics. 2000. PMID: 10745044
  15. Körkkö J, Cohn DH, Ala-Kokko L. Widely distributed mutations in the COL2A1 gene produce achondrogenesis type II/hypochondrogenesis. American journal of medical genetics. 2000. PMID: 10797431
  16. Richards AJ, Baguley DM, Yates JR. Variation in the vitreous phenotype of Stickler syndrome can be caused by different amino acid substitutions in the X position of the type II collagen Gly-X-Y triple helix. American journal of human genetics. 2000. PMID: 11007540
  17. Wilkin DJ, Artz AS, South S. Small deletions in the type II collagen triple helix produce kniest dysplasia. American journal of medical genetics. 1999. PMID: 10406661
  18. Zabel B, Hilbert K, Stöss H. A specific collagen type II gene (COL2A1) mutation presenting as spondyloperipheral dysplasia. American journal of medical genetics. 1996. PMID: 8723097
  19. Tiller GE, Polumbo PA, Weis MA. Dominant mutations in the type II collagen gene, COL2A1, produce spondyloepimetaphyseal dysplasia, Strudwick type. Nature genetics. 1995. PMID: 7550321
  20. Cheah KS, Stoker NG, Griffin JR. Identification and characterization of the human type II collagen gene (COL2A1). Proceedings of the National Academy of Sciences of the United States of America. 1985. PMID: 3857598
Educational content. This page is not medical or genetic advice, is not individually reviewed by a clinician for each reader, and should not replace a consultation with a qualified healthcare professional or genetic counsellor. If you are considering genetic testing or acting on a test result, book a consultation.
Data sources Last updated 17 July 2026. Content compiled from HGNC · MedlinePlus Genetics · ClinGen · Genomics England PanelApp · NHS National Genomic Test Directory · ClinVar · UniProt · AlphaFold .