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COL27A1
collagen type XXVII alpha 1 chain
COL27A1 is located on the long (q) arm of chromosome 9, at band 9q32. Arm ratio per GRCh38 - banding schematic.
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Overview
COL27A1 belongs to the collagen gene family, a diverse group responsible for producing the most abundant structural proteins in the human body. This particular gene encodes the alpha-1 chain of type XXVII collagen, which assembles into trimeric molecules that contribute to the extracellular matrix in cartilage and certain other tissues. Collagens are essential for maintaining tissue architecture, withstanding mechanical stress, and regulating cellular behaviour. Although COL27A1 is less extensively characterised than classical fibrillar collagen genes, emerging research suggests it plays a specialised role in skeletal development and connective tissue homeostasis. Understanding how genetic variation in COL27A1 influences protein function remains an active area of investigation.
What the gene does
The protein encoded by COL27A1 is designated as the alpha-1 chain of type XXVII collagen. Like other collagens, it contains characteristic glycine-X-Y amino acid repeats that enable three alpha chains to wind together into a stable triple helix. This triple-helical structure provides tensile strength and organises the extracellular matrix. Type XXVII collagen is particularly abundant in developing cartilage, where it interacts with other matrix components to regulate chondrocyte differentiation and skeletal patterning. Evidence suggests the protein may also modulate signalling pathways that influence cell proliferation and tissue remodelling. The precise molecular interactions and binding partners of type XXVII collagen continue to be elucidated through biochemical and structural studies.
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Chromosome location
COL27A1 is located on the long arm of chromosome 9 at cytogenetic band 9q32. This chromosomal region encompasses multiple genes involved in skeletal and connective tissue biology. The gene spans a genomic interval that includes regulatory sequences controlling tissue-specific expression patterns. Detailed exon structure and transcript variants have not been comprehensively annotated in public databases, reflecting the relatively recent characterisation of this collagen family member.
Protein structure
Domain architecture has not been experimentally characterised in detail for this protein.
Key variants
Genetic variants in COL27A1 encompass single nucleotide changes, small insertions, and deletions that may alter protein structure or expression levels. Variants are classified using American College of Medical Genetics and Genomics guidelines, which integrate evidence from population frequency, computational predictions, functional studies, and segregation analysis. The clinical significance of most COL27A1 variants remains uncertain, as large-scale genotype-phenotype correlation studies are still emerging for this gene.
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.1216C>T | p.Gln406Ter | Pathogenic/Likely pathogenic | ★★☆☆ | COL27A1-related disorders |
c.2089G>C | p.Gly697Arg | Pathogenic | ★★☆☆ | Steel syndrome |
c.2119C>T | p.Arg707Ter | Pathogenic | ★★☆☆ | Steel syndrome |
c.2320C>T | p.Arg774Ter | Pathogenic/Likely pathogenic | ★★☆☆ | Steel syndrome |
c.3083dup | p.Met1029fs | Pathogenic/Likely pathogenic | ★★☆☆ | Steel syndrome |
c.3439G>T | p.Gly1147Ter | Pathogenic/Likely pathogenic | ★★☆☆ | Steel syndrome |
c.3616del | p.Arg1206fs | Pathogenic/Likely pathogenic | ★★☆☆ | Steel syndrome |
c.371del | p.Leu124fs | Pathogenic | ★★☆☆ | Inborn genetic diseases |
c.4357dup | p.Ala1453fs | Pathogenic/Likely pathogenic | ★★☆☆ | Steel syndrome |
c.2815del | p.Arg939fs | 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
No specific inherited conditions have been definitively linked to pathogenic variants in COL27A1 in major clinical genetics databases at present. Research into potential skeletal or connective tissue phenotypes associated with disrupted type XXVII collagen function is ongoing. As our understanding of this gene's biological role deepens, clearer genotype-phenotype relationships may be established through collaborative clinical and laboratory investigations.
No disease links recorded for this gene in our reference set.
UK clinical status
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Frequently asked questions
What does the COL27A1 gene do?
COL27A1 provides instructions for making the alpha-1 chain of type XXVII collagen, a structural protein found in cartilage and other connective tissues. The protein helps maintain tissue architecture and regulates cellular processes during skeletal development.
Where is COL27A1 located in the genome?
COL27A1 is located on chromosome 9 at band 9q32, on the long arm of the chromosome. This region contains several genes involved in skeletal and connective tissue biology.
Are there known diseases linked to COL27A1 variants?
No specific inherited conditions have been definitively associated with pathogenic COL27A1 variants in clinical genetics databases to date. Research continues to explore potential skeletal or connective tissue phenotypes that may result from disrupted type XXVII collagen function.