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COL10A1
collagen type X alpha 1 chain
COL10A1 encodes the alpha-1 chain of type X collagen, a short-chain collagen secreted by hypertrophic chondrocytes at the growth plate. Heterozygous pathogenic COL10A1 variants cause autosomal dominant Schmid-type metaphyseal chondrodysplasia, a mild skeletal dysplasia with short stature, bowing of the legs and waddling gait typically noticed after the child begins to walk.
COL10A1 is located on the long (q) arm of chromosome 6, at band 6q22.1. Arm ratio per GRCh38 - banding schematic.
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Overview
COL10A1 is located on chromosome 6 at position 6q22.1 and encodes a highly specialised collagen protein found only in certain regions of developing bone. Unlike the more abundant collagens found throughout connective tissues, type X collagen has a restricted expression pattern, appearing predominantly in the hypertrophic zone of growth plates where cartilage undergoes transformation into bone tissue.
The protein encoded by this gene assembles into trimeric structures that help organise the extracellular matrix during bone formation. Pathogenic variants in COL10A1 cause metaphyseal chondrodysplasia, Schmid type (MCDS), a skeletal dysplasia affecting bone growth and structure. Understanding this gene's function has provided important insights into the molecular mechanisms underlying endochondral ossification and skeletal dysplasias.
What the gene does
The COL10A1 protein forms part of type X collagen, which exists as a homotrimer composed of three identical alpha-1(X) chains. This collagen type is classified as a short-chain, non-fibrillar collagen, distinguishing it from the more common fibril-forming collagens found in skin, bone, and tendons.
Type X collagen plays a regulatory role in the growth plate, the region of developing tissue near the ends of long bones responsible for skeletal growth during childhood and adolescence. The protein is expressed specifically by hypertrophic chondrocytes, the enlarged cartilage cells that prepare the matrix for mineralisation and bone formation. Research suggests that type X collagen helps to organise and stabilise the extracellular matrix in these regions, creating an environment conducive to calcium deposition and vascular invasion.
The protein appears to regulate matrix calcification and may interact with other matrix components to control the transition from cartilage to bone. Evidence indicates that type X collagen influences chondrocyte differentiation and apoptosis, processes essential for the orderly progression of endochondral bone formation. The precise molecular mechanisms through which type X collagen exerts these effects continue to be investigated, but the protein's restricted expression pattern highlights its specialised function in skeletal development.
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Chromosome location
COL10A1 is positioned on the long arm of chromosome 6 at band 6q22.1, a region that contains several genes involved in skeletal and connective tissue development. The gene spans a relatively compact genomic region, reflecting its specialised function and restricted expression pattern.
The chromosomal location at 6q22.1 places COL10A1 in a region that has been studied in the context of skeletal development disorders. The gene's structure includes multiple exons that encode the characteristic collagenous and non-collagenous domains of the type X collagen protein.
Protein structure
Type X collagen contains characteristic structural features common to collagen proteins. Like other collagens, it contains repeating glycine-X-Y amino acid sequences that enable the formation of its triple-helical structure. The protein includes a central collagenous domain flanked by non-collagenous regions at both the amino and carboxyl termini, and the carboxyl-terminal NC1 domain in particular has been studied in structural detail and plays an important role in trimer assembly.
The collagenous domain contains the repetitive sequences necessary for triple helix formation, whilst the non-collagenous domains contribute to protein assembly, secretion, and interactions with other matrix components. The relatively short length of the collagenous domain compared to fibrillar collagens contributes to the distinct structural and functional properties of type X collagen.
Key variants
Genetic variants in COL10A1 have been identified that affect the structure and function of type X collagen. These variants typically involve changes within the collagenous domain or the non-collagenous regions that disrupt either the triple helix formation or protein processing and secretion.
Pathogenic variants often result from missense changes that substitute glycine residues in the repetitive collagenous sequence, disrupting the tight packing required for stable triple helix formation. Other variants may affect splicing, protein folding, or post-translational modifications. COL10A1-related skeletal dysplasia (metaphyseal chondrodysplasia, Schmid type) follows autosomal dominant inheritance, meaning that one altered copy of the gene is sufficient to cause the condition. The altered gene may be inherited from an affected parent, or it may arise as a new (de novo) change in an individual with no family history of the condition.
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.1789T>C | p.Tyr597His | Pathogenic/Likely pathogenic | ★★☆☆ | not provided |
c.1823del | p.Thr608fs | Pathogenic/Likely pathogenic | ★★☆☆ | not provided |
c.1989C>A | p.Tyr663Ter | Pathogenic | ★★☆☆ | not provided |
c.2011T>C | p.Ser671Pro | Pathogenic/Likely pathogenic | ★★☆☆ | Metaphyseal chondrodysplasia, Schmid type |
c.211C>T | p.Arg71Ter | Pathogenic/Likely pathogenic | ★★☆☆ | See cases |
c.1725del | p.Leu575fs | Pathogenic | ★☆☆☆ | not provided |
c.1772G>T | p.Cys591Phe | Pathogenic | ★☆☆☆ | Metaphyseal chondrodysplasia, Schmid type |
c.1784G>A | p.Gly595Glu | Pathogenic | ★☆☆☆ | Metaphyseal chondrodysplasia, Schmid type |
c.1792T>G | p.Tyr598Asp | Pathogenic | ★☆☆☆ | Metaphyseal chondrodysplasia, Schmid type |
c.1775dup | p.Ile593fs | Likely pathogenic | ★★☆☆ | Metaphyseal chondrodysplasia, Schmid type |
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 COL10A1 cause metaphyseal chondrodysplasia, Schmid type (MCDS), an autosomal dominant skeletal dysplasia affecting growth plate development and bone formation. MCDS is the primary condition associated with this gene and typically manifests as abnormalities in bone growth, particularly affecting the metaphyses - the regions of developing bone adjacent to the growth plates.
Features of MCDS commonly include disproportionate short stature, bowing of the legs, a waddling gait, and characteristic radiographic changes in the metaphyses of long bones. The condition is usually recognised in early childhood, often after a child begins to walk. Severity and specific features can vary between individuals, even within the same family, depending on the nature and location of the genetic variant.
No disease links recorded for this gene in our reference set.
UK clinical status
In the UK, genetic testing for COL10A1 is available through NHS clinical genetics services as part of the NHS Genomic Medicine Service. Testing is typically offered via skeletal dysplasia gene panels, such as the R104 panel for skeletal dysplasias listed in the National Genomic Test Directory, rather than as a single-gene test. Test panel composition and eligibility criteria are subject to periodic review; current information should be confirmed with the referring clinician or local genetics service.
Referral for genetic testing is usually made by a paediatrician, clinical geneticist, or other specialist following clinical and radiographic assessment. Eligibility depends on the clinical presentation and established NHS testing criteria, which generally require features suggestive of a skeletal dysplasia. Families affected by, or thought to be at risk of, a COL10A1-related condition can also be referred to an NHS Regional Clinical Genetics Service for genetic counselling, which may include discussion of inheritance, testing options, and implications for other family members.
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Diet & lifestyle considerations
For individuals with skeletal conditions related to COL10A1 variants, general bone health principles observed in research populations may be relevant. Studies in broader skeletal health suggest that adequate calcium and vitamin D intake supports bone mineralisation, though no evidence indicates these measures alter the course of genetic skeletal dysplasias.
Weight-bearing physical activity appropriate to individual capabilities has been associated with bone health maintenance in general populations, though activity recommendations should be tailored to specific skeletal features and functional limitations. Research indicates that avoiding smoking and excessive alcohol consumption supports overall bone health, as these factors have been linked to reduced bone density in population studies.
Supplement considerations
No supplements have been shown to prevent or modify skeletal dysplasias associated with COL10A1 variants. Whilst calcium and vitamin D are essential for general bone health and are often recommended to support bone mineralisation, there is no evidence that supplementation alters the underlying genetic condition or prevents the skeletal manifestations of COL10A1 variants.
Some healthcare providers may recommend standard bone health supplements as part of overall management, but individuals should discuss any supplementation with their healthcare team before use, as requirements vary based on individual circumstances, dietary intake, and any concurrent medical conditions.
Frequently asked questions
What is the function of type X collagen?
Type X collagen is a specialised protein found exclusively in the hypertrophic cartilage of growth plates, where it helps organise the extracellular matrix during the process of bone formation. It plays a regulatory role in endochondral ossification, supporting the transition from cartilage to bone.
How do COL10A1 variants cause skeletal problems?
Variants in COL10A1 typically disrupt the normal structure or function of type X collagen, interfering with growth plate organisation and the process of endochondral ossification. This disruption can affect normal bone growth and development, particularly in the metaphyseal regions of long bones.
Are COL10A1-related conditions always inherited?
COL10A1-related skeletal dysplasia (metaphyseal chondrodysplasia, Schmid type) follows autosomal dominant inheritance. This means one altered copy of the gene is sufficient to cause the condition. It may be inherited from an affected parent or occur as a new (de novo) change in an individual with no family history. Each child of an affected parent has a 50% chance of inheriting the altered gene.
Can lifestyle changes affect COL10A1-related skeletal conditions?
Lifestyle measures supporting general bone health, such as adequate nutrition and appropriate physical activity, may benefit overall skeletal well-being, but no lifestyle interventions have been shown to modify the underlying genetic condition. Management should be discussed with healthcare providers familiar with skeletal dysplasias.
What makes type X collagen different from other collagens?
Type X collagen is a short-chain, non-fibrillar collagen with highly restricted expression, found almost exclusively in hypertrophic cartilage of growth plates. Unlike the abundant fibril-forming collagens found throughout the body, type X collagen has a specialised role specific to skeletal development and endochondral bone formation.