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The official name of this gene is “collagen, type XI, alpha 1.”
COL11A1 is the gene's official symbol. The COL11A1 gene is also known by other names, listed below.
The COL11A1 gene provides instructions for making one component of type XI collagen, called the pro-alpha1(XI) chain. Type XI collagen adds structure and strength to the connective tissues that support the body's muscles, joints, organs, and skin. Type XI collagen is normally found in cartilage, a tough but flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone, except for the cartilage that continues to cover and protect the ends of bones and is present in the nose and external ears. Type XI collagen is also part of the clear gel that fills the eyeball (the vitreous), the inner ear, and the center portion of the discs between the vertebrae in the spine (nucleus pulposus).
The pro-alpha1(XI) chain combines with two other collagen chains (pro-alpha2(XI) and pro-alpha1(II)) to form a procollagen molecule. These triple-stranded, ropelike procollagen molecules are then processed by enzymes in the cell. Once processed, procollagen molecules leave the cell and arrange themselves into long, thin fibrils that link to one another (cross-link) in the spaces around cells. The cross-linkages result in the formation of very strong mature type XI collagen fibers.
Type XI collagen also helps maintain the spacing and diameter of type II collagen fibrils. Type II collagen is an important component of the eye and mature cartilage tissue. The size and arrangement of type II collagen fibrils is essential for the normal structure of these tissues.
Mutations in the COL11A1 gene have been identified in some people with Stickler syndrome. Some mutations change one of the protein building blocks (amino acids) used to make the pro-alpha1(XI) chain. Other mutations cause segments of DNA to be skipped when the protein is being made, resulting in an abnormally short pro-alpha1(XI) chain. These alterations of type XI collagen impair its function, which can lead hearing loss, a tearing of the lining of the eye (retinal detachment), and abnormalities of the bones and joints.
Mutations in the COL11A1 gene are also responsible for some cases of Marshall syndrome, a disorder that is very similar to Stickler syndrome. In most mutations that cause this syndrome, a segment of DNA is skipped when the protein is made, resulting in an abnormally small pro-alpha1(XI) chain. This shortened protein hinders the formation of mature type XI collagen, which results in the features of Marshall syndrome. Whether Marshall syndrome represents a variant form of Stickler syndrome or a separate disorder is controversial.
In some people, variations in the COL11A1 gene may increase the risk of developing osteoarthritis, a degenerative disease of joint cartilage. As a result of these genetic changes, incorrect amino acids are used in making the pro-alpha1(XI) chain of type XI collagen. The altered pro-alpha1(XI) chain may weaken collagen fibers, which could play a role in the erosion of cartilage in the joints, a characteristic feature of osteoarthritis.
Cytogenetic Location: 1p21
Molecular Location on chromosome 1: base pairs 103,342,022 to 103,574,051
The COL11A1 gene is located on the short (p) arm of chromosome 1 at position 21.
More precisely, the COL11A1 gene is located from base pair 103,342,022 to base pair 103,574,051 on chromosome 1.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about COL11A1 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
acids ; cartilage ; cell ; collagen ; cross-link ; degenerative ; diameter ; DNA ; gene ; joint ; molecule ; nucleus ; protein ; syndrome ; tissue
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.