ITGB3

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What is the official name of the ITGB3 gene?

The official name of this gene is “integrin, beta 3 (platelet glycoprotein IIIa, antigen CD61).”

ITGB3 is the gene's official symbol. The ITGB3 gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the ITGB3 gene?

The ITGB3 gene provides instructions for making the beta3 subunit of a receptor protein called integrin alphaIIb/beta3 (αIIbβ3), which is found on the surface of small cell fragments called platelets. Platelets circulate in blood and are an essential component of blood clots. The beta3 subunit attaches (binds) to the alphaIIb subunit, which is produced from the ITGA2B gene, to form integrin αIIbβ3. It is estimated that 80,000 to 100,000 copies of integrin αIIbβ3 are present on the surface of each platelet.

During clot formation, integrin αIIbβ3 binds to a protein called fibrinogen. Attachment of integrin αIIbβ3 from adjacent platelets to the same fibrinogen protein helps platelets cluster together (platelet cohesion) to form a blood clot. Blood clots protect the body after injury by sealing off damaged blood vessels and preventing further blood loss. Integrin αIIbβ3 can also bind other proteins on platelets and in the blood as well as proteins within the intricate lattice that forms in the space between cells (extracellular matrix) to ensure proper clot formation and promote wound healing.

Does the ITGB3 gene share characteristics with other genes?

The ITGB3 gene belongs to a family of genes called CD (CD molecules). It also belongs to a family of genes called ITG (integrins).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? in the Handbook.

How are changes in the ITGB3 gene related to health conditions?

Glanzmann thrombasthenia - caused by mutations in the ITGB3 gene: At least 130 mutations in the ITGB3 gene have been found to cause Glanzmann thrombasthenia, which is a rare bleeding disorder. The mutations that cause this disorder occur in both copies of the gene in each cell and impair the production or activity of the beta3 subunit, which disrupts the formation of functional integrin αIIbβ3. A shortage (deficiency) of functional integrin αIIbβ3 prevents sufficient binding of fibrinogen or other proteins, impairing the formation of blood clots. A lack of platelet cohesion leads to prolonged or spontaneous bleeding episodes experienced by people with Glanzmann thrombasthenia.
other disorders - caused by mutations in the ITGB3 gene: Mutations in the ITGB3 gene can also cause another rare bleeding disorder called platelet-type bleeding disorder 16. People with this disorder have signs and symptoms similar to Glanzmann thrombasthenia (described above), including frequent nosebleeds (epistaxis), bleeding from the gums, or red or purple spots on the skin caused by bleeding underneath the skin (petechiae), but the episodes are typically milder.
Unlike Glanzmann thrombasthenia, this disorder results from a mutation in only one copy of the ITGB3 gene in each cell, and the mutations result in the formation of some integrin αIIbβ3 that is abnormally turned on (active), even when no clot is being formed. This abnormally active protein is unable to reach the surface of the platelet where it is needed to bind to other platelets during clot formation. The overactive integrin αIIbβ3 binds inappropriately to clotting proteins within the cell during the formation of platelets, causing the platelets to become misshapen and large. The abnormally shaped platelets have a shortened lifespan, so platelet numbers are often reduced, which impairs clot formation. (The combination of reduced numbers of enlarged platelets is referred to as macrothrombocytopenia.)
Because the mutation that causes this disorder affects only one copy of the ITGB3 gene, some normal integrin is formed and normal platelets produced, which accounts for the mild signs and symptoms in affected individuals.

Genetics Home Reference provides information about osteopetrosis, which is also associated with changes in the ITGB3 gene.

Where is the ITGB3 gene located?

Cytogenetic Location: 17q21.32

Molecular Location on chromosome 17: base pairs 47,253,841 to 47,312,710

The ITGB3 gene is located on the long (q) arm of chromosome 17 at position 21.32.

More precisely, the ITGB3 gene is located from base pair 47,253,841 to base pair 47,312,710 on chromosome 17.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about ITGB3?

You and your healthcare professional may find the following resources about ITGB3 helpful.

Educational resources - Information pages (2 links)
Genetic Testing Registry - Repository of genetic test information (1 link)

You may also be interested in these resources, which are designed for genetics professionals and researchers.

PubMed - Recent literature
OMIM - Genetic disorder catalog (2 links)
Research Resources - Tools for researchers (6 links)

What other names do people use for the ITGB3 gene or gene products?

beta 3 integrin
CD61
GP3A
GPIIIa
integrin beta 3
integrin beta-3 precursor
platelet glycoprotein IIIa
platelet glycoprotein IIIa
platelet GPIIIa
platelet membrane glycoprotein IIIa
vitronectin receptor beta chain

See How are genetic conditions and genes named? in the Handbook.

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding ITGB3?

cell ; clotting ; cohesion ; deficiency ; extracellular ; extracellular matrix ; fibrinogen ; gene ; gums ;injury ; mutation ; petechiae ; platelets ; precursor ; protein ; receptor ; spontaneous ; subunit

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References (7 links)

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? in the Handbook