lunes, 28 de septiembre de 2015

Glanzmann thrombasthenia - Genetics Home Reference

Glanzmann thrombasthenia - Genetics Home Reference

Genetics Home Reference: your guide to understanding genetic conditions

Glanzmann thrombasthenia

What is Glanzmann thrombasthenia?

Glanzmann thrombasthenia is a bleeding disorder that is characterized by prolonged or spontaneous bleeding starting from birth. People with Glanzmann thrombasthenia tend to bruise easily, have frequent nosebleeds (epistaxis), and may bleed from the gums. They may also develop red or purple spots on the skin caused by bleeding underneath the skin (petechiae) or swelling caused by bleeding within tissues (hematoma). Glanzmann thrombasthenia can also cause prolonged bleeding following injury, trauma, or surgery (including dental work). Women with this condition can have prolonged and sometimes abnormally heavy menstrual bleeding. Affected women also have an increased risk of excessive blood loss during pregnancy and childbirth.
About a quarter of individuals with Glanzmann thrombasthenia have bleeding in the gastrointestinal tract, which often occurs later in life. Rarely, affected individuals have bleeding inside the skull (intracranial hemorrhage) or joints (hemarthrosis).
The severity and frequency of the bleeding episodes in Glanzmann thrombasthenia can vary greatly among affected individuals, even in the same family. Spontaneous bleeding tends to become less frequent with age.

How common is Glanzmann thrombasthenia?

Glanzmann thrombasthenia is estimated to affect 1 in one million individuals worldwide, but may be more common in certain groups, including the French Manouche community.

What genes are related to Glanzmann thrombasthenia?

Mutations in the ITGA2B or ITGB3 gene cause Glanzmann thrombasthenia. These genes provide instructions for making the two parts (subunits) of a receptor protein called integrin alphaIIb/beta3 (αIIbβ3). This protein is abundant on the surface of platelets. Platelets are small cell fragments that circulate in blood and are an essential component of blood clots. During clot formation, integrin αIIbβ3 helps platelets bind together. Blood clots protect the body after injury by sealing off damaged blood vessels and preventing further blood loss.
ITGA2B or ITGB3 gene mutations result in a shortage (deficiency) of functional integrin αIIbβ3. As a result, platelets cannot clump together to form a blood clot, leading to prolonged bleeding.
Three types of Glanzmann thrombasthenia have been classified according to the amount of integrin αIIbβ3 that is available. People with type I (the most common type) have less than 5 percent of normal integrin αIIbβ3 levels, people with type II have between 5 and 20 percent of normal integrin αIIbβ3 levels, and people with the variant type have adequate integrin αIIbβ3 levels but produce only nonfunctional integrin.
Some people with Glanzmann thrombasthenia do not have an identified mutation in either theITGA2B or ITGB3 gene; the cause of the disorder in these individuals is unknown.
Read more about the ITGA2B and ITGB3 genes.

How do people inherit Glanzmann thrombasthenia?

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Where can I find information about diagnosis or management of Glanzmann thrombasthenia?

These resources address the diagnosis or management of Glanzmann thrombasthenia and may include treatment providers.
You might also find information on the diagnosis or management of Glanzmann thrombasthenia inEducational resources and Patient support.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.

Where can I find additional information about Glanzmann thrombasthenia?

You may find the following resources about Glanzmann thrombasthenia helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for Glanzmann thrombasthenia?

  • deficiency of glycoprotein complex IIb-IIIa
  • deficiency of platelet fibrinogen receptor
  • Glanzmann disease
  • Glanzmann-Naegeli disorder
  • glycoprotein IIb/IIIa defect
  • hereditary hemorrhagic thrombasthenia
  • hereditary thrombasthenia
  • platelet fibrinogen receptor deficiency
For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.

What if I still have specific questions about Glanzmann thrombasthenia?

Where can I find general information about genetic conditions?

What glossary definitions help with understanding Glanzmann thrombasthenia?

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
References (5 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

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