Definition of Syndrome, giant platelet

Syndrome, giant platelet (Bernard-Soulier syndrome):

This condition is a primary problem of platelets in which the platelets lack the ability to stick adequately to injured blood vessel walls and as a result of this problem there is abnormal bleeding.

The giant platelet syndrome usually presents in the newborn period, infancy, or early childhood with bruises, nose bleeds (epistaxis), and/or gum (gingival) bleeding. Later problems can occur with anything which can induce bleeding such as menstruation, trauma, surgery, or stomach ulcers.

This is an inherited disease transmitted in an autosomal recessive pattern. Both parents must carry a gene for the giant platelet syndrome and transmit that gene to the child for the child to have the disease. The molecular basis is known and is due to a deficiency in platelet glycoproteins Ib, V, and IX. The parents have a decrease in the glycoprotein but no impairment of platelet function and no abnormal bleeding. The gene responsible for the syndrome has been mapped to the short (p) arm of chromosome 17.

There is no specific treatment for the giant platelet syndrome. Bleeding episodes may require platelet transfusions.

The abnormal platelets in the Bernard-Soulier syndrome are usually considerably larger than normal platelets when viewed on blood films or sized by automated instruments. However, this is not the only syndrome with large platelets. Specific platelet function tests as well as tests for the glycoproteins can confirm the diagnosis.

This disease was first recognized in 1948 by two French hematologists, Jean Bernard and Jean-Pierre Soulier, and so is also known as the Bernard-Soulier syndrome.