Giant Platelet Syndrome (Bernard-Soulier Disease)

The Bernard-Soulier syndrome (B-SS) is a rare inherited bleeding disorder caused by abnormal platelets and subsequent abnormal clotting. It is one of the giant platelet syndromes. This syndrome was originally described in 1948 by two physicians who were treating a patient with a bleeding problem. They discovered that this patient had a prolonged bleeding time, fewer platelets, and larger platelets than the normal individual. Since then, the platelet abnormality has been described and determined to be due to the platelets lacking the ability to stick adequately to injured blood-vessel walls. This is a crucial aspect of the process of forming a blood clot, and as a result of this problem, there is excessive bleeding.

Giant platelet syndrome (Bernard-Soulier syndrome) causes bruises, nosebleeds, and/or gum bleeding.

Bernard-Soulier syndrome usually presents in the newborn period, infancy, or early childhood with

• bruises,
• nosebleeds (epistaxis), and/or
• gum (gingival) bleeding.

Later problems can occur with anything that can induce bleeding such as

• menstruation,
• trauma,
• surgery, or
• stomach ulcers.

Bernard-Soulier syndrome is a rare inherited disease and is transmitted in an autosomal recessive pattern. This means that both parents must carry a gene for the Bernard-Soulier syndrome and transmit that gene to the child for the child to have the disease. The prevalence is believed to be less than one in 1 million individuals. The molecular basis is now known and is due to a defect in the platelet glycoprotein complex 1b-IX-V. This is referred to as an adhesion complex and forms a receptor that enables platelets to stick together to form a clot. Normal platelets circulate in the blood and are the primary cells responsible for initiating clotting. Without this receptor, platelets cannot stick together and clotting does not occur normally. The parents of a child with B-SS will have a decrease in the glycoprotein but no impairment of platelet function and no abnormal bleeding. The Bernard-Soulier gene has been mapped to the short (p) arm of chromosome 17 (in the region 17pter-17p12).

Patients are often diagnosed with B-SS after seeking medical attention following prolonged or recurring bleeding episodes.

• Some infants are diagnosed with excessive bleeding following circumcision.
• Other children and adults may be diagnosed after bleeding excessively following trauma or tooth extraction.
• Very frequently there is a history of another family member with similar symptoms, and the physician evaluating the patient will often document a detailed family history to assist in the diagnosis.

B-SS ultimately is a laboratory diagnosis and usually requires a specialized laboratory to confirm the suspicion of the disease and involves platelet aggregation studies (testing for the "stickiness" of platelets) and flow cytometry. It is important to distinguish this syndrome from other platelet disorders (such as von Willebrand disease and immune thrombocytopenia purpura) since the treatments and management differ.

• There is no specific treatment for Bernard-Soulier syndrome.
• Patients should avoid any drugs which may interfere with clot formation, such as aspirin, ibuprofen, and naproxen.
• Severe bleeding episodes may require platelet and blood transfusions.
• Recombinant clotting factors and a coagulation drug known as DDAVP may also be of short-term benefit in selected patients.
• Affected individuals should avoid participation in contact sports.
• Iron supplements are often recommended to patients with the disease to help minimize the anemia often observed in patients with frequent blood loss.

Currently, there is no cure for B-SS; however, researchers are studying the efficacy of bone-marrow transplantation and have had some success in treating the syndrome in several severely affected patients.