Bernard Soulier syndrome (BSS) is a rare autosomal recessive platelet disorder characterized by macrothrombocytopenia (unusually large platelets that are fewer than normal in number), epistaxis, and bruising susceptibility. Affected individuals may experience spontaneous bleeding or abnormally heavy and prolonged bleeding following minor injuries. Additionally, some patients may have petechiae as a result of bleeding under their skins. Women with BSS usually experience heavy or prolonged menstrual periods.
BSS is estimated to occur 1 in one million individuals. Diagnosis of the condition is based on the findings of prolonged bleeding time, reduced platelet glycoprotein Ib complex, and absence of platelet agglutination in presence of ristocetin. Hematological findings include the presence of large platelets and mild thrombocytopenia. Like most genetic conditions, there is no cure for BSS. Bleeding episodes can be managed by platelet transfusions, preferably from HLA-matched donors. Affected individuals are advised to avoid contact sports and other situations which might lead to bleeding.
BBS is caused by mutations in one of three genes: GP1BA, GP1BB, or GP9. These genes produce a protein complex called glycoprotein (GP) Ib found on the surface of platelets and plays a vital role in blood clotting. Mutations in GP1BA, GP1BB, or GP9 prevent the formation of the GPIb complex or impair its ability to interact with von Willebrand factor. As a result clot formation is impaired, leading to the excessive bleeding seen in patients with BSS.