The defective prothrombin consumption in Bernard-Soulier syndrome. Hypotheses from 1948 to 1982.

Bernard-Soulier syndrome (BSS) was described in 1948 as a constitutional platelet disorder characterized by giant sized platelets, a prolonged bleeding time, and a defect in prothrombin consumption. The accurate mechanisms of these abnormalities remain unexplained, especially the defect in prothrombin consumption on which we focus in this paper. Several hypotheses are proposed: firstly, a defective reaction between the platelet membrane, where the phospholipid composition is abnormal, and the proteins which initiate thromboplastin generation such as collagen, factor XI; secondly, an abnormal reaction between thrombin, whose synthesis is increased, and its receptor, possibly glycoprotein V, which is defective; lastly, as factor VIII/vW binding is diminished, an abnormal dissociation of the complex VIII/vW-VIIIc at the site of the platelet membrane, which leads to an inactivation of factor VIIIc.