Bernard–Soulier syndrome (BSS), also called hemorrhagiparous thrombocytic dystrophy, is a rare autosomal recessive coagulopathy (bleeding disorder) that causes a deficiency of glycoprotein Ib (GpIb), the receptor for von Willebrand factor, an important glycoprotein involved in hemostasis.
The incidence of BSS is estimated to be less than 1 case per million persons, based on cases reported from Europe, North America, and Japan.
BSS is a giant platelet disorder, meaning that it is characterized by abnormally large platelets.