Bernard-Soulier syndrome: A disorder in which the platelets crucial to normal blood clotting lack the ability to adequately stick to injured blood vessel walls, leading to abnormal bleeding. Bernard-Soulier syndrome usually appears in the newborn period, infancy, or early childhood, with bruises, nosebleeds, and gum bleeding. Bernard-Soulier syndrome is an inherited disease, transmitted as an autosomal recessive trait. There is no specific treatment. Bleeding episodes may require platelet transfusions. Specific platelet function tests, as well as tests for the glycoproteins common to Bernard-Soulier syndrome, can confirm the diagnosis. Also known as giant platelet syndrome.