Easy bruising and a tendency to bleed easily are signs of von Willebrand disease, another inherited clotting disorder that is usually far less severe than hemophilia. Affected persons lack a plasma protein, von Willebrand factor, that is secreted by endothelial cells lining blood vessels and enables platelets to adhere to damaged blood vessel walls, a key step preceding actual clotting. Sometimes the condition can cause spontaneous bleeding from the mucous membranes of the gastrointestinal and urinary tracts.