Glanzmann's thrombasthenia (otterhound type) is an inherited bleeding disorder affecting dogs. Affected dogs have abnormal platelet activity. Platelets are blood cells that are necessary for the normal clotting of blood. Affected dogs often present before one year of age with bleeding gums as their permanent teeth are erupting. Affected dogs may also have frequent bloody noses, blood in the urine (hematuria), dark red-black tarry stool (melena), bruising of the skin and prolonged bleeding after surgery or trauma.