The disorder is caused by the deficiency of the intrinsic clotting factor XI which leads to abnormally slow clot formation at the site of vascular injury. In most cases, the disorder causes mild, spontaneous bleeding which may presents as hematuria (blood in the urine), gingival bleeding, or epistaxis (bleeding from the nose). Many affected dogs may also remain asymptomatic. The disorder can sometimes cause severe, life-threatening bleeding 12 to 24 hours after surgical intervention. Excessive bleeding may also occur after trauma.

Affected dogs should be monitored closely for excessive and prolonged bleeding during and after any required surgical procedures or after any trauma. Fresh-frozen plasma transfusions should be provided as necessary to ensure proper clotting if other means are unsuccessful.

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disease is autosomal dominant meaning that one copy of the mutation is needed for disease signs to occur. Use of dogs with one or two copies of the disease mutation is not advised, as there is a risk that the resulting litter will contain affected puppies. For example if a dog with one copy of the Factor XI Deficiency mutation is bred with a clear dog with no copies of the Factor XI Deficiency mutation, about half of the puppies will have one copy and half will have no copies of the Factor XI Deficiency mutation. Please note: It is possible that disease signs similar to the ones caused by the Factor XI Deficiency mutation could develop due to a different genetic or clinical cause.