Haemophilia B or Christmas disease is a monogenic X-linked recessive bleeding disorder. It is a rare disease that affects different dog breeds. It is described by genetic variants in the clotting factor IX, which is a plasma glycoprotein that is required for activation of factor X in the blood coagulation cascade. The mutations in the gene that codes factor IX result in the insufficient or absent levels of factor IX in the blood, causing excessive bleeding. The symptoms include frequent and spontaneous bleeding into joints, muscles and body cavities, that can eventually lead to arthropathy associated with progressive cartilage damage, chronic pain, lameness and joint destruction. Current treatment requires the infusion of factor IX-rich plasma concentrates during bleeding episodes. For the affected dogs that have extremely low levels of factor IX, the bleeding episodes are life threatening.

Inheritance: X-linked recessive - read more

Mutation: F9 gene

Genetic test: The method used for genetic testing is extremely accurate and allows complete differentiation between affected animals, carriers and healthy dogs. DNA testing can be done at any age.

DNA test sample: EDTA whole blood (1.0 ml) or buccal swabs. Detailed information about sampling can be found here.