Thrombopathia Basset Hound Type
Thrombopathia Basset Hound type is an inherited bleeding disorder affecting the Basset Hound breed. Thrombopathia in Basset Hound has been for the first time reported in 1979 as a bleeding disorder associated with abnormal platelet function. Researches have continued, and detailed research about this defect started in 1981. Also other bleeding disorders have been documented in this breed, such as von Willebrand’s syndrome and hemophilia.
Platelets, or thrombocytes, have a key role in bleeding prevention through clumping of blood vessel injuries. At a site of vascular injury, platelets are exposed to surface which is not from blood vessel, and they initiate to aggregate to each other, which results in formation of a hemostatic plug that will seal the defect. In the formation of this plug, fibrin has a role as its stabilizer.
Excessive bleeding disorders in dogs, or canine hemorrhagia, can be divided into two groups: intrinsic, inherent platelet defects, in which platelet itself is abnormal, and extrinsic, external defects, where the abnormality underlies in some factor necessary for normal platelet function. Like this, most known canine extrinsic platelet defect is recognized in von Willebrand’s syndrome, while intrinsic platelet defects are less commonly recognized. Thrombopathia Basset Hound Type is an inherent platelet defects type hemorrhagia. Due to defect within the platelets, they are unable to form blood clot. The defect in the platelets of the basset hounds is suspected to be related to a structural or functional deficiency of specific surface glycoprotein receptors, similar as has been reported in humans with Glanzmann’s disease and Bernard-Soulier syndrome, human bleeding disorders.
Thrombopathia Basset Hound type is characterized by cutaneous and mucosal bleeding and prolonged bleeding time, as a consequence of abnormal platelet function. The bleeding severity can vary, from mild to severe. However, platelets in affected Basset Hounds appear as normal sized.
Some signs of disease can be recognized by the owner. When puppy’s teeth are shed, excessive bleeding can occur. Also, small pinpoints that appear and disappear easily can be seen on the dog’s abdomen, as a symptom of capillary bleeding in the skin. Bleeding on tips of the ear, around the gums and nasal bleeding can appear. As the disorder can vary in its severity, dogs with mild form of the disorder may not exhibit any of these signs and have no or only minor bleeding post operation, due to sufficient level of normal functioning platelets.
Thrombopathia Basset Hound type is caused by a mutation in the RASGRP1 gene. The frequency of the mutation is unknown.
The disorder is inherited in an autosomal recessive manner. Healthy parents of an affected puppy are obligate heterozygotes, and therefore carry one mutant allele. Heterozygotes have no symptoms. Dogs homozygous for the mutation will display the symptoms of the Thrombopathia Basset Hound type. At conception, each cub has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier.