Thrombasthenia

Thrombasthenia is a blood disorder characterized by impaired aggregation of platelets during wound healing. The defect was originally described by Swiss pediatrician Edward Glanzmann in humans in 1918 as a bleeding disorder that differed clinically from other known blood clotting defects. In humans, Glanzmann thrombasthenia (GT) is thought to be caused by lack or depletion of certain proteins (glycoproteins alpha IIb and beta 3). The defect causes prolonged bleeding resulting in anemia. A similar autosomal recessive inherited platelet defect called thromboasthenic thrombopathia has been described in dogs.

Affected dogs experience uncontrolled nosebleeding despite results of coagulation screening tests for platelet count and von Willebrand factor quantitation that are within normal ranges. Bleeding episodes may be associated with vaccination, hypothyroidism, or estrus.⁶ Clinical signs of bleeding in affected dogs are usually recognized before 1 year of age.

Breeds at Risk

The disease has been described in Great Pyrenees dogs, foxhounds and Otterhounds. Similar platelet defect i seen in Basset hounds. hrombasthenia of Otterhounds is similar to type-I Glanzmann thrombasthenia in humans.

Recent studies suggest that GT and perhaps other severe inherited platelet disorders can be corrected using bone marrow transplantation to establish normal platelets.

References

1. Type I Glanzmann's thrombasthenia in a Great Pyrenees dog. M. K. Boudreaux, K. Kvam, A. R. Dillon, C. Bourne, M. Scott, K. A. Schwartz and M. Toivio-Kinnucan
2. Two Genetic Defects in IIb Are Associated with Type I Glanzmann's Thrombasthenia in a Great Pyrenees Dog: A 14-base Insertion in Exon 13 and a Splicing Defect of Intron 13.
3. Correction of a large animal model of type I Glanzmann"s thrombasthenia by nonmyeloablative bone marrow transplantation. Experimental Hematology , Volume 31 , Issue 12 , Pages 1357 - 1362 G . Niemeyer
4. Genetics for Dog Breeders. Roy Robinson
5. Black's Veterinary Dictionary. Edward Boden, Geoffrey Philip West
6. Molecular and genetic basis for thrombasthenic thrombopathia in otterhounds. Boudreaux MK, Catalfamo JL.
7. A guide to hematology in dogs and cats. A. H. Rebar

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