title: Hypercoagulable state associated with a deficiency of protein C in a thoroughbred colt.
abstract: Protein C is a vitamin K-dependent serine protease with anticoagulant and profibrinolytic activity which is synthesized in the liver. Decreased protein C activity was detected in a Thoroughbred colt with clinical and histopathologic evidence of recurrent venous thrombosis. Although protein C activity was reduced, protein C antigen concentration was normal. Consumptive coagulopathies produce a decrease in both the functional and antigenic concentrations of protein C, thus a defect in protein C synthesis was suspected. Inhibition of gamma-carboxylation secondary to vitamin K antagonism results in the synthesis of a protein C molecule with antigenicity, but without biological activity. However, there was no evidence of vitamin K antagonism. The hypercoaguable state resulting from the reduced activity of protein C in this colt was associated with uncomplicated renal disease, rather than a protein C consumptive process such as endotoxemia. A primary hypercoagulable state due to a deficiency of protein C activity was diagnosed. Primary deficiencies of protein C activity have not been previously documented in horses.
authors.affiliation: Marion duPont Scott Equine Medical Center, Leesburg, Virginia.
authors.forename: L M
authors.initials: LM
authors.lastname: Edens
authors.forename: D D
authors.initials: DD
authors.lastname: Morris
authors.forename: K W
authors.initials: KW
authors.lastname: Prasse
authors.forename: M R
authors.initials: MR
authors.lastname: Anver
mesh_terms: D000818:Animals; D006734:Horse Diseases / Q000097:blood / Q000201:enzymology* / Q000473:pathology; D006736:Horses; D020151:Protein C Deficiency; D012008:Recurrence; D013924:Thrombophlebitis / Q000201:enzymology / Q000473:pathology / Q000662:veterinary*