Hereditary blood coagulation factor-VII deficiency: a comparison of the defect in beagles from several sources.

1. Hereditary blood coagulation factor-VII deficiency has previously been identified in Beagles from a number of sources in Britain and North America. 2. A study is now reported in which the nature of the defect is compared in plasma samples from these sources. 3. When prothrombin times and Russell's Viper venom clotting times were determined on mixtures of samples, no cross-correction of the defective coagulation activity was detected. 4. Antibody neutralization assays of factor-VII related antigen and assays of factor-VII procoagulant activity revealed essentially similar levels in all samples. 5. Thus no significant genetic variants of the defect were identified.