[Congenital deficiency of factor VII in a canine family].

Prolonged prothrombin time in the blood coagulation test was seen in some beagle dogs whose activated partial prothrombin times were distributed within the normal range. This phenomenon suggested possible abnormalities in coagulation factors II, V, VII, and/or X. Therefore, a revised cross-matching test was given and a determination of coagulation factors related to the extrinsic system was performed. We also determined whether or not factor VII inhibitor was present. The results were as follows: 1) In the revised cross-matching test, the prolonged prothrombin times were revised when normal canine serum was added to the plasma that showed prolongation of prothrombin time, but not when pooled normal canine plasma absorbed with BaSO4 was added to it. 2) The level of factor VII in the plasma with prolonged prothrombin time was 5 approximately 10% of the level in normal canine plasma. 3) Factor VII inhibitor was not detected in the plasma with prolonged prothrombin time or in normal plasma. Consequently, the prolongation of prothrombin time was attributed to a deficiency in factor VII. This abnormality was confirmed to be congenital.