Studies on a family with the factor VII defect.

Investigations in a family with an isolated factor VII deficiency are reported. In one of the propositi VII Ag was reduced, in all other family members VII Ag was in the low normal range. Other investigators have observed various activation patterns of factor VII in four deficient families which were tested with thromboplastins from different sources. In contrast to most of these earlier studies the degree of activation with different thromboplastins was very similar regardless which thromboplastin was tested. These results confirm the heterogeneity of the factor VII defect. Platelet aggregation which was tested in one of the propositi with ADP, adrenaline, and collagen was found to be normal. No cold activation of factor VII was observed.