A syndrome of factor VII deficiency and abnormal platelet release reaction

A 15-year-old girl with severe factor VII deficiency and chronic arthropathy showed an excessively prolonged bleeding time. Further studies demonstrated low platelet adhesiveness and abnormal platelet aggregation with ADP, collagen and epinephrine. Release of 14C-serotonin was deficient after aggregation with ADP and epinephrine, but was normal with thrombin. Transfusion of plasma or prothrombin complex concentrate resulted in a partial or complete correction of the bleeding time, respectively, but had no effect on in vitro platelet function tests. Both parents and the only sister had factor VII activities of 42%-72% and factor VII antigen levels of 45%-66% of normal and may thus be heterozygotes with respect to factor VII deficiency. All three had normal bleeding times in spite of abnormal in vitro platelet functions. The observations are interpreted to mean that in this family with factor VII deficiency and abnormal platelet release reaction the platelet abnormality as such was not sufficiently severe to prolong the bleeding time unless the factor VII activity was also very low.