Inherited platelet abnormalities associated with low factor VIII activity in the same family.

Six of eight examined members belonging to two generations of the same (NEG-TUR) family were shown to have functional changes in platelets and/or a moderate decrease of factor VIII activity (FVIII:C) in plasma, with normal values of factor VIII-related antigen (VIII R:AG). Platelet defects (mainly a reduced PF3 availability, present in five patients) and factor VIII decrease were combined differently in individual members. Only two male members with both the PF 3 and FVIII:C defects had moderate haemorrhagic symptoms following traumatic injuries. One of them had also an absent adhesiveness to glass, the other one an absent adhesiveness to collagen and a reduced platelet aggregation by ADP and by collagen. Bleeding time, platelet function tests (in the other members), and routine coagulation tests were within normal range; ristocetin aggregation was also normal in all members. We think that two inherited defects, a mild haemophilia A and a "sui generis" thrombocytopathy, co-exist in this family.