Abstract
Three patients in a Japanese family with congenital protein S deficiency are reported.
The propositus (case 1), his niece (case 2) and his brother (case 3) had cerebral infarction due to intracranial thrombosis, and two of them (case 1 and case 3) had also recurrent venous thrombosis of the legs.
In these 3 patients, plasma proteins known to be associated with familial thrombotic disease, including AT-III, plasminogen, fibrinogen and protein C were normal except for protein S. The level of protein S antigen (PS: Ag) in case 1 and case 3 was about 40% respectively. By using enzyme-linked immunosorbent assay and crossed immunoelectrophoretic techniques, it was found that the plasma PS: Ag in these 2 patients exist as complexed form with C4b-binding protein (C4bp), and free PS: Ag and PS activity were undetectable. In case 2, the levels of total PS: Ag, PS: Ag complexed with C4bp, free PS: Ag and PS activity were all about half of normal values.
From these findings, it is considered that the thrombotic tendency in this family is associated with an inherited deficiency of PS activity. These patients are now being well controlled under the anticoagulation therapy with warfarin.
