A family with a high incidence of spontaneous thromboembolism was investigated and those members affected were found to have significantly depressed levels of plasma and serum heparin cofactor activity; i.e., antithrombin III and anti Xa activity. Further studies revealed that despite a marked diminution of antithrombin III activity in these patients measurement of antithrombin III by immunological techniques showed the levels to be normal. It is concluded that this anomaly represents a defect in the synthesis of the antithrombin III molecule. The abnormality appeared to be inherited but the mode of inheritance could not be determined with the available data.
ASJC Scopus subject areas