[Thrombophilia in a family with resistance to activated protein C and protein S deficiency].

Although patients with thromboembolic disease frequently have family histories of thrombosis, well-defined defects such as inherited deficiencies of anticoagulant proteins are found only in minority of cases. Herein, we present a family study of 42 years old woman with recurrent deep vein thrombosis which occurred first time four years ago during pregnancy, in subclavian vein, in relation to cardiac stimulator implantation because of atrio-ventricular III(0) block. Her laboratory investigation demonstrated normal APTT time, prothrombin time, platelet number, antithrombin III and protein C activity. Plasma antiphospholipid antibodies contents was within the normal range. The result of activated protein C(APC) resistance test was abnormal (R=1.64). Family study revealed similar degree of APC-resistance defect in her DVT symptomatic mother and two healthy young daughters (R=1.73 and 1.54 respectively). Additionally, a slightly reduced total protein S plasma concentration was found in the patient and her two children. The influence of a slightly reduced protein S level on the results of APC-resistance was excluded by evaluation of normalized activated protein C sensitivity ratio (nAPC-SR) as described de Ronde and Bertina.