[Deficiencies of physiological coagulation inhibitors in children with venous thromboses of the lower limbs. Prospective study of 6 cases].

Six patients aged 3 to 14 years with lower limb vein thrombosis were included in a prospective study of deficiencies in physiological coagulation inhibitors. The laboratory evaluation included standard hemostasis tests, tests for circulating anticoagulants, immunological and functional assays of protein C, protein S, and antithrombin III, and a study of fibrinolysis. A qualitative protein S deficiency with decreased fibrinolysis and protein C deficiency were found. The family study detected asymptomatic heterozygotes in both families investigated. No antithrombin III deficiency or circulating anticoagulants were found.