Summary
A 15-month-old girl from Coimbra (Portugal) had a history of numerous hemorrhagic
episodes with multiple bruises, hematomas but not hemarthroses. On serial testing
she showed deficiency of factors II, VII, IX, X and protein C. Malabsorption- induced
vitamin K deficiency, liver disease or ingestion of a coumarin compound were excluded.
An absence of detectable abnormalities was found among her relatives. Consanguinity
was not present. The immunologic assay, immunoelectrophoresis or antibody neutralization,
revealed much higher levels of these factors than the clotting assay. The non-physiological
activator (Echis carinatus venom) produced higher levels of prothrombin activation
than those detected by physiological activation. Twodimensional immunoelectrophoresis
of the patient’s plasma in calcium showed that prothrombin had the same mobility as
acarboxyprothrombin. No significant response to large doses of intravenous vitamin
K3 (6 mg) was observed. Transfusion of 120 ml of frozen fresh plasma led to an immediate
increase in the procoagulant activities of vitamin K dependent protein, similar to
that found after perfusion of plasma plus vitamin K3. The results obtained from this patient suggest a defect in the gammacarboxylation
mechanism inside the hepatocyte.
Keywords
Vitamin K-dependent proteins - Protein C - Congenital deficiency
