Studies on the Metabolism of Fibrinogen in Two Patients with Congenital Afibrinogenemia

Abstract

1. The rate of disappearance from the plasma of intravenously administered fibrinogen has been studied immunochemically in two children with congenital afibrinogenemia. 2. About half of the administered fibrinogen disappeared from the circulation in the first forty-eight hours, thus emphasizing the importance of the extravascular pool of plasma protein. 3. After the first two days, the fibrinogen followed a logarithmic decay curve, with a half life of four days; this is so close to the half life of 5.6 days estimated from radioisotope turnover studies that it indicates that the fundamental defect in these patients is a failure to synthesize adequate quantities of fibrinogen. 4. Traces of fibrinogen were detected immunochemically in the plasma of each patient; in one of them, the small amount found could not readily be attributed to prior infusion of blood or blood products. 5. The connective tissue in biopsy specimens of skin and muscle from one patient, when examined with fluorescein-labelled antisera, was found to be specifically deficient in fibrinogen. This deficit was quickly rectified by intravenous administration of fibrinogen.