Two cases of dysfibrinogenemia characterized by abnormal FPB release: fibrinogen Madrid I & II

Congenital dysfibrinogenemia was found in two non related and asymptomatic families. Low levels of plasma fibrinogen were found using a chronometric assay but normal levels were found using both an immunologic method and a method to measure the fibrin formed after two hours incubation with thrombin. Kinetic analysis of fibrinopeptide release revealed a delay in the thrombin catalyzed release of fibrinopeptide B from both abnormal fibrinogens. Timed release of fibrinopeptide A was normal. Analysis of fibrinopeptides by high-performance liquid chromatography showed the same retention times in both normal and abnormal fibrinogens. Polymerisation of fibrin monomers and the sialic acid content per mol of fibrinogen were normal. Although these cases seem similar, until their structural defects are determined, it is proposed to provisionally designate them fibrinogens Madrid I & II.