Fibrinogen Logroño. A new case of congenital dysfibrinogenemia.

An abnormal fibrinogen was discovered in a 9-year-old male subject without history of hemorrhagic diathesis. Coagulation time, prothrombin time and Reptilase time were prolonged. The thrombin time was corrected using increasing concentrations of normal plasma and bovine thrombin; there was a partial correction at pH 6.5 and ionic strength 0.05. A study of the family showed that the mother and a brother of the propositus presented the same abnormalities. Analysis of the purified fibrinogen showed normal fibrinopeptide release and normal levels of sialic acid and hexosamines. However, coagulation index, polymerization of fibrin monomers, isoelectric point and sedimentation coefficient were abnormal. In view of the abnormalities described and by comparison with the data reported in the literature, we believe that this should be considered a new variant of the fibrinogen molecule and we have designated it 'fibrinogen Logroño'.