Fibrinogen Amsterdam, Another Hereditary Abnormality of Fibrinogen

S ummary . A coagulation defect, characterized by a prolonged thrombin and pro-thrombin time, was discovered in a family without haemorrhagic diathesis. The disorder is caused by a delayed aggregation of fibrin monomers. Patient's and normal purified fibrin monomers showed the same aggregation properties, but the patient's fibrin monomers aggregated abnormally in the presence of the α₂-globulin fraction of plasma. The presence of an abnormal fibrinogen is postulated. The inheritance of this fibrinogen is compatible with an autosomal dominant trait.