An abnormal fibrinogen (Copenhagen II) with increased sialic acid content associated with thrombotic tendency and normal liver function.

An increased sialic acid content of the fibrinogen molecule is found in foetal fibrinogen and as an acquired disorder in hepatic disease. A qualitatively abnormal fibrinogen was detected in the plasma of a 25-year-old man with a thrombotic tendency. The purified fibrinogen had a significantly increased content of sialic acid, an abnormal fibrin monomer polymerization, and a changed mobility in crossed affinity-immunoelectrophoresis using immobilized helix pomatia lectin. The patient had no biochemical or clinical signs of liver disease. The occurrence of a thrombotic tendency and an increased fibrinogen sialic acid content without signs of liver disease may represent a new variant of congenital dysfibrinogenaemia.