The dysfibrinogenemias are a group of autosomal dominant disorders of qualitatively abnormal fibrinogen

Fibrinogen

Fibrinogen is a soluble plasma glycoprotein, synthesised by the liver, that is converted by thrombin into fibrin during blood coagulation. This is achieved through processes in the coagulation cascade that activate the zymogen prothrombin to the serine protease thrombin, which is responsible for...

s. There are more than 350 different fibrinogen abnormalities, each named after the place where it was discovered. Each dysfibrinogenemia is associated with slightly different effects on the thrombin time and on normal clotting. Some dysfibrinogenemias cause abnormal bleeding or even thrombosis

Thrombosis

Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...

, while others have no effect on either bleeding or thrombosis. Some examples are:

• Amsterdam is a major defect, characterized by aggregation of fibrin
  Fibrin
  Fibrin is a fibrous, non-globular protein involved in the clotting of blood. It is a fibrillar protein that is polymerised to form a "mesh" that forms a hemostatic plug or clot over a wound site....
  
   monomer
  Monomer
  A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
  
  s, prolonged thrombin time, and an inhibitory effect on normal clotting - but it is asymptomatic.
• Detroit is a major defect, there is fibrinopeptide release, the thrombin time is prolonged, there is an inhibitory effect on normal clotting and there is abnormal bleeding.
• Wiesbaden is a major defect, there is aggregation of fibrin monomers, the thrombin time is prolonged, there is an inhibitory effect on normal clotting and there is both bleeding and thrombosis.