Congenital afibrinogenemia is a rare, inherited blood disorder in which the blood does not clot normally. It occurs when you are missing or have a problem with a protein called fibrinogen, which is needed for the blood to clot.

This rare disease is caused by an abnormal gene that must be passed down from both parents. There may be either a lack of fibrinogen or a defect in the functioning of available fibrinogen. This condition can occur in both sexes. The main risk factor is a family history of bleeding disorders.

• Bruising
• Nosebleeds
• Excessive bleeding after injury or surgery
• Gastrointestinal bleeding
• Bleeding in joints
• Miscarriage

If the health care provider suspects a bleeding disorder, laboratory tests can determine the type and extent. This disorder usually shows up in childhood, often at birth.

Tests include:

• PTT
• Prothrombin time (PT)
• Clotting time
• Fibrinogen levels
• Thrombin time
• Reptilase time
• Bleeding time

All of these tests are abnormal in afibrinogenemia.

Patients may receive the liquid portion of the blood (plasma) or a blood product containing concentrated fibrinogen (cryoprecipitate) through a vein (transfusion) to treat bleeding episodes or to prepare for surgery to treat other conditions. People with this condition should have the hepatitis B vaccine because transfusion increases the risk of hepatitis.

Excess bleeding is common with this condition. These episodes may be severe, or even fatal. Bleeding in the brain is a leading cause of death in patients with this disorder.

• Bleeding from the umbilical cord
• Bleeding from the mucous membranes
• Gastrointestinal bleeding
• Intracranial bleeding
• Clotting with treatment
• Development of antibodies (inhibitors) to fibrinogen with treatment

Call your health care provider or seek emergency care if you have excessive bleeding.

Tell your surgeon before you have surgery if you know or suspect you have a blood disorder.

There is no known prevention. Couples who are thinking about having children may find genetic counseling helpful if at least one partner has this condition.

Hoffman R, Benz E, Shattil S, Furie B, Cohen H. Hematology: Basic Principles and Practice. 4th ed. Philadelphia, Pa: Churchill Livingstone, 2004.

Asselta R, Duga S, Tenchini ML. The molecular basis of quantitative fibrinogen disorders. J Thromb Haemost. October 2006;4:2115-2129.