Afibrinogenemia is a rare inherited bleeding disorder characterized by the absence or severe deficiency of fibrinogen, a protein essential for blood clotting. This condition is caused by mutations in one or more of the three genes responsible for producing fibrinogen: FGA, FGB, and FGG. The inheritance pattern of afibrinogenemia can be autosomal recessive or autosomal dominant, depending on the specific gene affected.
Autosomal recessive afibrinogenemia: This form of afibrinogenemia occurs when both copies of the gene responsible for producing fibrinogen are mutated. Individuals with autosomal recessive afibrinogenemia inherit one mutated gene from each parent. The parents themselves are usually unaffected carriers, meaning they have one normal and one mutated gene. In rare cases, both parents may have afibrinogenemia. The severity of symptoms can vary, but individuals with this form typically have very low or undetectable levels of fibrinogen in their blood.
Autosomal dominant afibrinogenemia: In this form, a mutation in one copy of the fibrinogen gene is sufficient to cause the disorder. Individuals with autosomal dominant afibrinogenemia inherit the mutated gene from an affected parent. The severity of symptoms can vary, and some individuals may have higher levels of fibrinogen compared to those with autosomal recessive afibrinogenemia.
While the exact cause of fibrinogen gene mutations is not always known, they can occur spontaneously or be inherited from parents who carry the mutated gene. Genetic testing can help identify the specific gene mutation responsible for afibrinogenemia in an individual.
Signs and symptoms: Afibrinogenemia primarily affects blood clotting, leading to symptoms such as spontaneous bleeding, easy bruising, nosebleeds, prolonged bleeding after injury or surgery, and excessive bleeding during menstruation. In severe cases, internal bleeding can occur, which may be life-threatening. The severity of symptoms can vary among individuals, even within the same family.
Treatment: There is currently no cure for afibrinogenemia, but treatment focuses on managing bleeding episodes and preventing complications. Replacement therapy with fibrinogen concentrates or cryoprecipitate, which contain fibrinogen, can be administered to control bleeding. In some cases, antifibrinolytic medications may be prescribed to prevent the breakdown of blood clots. It is important for individuals with afibrinogenemia to work closely with a hematologist to develop a personalized treatment plan.
Afibrinogenemia is a complex disorder with various genetic and clinical factors. Ongoing research aims to further understand the underlying causes and develop more effective treatments for this rare bleeding disorder.