Factor I Deficiency
(Also known as Fibrinogen Deficiency, Afibrinogenemia, Dysfibrinogenemia or Hypofibrinogenemia)
The incidence of Factor I deficiency is estimated at 1 to 2 per million. It is inherited in an autosomal recessive fashion, which means it affects men and women equally.
Fibrinogen helps platelets to glue together to form the initial “plug” in response to an injury. Therefore, people with factor I deficiency have a combined bleeding disorder because both platelets and clotting are abnormal. The severity of the disorder is directly related to the amount of fibrinogen present.
Factor I deficiency is actually a collective term for several rare inherited fibrinogen deficiencies:
- Fibrinogen may be absent from the blood altogether (Afibrinogenemia)
- Fibrinogen may be present in only very low levels in the blood (Hypofibrinogenemia)
- Fibrinogen may be measurable in normal quantities but defective (Dysfibrinogenemia)