They include afibrinogenemia and hypofibrinogenemia, and dysfibrinogenemia. The first two are called quantitative abnormalities because they have to do with an absent or low quantity of fibrinogen. The third is called a qualitative abnormality because the fibrinogen does not work well. Fibrinogen, also known as Factor I, is needed for most types of platelet aggregation. I deficiency have a combined bleeding disorder, meaning that both platelets and clotting are abnormal.
Afibrinogenemia is the complete absence of fibrinogen.
Hypofibrinogenemia is a low level of fibrinogen - less than 100mg in 1dL of blood. Both conditions are inherited in an autosomal fashion and can affect males and females. The severity of the disorder is related to the amount of fibrinogen. Afibrinogenemia is usually discovered in newborns and can cause bleeding from the umbilical cord, genitourinary tract, or central nervous system. People with hypofibrinogenemia may have little, moderate, or severe bleeding.