Genetic defects: multiple different genetic defects described
Inheritance: afibrinogenemia shows an autosomal recessive pattern
Clinical features:
(1) bleeding from the umbilical cord
(2) bleeding after trauma or surgery
(3) epistaxis
(4) bleeding from the gums
(5) intracranial bleeding
(6) acute gastrointestinal bleeding
(7) hemarthroses
(8) menorrhagia in females
(9) spontaneous abortion or abruptio placentae in pregnant females
(10) deep vein thrombosis and pulmonary emboli
Laboratory features:
(1) prolonged PT and aPTT
(2) prolonged thrombin time
(3) moderate to marked decrease in fibrinogen concentrations
(4) prolonged bleeding time with abnormal platelet function (corrected with fibrinogen replacement)
The risk of bleeding is significant when the fibrinogen is < 50 mg/dL.
