Clinical Information

Factor XIII (FXIII) is found in plasma and platelets. Plasma FXIII consists of 2 A subunits and 2 B subunits; platelet FXIII consists of only 2 A subunits. After FXIII is activated by thrombin, it catalyzes the formation of peptide bonds between adjacent molecules of fibrin monomers, thus conferring mechanical and chemical stability to the fibrin clot. Fibrin that is not covalently crosslinked exhibits an increased susceptibility to fibrinolysis.

Congenital FXIII deficiency is an autosomal recessive bleeding disorder. Individuals with severe FXIII deficiency (FXIII:C <1%) may experience intracranial hemorrhage, soft tissue hemorrhage, hemarthrosis, and hematomas. Typically, affected patients suffer from delayed bleeding occurring 24 to 48 hours after the initial hemostatic response to an injury. In newborns, bleeding from the umbilical stump may occur after separation of the umbilical cord, as well as intracranial bleeding. Poor wound healing and abnormal scar formation are also observed. Asymptomatic individuals with milder deficiencies may experience post-surgical or trauma-related bleeding; additionally female patients may experience recurrent spontaneous abortions and heavy menstrual bleeding.

Although felt to be rare, acquired FXIII deficiency is likely more commonly encountered than congenital deficiency state. In one series of patients, the large majority of patients had an acquired deficiency state as opposed to a congenital deficiency. The various etiologies included consumptive coagulopathy, infection related, or due to development of autoantibodies. These patients develop adult-onset bleeding.