Factor XIII Deficiency [D68.26]
Dipl.-Biol. Birgit Busse, B.Sc. Camilla Ladinig
Congenital factor XIII deficiency is an autosomal recessive inherited disorder of coagulation characterized by reduced amount and activity of factor XIII. It is a rare disorder of coagulation, which affects both sexes equally. The prevalence is estimated to be 1 in 2.5 million. Symptoms may arise at any age but usually the diagnosis is already made in infancy due to umbilical cord stump bleeding. Further symptoms include delayed wound healing, postoperative bleeding, subcutaneous or tissue bleeding, life threatening cerebral hemorrhage, and recurrent miscarriage in women.
Factor XIII (FXIII) is a transglutaminase, which consists of two catalytic A subunits and two non-catalytic B subunits. The activated factor XIII (aFXIII) is required for cross linking and stabilization of the fibrin thrombus and plays a vital role in coagulation due to its hemostatic and reparative function. In the majority of cases mutations in the F13A gene, which codes for the A subunit, are responsible for the FXIII deficiency. Only in rare cases mutations in the gene coding for the B subunit (F13B gene) were found. Homozygous or compound heterozygous carriers exhibit a severe susceptibility to bleeding. The residual activity of factor XIII is frequently lower than 5%. Heterozygous carriers generally show no increased susceptibility to bleeding and only exhibit a decreased FXIII activity of 30-60%. Susceptibility usually correlates with measured FXIII activity.
It is difficult to biochemically diagnose a factor XIII deficiency because it is not covered by the coagulation tests Quicks test, PTT and TT used in screening. These assays show normal results despite severe bleeding tendency. Therefore, in order to diagnose a factor XIII deficiency a quantitative, functional FXIII activity assay should be used as a first-line screening test. Diagnosis can be supported by molecular genetic testing.
A factor XIII deficiency may also be acquired e.g. due to severe liver disease, inflammatory bowel disease, disseminated intravascular coagulation and inhibitors of factor XIII (e.g. medication).
Factor XIII deficiency can be treated by factor XIII concentrates.