To review the relationship between factor XIII polymorphisms and venous thromboembolism.
Review of the medical literature using computerized databases and secondary sources identified through reviews of bibliographies.
Plasma factor XIII is the precursor of a transglutaminase that cross-links fibrin, thereby altering its properties, including resistance to fibrinolysis. It is, therefore, biologically plausible that alterations in factor XIII activity could affect thrombosis risk. There are 4 common polymorphic forms of factor XIII that differ among ethnic groups. The Val34Leu polymorphism results in an amino acid change near the thrombin cleavage site that may alter the rate of activation. Several case-control studies have investigated the relation of the Val34Leu polymorphism to venous thromboembolism. Some have shown a potentially protective effect of this polymorphism, but the association is not consistent.
Evidence is conflicting regarding the association of the factor XIII Val34Leu polymorphism with risk of venous thromboembolism, and further studies are needed before screening for this polymorphism can be recommended for evaluation of thrombophilia.