OMIM: *173360
Locus: 7q21.3-q22


The type 1 plasminogen activator inhibitor (PAI-1) is a primary regulator of the fibrinolytic system in vivo. PAI-1 binds to tissue plasminogen activator and inhibits plasminogen activation, which decreases fibrinolysis. A single guanosine insertion/deletion (4G or 5G) 675 base pairs from the start site of the genes promoter region affects an individual's predisposition for thrombosis.
Studies have shown a correlation between PAI-1 levels in plasma and the 4G/5G polymorphism. Subjects with the 4G/4G genotype have plasma PAI-1 concentrations that are 25% higher than those with the 5G/5G genotype. Increased PAI activity may be associated with increased risk for venous thrombosis and myocardial infarction. The prevalence of the 4G/4G genotype in the normal population is 26%.
An der Stelle -675 vor Beginn des PAI-1 Gens (SERPINE1) können 4 oder 5 Guanosin-Nukleotide stehen und die Bindung von Transkriptionsfaktoren beeinflussen. Das Vorliegen des 4G-Genotyps führt zu einer vermehrten Transkription des Gens und damit zu einem erhöhten PAI-1 Spiegel. Das resultiert in Folge in einer verminderten fibrinolytischen Aktivität des Plasminogenaktivators.

Indications for testing

  • Patients presenting with family histories of early heart disease or venous thrombosis
  • Pregnant women with past complications during pregnancy.

  • References:
  • Tsantes AE et al. Association between the plasminogen activator inhibitor-1 4G/5G polymorphism and venous thrombosis. A meta-analysis. Thromb Haemost. 2007;97:907-13.

  • Fabbro D et al. Association between plasminogen activator inhibitor 1 gene polymorphisms and preeclampsia. Gynecol Obstet Invest. 2003;56:17-22.