Thromb Haemost 2006; 95: 909–10 Dear Sir, Protein Z-dependent protease inhibitor (ZPI), together with its cofactor protein Z (PZ), inhibits activated factor Xa (Xa) (1–3). Studies in mice showed that the PZ null genotype increases the mortality in utero of homozygous factor V Leiden mice due to vascular thrombosis and hepatic fibrin deposition (4), suggesting a role for the PZ-ZPI pathway in th...

Protein Z (PZ) is a vitamin K-dependent factor identified in human plasma in 1984 characterized by an homology with other vitamin K-dependent factors (factor VII, IX, X, protein C). In contrast to these factors,PZ does not possess any enzymatic activity but is involved as a cofactor in the down-regulation of coagulation by forming a complex with the protein Z-dependent protease inhibitor (ZPI)....

Protein Z (PZ) is a vitamin K-dependent factor identified in human plasma in 1984 characterized by an homology with other vitamin K-dependent factors (factor VII, IX, X, protein C). In contrast to these factors,PZ does not possess any enzymatic activity but is involved as a cofactor in the down-regulation of coagulation by forming a complex with the protein Z-dependent protease inhibitor (ZPI)....

Protein Z (PZ) is a vitamin K-dependent protein isolated from human plasma, and acts as a cofactor for a serpin, called protein Z-dependent protease inhibitor (ZPI). A prothrombotic phenotype has been reported in PZ deficient mice, and PZ deficiencies have been observed in patients with arterial thrombotic events. PZ was immunologically detected in the endothelium of atherosclerotic arteries, s...

Protein Z (PZ) is a vitamin K-dependent factor identified in human plasma in 1984 characterized by an homology with other vitamin K-dependent factors (factor VII, IX, X, protein C). In contrast to these factors, PZ does not possess any enzymatic activity but is involved as a cofactor in the down-regulation of coagulation by forming a complex with the protein Z-dependent protease inhibitor (ZPI)...

In reply to the study by Gonzalez-Conjero et al, we found their results on 218 Spanish White patients very interesting. As suggested in their article, there does indeed appear to be an ethnic bias and possible founder affect with regard to the W303X mutation in thrombosis patients. The frequency of both the Factor V Leiden mutation and the prothrombin 20210A variant also varies within White pop...