title: Low protein Z levels and risk of occurrence of deep vein thrombosis.
abstract: BACKGROUND
  Protein Z (PZ) serves as a cofactor for activated factor X inhibition by the PZ-dependent protease inhibitor. In vivo and in vitro studies aimed at investigating the role of PZ levels in venous thombosis have produced conflicting results.
  
  
  OBJECTIVE
  We investigated whether reduced PZ levels and PZ gene common variants are associated deep vein thrombosis (DVT).
  
  
  METHODS
  In 197 patients with DVT and in 197 age-matched and sex-matched controls, PZ plasma levels and gene polymorphisms were evaluated by means of an enzyme-linked immunosorbent assay and direct cycle sequence analysis.
  
  
  RESULTS
  Similar PZ levels were found in controls (1.44; SD 0.63 microg mL-1) and in patients (1.44; SD 0.96 microg mL-1). The incidence of PZ levels below the 5.0 (0.52 microg mL-1) or the 2.5 percentile of controls (0.47 microg mL-1) was higher in patients (10.2% and 8.7%, respectively) than in controls {4.1% [odds ratio (OR) 2.7, 95% confidence interval (CI) 1.2-7.3], and 2.0% (OR 4.6, 95% CI 1.5-13.9), respectively}. This relationship was independent of the effect of age, sex, and factor V Leiden and FII A(20210) alleles [OR 2.8 (95% CI 1.1-7.3), and OR 4.9 (95% CI 1.4-17.3)]. PZ levels were associated with the intron C G-42A and the intron F G79A polymorphisms in cases (r2=0.129) and in controls (r2=0.140). However, frequencies of the PZ gene polymorphisms were similar in the two groups and were not associated with very low PZ levels.
  
  
  CONCLUSIONS
  The present data suggest an association between very low PZ plasma levels and the occurrence of DVT, with PZ gene polymorphisms contributing little to this relationship.
authors.affiliation: Genetica Medica, Università di Foggia, Foggia, and A. Cardarelli Hospital, Naples, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Santacroce
authors.forename: M
authors.initials: M
authors.lastname: Sarno
authors.forename: F
authors.initials: F
authors.lastname: Cappucci
authors.forename: F
authors.initials: F
authors.lastname: Sessa
authors.forename: D
authors.initials: D
authors.lastname: Colaizzo
authors.forename: V
authors.initials: V
authors.lastname: Brancaccio
authors.forename: E
authors.initials: E
authors.lastname: Grandone
authors.forename: M
authors.initials: M
authors.lastname: Margaglione
mesh_terms: D000328:Adult; D000368:Aged; D001798:Blood Proteins / Q000032:analysis* / Q000235:genetics*; D005260:Female; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011237:Predictive Value of Tests; D012307:Risk Factors; D020246:Venous Thrombosis / Q000097:blood* / Q000235:genetics*
chemical_list: D001798:Blood Proteins; C026080:plasma protein Z