title: Low protein Z levels but not the protein Z gene G79A polymorphism are a risk factor for ischemic stroke.
abstract: BACKGROUND
  Protein Z (PZ) is a vitamin K-dependent plasma protein that plays a role in both pro-and anticoagulant pathways, but its exact physiological function remains unclear. The aim of this study was to determine the association between the G79A PZ gene polymorphism in intron F, PZ levels and the occurrence of ischemic stroke.
  
  
  METHODS
  We performed a case-control study in 118 Caucasian patients with first ever ischemic stroke or TIA confirmed by CT, and 113 age-and sex-matched population controls. Venous blood samples for PZ levels were collected 7 to 14 days and 3 months after stroke onset. Estimates of relative risk (odds ratios) were adjusted for vascular risk factors.
  
  
  RESULTS
  The adjusted relative risk of ischemic stroke associated with PZ levels in the lowest quartile versus the highest quartile was 3.0 (95% CI: 1.1-8.7) at 7-14 days, and 5.1 (95% CI: 1.2-21.9) at 3 months after the stroke. PZ levels in the convalescent sample were significantly lower than in the acute sample. In the convalescent sample, odds ratios increased with lower quartiles of protein Z level (test for trend p=0.02). Thirty-nine patients (33%) and 32 (28%) controls were heterozygous for the G79A PZ gene polymorphism and 4 (3%) patients and 4 (4%) controls had the AA-genotype. The PZ levels were significantly lower in subjects with the AA-genotype and intermediate in heterozygote subjects. The odds ratio of ischemic stroke associated with A-allele carriers versus GG-homozygotes was 1.2 (95% CI: 0.7-2.1).
  
  
  CONCLUSIONS
  No association between the G79A PZ gene polymorphism and the occurrence of stroke was observed. However, low PZ levels are independently associated with an increased risk of ischemic stroke.
authors: Department of Neurology of the Erasmus MC, University Medical Center Rotterdam, PO Box 2040 3000 CA, The Netherlands.
authors: M P J
authors: MP
authors: van Goor
authors: D W J
authors: DW
authors: Dippel
authors: K S-G
authors: KS
authors: Jie
authors: M P M
authors: MP
authors: de Maat
authors: P J
authors: PJ
authors: Koudstaal
authors: F W G
authors: FW
authors: Leebeek
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D001798:Blood Proteins / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007511:Ischemia / Q000097:blood* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D012307:Risk Factors; D020521:Stroke / Q000235:genetics*; D013997:Time Factors
chemical_list: D001798:Blood Proteins; C026080:plasma protein Z