The G79A polymorphism of protein Z gene is an independent risk factor for cerebral venous thrombosis

Background and purpose   Protein Z (PZ), a vitamin Kdependent protein, plays a role in inhibiting coagulation. Its plasma level or PZ gene polymorphisms have been discussed as risk factors for stroke with conflicting results reported between various studies. Only one of these polymorphisms was studied in a cohort of patients suffering from cerebral venous thrombosis (CVT). Methods   We performed a retrospective genetic study comparing 100 healthy controls to 54 patients referred to our hemostasis unit after CVT occurrence. We compared the distribution of three PZ gene polymorphisms that may influence PZ plasma levels: A-13G in the promoter and G79A in intron F were tested using previously described techniques, and we developed a technique to evaluate the G-103A in intron A. Results   The G79A polymorphism was significantly more frequent in patients than in controls (p = 0.012): the presence of at least one A allele led to an odds ratio of 2.57 with a 95 % confidence interval of 1.23–5.34. The A-13G polymorphism also showed a nonsignificant trend towards a higher prevalence in patients. Conclusion   The G79A polymorphism of the PZ gene was shown to be a new independent risk factor for cerebral venous thrombosis. Nevertheless, these results have to be confirmed by a prospective study including plasma PZ evaluation.