Background: The recently described "APC resistance" caused by a mutant form of factor V (factor V Leiden) is the most frequent cause of hereditary thrombosis. This study was carried out to investigate the association between activated protein C resistance and central retinal vein occlusion (CRVO). We evaluated the prevalence of APC resistance in patients with CRVO, patients with a history of deep-vein thrombosis, and a healthy control group.
Patients and methods: We examined 107 patients with CRVO, 112 patients with deep-vein thrombosis and 70 healthy individuals. The test performed was a modified APC-resistance assay using factor V-deficient plasma.
Results: We identified APC resistance in 5.6 % of patients with CRVO and in 5.7 % of the control group. All carriers were heterozygous. In the deep-vein thrombosis group 23.2 % tested positive for APC resistance. Four patients were homozygous and 22 were heterozygous carriers.
Conclusion: These results indicate that APC resistance has no major role in the pathogenesis of CRVO. Routine testing for the presence of factor V Leiden mutant in CRVO is not necessary.