No Excess of Factor V:Q506 Genotype but High Prevalence of Anticardiolipin Antibodies without Antiendothelial Cell Antibodies in Retinal Vein Occlusion in Young Patients

Factor V:Q506 (factor V Leiden) is associated with venous thrombosis and has been reported to be a risk factor for retinal vein occlusion (RVO). Anticardiolipin antibodies (ACA), also associated with RVO, are a marker for the prothrombotic condition antiphospholipid syndrome, in which antiendothelial antibodies (AECA) are also frequently present. This study reviewed 45 younger patients <or=55 years old (21 with branch, 22 with central and 2 with hemispheric RVO) to examine: (1) the rôle of factor V:Q506 in the pathogenesis of RVO, and (2) the prevalence and titre of ACA and AECA in this group. No patient had the factor V:Q506 mutation indicating no increase in frequency above background. Our data suggest that primary screening for factor V:Q506 is not indicated for young patients with RVO who do not have historical evidence suggesting familial thrombophilia. Twenty-nine patients had low-titre ACA (>10 GPL units); in 6 of these, the titre was >20 GPL units (population reference range = 0-10 GPL units). No patient had antiendothelial cell reactivity. The low-titre ACA may therefore represent a non-specific response to vascular injury.