Factor XII deficiency: a thrombophilic risk factor for retinal vein occlusion

PURPOSE: Factor XII deficiency is among the coagulation disorders that have been implicated in major thromboembolic events. However, little is known about an association of this coagulation disorder and retinal vessel occlusion. In the current study, we investigated the prevalence of factor XII deficiency in patients with retinal vein occlusion (RVO) with reference to age and cardiovascular risk factors. DESIGN: Cross-sectional study. METHODS: A cohort of 150 consecutive patients with central or branch retinal vein occlusion and 135 subjects matched for age and gender were prospectively screened for factor XII deficiency. Both cohorts were divided into two subgroups (less than or equal to45 or >45 years), depending on the patients' age at the time of the RVO or a previous thromboembolic event. RESULTS: Overall, factor XII deficiency was found to be present in 14 (9.3%) of 150 patients and in 1 (0.7%) of 135 controls (P =.0009). Patient age :545 years at the time of the RVO or a previous thromboembolic event was associated with a high prevalence of factor XII deficiency (18%). By contrast, only 5 (5%) of 100 patients >45 years (P =.016) and none of the young controls (P =.0001) tested positive for factor XII deficiency. The prevalence among patients >45 years was similar to that found in age-matched controls (2%; P = .66). CONCLUSIONS: Our results indicate that factor XII deficiency is highly prevalent in RVO patients less than or equal to45 years of age. By contrast, the prevalence of factor XII deficiency in RVO patients older than 45 years appears to be similar to that seen in healthy individuals. (C) 2004 by Elsevier Inc. All rights reserved.