Effects of Common Thrombophilia Factor Mutations in Central Retinal Vein Occlusion

Abstract

Objectives: Central retinal vein occlusion (CRVO) is a severe eye disease that impairs vision. Although numerous systemic conditions have been reported to be a contributor, its exact pathophysiology has not yet been resolved. The purpose of this study was to study the role of some common thrombophilic polymorphisms in CRVO patients. Methods: A total of 33 CRVO patients (25 non-ischemic CRVO and 8 ischemic CRVO) and 30 controls were recruited. Factor V Leiden (G1691A), prothrombin (Factor II G20210A), MTHFR (C677T), MTHFR (A1298C), and PAI-1 5G/4G polymorphisms in venous blood DNA samples were examined, as well as the presence of hypertension, diabetes mellitus, glaucoma, smoking, and history of thrombosis. Results: It was determined that MTHFR C677T polymorphisms, either in heterozygous or homozygous form, might be a risk factor for CRVO and systemic thrombosis. No differences were detected between the CRVO and control groups in terms of diabetes mellitus (p=0.058>0.05), hypertension (p=0.3>0.05), smoking (p=0.923>0.05), glaucoma (p=0.06>0.05) or use of anticoagulant drugs (p=0.4>0.05). Analysis of patient history revealed a statistically significant difference regarding a thrombotic event in the medical history of the CRVO group (p=0.001<0.05; n=4) versus the control group. The ischemic CRVO group had a significantly higher incidence of diabetes mellitus (p=0.002<0.05) and hypertension (p=0.031<0.05) than the non-ischemic CRVO group. Conclusion: The MTHFR C677T mutation appears to be a risk factor for CRVO but factor V Leiden (G1691A), prothrombin (Factor II G20210A), MTHFR (A1298C), and PAI-1 5G/4G mutations were not determined to be specifically related to CRVO in this study. The presence of diabetes mellitus and hypertension was significant in the ischemic CRVO group. Further studies with larger sample sizes should be conducted.

Highlights on Genetic Polymorphism Associated with Thromboembolic Risk; Implications in Ophthalmic and Autoimmune Disorders—A Review

“…Although Virchow’s triad explains the systemic changes leading to CRVO, this condition may be caused by both local and systemic causes. The etiopathogenetic mechanisms can be divided into conditions that produce a physical blockage at the level of the lamina cribrosa and conditions in which hemodynamic factors contribute to obstructing the blood flow [ 3 , 4 ].…”

“…When a retinal venous occlusion occurs, a thrombus develops, usually at the lamina cribrosa level (particularly when we refer to the central retinal vein), leading to the obstruction of the retinal blood supply, causing local ischemia, retinal edema and decreased visual acuity. The condition has several triggers; with age, lamina cribrosa loses its elasticity, causing a compression of the vascular wall; furthermore, degenerative processes that arise from the central retinal artery (atherosclerosis) may induce rigidity of the central retinal artery, which causes compression of the venous wall; the resulting turbulent flow disturbs blood hemodynamics and determines endoluminal thrombus formation [ 3 , 4 ].…”

“…However, there are yet many studies necessary to draw a conclusion on this matter [ 24 ]. Therefore, the implications of various hematological abnormalities in the etiopathogenesis and treatment of CRVO remain partially unclear and there are contrasting clinical results [ 3 ].…”

“…Among the elements of Virchow’s triad, the contribution of thrombogenesis or hypercoagulability of the blood to the pathogenesis of CRVO has not been as well investigated as the other two factors. Therefore, the implications of various hematological abnormalities in the etiopathogenesis and treatment of CRVO remain partially unclear and there are contrasting clinical results [ 3 ].…”