Influence of factor V Leiden on the development of neovascularisation secondary to central retinal vein occlusion

Retinal obliterative vasculitis associated to contralateral retinal neovascularization in membranoproliferative glomerulonephritis

PURPOSE

To report our experience with a peculiar case of asynchronous bilateral retinal vascular occlusion in a patient suffering from membranoproliferative glomerulonephritis.

CASE REPORT

A 57-year-old dialysed male affected by membranoproliferative glomerulonephritis who underwent kidney transplantation complained of a sudden vision loss in his right eye (RE). His best-corrected visual acuity (BCVA) was 20/40 in RE and 20/20 in the left eye (LE); ophthalmological and fluorangiographic examinations revealed unilateral retinal obliterative vasculitis with panuveitis and apparent sparing of contralateral eye. About 6 months later the patient developed a branch retinal vein occlusion associated with a papillary neovascular membrane in LE. Corticosteroid therapy was administered and immunosuppressant dosage was increased with macular oedema reduction in both events.

CONCLUSION

We report a case of unilateral retinal obliterative vasculitis and subsequent contralateral retinal neovascularization and branch retinal vein occlusion in a patient affected by membranoproliferative glomerulonephritis.

Association of retinal vein occlusion, homocysteine, and the thrombophilic mutations in a Turkish population: A case-control study

PURPOSE

To compare homocysteine and thrombophilic mutations for the methylenetetrahydrofolate reductase (MTHFR) C677T, factor V Leiden, and prothrombin G20210A between retinal vein occlusion (RVO) and healthy controls in a Turkish population.

MATERIALS AND METHODS

Forty-nine subjects with RVO were compared for homocysteine status and the MTHFR C677T, prothrombin G20210A, and factor V Leiden mutations with those of 68 healthy controls. Then, the groups were subdivided into two subgroups according to age (less than 50 years old, equal to or more than 50 years old) and were further compared.

RESULTS

Mean plasma level of homocysteine was similar, but the frequency of hyperhomocysteinemia was significantly higher in the RVO group when compared with the control group (22.5% and 8.8%, respectively, p = 0.037). The frequency of all thrombophilic mutations was similar between the groups (p > 0.05). The frequency of all thrombophilic mutations and homocysteine levels was also similar between age subgroups (p > 0.05). Only hyperhomocysteinemia was significantly different between subgroups (p = 0.037); the frequency of hyperhomocysteinemia was significantly different in RVO patients less than 50 years old (22.7%) from that in healthy controls less than 50 years old (11.1%). Two RVO patients (4.1%) with bilateral involvement had MTHFR C677T mutation.

CONCLUSIONS

Screening for thrombophilic mutations such as MTHFR C677T, factor V Leiden, and prothrombin G20210A in RVO patients at all ages seems to be unnecessary and not cost-effective. However, thrombophilic disorders should be screened selectively, focusing on young individuals, especially with bilateral involvement, without additional cardiovascular risk factors, or a family history of thrombosis.

Prevalence of thrombophilic genetic factors among patients with retinitis pigmentosa

PURPOSE

To determine the prevalence of thrombophilic factors in patients with retinitis pigmentosa (RP).

METHODS

Fifty consecutive patients with RP and 50 controls matched by age and gender were tested for the presence of the following mutations: factor II (GA20210), factor V Leiden (GA1691), methylenetetrahydrofolate reductase (CT677), factor XIIIa (Val→Leu), β-fibrinogen (GA455), tumor necrosis factor receptor (TNFRII) (M196R), plasminogen activator inhibitor-1 (PAI-1) (4 G/5 G), and plasminogen activator inhibitor-1 (PAI-1) (GA844).

RESULTS

The following heterozygous mutations were found in patients/controls: factor V Leiden (12/14), factor XIIIa (20/30), methylenetetrahydrofolate reductase 677 TT (48/52), β-fibrinogen GA455 (36/36), TNFRII (M196R) (40/42), PAI-1 4 G/5 G (40/48), and PAI-1 GA844 (50/52). The difference between patients with RP and the control group was not statistically significant for the prevalence of any of the studied factors (P > 0.05).

CONCLUSION

In this study, thrombophilic mutations were not increased in patients with RP. Thrombophilic mutations do not seem to be risk factors for RP. Routine investigation of hereditary thrombophilia in these patients is not justified.

Thrombophilic risk factors in different types of retinal vein occlusion in Tunisian patients

BACKGROUND

Retinal vein occlusion (RVO) is the second most common cause of vision loss because of retinal vascular disease. There are 2 types of RVO: branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). The pathogenesis of RVO is multifactorial. The role of factor V Leiden (FVL) and prothrombin mutations was examined in patients with CRVO and BRVO.

METHODS

FVL and prothrombin were investigated by extracting DNA of 88 patients with RVO. Sixteen of the patients were diagnosed with CRVO, 4 with hemispheric retinal vein occlusion, and 68 with BRVO. The genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Significant differences were found in the frequencies of the genotypes for both the FVL (G1691A) (P<10(-3), odds ratio [OR]=17.4, confidence interval [CI]=6.20-59) and prothrombin (G20210A) (P=.007, OR=5.11, CI=1.30-29) polymorphisms between RVO patients and healthy controls. Additionally, the frequency of the GA genotype for the G1691A polymorphism was significantly higher among the patients in a subset of BRVO compared with controls (P<10(-3), OR=21.4, CI=7.34-74.2). However, no statistically significant differences were found in the frequencies of the prothrombin G20210A polymorphism between the BRVO group and healthy controls (P=.09, OR=3.13, CI=64-19.9). The frequency of both G1691A and G20210A genotypes among the patients of a CRVO subgroup was significantly higher compared with controls (P<10(-3), OR=11.4, CI=2.94-44.2; P=.007, OR=10.8, CI=2.15-54.1, respectively), suggesting an association between these polymorphisms and CRVO.

CONCLUSIONS

Large study would be required to understand completely the contribution of these markers in the risk of all types of RVO.

Surgical treatment of central retinal vein occlusion

The treatment of central retinal vein occlusion (CRVO) is still a subject of debate. Medical therapy efforts, as well as retinal laser photocoagulation, have mostly dealt with management of the sequelae of CRVO, and have shown limited success in improving visual acuity. The unsatisfactory results of such therapeutic efforts led to the development of new treatment strategies focused on the surgical treatment of the occluded retinal vein. The purpose of this review is to summarize the outcomes of commonly reported surgical treatment strategies and to review different opinions on the various surgical approaches to the treatment of CRVO.

Cosegregation of two unlinked mutant alleles in some cases of autosomal dominant familial exudative vitreoretinopathy

Familial exudative vitreoretinopathy (FEVR) is a bilateral, clinically and genetically heterogeneous hereditary eye disorder that affects both the retina and the vitreous body. The condition has a high degree of penetrance and variable expressivity. In some cases of autosomal dominant FEVR (AD FEVR), mutations in the frizzled-4 gene (FZD-4) have been shown to be involved in FEVR pathology. In this study, we report that a second unlinked gene (Factor V) is also mutated (Leiden mutation) in the same family, which harbors the FZD-4 gene mutation. These results show for the first time that some families with FEVR could be digenic. While this is unlikely to be a widespread problem, the occurrence of digenic disorders with apparently simple Mendelian inheritance patterns renders the current method of analysis of monogenic disorders by linkage and mutation screening incomplete.