Retinal vein occlusion, homocysteine and methylene tetrahydrofolate reductase genotype

Abstract

Abstract: : Purpose:The role of elevated homocysteine (Hcy) in retinal vein occlusion is still unresolved. We investigated the relationship between the tHcy, B group vitamin status and the methylene tetrahydrofolate reductase (MTHFR) polymorphism in patients presenting with retinal vein occlusion and compared them with age and sex matched controls. Methods: Two hundred and two subjects gave consent and entered the study (105 cases and 97 controls). The age, gender, smoking habit and cardiovascular status were noted and dilated fundal examination performed on both eyes. Total plasma Hcy (tHcy) was measured by high performance liquid chromatography. Serum B12 and folate were measured by radioassay. MTHFR genotype was determined following PCR amplification by polyacrylamide gel electrophoresis of the amplified product. Homocysteine, folate and B12 comparisons were obtained using the independent samples t–test. Chi squared tests were used to compare genotype and allele distribution between cases and controls. Results: Age and gender were well matched between cases and controls. A history of hypertension and exposure to cigarette smoking was more frequently recorded in cases compared with controls. There was no significant difference in plasma tHcy (p0.124) or thermolabile MTHFR allele frequency between cases and controls. There was no departure from Hardy Weinberg equilibrium. Similarly there was no significant difference in folate (p0.385) and vitamin B12 (p0.182) status between cases and controls. Univariate analysis of variance showed that the thermolabile allele genotype was a significant predictor of tHcy (p0.014) but not vitamin B12 or folate concentrations in either cases or controls. Conclusions: Neither plasma homocysteine nor MTHFR genotype were risk factors for retinal vein occlusion in this study.

Keywords: vascular occlusion/vascular occlusive disease