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Hyperhomocyst(e)inemia and MTHFR C677T genotypes in patients with central retinal vein occlusion
Martin Weger1, Olaf Stanger, Hannes Deutschmann
1Department of Ophthalmology, Karl-Franzens University, Auenbruggerplatz 4, 8036 Graz, Austria. martin.weger@kfunigraz.ac.at
Insights
High homocysteine levels are linked to central retinal vein occlusion. This study found hyperhomocysteinemia, not the MTHFR C677T mutation, significantly increases risk for this eye condition.
Area of Science:
- Ophthalmology
- Cardiovascular Medicine
- Genetics
Background:
- Elevated plasma homocysteine is a known risk factor for thrombosis and cardiovascular disease.
- Genetic factors like MTHFR C677T mutation and low folate levels can increase homocysteine.
- Central retinal vein occlusion (CRVO) is a serious vascular complication affecting vision.
Purpose of the Study:
- To investigate the association between hyperhomocysteinemia and central retinal vein occlusion.
- To determine if MTHFR C677T mutation plays a role in CRVO.
- To assess the impact of plasma folate and vitamin B12 levels on CRVO risk.
Main Methods:
- A case-control study involving 78 CRVO patients and 78 matched controls.
- Fasting plasma homocysteine measured by High-Performance Liquid Chromatography (HPLC).
- Plasma folate, vitamin B12 levels assessed via immunological assays; MTHFR C677T genotyping by PCR.
Main Results:
- Hyperhomocysteinemia (defined as >14.83 micromol/l) was significantly more prevalent in CRVO patients (16 vs. 3 controls, P=0.001).
- The odds ratio for CRVO associated with hyperhomocysteinemia was 5.29 (95% CI 1.33-21.13).
- CRVO patients had significantly lower mean plasma folate levels (3.94 ng/ml vs. 5.69 ng/ml, P<0.001), but MTHFR C677T genotype distribution did not differ.
Conclusions:
- Hyperhomocysteinemia is significantly associated with central retinal vein occlusion.
- The MTHFR C677T mutation itself does not appear to be an independent risk factor for CRVO.
- Lower folate levels may contribute to the increased homocysteine levels observed in CRVO patients.
Background:
Elevated plasma homocyst(e)ine is a major risk factor for venous thrombosis and cardiovascular disease. Homozygosity for the MTHFR C677T mutation and low plasma folate levels increase plasma homocyst(e)ine concentrations. The aim of this retrospective case-control study was to investigate a possible association between hyperhomocyst(e)inemia and central retinal vein occlusion.
Methods:
Our study included 78 consecutive patients with central retinal vein occlusion and 78 control subjects, matched for age and sex. High-performance liquid chromatography (HPLC) with fluorescence detection was used to determine fasting plasma homocyst(e)ine concentrations. Plasma folate and vitamin B12 levels were determined by immunological assays. Genotyping for the MTHFR C677T mutation was performed by polymerase chain reaction (PCR).
Results:
Hyperhomocyst(e)inemia was defined by the 95th percentile of plasma homocyst(e)ine concentrations in the control group (=14.83 micromol/l). Thus 16 patients with central retinal vein occlusion were diagnosed as hyperhomocyst(e)inemic, compared with three control subjects ( P=0.001). The odds ratio of hyperhomocyst(e)inemia for central retinal vein occlusion was 5.29 (95% CI 1.33-21.13). Mean plasma folate levels were significantly lower in patients than in controls (3.94+/-1.94 ng/ml vs. 5.69+/-2.09 ng/ml; P<0.001). Distribution of MTHFR C677T genotypes did not significantly differ between the two groups.
Conclusions:
Our study suggests that hyperhomocyst(e)inemia, but not the MTHFR C677T mutation, is associated with central retinal vein occlusion.